NEET Biology

Biology MCQs with answers for NEET The DNA

Question 1. ………….. was the first to isolate nucleic acids.

1. Miescher
2. Altman
3. Kornberg
4. Mendel

Answer: 1. Miescher

Nucleic acid was first isolated in 1868 by Swiss physician Friedrich Miescher from the nuclei of pus cells and he called it nuclein.

It was later named nucleic acid by Altman in1889

Question 2. The name nucleic acid is derived from

1. The type of sugar it contains
2. Its abundance in nuclei
3. Its hydrophilic or water-loving nature
4. The type of phosphates it contains

Answer: 1. The type of sugar it contains

The name of nucleic acid is derived from the type of sugar it contains. There are two types of nucleic acids. DNA contains deoxyribose sugar whereas RNA contains ribose sugar

Read And Learn More: NEET Biology Multiple Choice Question And Answers

Question 3. A nucleotide consists of

1. Purine, pyrimidine and phosphate
2. Purine, sugar, and phosphate
3. Nitrogen base, sugar, and phosphate
4. Pyrimidine, sugar, and phosphate

Answer: 3. nitrogen base, sugar, and phosphate

“questions about dna “

Nucleotide is a unit of DNA, which is formed of nitrogenous bases (purines and pyrimidines), sugar (pentose), and phosphate.

Biology MCQs with answers for NEET

NEET Biology DNA MCQs with answers

Question 4. Watson and Crick are known for their discovery that DNA

1. Is a single-stranded helix
2. Contains deoxyribose only
3. Is a double-stranded helix
4. Synthesizes rRNA

Answer: 3. is a double-stranded helix

According to the Watson-Crick Model, a DNA molecule consists of two long parallel chains that are spirally coiled around a common axis in a regular manner to form a double helix.

Question 5. DNA is a

1. Long Polymer Of Deoxyribonucleotides
2. Short Polymer Of Deoxyribonucleotides
3. Monomer Polymer Of Deoxyribonucleotides
4. Long Polymer Of Ribonucleotides

Answer: 1. Long polymer of deoxyribonucleotides

DNA is a long chain of polymer of deoxyribonucleotide in which a phosphate group is attached to 5′- OH of nucleoside through phosphodiester linkage.

Biology MCQs with answers for NEET

Question 6. Consider the following statements.

1. The double helix model of DNA resembles a twisted ladder.
2. In the DNA helix, purine and pyrimidines are found.

Choose the correct option.

1. Statement 1 is correct, but 2 is incorrect
2. Statement 1 is incorrect, but 2 is correct
3. Both statements 1 and 2 are correct
4. Both statements 1 and 2 are incorrect

Answer: 3. Both statements 1 and 2 are correct.

Base pairs are complementary nitrogen bases present in two DNA strands, with a purine lying opposite to a pyrimidine or vice-versa. This purine-pyrimidine association is required for proper spatial arrangement and hydrogen bonding.

Hydrogen bonding, base stacking, and hydrophobic interactions between bases are the forces that help to keep the two DNA strands together.

Question 7. DNA is a genetic material due to

1. Its stability.
2. Its ability to replicate.
3. Its ability to mutate.
4. Its ability to express itself.

Choose the correct combination.

1. 1 and 2
2. 1, 3 and 4
3. 3 and 4
4. 1, 2, 3 and 4

Answer: 4. 1, 2, 3 and 4

DNA acts as genetic material as it shows the following properties The replicated DNA is transferred faithfully from cells to its daughter cells or from one generation to another. It is able to express itself.

It undergoes occasional changes or mutations in the structure and functioning of its genes, which are of permanent nature and inheritable. It is relatively a stable molecule.

It is the same in both quality and quantity in all cells of an individual. Thus, option 4 is correct.

“questions on dna “

Question 8. Antiparallel strands of a DNA molecule mean that

1. One strand turns clockwise
2. One strand turns anti-clockwise
3. The phosphate groups of two DNA strands, at their ends, share the same position
4. The phosphate groups at the start of two DNA strands are in opposite positions (pole)

Answer: 4. the phosphate groups at the start of two DNA strands are in opposite positions (pole)

The two strands of DNA run in opposite directions to one another with hydrogen bonds between them. One strand of DNA has a 5′-3′ direction and the other strand has a 3′-5′ direction. So, they are antiparallel.

This direction is determined by the presence of a free phosphate or hydroxy (— OH) group at the end of the strand. The strand has a phosphate group at the 5′ end and a free OH group at the 3′ end.

Biology MCQs with answers for NEET

Question 9. In the double-helical structure of DNA, the pitch of the helix is Kerala

1. 3.4 nm
2. 0.34 nm
3. 6.6 nm
4. 34 nm
5. 6.6 x 10−9 m

Answer: 1. 3.4 nm

In the commonly found double helical structure of B-DNA, one turn of the spiral has about 10 nucleotides. It occupies a distance (pitch) of about 3.4 nm (34Å)

Question 10. The distance between the two consecutive base pairs of DNA is

1. 3.4 µm
2. 3.4 Å
3. 0.34 x 10−9 m
4. Both (2) and (3)

Answer: 4. Both (2) and (3)

The distance between the two nucleotide base pairs of DNA is 3.4 Å or 0.34 nm or 0.34 × 10−9m. Thus, the option is correct.

The DNA structure and function multiple choice questions for NEET

Question 11. Each strand of DNA has

1. 3′ end and 6′ end
2. 5′ end and 5′ end
3. 3′ end and 5′ end
4. 3′ end and 3′ end

Answer: 3. 3′ end and 5′ end

Each strand has one free phosphate group on the 5th carbon of the sugar molecule.

This end of the strand is called the 5′ end. The other end of the strand has a free — OH group on the 3rd carbon of the sugar molecule.

This is called the 3′ end of the strand. So, each strand has 3′ end and 5′ end

Question 12. The diploid content of human DNA is

1. 3.3 × 106 bp
2. 33 × 109 bp
3. 4.6 × 106 bp
4. 6.6 × 109 bp

Answer: 4. 6.6 × 109 bp

The haploid content of human DNA is also called the human genome (3.3 × 109bp). The diploid content of human DNA is about 6.6 × 109 bp.

“dna questions “

Question 13. If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNA double helix in a typical mammalian cell is 6.6 ×10 9 bp then the length of the DNA is approximately

1. 2.5 m
2. 2.2 m
3. 2.7 m
4. 2.0 m

Answer: 4. 2.0 m

The distance between two consecutive base pairs is 0.34 nm (0.34×10−9m). The length of the DNA double helix in a typical mammalian cell can be calculated by multiplying the total number of bp with the distance between the two consecutive bp, i.e. 6.6 ×109 bp × 0 34 10. × −9 m/bp = 2.2 m (the length of DNA). Thus, the option is correct.

Biology MCQ For NEET With Answers

Question 14. Which among the following pairs of nitrogen bases are correct?

1. A=C, T=G
2. A=T, C=G
3. A=G, C=T
4. All of the above

Answer: 2. A=T, C=G

According to Chargaff’s rules, the molar amount of adenine is always equal to the molar amount of thymine. Similarly, the molar concentration of guanine is equal to the molar concentration of cytosine

Question 15. Adenine pairs with thymine through

1. One hydrogen bond
2. Two hydrogen bonds
3. One phosphate bond
4. Four hydrogen bonds

Answer: 2. two hydrogen bonds

Adenine always pairs with thymine through two hydrogen bonds in DNA.

Similarly, adenine pairs with uracil through two hydrogen bonds in RNA. Guanine and cytosine always pair with three hydrogen bonds.

Important DNA questions for NEET Biology exam

Question 16. The diameter of the double helix of DNA is

1. 34Å
2. 20Å
3. 3.4Å
4. 340Å

Answer: 2. 20Å

The double helix of DNA is of constant diameter of 2 nanometers or 20 Å (angstrom).

Question 17. Purines found both in DNA and RNA are

1. Adenine and thymine
2. Adenine and guanine
3. Guanine and cytosine
4. Cytosine and thymine

Answer: 2. adenine and guanine

Purines found both in DNA and RNA are adenine and guanine.

Question 18. The left-handed form of DNA is called

1. A-DNA
2. cDNA
3. B-DNA
4. Z-DNA

Answer: 4. Z-DNA

Z-DNA is left-handed DNA. It is a double helical structure. The phosphate backbone of Z-DNA follows a zig-zag course. The helix of Z-DNA is 18 Å in diameter containing 12 base pairs per turn and one complete turn of helix is 45 Å long.

Biology MCQ For NEET With Answers

Question 19. One turn of the helix in a B-form DNA is approximately

1. 2 nm
2. 20 ìm
3. 0.34 nm
4. 3.4 nm

Answer: 4. 3.4 nm

B-DNA is right-handed DNA. Here, the double strand is coiled plectonemically in a right-handed fashion around a common axis like a rope staircase twisted in a spiral.

The pitch of the helix per turn is 3.4 nm. The diameter of the helix is 20Å. 10 base pairs are present per turn of the helix.

“dna questions “

Question 20. Which of the following is the common type of DNA present in all organisms?

1. A type DNA
2. B type DNA
3. C type DNA
4. Z type DNA

Answer: 2. B type DNA

B-form DNA is a right-handed double helix, which was discovered by Watson and Crick based on X-ray diffraction patterns. It is the common form of DNA that exists under normal physiological conditions.

Solved MCQs on DNA structure and replication for NEET

Question 21. Z-DNA is

1. Right-handed and has about 12 bases per turn
2. Left-handed and has about 12 bases per turn
3. Right-handed and has about 10 bases per turn
4. Left-handed and has about 10 bases per turn

Answer: 2. left-handed and has about 12 bases per turn

Z-DNA is left-handed DNA. It is a double helical structure. The phosphate backbone of Z-DNA follows a zig-zag course. The helix of Z-DNA is 18 Å in diameter containing 12 base pairs per turn and one complete turn of helix is 45 Å long.

Question 22. In a DNA strand of length 340 Å, there are

1. 100 nucleotides
2. 100 base pairs
3. 100 nitrogenous bases
4. 100 sugar phosphates

Answer: 2. 100 base pairs

“dna questions “

Distance between consecutive bases is 3.4 Å. 340 Å means, it has 340/3.4 = 100 base pairs.

Biology MCQ For NEET With Answers

Question 23. A-DNA is WB

1. Left-Handed Helix With 12 Nucleotide Pairs Per Turn
2. Right-Handed Helix With 11 Nucleotide Pairs Per Turn
3. Right-Handed Helix With 12 Nucleotide Pairs Per Turn
4. Left-Handed Helix With 11 Nucleotide Pairs Per Turn

Answer: 2. right-handed helix with 11 nucleotide pairs per turn

A-DNA is a right-handed double helix, made up of deoxyribonucleotides. The two strands of A-DNA are antiparallel with each other and not symmetrical.

The molecule is asymmetrical because the glycosidic bonds of a base pair are not diametrically opposite to each other. Therefore, major grooves and minor grooves can be observed in each turn. One turn of the helix consists of 11 base pairs with a length of 2.86 nm.

Question 24. Consider the following statements about A-DNA.

1. It appears when the relative humidity in the environment is less than 75%.
2. Its backbone is formed by sugar and phosphates linked by phosphodiester bonds.
3. The helix width of A-DNA is 0.3 nm.
4. A-DNA is narrower than B-DNA.

Choose the option representing incorrect statements.

1. 1 and 2
2. 3 and 4
3. 2 and 3
4. 2, 3 and 4

Answer: 2. 3 and 4

Statements 3 and 4 are incorrect and can be corrected as The helix width of A-DNA is 2.3 nm. Overall, A-DNA is wider than the commonly found B-DNA. Rest statements are correct about A-DNA.

Question 25. Pyrimidines are

1. Monocyclic
2. Dicyclic
3. Tetracyclic
4. Tricyclic

Answer: 1. Monocyclic

Pyrimidines are monocyclic means, they have one ring of atoms in their molecule.

Question 26. Given below are various types of DNA and their characteristics.

1. Z-DNA – Right-handed helix
2. B-DNA – Right-handed helix
3. A-DNA – Left-handed helix

Choose the option containing incorrectly matched pairs.

“dna questions “

1 and 2
2 and 3
1 and 3
1, 2 and 3

Answer: 3. 1 and 3

Pairs 1 and 3 are incorrectly matched and can be corrected as Z-DNA is a left-handed helix whereas A-DNA is a right-handed helix. 2 is a correctly matched pair.

Biology MCQ For NEET With Answers

Question 27. Identify the wrong statement about DNA.

1. The length of DNA is defined as the number of base pairs present in it
2. Cytosine is common to both DNA and RNA
3. In a nucleotide, the nitrogenous base is linked to a phosphate group
4. Thymine is chemically 5-methyl uracil
5. Deoxythymidine is a nucleoside

Answer: 3. In a nucleotide, the nitrogenous base is linked to a phosphate group

The statement in option (3) is wrong. In a nucleotide, the nitrogenous base is linked to the sugar molecule at first carbon by a glycosidic bond. Rest statements are right

Question 28. Match the following columns.

Answer: 1–3, 2–1, 3–2

Role of DNA in protein synthesis NEET MCQs with answers

Question 29. The amount of purines is equal to the number of pyrimidines suggested by

1. Robert Brown
2. Meischer
3. Chargaff
4. Khorana

Answer: 3. Chargaff

Chargaff suggested that purine and pyrimidine base pair are in equal amounts in nucleic acids, i.e. Adenine + Guanine = Thymine + Cytosin

Question 30. The purine-to-pyrimidine ratio in a DNA molecule is

1. 1: 1
2. Need not be 1: 1
3. 1: 2
4. 2: 1

Answer: 1. 1: 1

Chargaff’s rules state that DNA from any cell of any organism should have a 1:1 ratio (base pair rule) of pyrimidine and purine bases. More specifically, the amount of guanine should be equal to cytosine and the amount of adenine should be equal to thymine.

Question 31. Which one of the following ratios is constant in the DNA of different species?

1. A + T/C+G
2. A + G/T+C
3. A + C/U+G
4. A + U/C+G

Answer: 1. A + T/C+G

According to the Chargaff rule, in DNA, there is always equality in quantity between the bases A and T and between the bases G and C (A is adenine, T is thymine, G is guanine and C is cytosine). So, A+T: C+G ratio is constant in the DNA of different species

Question 32. In a DNA, the percentage of thymine is 20% then what will be the percentage of guanine?

1. 20%
2. 40%
3. 30%
4. 60%

Answer: 3. 30%

According to Chargaff’s rule, the ratio of purine bases to pyrimidine bases is equal. A=T;C=G. If T is 20% then A is 20% and C and G are 30% each.

Question 33. The backbone of DNA molecule is formed by

1. Alternate sugar – po4 – sugar component joined by a phosphodiester bond
2. Alternate sugar – po4 – sugar component joined by alternate glycoside c bond
3. Alternate sugar – po4 – sugar component joined by alternate peptide – sulfate bond
4. Polypeptide linkage

Answer: 1. alternate sugar – PO4 – sugar component joined by a phosphodiester bond

The backbone of DNA is made up of alternating deoxyribose sugar and phosphate groups. They are connected through phosphodiester bonds.

Question 34. In the polynucleotide chain of DNA, a nitrogenous base is linked to the – OH of

1. 2 C′ pentose sugar
2. 3 C′ pentose sugar
3. 5 C′ pentose sugar
4. 1 C′ pentose sugar

Answer: 4. 1 C′ pentose sugar

In a DNA polynucleotide chain, a nitrogenous base is linked to the hydroxy group (– OH) at 1′ C of pentose sugar. It is represented in the structure given below

Question 35. Phosphodiester linkage is formed between

1. C-3 of one nucleotide and c-5 of the next
2. C-l of one nucleotide and c-2 of the next
3. Purines of opposite strands
4. Pyrimidines of opposite strands

Answer: 1. C-3 of one nucleotide and C-5 of the next

In DNA and RNA, the phosphodiester bond is the linkage between the 3′ 3-carbon atom of one sugar molecule and the 5′ carbon atom of another.

The sugar molecule is deoxyribose in DNA and ribose in RNA. Strong covalent bonds form between the phosphate group and two 5-carbon ring carbohydrates (pentoses) over two ester bonds

Biology MCQ For NEET With Answers

Question 36. Nitrogenous bases are linked to sugar by

1. Hydrogen bond
2. Phosphodiester bond
3. N-glycosidic bond
4. Covalent bond

Answer: 3. N-glycosidic bond

Nitrogenous bases are linked to sugar by N-glycosidic bonds.

Question 37. Nucleotides are building blocks of nucleic acids. Each nucleotide is a composite molecule formed by

1. (Base-sugar-phosphate) N
2. Base-sugar-OH
3. Base-sugar-phosphate
4. Sugar-phosphate

Answer: 3. Base-sugar-phosphate

Nucleotides are the building blocks or monomeric units. Each nucleotide contains nitrogen bases (purines and pyrimidines), pentose sugar (5C), and a phosphate group

Best multiple choice questions on DNA and genetics for NEET preparation

Question 38. Which of the following is a nucleoside?

1. Adenosine
2. Adenine
3. Deoxyribose
4. Adenylic acid

Answer: 1. Adenosine

Nucleoside is formed when the nitrogenous bases are linked to sugar. These include adenosine, guanosine, cytidine, etc. So in the given options, adenosine is a nucleoside

Question 39. The charge on DNA is

1. Negative
2. Positive
3. No charge
4. Both +ve and –ve

Answer: 1. negative

DNA has a negative charge due to the negative charge of its phosphate component.

NEET Biology Mcq

Question 40. Nucleoside means

1. Sugar + nitrogen base
2. Nucleotide + phosphate
3. Deoxyribose sugar + n base
4. Both purines and pyrimidines

Answer: 1. Both purines and pyrimidines

A pentose sugar when attached tothe nitrogen base, either a purine or a pyrimidine is called a nucleoside. It does not contain a phosphate group.

Question 41. A nucleosome is the repeating unit of …………….. in a nucleus.

1. Chromosome
2. Genes
3. Chromatin
4. Chromatosome

Answer: 3. chromatin

Chromatins are thread-like stained (colored) bodies seen in the nucleus. The nucleosome is a repeating unit in chromatin and is seen as ‘beads on a string’ when viewed under an electron microscope.

Question 42. The diameter of nucleosome fiber is

1. 30 nm
2. 20 nm
3. 10 nm
4. 40 nm

Answer: 3. 10 nm

DNA is wrapped around a core of histones, forming a nucleosome fiber of about 10 nm diameter.

NEET Biology Watson and Crick model of DNA MCQs

Question 43. Nucleosome consists of

1. Nucleolus
2. Genes
3. Microfilaments
4. Histones

Answer: 4. histones

Histones are the main structural proteins found in eukaryotic cells. The nucleosome core is made up of four types of histone proteins, i.e. H A2, H B2, H3, and H4 occurring in pairs.

200 bp of DNA helix wraps around the nucleosome by turns, plugged by H1 histone protein. So, nucleosome consists of histones

Question 44. Five types of histone proteins are

1. H1, H2A, H2C, H2D and H3A
2. H1, H2A, H2B, H3 and H4
3. H1, H2A, H2B, H3A and H4
4. H1, H2A, H2B, H3 and H5

Answer: 2. H1, H2A, H2B, H3 and H4

Histones are the main structural proteins found in eukaryotic cells. The nucleosome core is made up of four types of histone proteins, i.e. H A2, H B2, H3, and H4 occur in pairs. 200 bp of DNA helix wraps around the nucleosome by turns, plugged by H1 histone protein. So, nucleosome consists of histones

Question 45. The number of nucleosomes present in a human cell is

1. 3.3 × 107 nucleosome
2. 1.1 × 107 nucleosome
3. 6.6 × 107 nucleosome
4. Indefinite

Answer: 1. 3.3 × 107 nucleosome

Approximately 200 bp are present per nucleosome. The total number of base pairs in human genetic material is =6.6 × 109. Number of nucleosomes

Question 46. The packaging of chromatin at a higher level requires an additional set of proteins that are collectively referred to as

1. Histone proteins
2. Non-histone proteins
3. Basic proteins
4. Histone octamer

Answer: 2. non-histone proteins

The packaging of chromatin at a higher level requires an additional set of basic proteins called non-histone proteins.

These are heterogeneous groups of proteins that play important roles in nucleosome remodeling, DNA processing, etc.

NEET Biology Mcq

Question 47. The densely packed and transcriptionally inactive part of chromatin is

1. Euchromatin
2. Heterochromatin
3. Solenoid fibre
4. NHC

Answer: 2. heterochromatin

In some places, chromatin is densely packed to form darkly stained heterochromatin. It is transcriptionally inactive.

Question 48. The lightly stained part of chromatin which remains loosely packed is

1. Euchromatin
2. Heterochromatin
3. Chromatosome
4. Chromonemata

Answer: 1. euchromatin

The loosely packed form of DNA in the chromosome is called it is euchromatin.

In heterochromatin, the density of DNA is high and it is stained dark, whereas in euchromatin, the density of DNA is low and it is lightly stained.

Question 49. The association of histone H1 with a nucleosome indicates

1. Transcription is occurring
2. Dna replication is occurring
3. The dna is condensed into a chromatin fibre
4. The dna double helix is exposed

Answer: 3. The DNA is condensed into a chromatin fiber

The association of H1 protein indicates the complete formation of nucleosomes in which DNA is condensed into chromatin fiber.

Question 50. Which amino acids are present in histones?

1. Lysine and histidine
2. Valine and histidine
3. Arginine and lysine
4. Arginine and histidine

Answer: 3. Arginine and lysine

Histones are alkaline proteins that wrap DNA into a condensed form. They consist of two basic (positively charged) amino acids, arginine and lysine.

NEET Biology Mcq

Question 51. Linker DNA is

1. A part of nucleosome
2. A part that joins two octamer cores
3. Ssdna
4. Both (1) and (2)

Answer: 4. Both (1) and (2)

Linker DNA is double-stranded DNA, 38-53 bp long in between two nucleosome cores that in association with histone H1, hold the cores (octamer) together. Linker DNA is seen as the string in the beads and string model. Thus, the option is correct

Question 52. In the given diagram, identify A B, and C.

1. A–DNA, B–H1 histone, C–Histone octamer
2. A–RNA, B–Cistron, C–DNA
3. A–DNA, B–H3 histone, C–Histone tetramer
4. A–RNA, B–H1 histone, C–Histone octamer

Answer: 1. A–DNA, B–H1 histone, C–Histone octamer

Question 53. The sequence of nitrogenous bases in one strand of DNA is 3 ′-TAC GCG ACG- 5 ′. The complementary DNA strand should have Karnataka

1. 5′- AUG CGC TGC- 3′
2. 3′ – ATG CGC TGC- 5′
3. 5′ – UAC GCG ACG- 3′
4. 5′- ATG CGC TGC- 3

Answer: 4. 5′- ATG CGC TGC- 3

Two strands of DNA molecules are held together by hydrogen bonds between their bases.

Adenine (A), a purine of one chain lies exactly opposite thymine (T), a pyrimidine of the other chain. Similarly, cytosine (C, a pyrimidine) lies opposite guanine (G, a purine). Thus, the complementary strand would be 5′- ATG CGC TGC – 3

 Evolution Miscellaneous Multiple Choice Question and Answers

Question 1. Consider the following statements.

1. The essence of Darwinian Theory about evolution can be seen in the phenomenon of natural selection.
2. The rate of appearance of new forms is not linked to evolution.
3. Adaptive ability is a complete evolution.
4. Mutations are random and directionless.

Choose the option containing incorrect statements.

1. 1 and 2
2. 2 and 3
3. 1 and 3
4. None of them

Answer: 2. 2 and 3

Statements 2 and 3 are incorrect and can be corrected as Evolution is always considered as the appearance of a new character, permanently.

NEET Biology Evidence of Evolution MCQs

The genes of the new characters should also be transmitted to the offspring otherwise the changes are lost.

Adaptive ability cannot be considered evolution because this ability may be temporary due to environmental changes. Rest all statements are correct.

Read And Learn More: NEET Biology Multiple Choice Question And Answers

Question 2. Which type of homology exists between arm and leg of man and horse?

1. Phylogenetic
2. Sexual
3. Serial
4. None of the above

Answer: 1. Phylogenetic

The arm and legs of man and horse are examples of homologous organs.

A homologous structure is an example of an organ or bone that appears in different animals, underlining anatomical commonalities demonstrating descent from a common ancestor.

So, we can say there is a phylogenetic relationship between man and horse.

NEET Biology Evolution MCQs with Answers

Question 3. Match the following columns.

Answer: 1. 1–2, 2–3, 3–4, 4–1

Question 4. Read the following statements and choose the correct answer from the codes given below.

1. The outcome of the evolutionary process is the adaptation of an organism to its environment.
2. Evolution is the property of the population and not of individuals.
3. Natural selection is the evolutionary force.
4. According to Weismann the changes occurring both in germplasm and somatoplasm are heritable and play an important role in evolution.

Choose the correct option.

1. 1 and 2 are correct
2. 1, 2, and 3 are correct
3. 2, 3, and 4 are correct
4. All statements are correct

Answer: 2. 1, 2, and 3 are correct

“evolution class 12 mcq “

All statements are correct except 4. The incorrect statement can be corrected as August Weismann (1834-1914) was a neo-Darwinian biologist who proposed the germplasm theory in his book Das Keimplasma.

This theory is based on the concept that living bodies are formed of two fundamentally different kinds of material, i.e. the germplasm (protoplasm of germ cells such as sperms and ova) and the somatoplasm (protoplasm of somatic or body cells).

The germplasm is responsible for the development of reproductive parts and remains in the organism, sealed and secluded from the somatoplasm which develops out of the germplasm.

NEET Biology Mcq Chapter Wise

Question 5. Match the following columns.

Answer: 1. 1–1, 2–4, 3–3, 4–2

Important MCQs on Evolution for NEET

Question 6. Match the following columns.

Answer: 1. 1–4, 2–1, 3–2, 4–3, 5–5

Hardy-Weinberg Principle and Evolution MCQs for NEET

Question 7. Read the following statements.

1. The increase in melanized moths after industrialization in Great Britain is proof of natural selection.
2. When more individuals in a population acquire a mean character value, it is called disruption.
3. Changes in allelic frequency in a population will lead to HardyWeinberg equilibrium.
4. Genetic drift changes the existing gene or allelic frequency in future generations.

Choose the correct option.

1. 2 alone is correct
2. 4 alone is correct
3. 1 and 4 are correct
4. 1 and 3 are correct
5. 2 and 4 are correct

Answer: 3. 1 and 4 are correct

“evolution neet mcqs “

Statements 1 and 4 are correct, while statements II and III are incorrect. These can be corrected as

When more individuals in a population acquire mean character value, the type of natural selection is called stabilizing selection.

It favors the average or normal phenotypes and eliminates the extreme variants.

Hardy-Weinberg equilibrium is defined as the relative frequencies of various kinds of genes in a large and randomly mating sexual population that tend to remain constant from generation to generation in the absence of mutation, selection, and gene flow

Question 8. Match Column 1 with Column 2

Answer: 2. 1–2, 2–4, 3–1, 4–3

Darwin’s Theory of Evolution MCQs for NEET

Question 9. Match the following columns.

Answer: 2. 1–3, 2–4, 3–1, 4–2

Question 10. Given below are four statements (A-D) each with one or two blanks. Select the option which correctly fills up the blanks in any two statements.

1. Wings of butterflies and birds look alike and are the results of …1 … evolution.
2. Miller showed that CH4, H2, NH3, and …1… when exposed to electric discharge in a flask resulted in the formation of …2…
3. The vermiform appendix is a …1… organ and an …2… evidence of evolution.
4. According to Darwin evolution took place due to …1… and …2… of the fittest.

choose the correct option 

1. A – 1 convergent, D-1 small variations 2 survival,
2. A-1 convergent, B-1 oxygen, 2 nucleosides
3. B-1 water vapor, 2 amino acids, C-1 rudimentary, 2 anatomical
4. C-1 vestigial, 2 anatomical, D-1 mutations, 2 multiplication

Answer: 1. A – 1 convergent, D-1 small variations 2 survival,

A–1 convergent B– 1 water vapor, 2 amino acids C–1 vestigial organ, 2 anatomical D–1 small variations, 2 survival

NEET Biology Mcq Chapter Wise

Question 11. Consider the following statements.

1. The microbial experiment proves existing advantageous mutations result in the occurrence of new phenotypes.
2. Neanderthal fossils represent a human relative.
3. Coelacanth (lobe fins) thought to be extinct evolved into the first living amphibian on both land and water.
4. Alfred Wallace, a naturalist, drew a similar conclusion on natural selection as reached by Darwinism.

Choose the option containing the correct statements.

1. 1 and 2
2. 2 and 3
3. 3 and 4
4. 1, 2, 3 and 4

Answer: 1, 2, 3, and 4 All the given statements are correct.

“questions about evolution “

Question 12. Match the following columns.

Answer: 3. 1–1, 2–2, 3–3, 4–4

Topic-wise Evolution MCQs for NEET with Explanation

Question 13. Match the following and choose the correct option from the codes given below.

Answer: 4. 1–4, 2–3, 3–1, 4–2

Speciation and Evolutionary Mechanisms MCQs for NEET

Question 14. Match the following columns.

“evolution means fill in the blanks “

Answer: 4. 1–4, 2–3, 3–2, 4–1

Question 15. Match the following columns.

Answer: 2. 1–1, 2–2, 3–3, 4–4

Biology MCQs With Answers For NEET Population Interaction

Question 1. Interaction between individuals of two different species is called

1. Interference interaction
2. Apparent interaction
3. Intraspecific interaction
4. Interspecific interaction

Answer: 4. Interspecific interaction

The interspecific interaction arises from the interaction of a population of two different species. They could be beneficial, detrimental, or neutral to one of the species or both.

Question 2. What sort of results can be observed in an interspecific interaction?

1. Beneficial
2. Detrimental
3. Neutral
4. All of the above

Answer: 4. All of the above

interactions biology

The interspecific interaction arises from the interaction of a population of two different species. They could be beneficial, detrimental, or neutral to one of the species or both.

Read And Learn More: NEET Biology Multiple Choice Question And Answers

Question 3. An interaction in which both species are neither harmed nor benefitted is called

1. Positive interaction
2. Negative interaction
3. Antagonistic interaction
4. Neutral interaction

Answer: 4. Neutral interaction

Different types of interspecific interactions have different effects on the two participants, which may be positive (+), negative (-) or neutral (0). In neutral interaction, both species are neither benefitted nor harmed from the interaction.

NEET Biology Population Interaction MCQs with answers

Question 4. Different types of interactions and the nature of interactions between species a and b are given in columns 1 and 2, respectively. Choose the correct answer from the answer key where they are matched.

“interactions biology “

Answer: 3. A–2, b–5, c–4, d–3, e–1

Biology MCQs with answers for NEET

Question 5. If the ‘+’ sign is assigned to beneficial interaction, the ‘–’ sign to detrimental, and the ‘0’ sign to neutral interaction, then the population interaction represented by ‘+’ ‘–’ refers to

1. Mutualism
2. Amensalism
3. Commensalism
4. Parasitism

Answer: 4. Parasitism

• The association of organisms that benefit one of the partners at the expense of the other is called parasitism and is denoted by + −. Commensalism refers to a relationship where one organism benefits, while the other remains unaffected and is denoted by + 0.
• Amensalism refers to the association where one partner is inhibited, while the other remains nearly unaffected and is denoted by – 0. Mutualism is an association of organisms where both are benefitted and is denoted by + +. Thus, the option is correct

Question 6. Predation and parasitism are which type of interactions?

1. (+, +)
2. (+, 0)
3. (–,–)
4. (+,–)

Answer: 4. (+,–)

Both predation and parasitism show negative interactions. In negative interaction, one species is harmed (–), while the other is benefitted (+). Predation occurs when members of one species eat those of another species. But not always, this involves the killing of prey. Parasitism is a kind of harmful coaction between two species.

Important MCQs on Population Interaction for NEET

Question 7. An association of two species where both the partners derive mutual benefit from each other is

1. Parasitism
2. Symbiosis
3. Commensalism
4. Predation

Answer: 2. Symbiosis

Symbiosis or mutualism is an obligatory positive interspecific interaction strongly beneficial to both species.

Biology MCQs with answers for NEET

Question 8. An interaction between two organisms of different species, without physically interacting with each other, in which both are benefitted are called

1. Commensalism
2. Protocooperation
3. Scavenging
4. Amensalism

Answer: 2. Protocooperation

Protocooperation is a relationship in which organisms in association are mutually beneficial to each other (without physically interacting). This interaction is similar to mutualism, but the relationships between the organisms in protocooperation are not obligatory as in mutualism.

Question 9. Interaction between two organisms of different species in which one organism inhibits the growth of another organism is called

1. Commensalism
2. Amensalism
3. Mutualism
4. Protocooperation

Answer: 2. Amensalism

competition interaction

Amensalism is any relationship between organisms of different species in which one organism is inhibited or destroyed while the other organism remains unaffected.

Question 10. In which of the following interactions both partners are adversely affected?

1. Parasitism
2. Mutualism
3. Competition
4. Predation

Answer: 3. Competition

Competition is the rivalry between two or more organisms to obtain the same resources such as food, light, water, space, shelter, mate, etc. Competitors adversely affect each other.

Biology MCQs with answers for NEET

Question 11. The relationship between the two organisms where one receives benefit at the host of the other is

1. Parasitism
2. Amensalism
3. Scavenging
4. Symbiosis

Answer: 1. Parasitism

Parasitism is the relationship between two organisms of different species in which one organism called a parasite obtains its food directly from another living organism called the host.

Question 12. The mode of nutrition by killing the host is called

1. Predation
2. Parasitism
3. Symbiosis
4. Commensalism

Answer: 1. Predation

In predation, the predator kills the prey and consumes it to draw nutrition.

Biology MCQs with answers for NEET

Question 13. If the stronger partner is benefitted and the weak partner is damaged, it is known as

1. Predation
2. Allelopathy
3. Symbiosis
4. Commensalism

Answer: 1. Predation

If the stronger partner is benefitted and the weak partner is damaged, it is known as predation. Predation is an interaction between members of two species in which members of one species capture, kill, and eat up members of other species. The former is called predator, while latter is called prey

“interaction define “

Question 14. Predation is

1. An unnatural way of transferring energy to a higher trophic level
2. A natural way of obtaining energy from lower trophic level
3. A natural way of obtaining nutrition
4. All of the above

Answer: 2. A natural way of obtaining energy from a lower trophic level

• Predation is a natural way of transferring energy to a higher trophic level or obtaining energy from a lower trophic level.
• It is an interaction between members of two species in which members of one species capture, kill, and eat up members of other species. The former is called predators, while later are spoken as prey.

Question 15. Predation helps keep a check on

1. Prey population
2. Biological control of weeds and pests
3. Species diversity
4. All of the above

Answer: 4. All of the above

Predators help maintain species diversity in a community by reducing the intensity of competition among competing prey species. Predators can also be used for biological control of weeds and pests. Thus, option (4) is correct.

Question 16. Which of the following statements is incorrect regarding predators? 

1. Predators keep prey populations under control
2. Predators help in maintaining species diversity in a community
3. If a predator is not efficient, then the prey population will become extinct
4. Herbivores (predators) have a greater advantage since the plants cannot run away to avoid predation
5. Tiger is an example of a predator

Answer: 3. If a predator is not efficient, then the prey population will become extinct

The statement in option (3) is incorrect and can be corrected as if a predator is too efficient and overexploits its prey, then the prey might become extinct, and following it, the predator will also become extinct for lack of food that is the reason prey species have to evolve various mechanisms to protect themselves so that the balance is maintained. Rest statements are correct regarding predators.

Biology MCQs with answers for NEET

Question 17. Assertion predation is an interspecific interaction with a feeding strategy. Reason (R) predator and their prey maintain a fairly stable population through time and rarely does one population become abundant or scarce.

1. Both a and r are true and r is the correct explanation of a
2. Both a and r are true, but r is not the correct explanation of a
3. A is true, but r is false
4. Both a and r are false

Answer: 1. Both a and r are true and r is the correct explanation of a

• Both a and r are true and r is the correct explanation of a. Predation is a natural way of transferring energy to a higher trophic level.
• It is the interaction between members of two species in which members of one species capture, kill, and eat up members of other species, i.e. Interspecific interaction.
• The former are called predators, while the latter are called prey. So, predator and their prey maintain a fairly stable population through time, and rarely does one population become abundant or scarce.

Question 18. Assertion Sometimes one population adversely affects the other by direct attack, but yet depends upon them. Reason (R) in predation, the contact is instant.

1. Both a and r are true and r is the correct explanation of a
2. Both a and r are true, but r is not the correct explanation of a
3. A is correct, but r is incorrect
4. Both a and r are false

Answer: 1. Both a and r are true and r is the correct explanation of a

• Both a and r are true and r is the correct explanation of a. All living things within an ecosystem are interdependent.
• Any change in the population of one organism affects all other organisms within the ecosystem. Further one population may adversely affect another by a direct attack like predator attacks prey.
• In predation, the predator may or may not kill the prey prior to feeding, during predation the contact is instant on the prey population. Nevertheless, this is unavoidable as the predator population survives on the prey population for its food.

Question 19. Predators also help in …A… Species diversity in a community, by …B… The intensity of competition among competing prey species.

Here A and  B can be

1. A–exceeding, b–increasing
2. A–maintaining, b–reducing
3. A–reducing, b–maintaining
4. A–maintaining, b–increasing

Answer: 2. A–maintaining, b–reducing.

Biology MCQ For NEET With Answers

Question 20. Pests are organisms that cause harm to plants and/or animals. They show …………………… Which is made use of in creating biological control methods towards it.

1. Predator-prey interaction
2. Prey feeding habitat
3. Prey interaction with other predators
4. Predator-predator interaction

Answer: 1. Predator-prey interaction

Biological control method in agriculture pest control based on the predator-prey interaction.

“mention the four aspects of interaction “

Question 21. Many species of fungi, for example. Dactylella, dactylaria, arthrobotrys, and zoophagus capture insects, nematodes, and other worm-like animals. These fungi are

1. Parasitic
2. Hyperparasites
3. Predatory
4. Holophytic

Answer: 3. Predatory

Predatory fungi attack nematodes and other microorganisms using a remarkable assay of trapping devices to attract, capture, kill, and digest nematodes for food.

Question 22. Plants have developed various means of protecting themselves from predators. One of the methods is by producing toxic chemicals. Identify such chemicals from the list given below.

1. Nicotine
2. Caffeine
3. Quinine
4. Strychnine
5. Opium

Choose the correct combination.

1. Only 1
2. 1, 2, 3 And 4
3. 1, 2 And 3
4. 1, 2, 3, 4 And 5

Answer: 4. 1, 2, 3, 4 And 5

A wide variety of chemical substances that we extract from plants on a commercial scale (nicotine, caffeine, quinine, strychnine, opium, etc….) Are produced by them actually as a defense against grazers and browsers. Thus, option (4) is correct.

Biology MCQ For NEET With Answers

Question 23. Monarch butterflies are highly distasteful to predator

1. As it can camouflage
2. Due to a special chemical present in his body
3. Due to a poison secreted by their special glands
4. None of the above

Answer: 2. Due to a special chemical present in his body

Monarch butterfly is highly distasteful to their predators because of a special chemical present in their body. Interestingly, the butterfly acquires this chemical during its caterpillar stage by feeding on poisonous weeds.

Question 24. Identify an example of a defense used by plants against herbivores.

1. Production of caffeine, tannin quinine.
2. Production of non-woody tissues.
3. Productions of hair, thorns, and spines.
4. Production of hormone-like chemicals that interfere with insect metamorphosis.

“interactions examples “

Select the correct pair.

1. 1 And 2
2. 2, 3 And 4
3. 1, 2 And 3
4. 1, 3, And 4

Answer: 4. Production of hormone-like chemicals that interfere with insect metamorphosis.

• Production of caffeine, tannin, and quinine are examples of secondary metabolites, that are secreted by plants against herbivores.
• Production of hormones like chemicals, thorns, and spines is also the strategy of plants to avoid grazing by herbivores. Production of non-woody tissues is not the adaptation for plants from predation. Thus, option (4) is correct.

Question 25. A secondary compound in plants is a result of

1. Normal metabolism
2. Secondary metabolism
3. Evolution
4. Genetic difference

Answer: 2. Secondary metabolism

Biology MCQ For NEET With Answers

Question 26. Prickly pear cactus species was introduced in Australia in

1. 1920’S
2. 1930’S
3. 1960’S
4. None of these

Answer: 1. 1920’S

The prickly pear cactus was introduced in Australia in the 1920s’s caused havoc by spreading rapidly into millions of hectares of range land. Finally, invasive cactus was brought under control only after a cactus-feeding predator (a moth) from its natural habitat was introduced into the country.

27. How does an exotic species become invasive?

1. Because of natural predators
2. Because of competition for natural resources
3. Because invaded land does not have native predators
4. Because of mutations occurring in their genome

Answer: 3. Because invaded land does not have native predators

When there is no natural predator for a species then it increases in number. Therefore an exotic species becomes invasive when that invaded land does not have any native or natural predator to control its increase.

Question 28. When an organism is ‘cryptically-colored’, it refers to a state where a

1. Prey can feed abundantly
2. Prey can lessen the impact of predator
3. Predator can increase their number
4. Predator can increase their reproductive fitness

Answer: 2. Prey can lessen the impact of predator

Prey species have evolved various defenses to lessen the impact of predation. Some species of insects and frogs are cryptically colored, i.e. Camouflage, to avoid being detected easily by the predator

Question 29. Why cannot a predator always have an upper hand over the prey?

1. Since prey populations evolve anti-predatory traits
2. Since prey populations reproduce at a fast rate
3. Since predator populations reproduce at a fast rate
4. Since predators are much larger in size than prey communities

Answer: 1. Since prey populations evolve anti-predatory traits

No predator becomes proficient in acquiring prey because prey populations also evolve anti-predatory traits to protect themselves.

NEET quiz on Population Interaction with solutions

Question 30. Animals have the innate ability to escape from predation. Examples for the same are given below. Select the incorrect example.

1. Colour change in chameleon
2. Enlargement of body size by swallowing air in puffer fish
3. Poison fangs in snakes
4. Melanism in moths

Answer: 3. Poison fangs in snakes

• Color change in chameleons and melanism in moths are examples of camouflage in animals adapted to prevent predation from prey. As a defense mechanism, puffers have the ability to inflate rapidly, filling their extremely elastic stomach with water or air until they are almost spherical.
• This prevents them from being identified by the predator. But poison fangs in snakes are a method adopted for preying and not escaping predation. Thus, option (3) is correct.

“interaction types “

Question 31. The starfish, disaster is an important predator in intertidal communities of

1. American pacific coast
2. Indian pacific coast
3. Middle pacific coast
4. None of the above

Answer: 3. Middle Pacific coast

Predator helps in maintaining species diversity. In the rocky intertidal, communities of the American Pacific coast, starfish pisaster is an important predator.

Question 32. Scavenging is an interaction between two organisms in which

1. Certain animals feed on dead organisms
2. One is benefitted, while the other is neither benefitted nor harmed
3. One organism inhibits the growth of another organism
4. None of the above

Answer: 1. Certain animals feed on dead organisms

Scavengers are animals that consume dead organisms that have died from causes other than predation. Thus, scavenging is an interaction between two organisms in which certain animals feed on dead organisms.

Question 33. When both partners/components are affected negatively, the nature of the interaction is

1. Commensalism
2. Predation
3. Competition
4. Amensalism

Answer: 3. Competition

Competition occurs when closely related species compete for the same resources that are limiting.

Biology MCQ For NEET With Answers

Question 34. Competition is best defined as a process in which the fitness of one species (measured in terms of its ‘r’ the intrinsic rate of increase) is significantly

1. Lower in the presence of another superior species
2. Higher in the presence of another superior species
3. Equal in the presence of another superior species
4. Competition exists irrespective of the presence or absence of competing species

Answer: 1. Lower in the presence of another superior species

Competition is best defined by the fitness of one species as compared to the other competitive species. It is lower in the case of other superior competing species.

Question 35. When the value of ‘r’ is significantly low as compared to others it is better known by

1. Competition exclusion
2. Resource partition
3. Interference competition
4. Competition release

Choose the correct option.

1. 1, 3 And 6
2. 6, 5 And 3
3. 1, 3 And 4
4. 1, 2 And 2

Answer: 3. 1, 3 And 4

When the value of ‘r’ is significantly low as compared to others it is better known by competition exclusion, interference competition, or competition release. It states that two competing species cannot co-exist in the same habitat at the same time for the same resource. Thus, option (3) is correct.

Question 36. Competition occurs when

1. Organisms are at their fittest for reproduction
2. Unrelated species compete for the same resources
3. Closely related species compete for the same resources
4. Both (2) and (3)

Answer: 4. Both (2) and (3)

Competition occurs for the same limited resources between closely related and unrelated species. It is said that competition occurs when closely related species compete for the same resources that are limiting. But this is not true, unrelated species also compete for the same resources. Thus, option (4) is correct.

37. Competition for food, light, and space is most severe between the two

1. Closely related species growing in different niche
2. Distantly related species growing in different niche
3. Closely related species growing in the same niche
4. Distantly related species growing in the same niche

Answer: 3. Closely related species growing in the same niche

Species that are living close to one another, i.e. In the same habitat and have similar or same requirements, there is maximum competition for food, light, and space between them.

NEET Biology Mcq

Question 38. Competition of species leads to

1. Extinction
2. Mutation
3. A greater number of niches are formed
4. Symbiosis

Answer: 1. Extinction

• When both partners/components are affected negatively the nature of interaction is known as competition. When two organisms compete for a particular resource in the same niche, both cannot survive.
• No two organisms can live in the same niche. One of the two is eliminated. So, in the course of time elimination may lead to extinction as only the fittest will survive.

Question 39. The level of competition between species depends on

1. Availability of resources
2. Population density
3. Climatic condition of an area
4. Group interaction of the organism

Choose the option containing

Correct combination.

1. 1 And 2
2. 1 And 3
3. 2 And 4
4. 1, 2 And 4

Answer: 4. Extinction

1. The level of competition depends upon many factors like
2. Resources availability
3. Population density
4. Group interaction of organisms.

Thus, option (4) is correct.

Question 40. To avoid the competitive exclusion principle two similar species living in the same area, may evolve to become more different in order to

1. Reduce competition
2. Increase competition
3. Use other species’ resources
4. Both (1) and (3)

Answer: 1. Reduce competition

To avoid the competitive exclusion principle two similar species adapt differently to reduce the competition. So, that two species can live in the same area. Therefore, competition does not always result in the extinction of species.

NEET Biology Mcq

Question 41. …A… Being the common food source for migratory flamingos and fishes in lakes of America, need not necessarily be limiting for competition to occur. Here, …B… Will be observed, where the feeding efficiency of any one species …C… Due to the interference of the other species.

1. A–zooplankton, b–sharing competition, c–increases
2. A–zooplankton, b–interference competition, c–decreases
3. A–phytoplankton, b–weak competition, c–reduces
4. A–phytoplankton, b–null competition, c–increases

Answer: 2. A–zooplankton, b–interference competition, c–decreases.

Question 42. Competition will be severe in a population with ………………. Distribution.

1. Non-random
2. Irregular
3. Uniform
4. Random

Answer: 1. Non-random

• Population dispersion can be defined as the spatial distribution of individuals on the basis of favorable conditions available for their survival non-random distribution is the most common type of dispersion found in nature. In this type of distribution, the distance between neighboring individuals is minimized.
• Animals need certain resources to survive and when the resources become rare during certain parts of the year animals tend to clump together around these crucial resources.

Question 43. Assertion interspecific competition is the only potent force in organic evolution. Reason (R) Unexceptionally two closely related species competing for the same resources cannot co-exist indefinitely.

1. Both a and r are true and r is the correct explanation of a
2. Both a and r are true, but r is not the correct explanation of a
3. A is true, but r is false
4. Both a and r are false

Answer: 4. Both a and r are false

• Population dispersion can be defined as the spatial distribution of individuals on the basis of favorable conditions available for their survival non-random distribution is the most common type of dispersion found in nature. In this type of distribution, the distance between neighboring individuals is minimized.
• Animals need certain resources to survive and when the resources become rare during certain parts of the year animals tend to clump together around these crucial resources.
• The same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually. This may be true if resources are limiting, but not otherwise.

NEET expected MCQs on Population Interaction 2025

Question 44. Hydroxylamine toxins are released by

1. All parasites
2. Members of actinomycetes
3. Blue-green algae
4. All of the above

Answer: 3. Blue-green algae

• Blue-green algae (BGA) are cyanobacteria. The toxins produced by cyanobacteria are called cyanotoxins. Hydroxylamine is an inorganic cyanotoxin secreted by the bag.
• This compound is highly toxic to aquatic life. When the bacteria form aquatic blooms they release a lot of cyanotoxins killing aquatic life on a large scale. When these cyanotoxins enter the shells of molluscans they lead to shellfish poisoning.

NEET Biology Mcq

Question 45. Interspecific competition between plants may manifest itself in chemical aggression called

1. Parasitism
2. Predation
3. Allelopathy
4. Ecological sere

Answer: 3. Allelopathy

Allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the germination, growth, survival, and reproduction of other organisms from the same community. So, interspecific competition between plants may manifest itself by chemical aggression called allelopathy.

Question 46. A high density of elephant population in an area can result in

1. Intraspecific competition
2. Interspecific competition
3. Predation on one another
4. Mutualism

Answer: 1. Intraspecific competition

• Competition is rivalry for obtaining the same resource. It is competition between individuals of the same species.
• The intraspecific competition may be very severe because all the members of a species have similar requirements of food, habitat, mate, etc., And they also have similar adaptations to meet their needs. So, if the density of the elephant population in an area increases, it will lead to intraspecific competition.

Question 47. Territoriality occurs as a result of

1. Parasitism
2. Predation
3. Co-operation
4. Competition

Answer: 4. Competition

• Territoriality is the separation of competitors. Due to competition between two or more organisms, populations of species that share the same environmental resources (when this is in short supply competition) ultimately result in displacement by one competitor to the others.
• It is to the advantage of the competitors to avoid one another wherever possible. So, territoriality occurs as a result of competition.

Question 48. An indirect competition for shared resources such as a particular nutrient is called

1. Mutualism
2. Exploitation
3. Advantageous
4. None of these

Answer: 2. Exploitation

An indirect competition for shared resources such as particular nutrients is called exploitation.

Question49. The principle of competitive exclusion was stated by

1. C. Darwin
2. Gf gause
3. Mac Arthur
4. Verhulst and pearl

Answer: 2. Gf gause

The principle of competitive exclusion was given by GF Gause

Question 50. Consider the following statements.

1. Two closely related species may not live in the same habitat.
2. The more dissimilar the niches of the two species the stronger their competition.
3. Two species can occupy the same niche in a geographical area.
4. No two species may occupy the same ecosystem.

Choose the option containing

Correct statements.

1. Only 1
2. 2, 3 And 4
3. 1, 2, 3 And 4
4. Only 4

Answer: 4. Only 4

• Only 4 statement is correct. Two or more species with closely niche requirements cannot exist indefinitely in the same area as sooner or later they come into competition for possession of it.
• This is called as Gause’s competitive exclusion principle, which states that an ecological niche cannot be simultaneously and completely occupied by established populations of more than one species.
• Two species can live in the same habitat but not in the same niche more similar the two niches are, severe the competition is so, the correct answer is no two species may occupy the same ecosystem.

NEET Biology Mcq

Question 51. ‘Two closely related species competing for the same resources cannot co-exist indefinitely’. This law is also called

1. Gause’s law
2. Competitive exclusion principle
3. Both (1) and (2)
4. None of the above

Answer: 3. Both (1) and (2)

• Gause (1934) found that out of two species of paramecium grown together, one is eliminated. This phenomenon is called Gause’s hypothesis or principle of competitive exclusion.
• This principle operates when the resources are limited and two species compete for the same resources. Thus, option (3) is correct.

Question 52. Gause’s principle of competitive exclusion states that

1. More abundant species will exclude the less abundant species through competition
2. Competition for the same resources excludes species having different food preferences
3. No two species can occupy the same niche indefinitely for the same limiting resources
4. Larger organisms exclude smaller ones through competition

Answer: 3. No two species can occupy the same niche indefinitely for the same limiting resources

Gause’s principle of competitive exclusion states that no two species can occupy the same niche indefinitely for the same limiting resources

Question 53. Gause’s law is true only when

1. Resources are limited
2. Resources are unlimited
3. Predation is absent
4. Prey are unlimited

Answer: 1. Resources are limited

Gause (1934) found that out of two species of paramecium grown together, one is eliminated. This phenomenon is called Gause’s hypothesis or principle of competitive exclusion. This principle operates when the resources are limited and two species compete for the same resources. Thus, option (3) is correct.

Question 54. Carnivorous animals, lions and leopards, occupy the same niche but lions predate mostly larger animals and leopards take smaller ones. This mechanism of competition is referred to as

1. Character displacement
2. Altruism
3. Resource partitioning
4. Competitive exclusion

Answer: 3. Resource partitioning

• Carnivorous animals, lions and leopards occupy the same niche but lion predate mostly larger animals and leopard takes smaller ones. This is called resource partitioning.
• It is a mechanism in which there is the division of limited resources by species to avoid competition in an ecological niche and in this way, they find ways to co-exist with one another. That is why lions predate mostly larger animals and leopards take small ones.

NEET Biology Mcq

Question 55. Resource partitioning includes

1. Temporal partitioning
2. Spatial partitioning
3. Morphological partitioning
4. All of the above

Answer: 1. Temporal partitioning

Resource partitioning is the phenomenon where the species are divided on the basis of their food, space, resting sites, etc. They divide a niche for the competition of resources. Thus option (1) is correct.

Question 56. When Darwin spoke of the struggle for existence and survival of the fittest in nature, he was convinced that

1. Interspecific competition is a potent force in organic evolution
2. Intraspecific competition is a potent force in organic evolution
3. Predator-prey interaction is a potent force in organic evolution
4. Both and (c)

Answer: 1. Interspecific competition is a potent force in organic evolution

It is generally believed that competition occurs when closely related species compete for the same resources that are limiting. But this is not true, unrelated species also compete for the same resources. This is called interspecific competition which proves to be the potent force in organic evolution.

Question 57. Diversity in the type of beaks of finches adapted to different feeding habits on the Galapagos islands, as observed by Darwin, provides evidence

1. Origin of species by natural selection
2. Intraspecific variations
3. Intraspecific competition
4. Interspecific competition

Answer: 1. Origin of species by natural selection

• Darwin during his famous voyage, observed that finches from various islands of the Galapagos had beaks of different sizes and shapes they observed that this was due to adaptation to different available food types.
• He concluded that the ancestral finches on reaching different islands occupied all empty ecological niches in the absence of competition and evolved into different species. This provides evidence for the origin of species by natural selection.

NEET Biology Mcq Chapter Wise

Question 58. In laboratory experiments, two species of paramecium were grown alone and in the presence of the other species. The following graphs show the growth of species 1 and species 2, both alone and when in mixed culture.

Interpretation of the graphs.

1. Competitive exclusion has occurred in these experiments
2. Both species are affected by interspecific competition but species 1 is less affected
3. Both species are affected by interspecific competition but species 2 is less affected
4. Both species are affected equally by interspecific competition

Answer: 3. Both species are affected by interspecific competition but species 2 is less affected

As we can see from graph I there is more gap between lines of species 1 and 2 than graph. So, it clearly infers that both species are affected by interspecific competition but species 2 is less affected.

NEET Biology Population Interaction MCQs with explanations

Question 59. Relationship between organisms of different species where one organism gets benefits and the other is harmed is called

1. Mutualism
2. Commensalism
3. Parasitism
4. Symbiosis

Answer: 3. Parasitism

Parasitism is a negative interaction in which one individual derives benefit at the expense of the other. So, the relationship between organisms of different species where one organism gets benefitted and the other is harmed is called parasitism.

Question 60. A true parasite is one which

1. Wholly completes its life cycle in one host
2. Completes its life cycle in different host
3. Is completely attached to the host
4. Is not completely dependent on the host

Answer: 1. Wholly completes its life cycle in one host

A true parasite is one which wholly completes its life cycle in one host. These parasites attach to the host or live and feed on it. The parasites are benefitted, while the host is harmed.

Question 61. Nosema notabilis is an example of

1. Commensalism
2. Symbiosis
3. Parasitism
4. Hyperparasitism

Answer: 3. Parasitism

When a parasitic species is parasitized by another parasite species. Such a parasite is called hyperparasite, as in the case of nosema notabilis, which is a hyperparasite on a myxosporidian. So, nosema notabilis is an example of parasitism

NEET Biology Mcq Chapter Wise

Question 62. Adaptation of parasites may be

1. Loss of unnecessary organs
2. Presence of adhesive organs
3. Origin of suckers to cling to host
4. Development of a digestive system
5. High reproductive capacity

Choose the option containing

Correct combination.

1. 1, 3 And 4
2. 2, 4 And 5
3. 1, 4 And 5
4. 1, 2, 3 And 5

Answer: 4. 1, 2, 3 And 5

In accordance with their lifestyle, parasites evolved special adaptations such as loss of digestive systems, loss of unnecessary organs, presence of adhesive organs, origin of suckers, and high reproductive capacity in accordance to their host. So, the development of the digestive system is not an adaptation of parasites. Thus, option (4) is correct.

Question 63. Which of the following is categorized as a parasite in true sense?

1. Koel (cuckoo)
2. Housefly
3. Head louse
4. Both (2) and (3)

Answer: 3. Head louse

Question 64. Man and Ascaris show

1. Predation
2. Parasitism
3. Commensalism
4. Symbiosis

Answer: 2. Parasitism

Scaris is an intestinal parasite of humans. It is the most common human worm infection. The larvae and adult worms live in the small intestine and cause intestinal diseases. So, man and Ascaris show parasitism.

Question 65. During parasitic life, the animal is bound to lose

1. All the sense organs
2. Most of the nervous system
3. Complete gut
4. Both (1) and (3)

Answer: 4. Both (1) and (3)

• A parasite must remain in close contact with its host. It depends on the host for its food and is unable to live a free life for a very long. This is because most parasites have become thoroughly adapted to parasitic existence.
• In doing so they have often lost the power of locomotion, their sense organs are reduced, the gut may be reduced or absent and the reproduction system and nervous system have become greatly developed. Thus, option (4) is correct.

Question 66. Parasitodism is a case where the larval form

1. Lives after host’s death
2. Dies with host’s death
3. Is a parasite but the adult is free-living
4. Is a parasite on another parasite

Answer: 3. Is a parasite but an adult is a free-living

The Ladybird beetle, Cuccinelli is a parasite in its larval stage and is free-living in adults. Other include parasitic hymenopteran and orthopteran.

NEET Biology Mcq Chapter Wise

Question 67. …A… Is observed in many parasites which have enabled …B… Of host-parasite. …C… Developed by the host and parasite enable them to survive the adaptations that each of them gain over the course of evolution.

1. A–parasite-specificity, b–co-evolve, c–counteract
2. A–host specificity, b–co-evolution, c–counter mechanisms
3. A–enzyme specificity, b–evolve, c–counteract
4. A–source-specific, b–extinction, c–counter mechanisms

Answer: 2. A–host specificity, b–co-evolution, c–counter mechanisms

Question 68. Parasite capable of living without a host is called

1. Facultative
2. Permanent
3. Obligate
4. None of the above

Answer: 1. Facultative

The facultative parasite is an organism that may survive and dwell in the absence of a host but that occasionally infects a host organism also.

Question 69. Cuscuta is an example of

1. Ectoparasitism
2. Brood parasitism
3. Predation
4. Endoparasitism

Answer: 1. Ectoparasitism

• Cuscuta or dodder plant, is a parasitic plant that wraps around other plants for nourishment. Cuscuta is found on the outer side of the host and is a total stem parasite. It is a good example of ectoparasitism.  It is commonly found growing on hedge plants. It has lost chlorophyll and leaves in the course of evolution.
• It attaches and wraps itself around the stem of the host plant and produces haustoria that gets inserted into the vascular system of the host. The parasitic plant sucks all the nutrients from the host plant with the help of haustoria.

Question 70. Endoparasites are the parasites which live

1. In the intercellular spaces of the host
2. Within the cells in the host’s body
3. On the surface of the host
4. Both (1) and (2)

Answer: 4. Both (1) and (2)

Endoparasites are the parasites that live inside the host’s body. It can live in the intercellular spaces or within the cells in the host’s body. Thus, option (4) is correct.

Question 71. A phenomenon when a parasite parasitizes another parasite is

1. Hyperparasitism
2. Parasitoids
3. Monoxenous parasitism
4. Polyxenous parasitism

Answer: 1. Hyperparasitism

• Hyperparasitism means that a parasite lives in or on another parasite. Common examples are insects that lay their eggs inside or near parasites which are themselves parasitizing the tissue of a host (insect).
• So, indirectly insect is feeding on itself only. Hyperparasitism results in a cycle of energy and nutrients between the host and its parasitoid.

NEET Biology Mcq Chapter Wise

Question 72. ‘Parasitic castration’ refers to

1. Parasites induce their hosts to form antibodies
2. Parasites make their hosts form fibrous capsules around them
3. Change brought about by the parasite on the host resulting in sexual impotency
4. None of the above

Answer: 3. Change brought about by the parasite on the host resulting in sexual impotency

Parasite castration refers to the change brought about by the parasite on the host resulting in sexual impotency. It is a strategy by the parasites. Blocking reproduction is its main target.

Question 73. Which of the following is brood parasitism?

1. Snake feeding on rat
2. Oxpeckers eat the parasites on rhinoceros
3. Jackals and hyenas feeding on dead lions and tigers
4. Cuckoo female lay their eggs in the crow’s nest

Answer: 4. Cuckoo females laying their eggs in the crow’s nest

Brood parasites also called social parasites which parasite birds lay eggs in to nests of their host. Thus, the cuckoo female laying their egg in the cow’s nest is brood parasitism.

Question 74. Obligate parasites are those organisms which

1. Live only on living host
2. Are essentially parasites, but can also become saprophyte
3. Live only on dead and decaying organic matter
4. Are essentially saprophytes, but can also parasites

Answer: 1. Live only on living host

Obligate parasites can grow only upon suitable living host tissues. The best examples of obligate parasites are the causal organisms of downy and powdery mildews as perenospora and erysiphe.

Question 75. The parasite that completely depends on the host for its entire requirement is called

1. Ectoparasite
2. Holoparasite
3. Hemiparasite
4. Semiparasite

Answer: 2. Holoparasite

The parasite which completely depends on the host for its entire requirement is called holoparasite.

NEET Biology Mcq Chapter Wise

Question 76. A parasite that lives within plant tissue is called

1. Ectophyte
2. Epiphyte
3. Hydrophyte
4. Endophyte

Answer: 4. Endophyte

• An endophyte parasite remains inside the cells of plant tissue. Other options are explained as ectophytes when the parasite remains outside the cells of plant tissue.
• Hydrophytes plants growing in water are called hydrophytes. Epiphytes are those plants that live on another plant for shelter only. They are photosynthetic and do not depend on another plant for nutrition.

Question 77. Which of the following is hemiparasite?

1. Rafflesia
2. Viscum
3. Loranthus
4. Both (2) and (3)

Answer: 3. Loranthus

Rafflesia is a hemiparasite.

Question 78. Newly developed pathogens are more damaging to the host therefore are called

1. Distant pathogen
2. Chronic pathogen
3. Instant pathogen
4. Bt pathogens

Answer: 3. Instant pathogen

Newly developed pathogens are more damaging than the host therefore are called instant pathogens, which have not yet developed adaptation to negative interaction, for example. Sars.

Question 79. Human liver fluke (a trematode parasite) depends on which two intermediate hosts.

1. Snail
2. Fish
3. Pig
4. Mosquito

Choose the option containing

Correct combination.

1. 1 And 2
2. 2 And 3
3. 3 And 4
4. 4 And 5

Answer: 1. 1 And 2

Human liverfluke depends upon two intermediate hosts, i.e. A snail and fish to complete its life cycle. Thus, option (1) is correct.

Question 80. Which one is incorrect regarding parasitism?

1. Parasite shows a special adaptation
2. Ectoparasite shows a more complex life cycle
3. Endoparasite shows a more complex life cycle
4. Crow is an example of a brood parasite

Answer: 2. Ectoparasite shows a more complex life cycle

The statement in option is incorrect and can be corrected as ectoparasites show a simple life cycle as compared to endoparasite as their life cycle involve mostly one host, whereas an endoparasite completes its life cycle as more than one host and hence has a complex life cycle. Rest options are correct regarding parasitism.

Question 81. Match the following columns.

Answer: 4. A–2,3; b–4, 5; c–1

82. Match the following columns.

Answer: 1. A–4, b–3, c–2, d–1

Question 83. Choose the incorrect statements.

1. Parasites might render the host more vulnerable to predation by making it physically weak
2. The majority of the parasites harm the host and reduce their population density
3. Ideal parasites should be able to thrive within the host without harming it
4. The malarial parasite does not need a vector in order to spread to another host.

Answer: 4. Malarial parasite does not need a vector in order to spread to another host.

The statement in the option is incorrect and can be corrected as the malarial parasite needs a vector female anopheles mosquito to spread to other hosts. Rest options are correct statements.

NEET Biology Mcq Chapter Wise

Question 84. Consider the following statements.

1. The life cycle of a human liver fluke involves only the snail as an intermediate host.
2. The malarial parasite needs a vector (mosquito) to spread to other hosts.
3. The female mosquito is not considered a parasite, however, it needs our blood for reproduction.
4. In case of brood parasitism, the eggs of parasitic birds (e.g. Cuckoo) are not detected and ejected from the nest because of parasite’s eggs resemble the host’s eggs in morphology and colour.
5. A population of frogs protected from all predators would increase indefinitely.

Choose the option containing

Correct statements.

1. 1 And 2
2. 2 And 3
3. 3, 4 And 5
4. 2, 3 And 4

Answer: 4. 2, 3 And 4

• Statements 2, 3, and iv are correct. Statements I and v are incorrect and can be corrected as the life cycle of a human liver fluke involves the snail and pig as intermediate hosts. A population of frogs protected from all predators would not increase indefinitely because nature’s resources are limited.
• Beyond a carrying capacity, the population would not increase because it is the maximum number of populations that can be sustained by the habitat.

Question 85. The percentage of insects known to be phytophagous is

1. Nearly 75%
2. Nearly 25%
3. Nearly 50%
4. Nearly 35%

Answer: 2. Nearly 25%

For plants, herbivores are the predators of nearly 25% of all insects known to be phytophagous (feeding on plant sap and other parts of plants). The problem is severe in the case of plants because they are non-motile.

Question 86. In a biotic community, which one of the following can be called a protective device?

1. Symbiosis (commensalism)
2. Mimicry
3. Competition
4. Parasitism

Answer: 3. Competition

Mimicry is the superficial but resemblance of one organism to another or to natural objects to secure its concealment or protection. Thus, mimicry can be called a protective device.

Question 87. In commensalism

1. One species is benefitted and the other is neither harmed nor benefitted
2. One species is no benefit and the other is harmed
3. One species is no benefit and the other is not harmed
4. Both species benefit

Answer: 1. One species is benefitted and the other is neither harmed nor benefitted

Commensalism is the interaction in which one species (commensal) benefits and another species (host) is neither harmed nor benefitted, for example. An orchid grows as an epiphyte on a mango branch to absorb sunlight in the tropics.

Question 88. In commensalism

1. The population of commensal and host remain unaffected
2. The population of commensal increases while that of the host remains unaffected
3. The population of both commensal and cost increases
4. The population of commensal increases, while the population of the host gradually decreases

Answer: 2. The Population of commensal increases while that of the host remains unaffected

In commensalism, the population of commensals increases while that of the host remains unaffected.

Question 89. The interaction between the organisms of one of the following pairs is an example of commensalism.

1. Cattle or sheep and grass
2. Wasps and fig tree
3. Orchid and mango tree
4. Cuckoo and crow

Answer: 1. Cattle or sheep and grass

• Commensalism is the type of interaction in which one of the partners is benefitted, while the other partner is unharmed. This type of interaction takes place in the cattle or other grazing animals and the egrets. The grazing animals, while grazing disturbs the grass come out.
• The egrets are present on the back of the grazing animals. The egrets feed on these insects. There is no harm done to the cattle. So, cattle or sheep and grass is an example of commensalism.

Question 90. Between which of the following, the relationship is not an example of commensalism?

1. Orchid and the tree on which it grows
2. Cattle egret and grazing cattle
3. Sea anemones and clown fish
4. Female wasp and fig species

Answer: 4. Female wasp and fig species

• Among the given examples, the relationship between a female wasp and fig species does not show commensalism. In commensalism, one species derives the benefit, and the other is neither harmed nor benefitted.
• Wasp and fig trees show mutualism. Here, the fig flower is pollinated by the wasp and the female wasp uses the fig fruit for oviposition. In this way, both organisms are benefitted. Other options show examples of commensalism.

Question 91. Pencillium does not allow the growth of the bacterium, staphylococcus. This sort of relationship is called

1. Commensalism
2. Antagonism
3. Amensalism
4. Mutualism

Answer: 3. Amensalism

Amensalism is an interaction between two living individuals of different species in which an organism does not allow another organism to grow or live near it. So, penicillium does not allow the growth of the bacterium staphylococcus.

Question 92. If the strong partner is benefitted and the weak partner is damaged, the relationship is known as

1. Amensalism
2. Symbiosis
3. Commensalism
4. Allotropy

Answer: 1. Amensalism

If the strong partner benefits and the weak partner is damaged, the relationship is known as amensalism.

Question 93. Which one of the following population interactions is widely used in medical science for the production of antibiotics?

1. Commensalism
2. Amensalism
3. Parasitism
4. Mutualism

Answer: 2. Amensalism

• Amensalism/antibiosis (0, –) is widely used in medical science for the production of antibiotics as
• Antibiotics are chemicals secreted by one microbial group (for example. Penicillium) that harm other microbes (for example. Staphylococcus).
• It has no effect on the penicillium or the organism that produces it

Question 94. A plant that grows inside a plant of another species symbiotically is called

1. A semiparasite
2. A parasite
3. An endophyte
4. A saprophyte

Answer: 3. An endophyte

• Endophyte is a plant growing inside a plant of another species symbiotically. Other options are explained as semiparasite depends upon other organisms for its practical requirements.
• A parasite is an organism that obtains some benefit from other organisms at its (other organisms) expense. Saprophyte finds its food from dead material.

Question 95. A praying mantis is a good example of

1. Warning coloration
2. Social insects
3. Camouflage
4. Mullerian mimicry

Answer: 3. Camouflage

A praying mantis is a good example of camouflage. Camouflage is the natural colouring of an animal which enables it to blend in with its surroundings. A praying mantis is the common name for an insect of the order–Mantodea.

Question 96. The pilot fish always accompanies …………… For feeding on falling pieces of food.

1. Shark
2. Hermit crab
3. Labeo
4. Golden fish

Answer: 1. Shark

The pilot fish always accompanies the shark to feed on falling pieces of food. This association between pilot fish and sharks is called commensalism.

Question 97. Which one is true?

1. Commensalism–when none of the interacting populations affect each other
2. Symbiosis–when the interaction is useful to both populations
3. Symbiosis–when neither population affects the other
4. Commensalism–when the interaction is useful to both populations

Answer: 2. Symbiosis–when the interaction is useful to both the populations

(2) Option (2) is true as when the interaction is useful to both populations it is called symbiosis. Symbiosis means living together. It is a beneficial co-action between two or more different species in which both species are benefitted. Rest options are false.

Question 98.

1. The concept of mimicry was given by …A…
2. …B… Is known as the father of Indian plant ecology.
3. The term ‘ecology’ was coined by …C….

Choose the option containing

1. A–Haeckel, B–Ramdeo Misra, C–reiter
2. A–Hw bates,  B–ramdeo misra, C–ernst haeckel
3. A– Ramdeo Misra, B–birbal sahani, C– reiter
4. A–Hw bates, B–birbal sahani, C– ernst haeckel

Answer: 2. A–hw bates, B–ramdeo misra, C–ernst haeckel

1. The concept of mimicry was first given by HW Bates (1) in 1862.
2. The Father of Indian plant ecology is Ramdeo Misra (2).
3. The term ‘ecology’ was coined by Ernst Haeckel (3) in 1861.

Question 99. An interesting modification of flower shape for insect pollination occurs in some orchids, in which a male insect mistakes the pattern on the orchid flower for the female of his species and tries to copulate with it, thereby pollinating the flower. This phenomenon is called

1. Mimicry
2. Pseudopollination
3. Pseudocopulation
4. Pseudoparthenocarpy

Answer: 1. Mimicry

• Mimicry is a resemblance of an organism to its natural surroundings, a non-living object or another organism to conceal itself from its enemies.
• Flowers of Ophrys muscifera resemble the female wasps of Colpa aurea so that the male wasp tries to copulate with the flowers and pollinate them.

Question 100. A type of mimicry where the mimic closely resembles the model and both are harmful to the predator is

1. Mullerian mimicry
2. Batesian mimicry
3. Webrian mimicry
4. None of the above

Answer: 2. Batesian mimicry

Batesian mimicry is a form of biological resemblance in which a noxious or dangerous, organism (the model), equipped with a warning system such as conspicuous coloration, is mimicked by a harmless organism (the mimic). The mimic gains protection because predators mistake it for the model and leave it alone.

Question 101. Which type of association is found between entomophilous flower and pollinating agent?

1. Mutualism
2. Commensalism
3. Cooperation
4. Co-evolution

Answer: 4. Co-evolution

Co-evolution can occur in any interspecific relationship like symbiosis or mutualism. The relation between an entomophilous flower and a pollinating insect shows co-evolved mutualism. In this, the plant depends exclusively on the insect for pollination and the insect relies on the plant for food.

Question 102. Assertion in mutualism, both the population benefit and neither can survive under natural conditions without the other. Reason (R) Both populations benefit from the association, but their relationships are not obligatory.

1. Both a and r are true and r is the correct explanation of a
2. Both a and r are true, but r is not the correct explanation of a
3. A is true, but r is false
4. Both a and r are false

Answer: 3. A is true, but r is false

A is true, but r is false. Reason can be corrected as in mutualism, both populations benefit by the association, but their relationships are obligatory, i.e. The species are in close proximity and interdependent with one another in a way that one cannot survive without the other.

Question 103. Mutualism is a kind of …………………. Interaction.

1. Positive interspecific
2. Negative interspecific
3. Positive intraspecific
4. Negative intraspecific

Answer: 1. Positive interspecific

Mutualism is defined as an interaction between individuals of different species that results in positive (beneficial) effects on per capita reproduction or survival of the interacting population. Thus, option (1) is correct.

Question 104. Mutualism is found in

1. Hermit crab and sea anemone
2. Butterfly and flower
3. Zoochlorella and hydra
4. E. Coli and man

Answer: 3. Zoochlorella and hydra

Mutualism is an obligatory positive interspecific interaction strongly beneficial to both species. Hydra can form a symbiotic relationship with algae such as zoochlorella which is green algae, zoxantheal which is referred to as brown algae. The relationship will assist in the benefits to both organisms.

Question 105. Which of the following associations shows mutualism?

1. Fig and wasp
2. Barnacles on whale
3. Roundworms in the human intestine
4. Orchids on mango tree

Answer: 1. Fig and wasp

• Mutualism is an interaction between two organisms of different species in which both partners benefit, with none of the two capable of living separately. In many species of fig trees there is a relationship with the pollinator species of wasp.
• The female wasp uses the fruit not only as an oviposition site but also uses the developing seeds within the fruit for nourishing its larvae.
• The wasp pollinates the fig inflorescence while searching for suitable egg-laying sites. So, fig and wasp associations show mutualism.

Question 106. Flagellate protozoan living in the gut of termites is a case of

1. Mutualism
2. Parasitism
3. Amensalism
4. Commensalism

Answer: 1. Mutualism

Termites feed on wood though they do not possess enzymes for digesting the same. Termites harbor cellulose-digesting flagellates (trichonympha campanula) for this purpose. Flagellates are unable and live independently. Termites would die of starvation in the absence of flagellates. Thus, flagellate protozoan living in the gut of termites is a case of mutualism.

Question 107. Orchids can be found associated with

1. Oryza sativa
2. Brassica crucifer
3. Nerium oleander
4. Shorea robusta

Answer: 4. Shorea robusta

Orchids can be found associated with Shorea robusta.

Question 108. The association of fungus and alga is an example of

1. Ammensalism
2. Commensalism
3. Competition
4. Symbiosis
5. predation

Answer: 4. Symbiosis

• The association of a fungus and an alga in the lichens is considered an example of symbiosis, in which each partner of the association derives something essential for its survival.

Question 109. A female fig wasp enters the syconium of a fig to lay her eggs in the process of which she pollinates the flower. The young larvae feed on some of the seeds and complete their life cycle. The fig is completely dependent on the wasps to pollinate its flowers and the fig wasp requires figs to complete their life cycle. The interaction between figs and fig wasps has aspects of

1. Mutualism
2. Host-parasite interaction
3. Competition
4. Ammensalism
5. Proto-cooperation

Select the correct option.

1. 1 And 2
2. 1 And 3
3. 5 And 6
4. 3 And 4

Answer: 1. 1 And 2

• The given examples show two types of interaction
• Mutualism – the fig plant is completely dependent on the fig wasp to pollinate its flower and the fig wasp requires figs to complete its life cycle.
• Host-parasite interaction– fig wasps are completely dependent on the fig plant for their food shelter, development, etc. Fig wasp acts as a parasite and fig plant acts as a host. Thus, option (1) is correct

Question 110. A free-living nitrogen-fixing cyanobacterium that can also form a symbiotic association with the water fern Azolla is

1. Chlorella
2. Nostoc
3. Anabaena
4. Tolypothrix

Answer: 3. Anabaena

Anabaena is a genus of filamentous cyanobacteria that exist as plankton. They are known for nitrogen-fixing abilities and they form symbiotic relationships with certain plants, such as the mosquito fern, azolla.

Question 111. The association between ants and petioles of certain plants is called

1. Interaction
2. Mutualism
3. Myrmecophily
4. All of these

Answer: 4. All of these

The association between ants and petioles of certain plants is called interaction mutualism or myrmecophily.

Question 112. The relationship between leguminous plants and the rhizobium present in their root nodules is

1. Synergism
2. Commensalism
3. Parasitism
4. Mutualism

Answer: 4. Mutualism

Root nodule symbiosis is a mutualistic interaction observed between mainly leguminous plants and nitrogen-fixing soil rhizobia, in which plants can obtain fixed atmospheric nitrogen and provide rhizobia with photosynthate as a carbon source.

Question 113. Besides paddy fields, cyanobacteria are also found inside the vegetative part of

1. Equisetum
2. Psilotum
3. Pinus
4. Cycas

Answer: 4. Cycas

Coralloid roots of cycas have symbiotic associations with blue-green algae like nostoc and anabaena. Coralloid roots are irregular, negatively geotropic, dichotomously branched coral-like roots that do not possess root hairs and root caps.

Question 114. Lichens are seen growing in areas with low pollution. They represent an intimate mutualistic relationship between

1. Fungus and bacteria
2. Fungus and photosynthetic algae
3. Fungus and archaebacteria
4. Fungus and roots of higher plants

Answer: 2. Fungus and photosynthetic algae

Lichens represent an intimate mutualistic relation between a fungus and photosynthetic algae or cyanobacteria. It is the interaction conferring benefit to both the interacting species, called mutualism.

Question 115. Mycobiont and phycobiont association is

1. Symbiotic
2. Commensal
3. Parasitic
4. Helotism

Answer: 4. Helotism

In lichens, there is the association of mycobiont and phycobiont called helotism because, in this relationship, algae act as slaves, prepare food for fungi and fungi act as masters. The reproduction in algae is inhibited by the influence of fungi.

Question 116. Pollination is an example of

1. Mutualism
2. Proto-cooperation
3. Synergism
4. Both (1) and (2)

Answer: 1. Mutualism

Pollination is an example of mutualism in which the pollinator obtains nectar, pollen grain, etc., And in turn, the flower gets pollinated.

Mock test on Population Interaction for NEET preparation

Question 117. Mycorrhiza, a relationship between fungi and roots of higher plants is

1. Parasitic relationship
2. Saprophytic relationship
3. Symbiotic relationship
4. Epiphytic relationship

Answer: 3. Mycorrhiza is a symbiotic association between fungi and roots of higher plants, which grow in mineral-deficient soil. It helps to absorb water and minerals like phosphorus from soil for the benefit of plants and in turn gets nutrition from the plant, as fungi cannot synthesize its own food.

Question 118. Which of the following is an example of symbiosis?

1. Sea anemone and hermit crab
2. Mycorrhiza
3. Lichens
4. All of the above

Answer: 4. All of the above

Symbiosis is a term given to any type of interspecific interaction. Thus, all options are correct.

Question 119. One of them shows a symbiotic relationship with man.

1. Paramecium
2. Trypanosoma
3. Leishmania
4. Entamoeba coli

Answer: 4. Entamoeba coli

Entamoeba coli is a non-pathogenic species of entamoeba that frequently exists in the human gastrointestinal tract and shows a symbiotic relationship. It relies on intestinal contents for nutrients and humans derive certain vitamins from e. Coli, particularly vitamin-k

Question 120. Mutualism observed in plants is a special kind of interaction involving …a… And …b… .the former obtains nutrition and the latter plays a role in its life cycle.

Whereas the latter gets pollinated in return.

1. A–insect, b–plants
2. A–plants, b–insect
3. A–prey, b–plants
4. A–predator, b–plants

Answer: 1. A–insect, b–plants.

Question 121. Which one of the following microbes forms a symbiotic association with plants and helps them in their nutrition?

1. Azotobacter
2. Aspergillus
3. Glomus
4. Trichoderma

Answer: 3. Glomus

Azotobacter, Aspergillus, and Trichoderma all are free-living microbes that help plants in their nutrition. Glomus is a fungus that symbiotically forms endomycorrhiza that helps in the absorption of nutrition especially phosphorus from soil.

Question 122. Roots of higher plants show symbiosis with mycorrhiza for obtaining

1. Sulfates
2. Nitrogen
3. Phosphates
4. All of these

Answer: 3. Phosphates

Mycorrhiza is an association of a soil fungus, e.g. Boletus, and with the roots of higher plants such as conifers, for example. Pinus. The fungus absorbs water and minerals (mainly phosphates) from the soil and passes them to the plant. The carbohydrate synthesized by the plant is absorbed by the fungus.

Question 123. The association between hermit crabs and sea anemones is

1. Symbiosis
2. Commensalism
3. Parasitism
4. Protocooperation

Answer: 4. Protocooperation

• In protocooperation, the two organisms are mutually benefitted by each other. But the association is non-obligatory, i.e. Not necessary for their existence, for example.
• Association between a hermit crab and sea anemone. Hermit crab takes sea anemone on their back to other feeding zone and in turn, gets protection from his enemies.

Question 124. A bird enters the mouth of a crocodile and feeds on parasitic leeches. The bird gets food and the crocodile gets rid of blood-sucking leeches. Both the partners can live independently. Such an association is called

1. Mutualism
2. Amensalism
3. Commensalism
4. Protocooperation
5. Answer:

Question 125. Which one of the following is a matching pair of certain organism(s) and the kind of association?

1. Shark and sucker fish–commensalism
2. Algae and fungi in lichens–mutualism
3. Orchids growing on trees–parasitism
4. Cuscuta (dodder) growing on other flowering plants–epiphytes

Answer: 2. Algae and fungi in lichens–mutualism

Mutualism is a type of symbiotic association between two organisms in which both are benefitted. Lichen is a symbiotic association of an alga and fungus in which an algal partner provides food to the fungal partner by photosynthesis and a fungal partner helps in the absorption of water and minerals.

Question 126. Consider the following statements.

1. The mutualistic relationship evolves when the benefit of both species outweighs the loss.
2. Mutualism evolves when the benefits of both species outweigh the loss.
3. Humans cause an ecological imbalance by eradicating common predators.
4. Humans bring about an alteration in competition between species.

Choose the option containing incorrect statements.

1. 1 And 3
2. 2 And 3
3. 1 And 4
4. 2 And 4

Answer: 2. 2 And 3

Statements 2 and 3 are incorrect and can be corrected as mutualistic relationships evolve when the benefit is more than the cost. Human causes ecological imbalance by eradicating common parasite and anthropogenic pollution is causing the extinction of many species. Rest all statements are correct.

Question 127. Which of the following can only reproduce only once in their lifetime?

1. Pacific salmon fish
2. Bamboo
3. Both (1) and (2)
4. None of the above

Answer: 3. Both (1) and (2)

The organism that breeds only once in its lifetime are called monocapric, for example. Pacific salmon fish, bamboo.

Question 128. …A… Are organisms that obtain their nutrition only from plants. This mode of nutrition is also a kind of … B…

Choose the correct option A and B.

1. A–herbivores, b–predation
2. A–herbivores, b–mutualism
3. A–omnivores, b–commensalism
4. A–omnivores, b–predation

Answer: 1. A–herbivores, b–predation

NEET practice test on Population Interaction

Question 129. Herbivores do not prefer calotropis

1. Due to its appearance
2. Due to the production of foul odor
3. Due to the formation of cardiac glycosides
4. Due to its distasteful leaves

Answer: 3. Due to the formation of cardiac glycosides

Question 130. Find the incorrect match.

Answer: 1. Only (1) is an incorrect match and can be corrected as crab and sacculina do not show positive interaction. They show negative or parasitic interaction. Parasitic sacculina destroys a crab’s gonads, rendering the crab permanently infertile. The rest matches are correct.

Question 131. Which of the following is inappropriately defined?

1. The parasite is an organism that only lives inside the body of other organisms and is detrimental to it.
2. A host is an organism that only provides food and shelter to another organism.
3. Amensalism is a relationship in which one species is benefitted, whereas the other is unaffected. 4. A predator is an organism that catches and kills other organisms of the same species for food.

Choose the correct option.

1. 1 And 4
2. 3 And 4
3. 1, 2, 3 And 4
4. 1, 3 And 4

Answer: 1. 1 And 4

• Statements I and iv are correct, while ii and iii are incorrect because a host is an animal or plant in which a parasite lives. Amensalim is a relationship between two organisms in which one is inhibited or destroyed and the other is unaffected.
• Predators are those that obtain food by the killing and consuming of other organisms. A parasite is an organism that lives in another organism called the host and harms it.

Question 132. Match the following columns.

Answer: 3. A–3, b–2, c–1, d–5, e–4

Question 133. Consider the following statements.

1. Some species of insects and frogs show critical coloration.
2. Some animals are poisonous.

Monarch butterflies are distasteful.

1. The above adaptations are against
2. Predation
3. Mimicry
4. Symbiosis
5. Protection

Answer: 1. Predation

Given statement are the adaptations through which prey can avoid their predators. Mimicry, camouflage, and poisonous chemicals are the different strategies to avoid predators.

Question 134. Match the items in column I with

Answer: 2. A–3, b–2, c–4, d–1

Question 135. Interactions observed in the ecosystem.

1. Fig: wasp:: sea anemone: …A…
2. …B… : Barnacle :: plants: grasshopper
3. Sacculina : crab:: …C… : Human
4. Cat: mouse:: grizzly bear: …d… Identify the option

With the correct set of answers.

1. A–shark, b–whale, c–plasmodia, d–sea lion
2. A–clown fish, b–dolphin, c–gut flora, d–salmon
3. A–clown fish, b–whale, c–plasmodia, d–salmon
4. A–crab, b–whale, c–plasmodia; d–elephant seal

Answer: 3. A–clown fish, b–whale, c–plasmodia, d–salmon

Question 136. Which of the following statements is incorrect?

1. Lichen, an association of fungus and algae is an example of mutualism
2. Those epiphytes which use other plants only for support and not for nutrition supply are examples of commensalism
3. Sea anemone on hermit crab is an example of protocooperation
4. Mutualism, protocooperation, and commensalism cannot be included under symbiosis

Answer: 4. Mutualism, protocooperation, and commensalism cannot be included under symbiosis

• The statement in the option is incorrect and can be corrected as symbiosis means ‘living together’. It is a beneficial co-action between two (or more) different species in which one or both the species are benefitted and neither species is harmed.
• Symbiotic relationships are manifested through commensalism, protocooperation, and mutualism and are widespread in nature.
• Commensalism is an association or relationship between two different organisms in which one is always benefitted, while the other is neither benefitted nor harmed.

137. Match the following columns.

Answer: 3. A–2, b–1, c–3

Question 138. In the case of the peppered moth (Biston betularia), the black-coloured form became dominant over the light-coloured form in England during the Industrial Revolution. This is an example of

1. The appearance of the darker-colored individuals due to very poor sunlight
2. Protective mimicry
3. Inheritance of darker color character acquired due to the darker environment
4. Natural selection whereby the darker forms were selected

Answer: 4. Natural selection whereby the darker forms were selected

• In the case of the peppered moth (Biston betularia), the black-coloured form became dominant over the light-coloured form in England during the Industrial Revolution.
• This is an example of natural selection. This group is about species that gain protection from predators due to selection caused by nature.

Question 139.

1. Bears go into …A… During winters.
2. Conical age pyramid with a broad base …B… Human population.
3. Pollination of fig by wasp …C…
4. An area with a high level of species richness is known as …D…

Choose the correct combination.

1. A–hibernation, B–expanding, C–mutualism, D–hotspot
2. A–hibernation, B–expanding, C–mutualism, D–hotspot
3. A–hibernation, B–expanding, C–hotspot, D–mutualism
4. A–aestivation, B–hotspot, C–expanding, D–mutualism

Answer: 2. A–hibernation, b–expanding, c–mutualism, d–hotspot

Question 140. Match the column 1 with column 2 and select the correct option.

Answer: 4. A–4, b–3, c–1, d–2

Question 141. Which of the following statements regarding species interdependence are true?

1. An association of two species where one is benefitted and the other remains unaffected is called mutualism.
2. An interspecific association where both partners derive benefit from each other is called commensalism.
3. A direct food relation between two species of animals in which one animal kills and feeds on another is referred to as predation.
4. A relationship between two species of organisms where both the partners are benefitted from each other is called symbiosis.

Choose the correct option.

1. 1 And 2
2. 3 And 4
3. 1 And 3
4. 2 And 3
5. 2 and 4

Answer: 2. 3 And 4

Statements 3 and 4 are correct as predation is the direct food relation between two species of animals in which one animal (predator) captures and feeds on another (the prey). In symbiosis (mutualism) two organisms live together in close physical association in which both derive benefits, for example. Lichen.

1. Reproduction in Organisms MCQs
   • NEET Biology Introduction and Asexual Reproduction MCQs
   • NEET Biology Sexual Reproduction Polyspermy MCQs
2. Sexual Reproduction in Flowering Plants
   • NEET Biology Reproduction Flower Structure and Events of  Pre – Fertilisation MCQs
   • NEET Biology Structure And Events Of Pre Fertilisation MCQs
   • NEET Biology Pollination MCQs
   • NEET Biology Double Fertilisation MCQs
   • NEET Biology Post-fertilisation Structures : Endosperm, Embryo and Seed MCQs
   • NEET Biology Apomixis and Polyembryony MCQs
   • NEET Biology Sexual Reproduction in Flowering Plants Miscellaneous MCQs
3. Human Reproduction
   • NEET Biology Male Reproductive System MCQs
   • NEET Biology Female Reproductive System MCQs
   • NEET Biology Gametogenesis MCQs
   • NEET Biology Menstrual Cycle MCQs
   • NEET Biology Fertilisation and Implantation MCQs
   • NEET Biology Pregnancy and Embryonic Development MCQs
   • NEET Biology Parturition and Lactation MCQs
   • NEET Biology Human Reproduction Miscellaneous MCQs
4. Reproductive Health
   • NEET Biology Reproductive Health Problems and Strategies MCQs
   • NEET Biology Population Stabilisation and Birth Control MCQs
   • NEET Biology Medical Termination of Pregnancy MCQs
   • NEET Biology Sexually Transmitted Infections (STIs) MCQs
   • NEET Biology Reproductive Health Infertility MCQs
5. Principles of Inheritance and Variation
   • NEET Biology Introduction to Genetics MCQs
   • NEET Biology Mendelism MCQs
   • NEET Biology Deviation from Mendelism MCQs
   • NEET Biology Chromosomal Basis of Inheritance MCQs
   • NEET Biology Sex-Determination MCQs
   • NEET Biology Pedigree Analysis and Genetic Disorders MCQs
   • NEET Biology Principles of Inheritance and Variation Miscellaneous MCQs
6. Molecular Basis of Inheritance 
   • NEET Biology The DNA MCQs
   • NEET Biology The Search for Genetic Material MCQs
   • NEET Biology RNA World MCQs
   • NEET Biology DNA Replication MCQs
   • NEET Biology Transcription MCQs
   • NEET Biology Genetic Code and RNAt MCQs
   • NEET Biology Mutation MCQs
   • NEET Biology Translation MCQs
   • NEET Biology Regulation of Gene Expression MCQs
   • NEET Biology Human Genome Project MCQs
   • NEET Biology DNA Fingerprinting MCQs
   • NEET Biology Molecular Basis of Inheritance Miscellaneous MCQs
7. Evolution
   • NEET Biology Origin of Life MCQs
   • NEET Biology Evidences of Evolution MCQs
   • NEET Biology Biological Evolution and Mechanism of Evolution MCQs
   • NEET Biology A Brief Account of Evolution and Human Evolution MCQs
   • NEET Biology Evolution Miscellaneous MCQs
8. Human Health and Diseases
   • NEET Biology Human Health MCQs
   • NEET Biology Common Diseases in Human MCQs
   • NEET Biology Immune System MCQs
   • NEET Biology AIDS MCQs
   • NEET Biology Cancer MCQs
   • NEET Biology Drugs and Drug Abuse MCQs
   • NEET Biology Human Health and Diseases Miscellaneous MCQs
9. Strategies for Enhancement in Food Production
   • NEET Biology Animal Husbandry MCQs
   • NEET Biology Plant Breeding MCQs
   • NEET Biology Single Cell Protein and Tissue Cultur MCQs 
   • NEET Biology Strategies for Enhancement in Food Production Miscellaneous MCQs
10. Microbes in Human Welfare
    • NEET Biology Microbes in Household Products MCQs
    • NEET Biology Microbes in Industrial Products MCQs
    • NEET Biology Microbes in Sewage Treatment MCQs
    • NEET Biology Microbes in Production of Biogas MCQs
    • NEET Biology Microbes as Biocontrol Agents MCQs
    • NEET Biology Microbes as Biofertilisers MCQs
    • NEET Biology Microbes in Human Welfare Miscellaneous MCQs
11. Biotechnology : Principles and Processes
    • NEET Biology Principles of Biotechnology MCQs
    • NEET Biology Tools of Recombinant DNA Technology MCQs
    • NEET Biology Process of Recombinant DNA Technology MCQs
    • NEET Biology Biotechnology : Principles and Processes Miscellaneous MCQs
12. Biotechnology and its Applications
    • NEET Biology Biotechnological Applications in Agriculture MCQs
    • NEET Biology Biotechnological Applications in Medicine MCQs
    • NEET Biology Transgenic Animals and Ethical Issues MCQs
13. Organisms and Populations
    • NEET Biology Introduction to Ecology MCQs
    • NEET Biology Organism and Its Environment MCQs
    • NEET Biology Population Attributes MCQs
    • NEET Biology Population Interaction MCQs
14. Ecosystem
    • NEET Biology Structure and Function of Ecosystem, its Productivity and Decomposition MCQs
    • NEET Biology Energy Flow MCQs
    • NEET Biology Ecological Pyramids MCQs
    • NEET Biology Ecological Succession MCQs
    • NEET Biology Nutrient Cycling and Ecosystem Services MCQs
    • NEET Biology Ecosystem Miscellaneous MCQs
15. Biodiversity and its Conservation
    • NEET Biology Biodiversity and its Conservation Different Levels  MCQs
    • NEET Biology Patterns of Biodiversity and Their Importance MCQs
    • NEET Biology Loss of Biodiversity and its Causes MCQs
    • NEET Biology Biodiversity Conservation MCQs
    • NEET Biology Biodiversity and its Conservation Miscellaneous MCQs
16. Environmental Issues
    • NEET Biology  Air Pollution and Noise Pollution MCQs
    • NEET Biology Water Pollution MCQs
    • NEET Biology Solid Wastes, Agrochemicals and Radioactive Wastes MCQs
    • NEET Biology Greenhouse Effect, Global Warming and Ozone Depletion MCQs
    • NEET Biology Degradation by Improper Resource Utilisation MCQs
    • NEET Biology Environmental Issues Miscellaneous MCQs

Biology MCQ For NEET With Answers Pedigree Analysis And Genetic Disorders

Question 1. What is pedigree analysis?

1. Record of inheritance pattern
2. Linkage map
3. Quantitative genetic
4. Polygene analysis

Answer:  1. Record of inheritance pattern

Pedigree is a record of inheritance of certain genetic traits for two or more than two generations, represented in the form of a diagram.

Read And Learn More: NEET Biology Multiple Choice Question And Answers

Question 2. Which one of the following symbols and its representation, used in human pedigree analysis is correct?

Answer:
1.  Option (1) is correct. Rest other options are incorrect and can be corrected as

• Option (2) is unaffected female,
• Option (3) is unaffected male and
• Option (4) is affected individual with sex unspecified.

“pedigree analysis questions “

Question 3. The individual from which a pedigree analysis is initiated is called

1. Proposita
2. Propositus
3. Both 1 and 2
4. origin

Answer: 3. Both 1 and 2

If pedigree is initiated from male, it is called propositus. If pedigree is initiated from female, it is called proposita. So, an individual from which a pedigree is initiated could be proposita or propositus. Thus, option (3) is correct.

Biology MCQ For NEET With Answers

Question 4. Match the symbols with statement.

Answer:  4. A–6, B–5, C–7, D–4

NEET Biology Pedigree Analysis MCQs with answers

Question 5. Name the principle on which pedigree analysis work?

1. Regression
2. Probability
3. Random mating
4. ANOVA

Answer:  2. Probability

“principles of inheritance and variation pyq neet “

Pedigree analysis is used to study the transmission genetics where controlled process is not possible and it works on the principle of probability.

Question 6. The given symbol indicates.

1. Carrier female
2. Unaffected female
3. Death of female
4. Normal female

Answer: 1. Carrier female

Generally, the carriers are females therefore, they are rounded structure. Carrier is represented as dot or small circle within the gender symbol.

Question 7. Study the pedigree chart of a certain family given in figure and select the correct conclusion which can be drawn for the character.

“inheritance and variation mcq “

1. The female parent is heterozygous
2. The parents could not have had a normal daughter for this character
3. The trait under study could not be colour blindness
4. The male parent is homozygous dominant

Answer: 1. The female parent is heterozygous

The given pedigree chart shows that both the daughters received the gene from the parents, while son may be normal or affected. It shows that the female parent is heterozygous.

Biology MCQ For NEET With Answers

Question 8. Pedigree analysis represents

1. Still birth
2. Still death
3. Still carrier
4. Still mating

Answer: 1. Still birth

Symbol in pedigree chart represents still birth. It refers to foetal death at or after 20-28 weeks of pregnancy.

Question 9. Identify the symbols given below and the correct option with respect of A, B and C.

1. A-Male, B-Affected female, C-Sex unspecified
2. A-Affected male, B-Female, C-Sterile male
3. A-Male, B-Female, C-Fertile
4. A- Affected female, B- Sex unspecified, C- Male

Answer: 1. A-Male, B-Affected female, C-Sex unspecified

A–Male, B–Affected female, C–Sex unspecified

Important MCQs on Pedigree Analysis for NEET

Question 10. The given diagram A and B indicates.

1. A-Zygotic twins, B-Dizygotic twins
2. A-Dizygotic twins, B-Identical twins
3. A-Zygotic twins, B-Identical twins
4. A-bizygotic twins, B-Dizygotic twins

Answer:  2. A-Dizygotic twins, B-Identical twins

“pedigree questions “

• A–Dizygotic twins are twins, which result from the fusion of two sperms with two ova. It is very rare in case of human beings.
• B–Monozygotic twins (identical twins) are twins, which result from the fusion of one sperm with one ovum leading to zygote formation.
• This zygote on division, give rise to two or more zygotes. In this, cells of all progenies have the identical genome. Thus, twins are identical.

Question 11. Following pedigree chart show.

1. The trait is carried by Y-chromosome
2. The trait is sex-linked recessive
3. The trait is sex-linked dominant
4. The trait is recessive autosomal

Answer: 1. The trait is carried by Y-chromosome

In the given pedigree chart, only males are affected. So, it can be easily inferred that the given trait is connected to Y-chromosome. The genes, which are present on the Y-chromosome are called holoandric genes and express in males only.

Biology MCQ For NEET With Answers

Question 12. Consider the following chart.

The first child of a couple is albino. Whereas, their second, third and fourth children are normal. Given that, A= normal and a = Albino, find the genotype of the mother and father.

Father – Mother

1. Aa – AA
2. AA – Aa
3. AA – AA
4. Aa – Aa

Answer:  4. Albinism is the recessive trait which occurs only when a homozygous condition is present. In the given cross, the progenies are both albino and normal. This is possible only when their parents are heterozygous for normal colour (Aa).

Question 13. Find out the genotype of father and mother in the given pedigree chart.

Mother Father

1. AA AA
2. Aa Aa
3. AA aa
4. Aa Aa

Answer:  4. aa Aa

The expected genotype of father and mother is Aa and aa, respectively. Since 50% male and female progenies are affected, mother would be homozygous recessive (aa) and father is heterozygous (Aa).

“monohybrid test cross ratio “

Question 14. Following pedigree chart show.

1. Recessive and autosomal
2. Recessive and sex-linked
3. Dominant and sex-linked
4. Dominant and autosomal

Answer:  2. Recessive and sex-linked

Given pedigree analysis indicates the transmission of recessive sex-linked trait from parents to their offspring because only 25% male progenies are affected.

Biology MCQ For NEET With Answers

Question 15. Identify the type of inheritance in the given diagram.

1. Dominant X-linked
2. Recessive X-linked
3. Dominant Y-linked
4. Cytoplasmic or mitochondrial inheritance
5. Both 2 and 3

Answer:  4. Cytoplasmic or mitochondrial inheritance

• Cytoplasmic or mitochondrial inheritance is the inheritance in which the trait pass only from mother to all of their offspring.
• The genes of that inheritance present in the cytoplasm of ova that is way these genes go to all of their offspring. As sperm have very less cytoplasm, so this inheritance is not applicable for males.

NEET quiz on Pedigree Analysis and Genetic Disorders with solutions

Question 16. Hyperdactyly (the possession of more than 12 finger) is determined by the dominant allele (H) and normal condition by recessive allele (h). Observe the image given below. It represents family tree in which some members of the family are hyperdactylus. Identify A, B and C

Find out the genotype of A, B and C.

1. A-Hh, B-Hh, C-hh
2. A-HH, B-Hh, C-hh
3. A-Hh, B-HH, C-hh
4. A-HH, B-HH, C-HH

Answer:  1. A-Hh, B-Hh, C-hh

• Dominant allele shows its effect in homozygous or heterozygous condition and recessive allele shows its effect only in homozygous condition.
• Given pedigree chart is possible only when the male parent in heterozygous (Hh) for hyperdactyle. If it is homozygous for hyperdactyle then the son would also be the hyperdactyle as well. Thus, option (1) is correct.

Biology MCQs with answers for NEET

Question 17. In a family, the father carried a trait which the mother did not. All their offspring displayed this trait. Though their daughters married normal males, a few grand-daughters carried this trait. Choose the correct pedigree chart for this condition.

Answer: 1. Criss-cross inheritance is a type of sex-linked inheritance where a parent passes the traits to the grand child of the same sex through offspring of the opposite sex.

It appears in opposite sex progeny in subsequent generations. Pedigree chart in option (a) depict this inheritance pattern correctly.

Question 18. Study the pedigree chart given below. What does it show?

1. Inheritance of a condition like phenylketonuria as an autosomal recessive trait
2. The pedigree chart is wrong as this is not possible
3. Inheritance of a recessive sex-linked disease like haemophilia
4. Inheritance of a sex-linked inborn error of metabolism like phenylketonuria

Answer: 1. Inheritance of a condition like phenylketonuria as an autosomal recessive trait

The given chart shows inheritance of an autosomal recessive trait like phenylketonuria.An autosomal recessive trait may skip a generation but it affect both males and females equally. It appears in case of marriage between two heterozygous individuals.

“monohybrid cross ratio “

Question 19. Given below is a pedigree chart of a family with five children. It shows the inheritance of attached ear-lobes as opposed to the free ones. The squares represent the male individuals and circles represents the female individuals.

Which one of the following conclusions drawn is correct?

1. The parents are homozygous recessive
2. The trait is Y-linked
3. The parents are homozygous dominant
4. The parents are heterozygous

Answer:  4. The parents are heterozygous

The parents are heterozygous. It is an autosomal inheritance trait. It is controlled by a rare dominant allele say ‘E’ (free ear lobe). Here, the recessive homozygotes which do not have a dominant ‘E’ have attached ear lobes.

Biology MCQs with answers for NEET

Question 20. Given below is a pedigree chart showing the inheritance of a certain sex-linked trait in humans.

The trait traced in the above pedigree chart is

1. Dominant X-linked
2. Recessive X-linked
3. Dominant Y-linked
4. Recessive Y-linked

Answer:  1. Dominant X-linked

• The trait traced in the given pedigree is dominant X-linked. As seen in the figure, in first generation, male is affected, but female is not affected, i.e. female carries normal chromosomes in heterozygous condition.
• In second generation, both females are affected, but none of the males are affected. This shows that in spite of carrying single X-linked trait, they are affected, i.e. the trait is dominant.
• Likewise in the third generation when X-linked traits are again crossed with normal male, then, both male and female offspring carrying single Xlinked trait are affected. Thus, we can say that the trait is dominant X-linked.

Question 21. Assertion (A) In a pedigree analysis, represents five unaffected offspring. Reason (R) In pedigree analysis, the offspring are numbered with Arabic numerals (1, 2, 3 …..) and a generation is numbered with roman numerals (I, II, III ….).

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R false
4. Both A and R are false

Answer:  2. Both A and R are true, but R is not the correct explanation of A

Biology MCQs with answers for NEET

Both A and R are true, but R is not the correct explanation of A. In pedigree analysis, unaffected offspring are represented as non-shaded circle, square or diamond, representing the gender of progeny. The number of progenies are written in Arabic numerals within the gender symbol.

Question 22. Match the following columns.

“monohybrid ratio “

Answer:  4. A–3, B–5, C–6, D–2, E–4

Question 23. Which of the following is true for a recessive disease in family A and B?

1. In family A, both the parents are homozygous recessive
2. In family B, both the parents are homozygous dominant
3. In family B, both the parents are heterozygous recessive
4. In family A, both the parents are heterozygous recessive

Answer:  4. In family A, both the parents are heterozygous recessive

• Option (4) is true whereas option (1), (2) and (3) are incorrect. Incorrect options can be corrected as In family A, if both the parents are homozygous recessive, then both should be diseased and should have 100% diseased progeny.
• In family B, if both parents are homozygous dominant, they would not have got the recessive disease in first place. If both are heterozygous recessive, then also they would not have got the disease, neither 80% of progeny would be diseased.

Question 24. In the following human pedigree, the filled symbols represent the affected individuals. Identify the type of given pedigree.

1. Autosomal recessive
2. Autosomal dominant
3. X-linked dominant
4. X-linked recessive

Answer: 1. Autosomal recessive

Autosomal recessive traits are the traits which are caused by recessive autosomal genes when present in homozygous condition. The given pedigree can be explained as follows.

As the trait appears only in homozygous recessive individuals (aa), therefore it is an autosomal recessive trait.

Question 25. Which one is the incorrect statement with regard to the importance of pedigree analysis?

1. It helps to trace the inheritance of a specific trait
2. It confirms that DNA is the carrier of genetic information
3. It helps to understand whether the trait in question is dominant or recessive
4. It confirms that the trait is linked to one of the autosome

Answer:  2. It confirms that DNA is the carrier of genetic information

• Statement in option (2) is incorrect and can be corrected as Pedigree is a chart showing the record of inheritance of certain genetic traits for two or more ancestral generations of an individual, abnormality or disease.
• It does not confirm that DNA is the carrier of genetic information. Rest statements are correct with regard to the importance of pedigree analysis.

Biology MCQs with answers for NEET

Question 26. The process of mating between closely related individuals is

1. Self breeding
2. Inbreeding
3. Hybridisation
4. Heterosis

Answer:  2. Inbreeding

Inbreeding is the process of mating between closely related individuals. It leads to the expression of recessive characters, most of which are harmful.

Question 27. The square, blackened shape and horizontal lines in pedigree analysis represents

1. Female, healthy individual, parents
2. Female, affected individual, parents
3. Male, affected individual, parents
4. Male, affected individual, progeny

Answer:  3. Male, affected individual, parents

In pedigree, square represents male, blackened square or circle represents affected individual. Horizontal line represents parents.

Question 28. Double lines in pedigree analysis show

1. Unaffected offspring
2. Sex unspecified
3. Normal mating
4. Consanguineous marriage

Answer:  4. Consanguineous marriage

Double lines in pedigree analysis represent mating between relatives, i.e. consanguineous mating. Normal mating is shown by single line. Unaffected offspring are depicted by open and clear symbols (i.e. for male and O for female).

Question 29. Eugenics is defined as

1. The study of diseases resulting from environmental cause
2. The study of congenital defects in man
3. The study of human genetics from the point of view of the improvement of the genetic composition of the human stock during gestation or birth
4. The diseases caused by consanguinity

Answer:  3. The study of human genetics from the point of view of the improvement of the genetic composition of the human stock during gestation or birth

Eugenics is the study of human genetics from the point of view of the improvement of the genetic composition of the human stock during gestation or birth.

Biology MCQs with answers for NEET

Question 30. The term ‘eugenics’ was given by Francis Galton and inborn errors of metabolism were studied by

1. Galton
2. Garrod
3. Barr
4. Both 1 and 2

Answer:  2. Garrod

The term inborn errors of metabolism were coined by a British physician, Archibald Garrod (1857– 1936), in 1908. He is known for work that prefigured the ‘one gene-one enzyme’ hypothesis, based on his studies on the nature and inheritance of alkaptonuria.

NEET expected MCQs on Pedigree Analysis 2025

Question 31. A heterozygous individual carrying recessive sex-linked gene is called

1. Carrier
2. Crossing over
3. Transmitter
4. Albino

Answer: 1. Carrier

An individual with one abnormal gene (but no symptoms) is called a carrier. A heterozygous individual carrying recessive sex-linked genes is called carrier.

Question 32. A hereditary disease which is never passed on from father to son is

1. Autosomal linked disease
2. X-chromosomal linked disease
3. Y-chromosomal linked disease
4. None of the above

Answer:  2. X-chromosomal linked disease

X-chromosome linked diseases can never be passed on from father to son because the X-chromosome of the father can only be transferred to daughter and Y-chromosome is only passed on to the son.

Question 33. Y-linked recessive gene is transferred from

1. Father to son
2. Mother to son
3. Father to daughter
4. Mother to daughter

Answer: 1. Father to son

Because only males have a Y-chromosome, in Y-linked inheritance, a mutation can only be passed from father to son.

Question 34. Mendelian disorder may be of

1. Recessive
2. Dominant
3. Both 1 and 2
4. Cannot be determined

Answer: 3. Both 1 and 2

Mendelian disorder may be dominant or recessive type, e.g. haemophilia, colour blindness, sickle cell anaemia, cystic fibrosis, phenylketonuria, thalassaemia. Thus, option (4) is correct.

Question 35. Sex linked disorder is

1. Colour blindness
2. Tuberculosis
3. Diphtheria
4. Leprosy

Answer: 1. Colour blindness

Colour blindness is a recessive sex-linked trait in which the eye fails to distinguish red and green colours. The gene for the normal vision is dominant.

Question 36. Which are sex-linked traits?

1. Osteomalacia
2. Dental disorders
3. Pellagra
4. Haemophilia and hypertrichosis

Answer:  4. Haemophilia and hypertrichosis

NEET Biology Mcq

Sex-linked traits are the traits whose determining genes are found on the sex chromosomes. All the sex-linked traits present on a sex chromosome are inherited together. For example, haemophilia and hypertrichosis are sex-linked traits.

Question 37. Identify a Mendelian disorder from the following.

1. Down’s syndrome
2. Turner’s syndrome
3. Phenylketonuria
4. Klinefelter’s syndrome

Answer:  3. Phenylketonuria

The pattern of inheritance of Mendelian disorders can be traced in a family by the pedigree analysis. Some common Mendelian or gene related human disorders are phenylketonuria, alkaptonuria, albinism, sickle cell anaemia and cystic fibrosis, etc.

Question 38. Which of these is not a Mendelian disorder?

1. Down’s syndrome
2. Sickle-cell anaemia
3. Colour blindness
4. Haemophilia

Answer: 1. Down’s syndrome

• Mendelian disorders are determined by mutations in single genes. They are transmitted to the offspring as per Mendelian principles.
• The pattern of inheritance of such Mendelian disorders can be traced in a family by the pedigree analysis. Down’s syndrome is chromosomal not Mendelian disorder.

Question 39. Identify a non-hereditary disease from the following.

1. Thalassemia
2. Haemophilia
3. Cystic fibrosis
4. Cretinism

Answer:  4. Cretinism

Cretinism is a congenital deficiency of thyroid hormone. It is a non-hereditary disease.

Question 40. A man and a woman, who do not show any apparent signs of a certain inherited disease, have seven children (2 daughters and 5 sons). Three of the sons suffer from the given disease but none of the daughters affected. Which of the following mode of inheritance do you suggest for this disease?

1. Sex-linked dominant
2. Sex-linked recessive
3. Sex-limited recessive
4. Autosomal dominant

Answer:  2. Sex-linked recessive

Traits governed by sex-linked recessive genes produce disorders in males more often than in females or express themselves in males even when represented by a single allele because Y-chromosome does not carry any corresponding alleles.

NEET Biology Mcq

Question 41. Huntington’s chorea is

1. Recessive mutation associated with chromosome 14
2. Dominant mutation associated with chromosome 4
3. Recessive mutation associated with chromosome X
4. Sex-linked disease

Answer:  2. Dominant mutation associated with chromosome 4

Huntington’s chorea is a progressive brain disorder caused by a single defective gene on chromosome-4. This defect is dominant as anyone who inherit it from a parent will develop the disease.

Its symptoms include difficulty in concentrating, memory lapses, depression, mood swings, etc.

Question 42. The traits which are expressed in only a particular sex though their genes occurs in the opposite sex too are known as

1. Sex-linked trait
2. Sex influenced trait
3. Sex-limited traits
4. None of the above

Answer:  3. Sex-limited traits

• Sex-limited traits are genes that are present in both sexes of sexually reproducing species but are expressed in only one sex and remain ‘turned off’ in the other.
• In other words, sex limited genes cause the two sexes to show different traits or phenotypes, despite having the same genotype.

Question 43. The recessive genes located on X chromosome in humans are always

1. Lethal
2. Expressed in males
3. Sublethal
4. Expressed in females

Answer:  2. Expressed in males

X-linked recessive genes are expressed in females only if there are two copies of the gene (one on each X-chromosome). However, for males, there needs to be only one copy of an X-linked recessive gene in order for the trait or disorder to be expressed. Thus, these are always expressed in males.

Question 44. A diseased man marries a normal woman. They give birth to three daughters and five sons. All the daughters were diseased and sons were normal. The gene of this disease is’

1. Sex-linked dominant
2. Sex-linked recessive
3. Sex-limited character
4. Autosomal dominant

Answer:  1. Sex-linked dominant

Since only daughters are affected, the disease is X-linked. Daughters get one copy of affected X chromosome from father and other normal copy from mother. The trait is expressed in daughter in heterozygous condition, therefore it is a dominant trait. Thus, the gene of this disease is sex-linked dominant.

NEET Biology Mcq

Question 45. Abnormal gene is replaced by normal gene by

1. Gene therapy
2. Mutation
3. Cloning
4. None of these

Answer:  1. Gene therapy

• If a child or an embryo (foetus) is diagnosed to carry a defective gene leading to disability, this defect can be corrected by replacement of defective gene with a normal gene.
• It is done by correcting the defective gene through gene targeting or by gene augmentation either through increasing the number of copies of the gene or through a higher level of expression of the introduced gene. Such a correction of genetic defect is described as gene therapy.

Question 46. Which one of the following techniques is employed in human genetic counselling?

1. Serological technique
2. Polyploidy
3. Pedigree analysis
4. Genetic engineering
5. Amniocentesis

Answer:  3. Pedigree analysis

Pedigree analysis is the techniques which is employed in human genetic counselling because it shows the phenotypes and family relationships of the individuals through charts of family histories.

Question 47. Which of the following is an inherited disorder?

1. Leprosy
2. Goitre
3. AIDS
4. Albinism
5. Parkinson’s disease

Answer:  4. Albinism

Out of the given options, only albinism is an inherited disorder. Albinism is the recessive trait which occurs only when a homozygous condition is present.

Question 48. Carrier of genes of colour blindness are present in

1. Father
2. Mother
3. Father and mother
4. None of the above

Answer:  2. Mother

Colourblindness is a X-linked recessive trait. A man possesses only one gene for colour vision, whereas woman possesses two. Therefore,
only mother will be a carrier when she has gene for colour blindness in one X-chromosome.

NEET Biology Mcq Chapter Wise

Question 49. A marriage between normal visioned man and colourblind woman will produce

1. Colourblind sons and 50% carrier daughters
2. 50% colourblind sons and 50% carrier daughters
3. Normal sons and carrier daughters
4. Colourblind sons and carrier daughters

Answer:  4. Colourblind sons and carrier daughters

• Colour blindness is the inability of certain human beings to distinguish red from green colour. It is produced by a recessive gene which lies on X chromosome.
• A marriage between a normal visioned man (XY) and colourblind woman (Xc cX ) results in
  colourblind sons (XcY) and carrier daughters (XXc).

Question 50. Which is true for colour blindness?

1. It is a sex-linked disorder
2. A person is not able to recognise red and green
3. The person lacks red and green pigments differentiating cells in eyes
4. All of the above

Answer:  4. All of the above

All the given statements are true for colour blindness. Thus, option (d) is correct.

Question 51. A person whose father is colourblind marries a lady whose mother is a daughter of a colourblind man. Their children will be

1. All sons colourblind
2. Some sons normal and some colourblind
3. All colourblind
4. All daughters normal

Answer:  4. All daughters normal

To solve the given quesiton, genotype of different individuals is needed to be predicted in steps. To find out the genotype of person, whose father is colurblind.

X^CY × XX
↓
Offspinings X^CX, X^CX, XY, XY

As all sons will be normal, therefore the genotype of the person will be XY. ….

To find out the genotype of lady whose mother is a daughter of colourblind man

X^CY × XX
↓
X^CX, X^CX, XY, XY

So, the mother of lady would be carrier, having genotype X^CX … Performing cross between to find out lady’s genotype.

XX × X^CY
↓
X^CX, XX, X^CY, XY

As 50% daughters are carrier and 50% daughters are normal. So, the lady can be normal or carrier having genotype XX, X^CX, respectively. …

Now considering both the genotypes of the lady and the genotype of the person, the result would be as follows

XY × X^CX
↓
X^CX, XY, XY, X^CY, XY × XX
↓
XX,XX, XY , XY

Above cases show that if, mother (lady) is carrier then option (1) and (3) are not true. Option (2) is true and option (4) stating all daughters normal (though phenotypically) is also true. If mother is normal then options (1), (2) and (3) are not true and option (4) is true. So, from both the cases, it is concluded that option (4) is true.

NEET Biology Mcq Chapter Wise

Question 52. More men suffer from colour blindness than women because

1. Women are more resistant
2. Male sex hormone, testosterone causes the disease
3. The colourblind gene is carried by Y-chromosome
4. Men are hemizygous and one defective gene is enough to cause colour blindness

Answer:  4. Men are hemizygous and one defective gene is enough to cause colour blindness

• More men suffer from colour blindness than women because men are hemizygous and one defective gene is enough to cause colour blindness.
• Also colourblindness is a sex-linked recessive disease. The recessive genes located on X-chromosome of humans are always expressed in males.

Question 53. If a colourblind woman marries a normal visioned man, their sons will

1. All be colourblind
2. All be normal visioned
3. Be one-half colourblind and one-half normal
4. Be three-fourths colourblind and one-fourth normal

Answer: 1. All be colourblind

A marriage between normal visioned man (XY) and colourblind woman (X^CX^C), results in colour blind sons (XcY) and carrier daughters (XXc). Thus, all sons will be colourblind.

Question 54. A woman with normal vision, but whose father was colourblind, marries a colourblind man. Suppose that the fourth child of this couple was a boy. This boy

1. May be colourblind or may be of normal vision
2. Must be colourblind
3. Must have normal colour vision
4. Will be partially colourblind since he is heterozygous for the colourblind mutant allele

Answer:  1. May be colourblind or may be of normal vision

Colour blindness is a recessive sex-linked trait. Since the woman’s father was colourblind. She should be carrier of the colourblind gene (X cX). When she marries to colourblind man their progeny could be as given below

Thus, the boy progeny of this couple may be colourblind or normal visioned.

Question 55. A normal woman, whose father was colourblind is married a normal man. The sons would be

1. 75% colourblind
2. 50% colourblind
3. All normal
4. All colourblind

Answer:  2. 50% colourblind

Woman whose father is colourblind would have genotype XcX. So, woman is carrier. She marries a normal man, then progeny are

Thus, 50% colourblind sons would born.

Question 56. If all the sons of a couple are colourblind then

1. Mother is homozygous colourblind
2. Mother is homozygous and father is normal
3. Mother is homozygous and father is colourblind
4. Mother is normal and father is colourblind

Answer:  1. Mother is homozygous colourblind

Whenever mother is homozygous colourblind, all her sons will be colourblind irrespective of their father’s genotype.

So, option (1) is correct.

NEET Biology Mcq Chapter Wise

Question 57. A child’s father is colourblind and mother has also a gene for the same. The probability of the girls to be colourblind is

1. 100%
2. 50%
3. 25%
4. 75%

Answer:  2. 50%

If the mother carries the gene but is not colourblind (X X^C ) and father is colourblind (X Y^C ) then, there is a 50% chance that their sons and daughter will be colourblind.

Question 58. Both husband and wife have normal vision though their fathers were colourblind. The probability of their daughter becoming colourblind is

1. 0%
2. 25%
3. 50%
4. 75%

Answer:  1. 0%

The probability of the daughter becoming colourblind arises only when the father is also colourblind. Husband-XY, Wife – XX^C (wife is carrier because her father is colourblind and husband is normal).

So, probability of their daughter becoming colourblind is 0%.

Question 59. I. Haemophilia

1. Cystic fibrosis
2. Sickle-cell anaemia
3. Colour blindness
4. Cancer
5. Plague
6. Phenylketonuria
7. Down’s syndrome

Choose the correct options for Mendelian disorders.

1. 1, 2, 3, 4, 6, 8
2. 1, 2, 3, 4, 7
3. 1, 2, 3, 4, 5, 6
4. 1, 2, 3, 4, 5, 8

Answer:  2. 1, 2, 3, 4, 7

• Option (2) is correct. Genetic disorder mainly caused due to alternation and mutation in a single gene.
• These genes are transmitted to offspring by the principle of inheritance. Mendelian disorders can be dominant or recessive, e.g. haemophilia, colour blindness, sickle-cell anaemia, cystic fibrosis, phenylketonuria, thalassaemia. Rest other diseases do not represent Mendelian disorder.

Question 60. A colourblind man, whose parents had normal vision and whose paternal and maternal grandparents had normal vision, probably inherited the gene for colour blindness from his

1. Maternal or paternal grandmother
2. Maternal or paternal father
3. Father
4. Mother

Answer:  4. Mother

A male always carries X- chromosome from his mother. Thus, if a male is colourblind, this gene is inherited from his mother only.

NEET Biology Mcq Chapter Wise

Question 61. The cure for night blindness is administration of vitamin …p… medicines but colour blindness is not curable because it is a …q… disease. Identify p and q.

1. p-A, q-genetic
2. p-B, q-autosomal
3. p-C, q-non-genetic
4. p-D, q-genetic

Answer:  1. p-A, q-genetic

Question 62. A colourblind man marries the daughter of another colourblind man whose wife has a normal genotype for colour vision. In their progeny

1. All the children would be colourblind
2. All their sons are colourblind
3. None of the daughters would be colourblind
4. Half of their sons and half of their daughters would be colourblind

Answer:  4. Half of their sons and half of their daughters would be colourblind

Colour blindness is a X-linked recessive disorder. It shows criss-cross inheritance. A colourblind man has a genotype XcY. He married daughter of a colourblind man (X^CY) and a normal woman (XX), thus his wife should have X^CX genotype. The genotypes of their children can be worked out as follows

Thus, 50% of their sons and 50% of their daughters would be colourblind.

Question 63. If daughter of colourblind marries another colourblind then possibility of their first daughter to be colourblind is

1. 50%
2. 25%
3. 7%
4. None of these

Answer:  1. 50%

• Daughter of a colourblind person will be a carrier of the disease and only one of the two X-chromosomes will bear the recessive gene for the disease (X Xc ).
• If she marries another colourblind man (X Y)c then the possibility of first daughter to be colourblind is 50%.

Question 64. A colourblind man marries a woman with normal sight who has no history of colour blindness in her family. What is the probability of their grandson being colourblind?

1. Nil
2. 0.25
3. 0.5
4. 1

Answer: 3. 0.5

When a colourblind man (X^CY) marries a normal woman (XX), all of their daughters are carriers and all of their sons are normal, as shown in following cross.

When the carrier daughter (XX^C) is married to a normal man, the probability of their son being colourblind is 0.25, as shown in following cross.

From above crosses, it is clear that the probability of occurrence of colour blindness in the grandson of a colourblind man and a normal woman is 0.5.

Question 65. Proportion of colourblind children when normal man marries to carrier woman is

1. 25%
2. 50%
3. 75%
4. 100%

Answer: 1. 25%

When a normal man (XY) marries a carrier woman (X^CX) for colour blindness, then 25% of progeny would be colourblind.

Question 66. A normal-visioned man whose father was colourblind, marries a woman whose father was also colourblind. They have their first child as a daughter. What are the chances that this child would be colourblind?

1. 100%
2. 0 %
3. 25%
4. 50 %

Answer:  2. 0 %

If a normal-visioned man marries a woman whose father was also colourblind, then his wife would be carrier of this disease (if her mother was normal).

This trait is passed to children but daughters produced by this couple are carrier not the colourblind.

Thus, 0% daughters are colourblind.

Question 67. Red-green colour blindness in humans is governed by a sex-linked recessive gene. A normal woman whose father was colourblind marries a colourblind man. What proportion of their daughters is expected to be colourblind?

1. 3/4
2. 1/2
3. 1/4
4. All

Answer:  2. 1/2

Normal woman whose father was colourblind would be a carrier (X^CX). She married a colourblind man (X^CY) and thus, half (1/2) of their daughters are expected to be colourblind.

Question 68. In colour blindness, a person fails to differentiate between

1. Red and blue
2. Red and green
3. Red and black
4. Red and white

Answer:  2. Red and green

Red and green colour blindness results in defect in either red or/and green cone cells of eye, resulting in failure to discriminate between red and green colour.

Question 69. Of both normal parents, the chance of a male child becoming colourblind are

1. Nil
2. Possible only when all the four grandparents had normal vision
3. Possible only when father’s mother was colourblind
4. Possible only when mother’s father was colourblind

Answer:  4. Possible only when mother’s father was colourblind

On crossing carrier colourblind woman with a normal man, the sons become colourblind. This is an example of criss-cross inheritance. The genes for colour blindness is inherited from mother’s father.

Question 70. A colourblind son will be born when

1. Mother is carrier and father is normal
2. Mother is colourblind and father is normal
3. Mother is carrier and father is colourblind
4. All the cases are correct

Answer:  4. All the cases are correct

A colourblind son will be born to a carrier mother and a colourblind mother irrespective of father being colourblind or not. A carrier mother is a normal female who carries recessive allele for colour blindness in heterozygous state. Thus, option (d) is correct.

Question 71. Anish is having colourblindness and married to Sheela, who is not colourblind. What is the chance that their son will have the disease?

1. 100%
2. 50%
3. 25%
4. 0%

Answer: 2 & 4 50% & 0%

If Sheela (mother) is a carrier then chances of having colourblind son are 50%. If Sheela is normal then chances of their son being colourblind are 0%. It can be represented as follows

Thus, there are 50% chances of their son being colourblind.

Thus, there are 0% chances of their son being colourblind. Thus, both options (b) and (d) are correct.

Question 72. Colour blindness, in which all the colours are perceived as grey, is termed as

1. Monochromasia
2. Chromasia
3. Dichromasia
4. All of these

Answer:  1. Monochromasia

• Colour blindness is the inability of certain human beings to distinguish between colours. It is produced by an X-linked recessive gene by causing lack of one of the primary cone pigments of the retina.
• Colour blindness, in which all colours are perceived as grey, is termed monochromasia. The person suffering from this disease is completely colourblind.

Question 73. If both parents of a male child are normal, what are the chances of the child being colourblind?

1. It is impossible
2. It is possible only if father’s mother was colourblind
3. It is possible only if mother’s father was colourblind
4. It is possible even when all the four grandparents had normal vision

Answer:  3. It is possible only if mother’s father was colourblind

• In this problem, an X-linked recessive allele is passed from an affected male, to a daughter who is a heterozygous carrier and subsequently to an affected grandson.
• Thus in given case, maternal father is likely to be colourblind. Such criss-cross trait is called as diagynic trait.

Question 74. If a colourblind man marries a woman who is homozygous for normal colour vision, the probability of their son being colourblind is

1. 0
2. 0.5
3. 0.75
4. 1

Answer: 1. 0

If a colourblind man marries a woman who is homozygous for normal colour vision, the probalility of their son being colourblind is zero.

Question 75. X h is the chromosome with gene for haemophilia and X is the chromosome with normal gene. Which of the following individuals will act as carrier for haemophilia?

1. Xh Y
2. XY
3. Xh Xh
4. Xh X

Answer:  4. Xh X

Males are never the carrier of sex-linked recessive traits, e.g. haemophilia Heterozygous female for this condition (e.g. X X)h acts as carrier. XY is normal male. X Xh h and X h Y are haemophilic.

Question 76. Haemophilic man marries a normal woman. Their offsprings will be

1. All haemophilic
2. All boys haemophilic
3. All girls haemophilic
4. All normal

Answer:  4. All normal

• Haemophilia is a defect of blood which prevents its clotting. It is caused by a recessive gene located in the X-chromosome.
• When a haemophilic man (X h Y) marries a normal woman (XX), they would produce carrier girls (XX h ) and normal boys (XY), i.e. all their offspring will be normal.

Thus, option (4) is correct.

Question 77. The most common type of haemophilia results from the congenital absence of

1. Factor 2
2. Factor 5
3. Factor 8
4. Factor 11

Answer: 3. Factor 8

• Haemophilia is a group of inherited blood disorders in which the blood does not clot properly.
• It is caused by a fault in one of the genes that determine how the body makes blood clotting factor 8 or 9. These genes are located on the X-chromosome 10.

Question 78. A man known to be a victim of haemophilia marries a normal woman whose father was known to be a bleeder. Then it is expected that

1. All their children will be bleeders
2. Half of their children will be bleeders
3. One fourth of their children will be bleeders
4. None of their children will be bleeder

Answer:  2. Half of their children will be bleeders

Man is haemophilic with genotype XhY. The normal woman whose father was bleeder or diseased, would be a carrier of disease (XhX).

Thus, half of their children (50% girls and 50% boys) would be bleeders.

Question 79. Haemophilic female marries a normal male, the theoretical ratio of their offsprings regarding haemophilia will be

1. All offspring are haemophilic
2. All girls are haemophilic
3. All sons are haemophilic
4. Half daughters and half sons are haemophilic

Answer: 3. all sons are haemophilic

When a haemophilic female (XhXh) marries a normal male (XY), all sons would be haemophilic .

Question 80. If a boy’s father has haemophilia and his mother has one gene for haemophilia, what is the chance that the boy will inherit the disease?

1. 25%
2. 50%
3. 75%
4. 100%

Answer:  2. 50%

The boy’s father is haemophilic and mother is carrier.

Thus, there are 50% chances that boy will inherit the disease.

Question 81. A woman carrier with two genes for haemophilia on one X-chromosome and for colour blindness on other X-chromosome marries a normal man. How will the progeny be?

1. 50% haemophilic colourblind sons and 50% normal sons
2. 50% haemophilic daughters (carrier) and 50% colourblind daughters (carrier)
3. All sons haemophilic and colourblind
4. Haemophilic and colourblind daughters

Answer: 3. All sons haemophilic and colourblind

• Haemophilia is a defect of blood which prevents its clotting. Colour blindness is the inability of certain human beings to distinguish red from green colour.
• Both these diseases are produced by a recessive gene which lies on the X-chromosomes. A woman having one gene for haemophilia on one X-chromosome and other gene for colour blindness on another X-chromosome will have genotype X Xh c.

Thus, sons would either be colourblind or haemophilic and daughters will be the carriers.

Question 82. Of a normal couple, half the sons are haemophilic, while half the daughters are carriers. The gene is located on

1. X-chromosome of father
2. Y-chromosome of father
3. One X-chromosome of mother
4. Both the X-chromosomes of mother

Answer: 3. One X-chromosome of mother

Of a normal couple, half the sons are haemophilic, while half the daughters are carriers. The gene is located on one X-chromosome of mother. Cross between a haemophilic carrier female X h X and normal male would yield 50% of the sons being haemophilic and 50% of the carrier daughters.

Question 83. Assertion (A) Haemophilia is a genetically linked disease. Reason (R) It is predominantly found in females.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. Both A and R are false

Answer:  3. A is true, but R is false

• A is true, but R is false. Reason can be corrected as Haemophilia predominantly occurs in males, since the gene can be passed from mother to son.
• A single copy of defected gene can cause disease in males. In contrast, woman is affected in the presence of two defected alleles which is a rare phenomena.

Question 84. Which is genetically not possible?

1. Haemophilic father transfers the haemophilic gene to his son
2. Haemophilic father transfers the haemophilic gene to his daughter
3. Carrier mother transfers the haemophilic gene to her son
4. Carrier mother transfers the haemophilic gene to her daughter

Answer: 1. Haemophilic father transfers the haemophilic gene to his son

• Statement in option (1) is not possible and can be corrected as Haemophilia is a sex-linked disease. It follows criss-cross inheritance in which father does not pass the sex-linked allele of a trait to his son.
• The same is passed to the daughter, from where it reaches the grandson, i.e. diagynic. It is because the males have only one X-chromosome which is transferred to the female offspring.

Question 85. Which of the following diseases is also called Christmas disease?

1. Sickle-cell anaemia
2. Haemoglobinuria
3. Myocardial infarction
4. Haemophilia-B

Answer:  4. Haemophilia-B

Haemophilia-B occurs due to deficiency of factor IX (Christmas factor). The patient may experience prolonged bleeding following any injury or wound and in severe cases there is spontaneous bleeding into muscles and joints.

Question 86. Which of the following most appropriately describes haemophilia?

1. Recessive gene disorder
2. X-linked recessive gene disorder
3. Chromosomal disorder
4. Dominant gene disorder

Answer:  2. X-linked recessive gene disorder

• Genes related with haemophilia are always present on X-chromosome and it is a recessive gene disorder as it expresses itself in females when it comes a homozygous condition.
• It causes a defect in the clotting factor formation, thus a simple cut can bleed continuously leading to even death. Thus, it is also known as ‘Bleeders’ disease or ‘Royal Disease’ as Queen Victoria is a carrier for this disease.

Question 87. One child is haemophilic (sex-linked trait), while its fraternal twin brother is normal. Which one of the following information is most appropriate?

1. The mother must have been heterozygous
2. The child is a monozygotic twin
3. The other child is a female and the father is haemophilic
4. The haemophilic child is a male

Answer:  1. The mother must have been heterozygous

The mother must have been a heterozygous haemophilic carrier (X h X). One of the twins would have inherited the normal X-chromosome and the other would have received the X-chromosome carrying the gene for haemophilia.

Question 88. Choose the incorrect statement with regard to haemophilia.

1. It is a recessive disease
2. It is a dominant disease
3. A single protein involved in the clotting of blood is affected
4. It is a sex-linked disease

Answer: 2. It is a dominant disease

Statement in option (2) is not correct. Haemophilia is sex-linked recessive disease. Rest statements are correct with regard to haemophilia.

Question 89. G-6-P dehydrogenase deficiency is associated with haemolysis of

1. Leucocytes
2. Lymphocytes
3. Platelets
4. RBCs

Answer:  4. RBCs

• Glucose-6-P dehydrogenase is the first enzyme of glucose oxidation during pentose phosphate pathway.
• RBC contains haemoglobin which combines with oxygen to form oxyhaemoglobin which gives its oxygen for oxidation of food. In haemolysis, there is destruction of RBCs with release of haemoglobin into plasma resulting in jaundice.
• Thus, RBCs cannot provide oxygen for oxidation of food thereby, causing deficiency of G-6-P dehydrogenase.

Question 90. A female becomes haemophilic definitely if

1. Mother is carrier
2. Father is carrier
3. Father is affected
4. Both mother and father affected

Answer:  4. Both mother and father affected

Males and female are definitely haemophilic, if their father and mother, both are haemophilic.

Question 91. A male human is heterozygous for autosomal genes A and B and is also hemizygous for haemophilic gene h. What proportion of his sperms will be abh?

1. 1/8
2. 1/32
3. 1/16
4. 1/4

Answer:  1. 1/8

Chance of getting ‘a’ = 1/2

Chance of getting ‘b’ = 1/2

Chance of getting ‘h’ = 1/2

Chance of getting sperms with abh

1/2 × 1/2 × 1/2 = 1/8

Question 92. Marriages between close relatives should be avoided because it induces more

1. Blood group abnormalities
2. Mutations
3. Recessive alleles to come together
4. Multiple births

Answer: 3. Recessive alleles to come together

The risk of a child inheriting two copies of a dangerous recessive allele is elevated in marriages between close relatives as compared to non-related marriages since they have a greater chance of inheriting the same recessive allele from their common ancestors.

Question 93. Haemophilia is a genetic disorder, in which

1. Blood fails to coagulate after an injury
2. There is delayed coagulation of blood
3. Blood clots in blood vessels
4. Blood cell count falls

Answer: 1. Blood fails to coagulate after an injury

Haemophilia is a defect of blood which prevents its clotting or coagulation after an injury. It is produced by a recessive gene which lies on the X-chromosomes.

Question 94. In which disease, the RBC of a person becomes half moon-shaped?

1. Haemophilia
2. Sickle-cell anaemia
3. Thalassemia
4. Leukemia

Answer:  2. Sickle-cell anaemia

Sickle-cell anaemia is a biochemical disorder in which shape of RBCs become sickle-shaped or half moon-shaped due to the defective haemoglobin. Haemoglobin becomes useless for oxygen transport.

Question 95. Haemophilia is related to which of the following?

1. Colour blindness
2. Polio
3. Cataract
4. Tumour

Answer: 1. Colour blindness

Haemophilia and colour blindness are sex-linked (X-linked recessive) disease. Option (a) is correct.

Question 96. Which one is ineffective against antibiotics?

1. Bacterial infected wound
2. Bacterial infected throat
3. Haemophilia
4. Bacterial infected gonorrhoea

Answer: 3. Haemophilia

Haemophilia is a genetic disease. Therefore, it is not affected by any antibiotics. These are used to treat bacterial diseases.

NEET Biology Genetic Disorders MCQs with explanations

Question 97. The α and β-globin chain is coded by genes located on chromosome number

1. 16 and 11
2. 10 and 12
3. 9 and 8
4. 15 and 16

Answer: 1. 16 and 11

The genes that encode the alpha (α) globin chains are on chromosome 16. Those that encode the non-alpha or β-globin chains are on chromosome 11.

Question 98. Persons suffering from sickle-cell anaemia normally do not suffer from

1. Cholera
2. Malaria
3. High blood pressure
4. Hepatitis

Answer:  2. Makaria

• Sickle-cell anaemia is caused by the formation of an abnormal haemoglobin called haemoglobin-S which differs from normal haemoglobin-A in only one amino acid, i.e. 6th amino acid ofβ-chain.
• Despite having harmful effect, the allele for sickle-cell anaemia continues to persist in human population because it has survival value in malaria infested areas like tropical Africa.
• Malarial parasite is unable to survive in abnormal shaped erythrocyte. Thus, persons suffering from sickle-cell anaemia normally do not suffer from malaria.

Question 99. Sickle-cell anaemia, a hereditary disease was first described by

1. James B Herrick
2. William Harvey
3. Carl Landsteiner
4. J Priestley

Answer: 1. James B Herrick

James Bryan Herrick (1861-1954), an American physician was credited with the description of sickle-cell anaemia (an autosomal hereditary disorder). He was one of the first physicians to describe the symptoms of myocardial infarction.

Question 100. The gene of sickle-cell anaemia is inherited by

1. Blood cells
2. Bone cells
3. Sex chromosomes
4. Autosomes

Answer:  4. Autosomes

Sickle-cell anaemia is inherited in an autosomal recessive pattern, which means that both copies of the gene in each cell have mutations.

Question 101. Assertion (A) Sickel-cell anaemia is a genetically determined disorder affecting many newborn babies. Reason (R) It is caused by heterozygosity for allele HbS producing a single amino acid substitution in the α-chain of the normal haemoglobin molecule determined by allele Hb A.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R false
4. Both A and R are false

Answer: 3. A is true, but R false

A is true, but R is false. Reason can be corrected as Sickle-cell anaemia is caused when Hb S allele is present in homozygous condition. It is the resultant of single amino acid substitution in β-chain of haemoglobin.

Question 102. Sickle-cell anaemia results due to mutation caused by

1. Substitution
2. Insertion
3. Deletion
4. Duplication

Answer: 1. Substitution

• Sickle-cell anaemia is caused due to inheritance of a defective allele coding for β-globin. It results in the transformation of Hb A into Hb S in which glutamic acid is replaced by valine at sixth position in each of two β -chains of haemoglobin.
• The substitution of amino acid in the globin protein results due to the single base substitution at the sixth codon of the beta globin gene from GAG (Glu) to GUG (Val). Sickle-cell anaemia is a disease where the red blood cells become sickle-shaped instead of biconcave disc-shape.

Question 103. Genetic or chromosomal symbol used for the person who is having sickle-cell anaemia is

1. Hb HbS S
2. Hb Hba a
3. Hb Hbg g
4. Hb Hbb b

Answer: 1. Hb HbS S

Genetic or chromosomal symbol used for person who is having sickle-cell anaemia is Hb S Hb S.

Question 104. Both sickle-cell anaemia and Huntington’s chorea are

1. Congenital disorders
2. Pollutant-induced disorders
3. Virus-related diseases
4. Bacteria-related diseases

Answer: 1. Congenital disorders

• Sickle-cell anaemia is a biochemical disorder in which shape of RBCs become sickle-shaped due to the defective haemoglobin.
• Huntington Chorea in a disease in which atrophy of brain occurs resulting to respiratory irregulations, articulation of speech and irregular limb movements take place. They both are genetic disease present in any person since birth hence, called congenital diseases.

Question 105. Sickle-cell anaemia is a case of

1. Single mutation in a gene on chromosome 10
2. Pleiotropism
3. Both 1 and 2
4. None of the above

Answer:  2. Pleiotropism

Sickle-cell anaemia is a classic example of the mixed benefit given by the staying power of pleiotropic genes, as the mutation to Hb-S provides the fitness benefit of malaria resistance to heterozygotes, while homozygotes have significantly lowered life expectancy.

Question 106. In sickle-cell anaemia, the sequence of amino acids from the first to the seventh position of the β -chain of haemoglobin-S(HbS ) is

1. His, Leu, Thr, Pro, Glu, Val, Val
2. Val, His, Leu, Thr, Pro, Glu, Glu
3. Thr, His, Pro, Val, Pro, Val, Glu
4. Glu, His, Leu, Pro, Val, Glu, Glu
5. Val, His, Leu, Thr, Pro, Val, Glu

Answer:  5. Val, His, Leu, Thr, Pro, Val, Glu

The amino acid sequence in person with sickle-cell anaemia is Val, His, Leu, Thr, Pro, Val, Glu.

Question 107. Sickle-cell anaemia is caused due to the substitution of

1. Valine at the 6th position of beta globin chain by glutamine
2. Valine at the 6th position of alpha globin chain by glutamic acid
3. Glycine at the 6th position of alpha globin chain by glutamic acid
4. Glutamic acid at the 6th position of beta globin chain by valine
5. None of the above

Answer:  4. Glutamic acid at the 6th position of beta globin chain by valine

Sickle-cell anaemia is the example of point mutation in which the glutamic acid (Glu) is replaced by valine (Val) at the sixth position of β-globin chain of haemoglobin molecule.

Question 108. A marriage between two carriers of sickle-cell anaemic gene will result into

1. 1 normal and 2 carriers
2. 1 sickle-cell anaemic
3. 2 normal and 2 sickle-cell anaemic
4. Both 1 and 2

Answer:  4. Both 1 and 2

Sickle-cell anaemia occurs when a person inherits two sickle-cell genes, one from each parent. If both partner carry sickle-cell gene, there will be 1 normal, 2 carriers and 1 sickle-cell anaemic progeny.

Question 109. Marriage between two sickle-cell carriers results into normal and sickle-cell carrier progenies in the ratio of

1. 2: 1
2. 3: 1
3. I: 2 : 1
4. 1: 2

Answer:  4. 1: 2

Question 110. A couple, both carriers for the gene sickle-cell anaemia planning to get married, wants to know the chances of having anaemic progeny?

1. 100%
2. 75%
3. 50%
4. 25%

Answer:  2. 25%

A marriage between two carriers of sickle-cell anaemia will produce normal, carrier and anaemic with progeny in 1: 2: 1 ratio. Out of this 25% are diseased or anaemic, 50% are carrier and 25% are normal.

Question 111. Choose a false statement with reference to sickle-cell anaemia.

1. Have genotype Hb / HbS S
2. Have genotype Hb / HbA A
3. Substitution of glutamic acid to valine
4. Have sickle shape RBC

Answer: 2. Have genotype Hb / HbA A

Statement in option (2) is false and can be corrected as Genotype- Hb A /Hb A represents a normal individual. Whereas sickel-cell anaemia is represented by genotype Hb S/Hb S Rest options are correct.

Question 112. Sickle-cell anaemia has not been eliminated from the African population because

1. It is not a fatal disease
2. It provides immunity against malaria
3. It is controlled by dominant genes
4. It is controlled by recessive genes

Answer: 2. It provides immunity against malaria

Question 113. Sickle-cell anaemia occurs as a result of …A… mutation in …B… of haemoglobin. Fill the correct option for A and B.

1. A–point, B– β-chain
2. A–chromosomal, B– β-chain
3. A–allele, B– β-chain
4. A–non-allele, B– α-chain

Answer:  1. A–Point, B–β-chain.

Question 114. In sickle-cell anaemia, GAG is replaced by

1. GGA
2. GUG
3. UUG
4. GGG

Answer:  2. GUG

GAG that code for glutamic acid in haemoglobin mRNA is replaced by GUG code which code for valine in haemophilic haemoglobin mRNA. So, in sickle-cell anaemia GAG is replaced by GUG.

Question 115. The genotype of a carrier carrying a gene for sickle-cell anaemia is

1. HbS
2. HbA/HbS
3. HbA
4. HbO

Answer: 2. HbA/HbS

Sickle haemoglobin is often shortened to S or Hb S. If a person have only one copy of the sickle haemoglobin along with one copy of the more usual haemoglobin (A or Hb A ) he is said to have sickle-cell trait. This is not an illness but means that he ‘carry’ the gene and can pass it on to children.

Question 116. Which type of thalassemia is more dangerous?

1. Thalassemia minor
2. Alpha thalassemia
3. Thalassemia junior
4. None of the above

Answer: 2. Alpha thalassemia

Thalassemia minor is a less serious form of the disorder. There are two main forms of thalassemia that are more serious. In alpha thalassemia, at least one of the alpha globin genes has a mutation or abnormality. In beta thalassemia, the beta globin genes are affected.

Question 117. Which of the following disease is called Cooley’s anaemia?

1. Down’s syndrome
2. Thalassemia
3. Haemophilia
4. Turner’s syndrome

Answer: 2. Thalassemia

Thalassemia major or Cooley’s anaemia is the most severe form of beta thalassemia in which the complete lack of beta protein in the haemoglobin causes a life-threatening anaemia that requires regular blood transfusions and extensive ongoing medical care.

Question 118. Thalassemia and sickle-cell anaemia are caused due to a problem in globin molecule synthesis. Select the correct statement.

1. Both are due to a qualitative defect in globin chain synthesis
2. Both are due to a quantitative defect in globin chain synthesis
3. Thalassemia is due to less synthesis of globin molecules
4. Sickle-cell anaemia is due to a quantitative problem of globin molecules

Answer:  3. Thalassemia is due to less synthesis of globin molecules

• Statement in option (3) is correct. Other statements are incorrect and can be corrected as
• Thalassemia is a quantitative problem whereas sickle-cell anaemia is a qualitative problem. Thalassemia occurs due to either mutation or deletion resulting in reduced rate of synthesis of one of globin chains of haemoglobin.
• In sickle-cell anaemia due to point mutation, glutamic acid (Glu) is replaced by valine (Val) at the sixth position ofβ-globin chain of haemoglobin molecule.

Question 119. The disease caused due to the quantitative abnormality of polypeptide chain of globin chain synthesis is

1. Down’s syndrome
2. Thalassemia
3. Turner’s syndrome
4. Klinefelter’s syndrome

Answer:  2. Thalassemia

In thalassemia, the reduced production of one of the globin chains upsets the balance of alpha to beta chains and causes abnormal haemoglobin to form or causes an increase of minor haemoglobin components, such as HbA2. Thus, it is caused due to quantitative abnormality of globin chains.

Question 120. Thalassemia is

1. An autosomal recessive disease
2. An autosomal dominant disease
3. A sex-linked dominant disease
4. A sex-linked recessive disease

Answer:  1. An autosomal recessive disease

Thalassemiais is an autosome-linked recessive disease. It occurs due to either mutation or
deletion resulting in reduced rate of synthesis of one of globin chains of haemoglobin.

Question 121. Which of the following statement about Huntington’s disease is true?

1. Genetic test to detect the presence of the allele responsible for Huntington’s disease do not exist at this time
2. The onset of Huntington’s disease is typically between birth and three years of age
3. There is currently no effective treatment of this disease
4. It is caused by the expression of recessive allele

Answer:  3. There is currently no effective treatment of this disease

• Statement in option (3) is true. Other statements are false and can be corrected as Genetic test to detect Huntington’s disease counts the number of CAG repeats in HD gene, using DNA from blood sample.
• The presence of 36 or more repeats confirms the disease. Huntington’s disease develops between 30 and 50 years of age. It is not caused by the expression of recessive allele.

Question 122. Which of the following disease is characterised by excessive trinucleotide repeats (CAG)?

1. Cystic fibrosis
2. PTC testing
3. Dwarfism
4. Huntington’s disease

Answer:  4. Huntington’s disease

Question 123. In α -thalassemia, the ……………… chromosome is affected.

1. 16th
2. 17th
3. 18th
4. 22nd

Answer: 1. 16th

In α-thalassemia, production of α-globin chain is affected. It is controlled by the closely linked genes HBA1 and HBA2 on chromosome 16. It occurs due to the mutation or deletion of one or more of the four genes.

Question 124. If parents are carriers for thalassemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child?

1. 50%
2. 25%
3. 100%
4. No chance

Answer: 2. 25%

• In the given case, both the partners are unaffected carriers for the gene, i.e. have heterozygous genotype Tt. People homozygous for the autosomal recessive gene of thalassemia suffer from severe haemolytic anaemia.
• Heterozygous people are also not normal, but show the defect in a less severe form (Thalassemia minor). Genotype of carrier parents is Aa (male parent) and Aa (female parent).

AA → Normal child (25%)
Aa → Carrier child (50%)
aa → Affected child (25%)

Question 125. Phenylketonuria disease is a

1. Autosomal dominant
2. Autosomal recessive
3. Sex linked recessive
4. Sex linked dominant

Answer:  2. Autosomal recessive

Phenylketonuria is an autosomal recessive disease that is being carried on chromosome 12.

Question 126. With respect to phenylketonuria identify which statement is not correct.

1. It is a case of aneuploidy
2. It is an example of pleiotropy
3. Caused due to autosomal recessive trait
4. It is an error in metabolism

Answer:  1. It is a case of aneuploidy

Statement in option (1) is incorrect and can be corrected as Phenylketonuria occurs due to defective gene of chromosome 12, not due to aneuploidy.

Question 127. In phenylketonuria, the phenylalanine gets converted to

1. Acetic acid
2. Phenyl acetic acid
3. Phenyl pyruvic acid
4. Pyruvic acid

Answer: 3. Phenyl pyruvic acid

Due to the absence of phenylalanine hydroxylase, the phenylalanine changes into phenyl pyruvic acid in phenylketonuria. Lack of this enzyme is due to autosomal recessive defective gene on chromosome number 12.

Question 128. In order to lessen the suffering of phenylketonurics, their diet should have

1. No phenylalanine and no tyrosine
2. Low phenylalanine and normal requirement of tyrosine
3. Normal recommended amount of phenylalanine
4. Normal recommended amount of both phenylalanine and tyrosine

Answer:  2. Low phenylalanine and normal requirement of tyrosine

• Phenylketonuria is an inborn error of metabolism in which an individual lacks an enzyme (phenylalanine hydroxylase PAR) that converts amino acid phenylalanine into tyrosine.
• In order to lessen the suffering of phenylketonurics, their diet should have low phenylalanine and normal requirement of tyrosine.

Mock test on Pedigree Analysis for NEET preparation

Question 129. Assertion (A) Phenylketonuria is an inborn error of metabolism. Reason (R) Phenylalanine is not converted into alanine in individuals suffering from this disease.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R false
4. Both A and R are false

Answer: 3. A is true, but R false

• A is true, but R is false. Phenylketonuria is an inborn, autosomal, recessive metabolic disorder in which the homozygous recessive individual lacks the enzyme phenylalanine hydroxylase needed to change phenylalanine (amino acid) to tyrosine (amino acid) in liver.
• It results in hyperphenylalaninemia, which is characterised by accumulation and excretion of phenylalanine, phenylpyruvic acid and related compounds.

1. Question 130. A person affected with phenylketonuria, lacks an enzyme that converts the amino acid phenylalanine intoValine
2. Proline
3. Histidine
4. Tyrosine
5. Methionine

Answer:  4. Tyrosine

Question 131. The disorders such as alkaptonuria and phenylketonuria are referred to as

1. Acquired disease
2. Congenital disease
3. Infectious disease
4. All of the above

Answer:  2. Congenital disease

Alkaptonuria and phenylketonuria are inborn metabolic disorders (congenital).

Question 132. Albinism and phenylketonuria are disorders due to

1. Recessive autosomal genes
2. Dominant autosomal genes
3. Recessive sex genes
4. Dominant sex genes

Answer: 1. Recessive autosomal genes

Albinism and phenylketonuria are recessive autosomal trait which occurs only when a homozygous condition is present.

Question 133. Condition of sex chromosomes in male child with Patau’s syndrome is

1. XX
2. XY
3. XO
4. XXY

Answer:  2. XY

Patau’s syndrome is a serious rare genetic disorder caused by having an additional copy of chromosome 13 in some or all of the body’s cells. It’s also called trisomy 13.Thus, the genetic makeup of male child would be normal, XY.

Question 134. Progressive degeneration of skeletal muscle, mostly due to genetic disorder occurs in

1. Myasthenia gravis
2. Muscular dystrophy
3. Tetany
4. Osteoporosis
5. Arthritis

Answer: 2. Muscular dystrophy

• Muscular dystrophy is a group of muscle diseases, marked by weakness and wasting of selected muscles, in which there is a recognisable pattern of inheritance.
• The affected muscle fibres degenerate and are replaced by fatty tissue. The muscular dystrophies are classified according to the patient’s age at onset, distribution of the weakness, the progression of the disease and the mode of inheritance. Isolated cases may occur as a result of gene mutation.

Question 135. Muscular dystrophy is

1. Dominant
2. Sex-linked dominant
3. Sex-linked recessive
4. All of the above

Answer: 4. All of the above

Muscular dystrophy is inherited as X-linked, autosomal dominant or autosomal recessive trait.

Question 136. Match the type of syndromes listed under Column 1 with the causes given under Column 2.

Answer: 4. A–4, B–2, C–1, D–3

Question 137. The hereditary disease in which the urine of a person turns black on exposure to air due to the presence of homogentisic acid is known as

1. Ketonuria
2. Phenylketonuria
3. Haematuria
4. Alkaptonuria

Answer:  4. Alkaptonuria

Alkaptonuria is an autosomal recessive disorder and inborn metabolic disorders (congenital). Alkaptonuria in man is caused due to accumulation of homogentisic acid. On exposure to air, urine containing this acid turns black.

Question 138. Edward’s syndrome is an abnormality leading to mental deficiency caused by trisomy of chromosome number

1. 5
2. 9
3. 15
4. 18

Answer:  4. 18

Edward’s syndrome occurs due to trisomy of 18th chromosome.

Question 139. Which of the following disorder is not hereditary?

1. Haemophilia
2. Cataract
3. Sickle-cell anaemia
4. Colour blindness

Answer: 2. Cataract

Cataract is not hereditary. Some inherited genetic disorders that cause other health problems can increase the risk of cataracts.

Question 140. Which of the following is not a X-linked recessive disease?

1. Haemophilia
2. Colour blindness
3. Thalassemia
4. Glucose-6-phosphatedehydrogenase deficiency

Answer: 3. Thalassemia

Thalassemia is an autosomal recessive disease.

Question 141. Usually, the recessive character is expressed only when present in double recessive condition. However, single recessive gene can express itself in human beings when the gene present on

1. Any autosomes
2. The X-chromosome of the female
3. The X-chromosome of the male
4. Either can autosome or X-chromosome

Answer: 3. The X-chromosome of the male

• Females have two X-chromosomes, whereas males have one X and one Y-chromosome. Genes on the X-chromosome can be recessive or dominant. Their expression in females and males is not the same.
• Genes on the Ychromosome do not exactly pair up with the genes on the X chromosome. X-linked recessive genes are expressed in females only if there are two copies of the gene (one on each X-chromosome).
• However, for males, there needs to be only one copy of an X-linked recessive gene in order for the trait or disorder to be expressed.

Question 142. Select the incorrect statement from the following.

1. Galactosemia is an inborn error of metabolism
2. Small population size results in random genetic drift in a population
3. Baldness is a sex -limited trait
4. Linkage is an exception to the principle of independent assortment in heredity

Answer: 3. Baldness is a sex -limited trait

Statement in option (3) is incorrect and can be corrected as Baldness is a sex influenced trait. The dominance of alleles may differ in heterozygotes of the two sexes. Rest other statements are correct.

Question 143. Consider the following statements.

1. Myotonic dystrophy is an autosomal dominant trait.
2. Sickle-cell anaemia is an autosomal recessive trait.
3. Hypertrichosis is a holandric inheritance.
4. Failure of segregation of alleles results in chromosomal gain.
5. Cystic fibrosis is a Mendelian disorder.

Choose the correct option.

1. 1, 2, 3 and 4
2. 1, 3, 4 and 5
3. 1, 2, 4 and 5
4. 1, 2, 3, 4 and 5

Answer:  4. 1, 2, 3, 4 and 5

All the given statements are correct.

Question 144. Phenylketonuria, Huntington’s disease and sickle- cell anaemia are caused due to the disorder associated with

1. Chromosome-7, chromosome-11, chromosome-12
2. Chromosome-11, chromosome-4, chromosome-12
3. Chromosome-7, chromosome-22, chromosome-46
4. Chromosome-12, chromosome -4, chromosome-11

Answer:  4. Chromosome-12, chromosome -4, chromosome-11

Phenylketonuria–Chromosome 12 Huntington Diseases–Chromosome 4 Sickle-cell anaemia – Chromosome 11

Question 145. Mental retardation in man associated with sex chromosomal abnormality is usually due to

1. Increase in X complement
2. Moderate increase in Y complement
3. Large increase in Y complement
4. Reduction in X complement

Answer: 1. Increase in X complement

Mental retardation is usually found when there are one or more extra X-chromosomes in males.

Question 146. The interphase nuclei of a person are showing two sex chromatins/nucleus. The possible genotype of the person is

1. 44 + XXY
2. 44 + XYY
3. 44 + XXX
4. 44 + XXYY

Answer: 3. 44 + XXX

• Soon after the start of cell division during embryonic development, one of the two X-chromosomes of the somatic cells in normal females becomes functionally inactive.
• This inactive X-chromosome condense (heterochromatic) and can be seen as Barr body. Individual with two sex chromatins, show 44+ XXX genotype, in which only one remains active, while the others two are sex chromatins.

Question 147. In man, which of the following genotypes and phenotypes may be the correct result of aneuploidy in sex chromosomes?

1. 22 pairs + XXY males
2. 22 pairs + XX females
3. 22 pairs + XXXY females
4. 22 pairs + Y females

Answer: 1. 22 pairs + XXY males

Aneuploidy is the condition of cells having more or less than integral multiple of typical haploid chromosome number. Thus, 22 pairs + XXY is an extra sex chromosome due to non-disjunction of a pair of sex chromosome either in an ovum or sperm.

Question 148. The diagrammatic representation of the chromosomes of an individual is called

1. Idiogram
2. Karyotype
3. Phenotype
4. Diploidy

Answer: 1. Idiogram

The diagrammatic representation of the chromosomes of an individual is called idiogram whereas karyotype is the morphological representation of somatic chromosomes of an individual in descending order.

NEET practice test on Pedigree Analysis and Genetic Disorders

Question 149. The basic set of chromosomes in an organism is known as

1. Karyotype
2. Idiogram
3. GTenome
4. Plasmosome

Answer: 1. Karyotype

The basic set of chromosomes in an organism is known as karyotype.

Question 150. Given below is a highly simplified representation of the human sex chromosomes from a karyotype. The genes a and b could be of

1. Colour blindness and body height
2. Attached ear lobe and Rhesus blood group
3. Haemophilia and red-green colour blindness
4. Phenylketonuria and haemophilia

Answer: 3. Haemophilia and red-green colour blindness

The figure shows, human sex chromosome with genes ‘a’ and ‘b’. So, ‘a’ and ‘b’ are sex linked genes, that are inherited through sex chromosomes of X type (X is larger than Y). The most important character of sex linked inheritance is colour blindness and haemophilia.

Question 151. Which of the following statement about Barr bodies is wrong?

1. It was first discovered in female cat by Murray Barr
2. It is also present in males
3. It is present in all females
4. It lies against the nuclear membrane and appears like rounded disc

Answer: 2. It is also present in males

Statement in option (2) is wrong and can be corrected as Barr body is a condensed heterochromatic copy of the X chromosome, visible by staining the interphase nucleus of somatic cells of the homogametic sex, e.g. the human female. It is not present in normal
males.

Question 152. Number of Barr body present in each somatic cell of a female is

1. 1
2. 2
3. 3
4. 4

Answer: 1. 1

One Barr body is present in each somatic cell of female (XX). The number of Barr bodies is one less than the number of X-chromosomes in the cell.

Question 153. Barr body is missing in the female suffering from

1. Huntington’s disease
2. Tay-sach’s disease
3. Klinefelter’s syndrome
4. Turner’s syndrome

Answer: 4. Turner’s syndrome

Turner’s syndrome (44 + XO) is a genetic disorder that affects only females. In this condition, cells of the affected female possess only one X-chromosome, instead of two. Due to the presence of only one X-chromosome, no Barr body is present in females suffering from Turner’s syndrome.

Question 154. Barr body is found in the cytoplasm during

1. Interphase in cell of female mammal
2. Interphase in cell of male mammal
3. Prophase in cell of female mammal
4. Prophase in cell of male mammal

Answer: 1. Interphase in cell of female mammal

Barr body is a mass of condensed sex chromatin in the interphase nuclei of normal female somatic cells due to inactive X-chromosome. Thus, Barr body represents the inactivated X-chromosome.

Question 155. Barr body is observed in

1. Basophils of male
2. Neutrophils of female
3. Basophils of female
4. Eosinophils
5. Neutrophils of male

Answer: 2. Neutrophils of female

Barr body is found attached to nuclear envelope in oral mucosa, anywhere in the nucleus in nerve cells and as drumstick or small rod at one side of nucleus in neutrophil or polymorphonuclear leucocytes (Davidson and Smith).

Question 156. Which of the following genotypes of man shows presence of one Barr body?

1. XY
2. XXXY
3. XXY
4. All of these

Answer:  3. XXY

XXY type of genotypes of man shows presence of one Barr body. The total number of Barr bodies is always one less than the total number of X-chromosome present in the cell of the organism. Thus, XXY would contain one Barr body.

Question 157. Studies related to human sex-linked traits depicts that mostly

1. Male are affected
2. Female are carrier
3. Both 1 and 2
4. Neither 1 or 2

Answer: 3. Both 1 and 2

Males are affected and females are carrier in most cases regarding human sex-linked traits. The recessive genes located on X-chromosome of humans are always expressed in males, e.g. colour blindness is a recessive sex-linked trait in which the eye fails to distinguish red and green colours. The gene for the normal vision is dominant.

Question 158. Barr body is produced due to partial inactivation of one X-chromosome in female. This is called

1. Dosage compensation
2. Facultative heterochromatisation
3. Both 1 and 2
4. None of the above

Answer: 3. Both 1 and 2

• Barr body is produced due to partial inactivation of one X-chromosome and development of facultative heterochromatin in it. Any of the two X-chromosomes can become heterochromatic.
• It begins in the late blastocyst stage (roughly 16 day of embryonic life). Partial inactivation of one X-chromosomes in females is called dosage compensation.

Question 159. If the genetic complement of a person is XXXX, how many Barr bodies can you locate?

1. One
2. Two
3. Three
4. Four

Answer: 3. Three

The total number of Barr bodies is always one less than the total number of X-chromosomes present in the cell or the organism. Therefore, it should be 3 in case of XXXX.

Question 160. A medical technician while observing a human blood smear under the microscope notes the presence of a Barr body close to the nuclear membrane in the WBC. This indicates that the person under investigation is a

1. Colourblind
2. Haemophilic
3. Normal female
4. Normal male

Answer: 3. Normal female

The total number of Barr bodies is always one less than the total number of X-chromosomes present in the cell or the organism. Thus, presence of one Barr body indicates that person under investigation is normal female.

Question 161. Three copies of chromosome – 21 in a child with Down’s syndrome have been analysed using molecular biology technology to detect any possible DNA polymorphism with reference to different alleles located on chromosome – 21. Results showed that out of 3 copies, 2 of the chromosomes of the child contain the same alleles as one of the mother’s alleles. Based on this when did the non-disjunction event most likely occur?

1. Paternal meiosis-1
2. Maternal meiosis-1
3. Paternal meiosis-2
4. Maternal meiosis-2

Answer:  2. Maternal meiosis-1

• Down’s syndrome is an autosomal aneuploidy, caused by the presence of an extrachromosome number 21. Both the chromosomes of pair 21 pass into a single egg due to non-disjunction during oogenesis.
• The non-disjunction is more common in females. The frequency of non-disjunction of chromosome pair 21 increases with mother’s age. Usually non-disjunction of chromosomes takes place in maternal meiosis-I.

Question 162. G-6-P-O deficiency inheritance is an example of ………….. inheritance.

1. X-linked recessive
2. Autosomal dominan
3. Autosomal recessive
4. X-linked dominant

Answer: 1. X-linked recessive

Glucose-6- phosphatedehydrogenase deficiency is most common human enzyme defect. It (also known as favism) is an X-linked recessive genetic condition that predisposes to haemolysis (spontaneous destruction of RBCs) and results in jaundice in response to a number of triggers, such as certain food, illness or medication.

Question 163. Syndrome stands for

1. A group of symptoms
2. Viral disease
3. Diseased condition
4. Dwarf organism

Answer: 1. A group of symptoms

Syndrome stands for the group of symptoms, which indicates to a particular disease.

Question 164. Match the syndrome and chromosomal abnormalities given in columns 1 and 2, respectively.

Answer: 1. A–3, B–5, C–4, D–1

Question 165. Trisomy 18 is

1. Edward’s syndrome
2. Patau’s syndrome
3. Turner’s syndrome
4. Klinefelter’s syndrome

Answer: 1. Edward’s syndrome

• Edward’s syndrome is due to an extra chromosome number 18. Thus, the total number of chromosome is 47 instead of normal 46. Patau’s syndrome is due to trisomy of chromosome 13.
• Turner’s syndrome is due to monosomy (2n –1), the individual has 45 chromosomes (44 + XO). Klinefelter’s syndrome is due to trisomy of sex (X) chromosome. The individual has 47 chromosomes (44 + XXY).

Question 166. Which of the following chromosomal constitution refers to Jacob’s syndrome in human?

1. 44 + XO
2. 44 + XXY
3. 44 + XYY
4. 45 + XYY

Answer: 3. 44 + XYY

Jacob’s syndrome is a rare genetic disorder that occurs due to aneuploidy. It is characterised by the presence of an extra Y-chromosome making the chromosome complement 44 + XYY. Diseased persons show higher growth rate. Any other symptoms are not prominent.

Question 167. The syndrome in which individual somatic cell contains three sex chromosomes XXX is called

1. Klinefelter’s syndrome
2. Turner syndrome
3. Down’s syndrome
4. Super female

Answer: 1. Klinefelter’s syndrome

Klinefelter’s syndrome is formed by the union of an XX egg and a normal Y sperm or normal X egg and abnormal XY sperm. The individual has 47 chromosomes (44 + XXY) or (47+XXX).

Question 168. Low pitched voice, bearding and moustaches are a type of

1. Sex limited traits
2. Sex linked trait
3. Nullisomic traits
4. Sex influenced traits

Answer: 4. Sex influenced traits

Low pitched voice, bearding and moustaches are a type of sex influenced traits.

Question 169. One of the following in man is controlled by dominant genes

1. Colour blindness
2. Brachydactyly
3. Nyctalopia
4. Juvenile glaucoma

Answer: 2. Brachydactyly

Brachydactyly is a shortening of the fingers and toes due to unusually short bones. This is an inherited condition, and in most cases does not present any problems for the person who has it. It is an autosomal dominant condition, which means you only need one parent with the gene to inherit the condition.

Question 170. Name the syndrome which is caused when there is trisomy of the sex chromosomes.

1. Turner’s syndrome
2. Down’s syndrome
3. Klinefelter’s syndrome
4. Patau’s syndrome

Answer: 3. Klinefelter’s syndrome

• Klinefelter’s syndrome is formed by the union of an abnormal XX egg and a normal Y sperm or normal X egg and abnormal XY sperm. The individual has 47 chromosomes (44 + XXY) due to the trisomy of sex chromosomes.
• Such persons are sterile males with undeveloped testes, mental retardation, sparse body hair and long limbs and with some femalecharacteristics such as enlarged breasts.
• It is considered that the more the X-chromosomes, the greater is the mental defect. As the syndrome has two X-chromosomes, one Barr body is seen in this case.

Question 171. Which one of the following conditions in humans is correctly matched with its chromosomal abnormality/linkage?

1. Klinefelter’s syndrome-44 autosomes + XXY
2. Colour blindness – Y-linked
3. Erythroblastosis foetalis – X-linked
4. Down’s syndrome – 44 autosomes + XO

Answer: 1. Klinefelter’s syndrome-44 autosomes + XXY

• Option (1) is correct as Klinefelter’s syndrome is a genetic disorder affecting men in which an individual gains an extra X chromosome, so that the usual karyotype of XY is replaced by one of XXY.
• Other options are not correct. Colour blindness is X-linked, Down’s syndrome is 21 trisomy and erythroblastosis foetalis is related to Rh incompatibility.

Question 172. What is the genetic disorder in which an individual has an overall masculine development gynaecomastia and is sterile?

1. Turner’s syndrome
2. Klinefelter’s syndrome
3. Edward’s syndrome
4. Down’s syndrome

Answer: 2. Klinefelter’s syndrome

Individuals with Klinefelter’s syndrome have trisomy of sex chromosome as 44 + XXY (47). They show overall masculine development, gynaecomastia and are sterile.

Question 173. Spermatogenesis is absent in person suffering from

1. Klinefelter’s syndrome
2. Down’s syndrome
3. Turner’s syndrome
4. Thalassemia

Answer: 1. Klinefelter’s syndrome

Klinefelter Syndrome (KS) was first described by Harry F. Klinefelter in 1942 as a clinical entity characterised by gynecomastia, small testes, absent spermatogenesis, normal to moderately reduced Leydig cell function and increased secretion of FSH.

Question 174. In Klinefelter’s syndrome, the sex chromosome compliment is

1. 22 A+ XXY
2. 22A + XY
3. 22A+XO
4. 22 A + XX

Answer: 1. 22 A+ XXY

Klinefelter’s syndrome is formed by the union of an XX egg and a normal Y sperm or normal X egg and abnormal XY sperm. The individual has 47 chromosomes (22A + XXY).

Question 175. A man having Klinefelter’s syndrome is

1. Intersex with secondary sexual characters on the side of female
2. Male with secondary sexual characters of female
3. Female with secondary sexual characters of male
4. Normal fertile male

Answer: 2. Male with secondary sexual characters of female

Phenotypically Klinefelter individuals are males, but they can show some female secondary sexual characteristics and are usually sterile.

Question 176. Which of the following set of syndromes show 47 chromosomes in their genetic makeup?

1. Down’s syndrome, Patau’s syndrome, Edward’s syndrome
2. Turner’s syndrome, Edward’s syndrome, Klinefelter’s syndrome
3. Klinefelter’s syndrome, Turner’s syndrome, Edward’s syndrome
4. All of the above

Answer: 1. Down’s syndrome, Patau’s syndrome, Edward’s syndrome

• Syndromes which show 47 chromosomes (instead of normal 2n = 46 chromosomes) in the genetic
  makeup of affected individual include Down’s syndrome, Patau’s syndrome, Edward’s syndrome and Klinefelter’s syndrome.
• Individuals suffering from Down’s syndrome contain 45+XY chromosomes in males and 45 + XX chromosomes in females. Patau’s syndrome (13-trisomy) is due to an extra chromosome number 13 and Edward’s syndrome (18-trisomy) is due to an extra chromosome number 18.
• Klinefelter’s syndrome occurs due to trisomy of sex (X) chromosome and the affected individual possesses 47 chromosomes (44+XXY). Turner’s syndrome occurs due to monosomy of sex chromosome and the affected individual possesses 2n = 45 chromosomes (44+XO) instead of 46.

Question 177. Edward, Patau, Down’s syndromes are

1. Change in autosomes
2. Change in sex chromosomes
3. Mutation due to malnutrition
4. Both change in sex chromosome and autosomes

Answer: 1. Change in autosomes

Edward’s, Patau’s and Down’s syndromes are disorders which occur due to autosomal chromosomal changes. Edward’s syndrome occurs due to trisomy of 18th chromosome, Patau’s syndrome arises due to trisomy of 13th chromosomes and Down’s syndrome occurs due to trisomy of 21st chromosomes.

Question 178. Number of sex chromosomes is normal in

1. Super female
2. Turner’s syndrome
3. Klinefelter’s syndrome
4. Down’s syndrome

Answer: 4. Down’s syndrome

Down’s syndrome is an autosomal aneuploidy. The 21st pair of chromosomes has three chromosomes instead of two. The sex chromosomes remain unchanged.

Question 179. Who reported that Down’s syndrome is due to extra 21st chromosome?

1. JL Down (1866)
2. Lejeune (1959)
3. Klinefelter (1942)
4. Huntington (1872)

Answer: 1. JL Down (1866)

• For centuries, people with Down’s syndrome have been alluded in art, literature and science. It was not until the late 19th century, however, that John Langdon Down, an English physician, published an accurate description of a person with Down syndrome.
• It was this scholarly work, published in 1866, that earned Down the recognition as the ‘father’ of the syndrome.

Question 180. In Down’s syndrome, karyotyping has shown that the disorder is associated with trisomy of chromosome number 21 usually due to

1. Non-disjunction during egg cell formation
2. Non-disjunction during sperm cell formation
3. Non-disjunction during formation of egg cells and sperm cells
4. Addition of extra chromosome during mitosis of the zygote

Answer: 3. Non-disjunction during formation of egg cells and sperm cells

Down’s syndrome caused by trisomy 21, arises due to an occasional non-disjunction during meiosis when a gamete comes to possess an extra chromosome (n+ 1).

Fusion of this chromosome with a normal gamete containing normal chromosome (n) result in [n + (n + 1)] trisomy.

Question 181. Freqeuency of Down’s syndrome increases when the maternal age is

1. Above 35 years
2. Below 35 years
3. During 1st pregnancy
4. If she is a mother of at least 3 children

Answer: 1. Above 35 years

The chance of a woman having a baby with Down’s syndrome increases as she gets older. Only 1 in 2000 births from teenage mothers are affected by Down’s syndrome, but this goes up to 1 in 10 in 48-years old women. The risk starts above 35 years of age

Question 182. Consider the following statements.

1. Short statured with small round head.
2. Tongue is furrowed and mouth partially opened.
3. Also called Mongolian Idiocy.
4. Physical, psycomotor and mental development is slow.

Choose the correct option.

1. Down’s syndrome
2. Turner’s syndrome
3. Klinefelter’s syndrome
4. Patau’s syndrome

Answer: 1. Down’s syndrome

All the listed symptoms belong to Down’s syndrome 21 trisomy.

Question 183. Down’s syndrome is caused by an extra copy of chromosome number 21. What percentage of offspring produced by an affected mother and a normal father would be affected by this disorder?

1. 100 %
2. 75 %
3. 50 %
4. 25 %

Answer: 3. 50 %

Down’s syndrome is the example of autosomal aneuploidy. Here, an extra copy of chromosome 21 occurs. As it is an autosomal disease, the offspring produced from affected mother and normal father should be 50%.

Question 184. Which of the following occurs due to monosomy of sex chromosome?

1. Down’s syndrome
2. Turner’s syndrome
3. Haemophilia
4. Sickle-cell anaemia

Answer: 2. Turner’s syndrome

• Turner’s syndrome is caused due to the absence or monosomy of one of the X-chromosome, i.e. 45 chromosomes total with sex chromosomes as XO.
• Such females are sterile as ovaries are rudimentary. Besides this, other features include lack of other secondary sexual characters, etc.

Question 185. Which is correct for Turner’s syndrome?

1. It is a case of monosomy
2. It causes sterility in females
3. Absence of Barr body
4. All of the above

Answer: 4. All of the above

• All given statements are correct regarding Turner’s syndrome. It is a genetic disorder of women caused by the absence of the second sex chromosome (such women are XO, rather than the normal XX).
• It is characterised by a lack of ovaries and menstrual cycle. Affected women are sterile and lack secondary sexual characteristics, In the case of Turner’s syndrome, it is 1 – 1 = 0, i.e. Barr bodies are absent. Thus, option (4) is correct.

Question 186. A sterile female having reduced mental ability is said to be suffering from

1. Turner’s syndrome
2. Klinefelter’s syndrome
3. Down’s syndrome
4. Edward’s syndrome

Answer: 1. Turner’s syndrome

• Unlike some other genetic conditions, Turner’s syndrome does not cause mental retardation or decreased intelligence.
• However, some girls with Turner’s syndrome have learning disabilities, especially in areas involving spatial skills, such as math. It can affect their ability to connect with others.

Question 187. The person with Turner’s syndrome has

1. 45 autosomes and X sex chromosome
2. 44 autosomes and XYY sex chromosomes
3. 45 autosomes and XYY sex chromosomes
4. 44 autosomes and X sex chromosome

Answer: 1. 45 autosomes and X sex chromosome

Turner’s syndrome is caused due to absence of one of the X-chromosomes, i.e. 45 with XO.

Question 188. Turner’s syndrome in humans is caused by

1. Autosomal aneuploidy
2. Sex chromosome aneuploidy
3. Polyploidy
4. Point mutation

Answer: 2. Sex chromosome aneuploidy

Turner’s syndrome is 23 monosomic (sex chromosome aneuploidy) conditions, in which only one X-chromosome is present.

Question 189. Turner’s syndrome was first discovered by

1. JL Down
2. Huntington
3. HH Turner
4. Lejeune

Answer: 3. HH Turner

Turner syndrome was first discovered in 1938 by Dr. Henry Turner while studying a group of 7 girls who all had the same unusual developmental and physical features.

Question 190. A human female with Turner’s syndrome

1. Has 45 chromosomes with XO
2. Has one additional X chromosome
3. Exhibits male characters
4. Is able to produce children with normal husband

Answer: 3. Exhibits male characters

• Turner’s syndrome is due to monosomy (2n – 1). It is caused by the union of an allosome free egg (22 + 0) and a normal X sperm or a normal egg and an allosome free sperm (22 + 0).
• The individual has 2n = 45 chromosomes (44 + XO) instead of 46. Such people are sterile
  females who have rudimentary ovaries filled with connective tissues (therefore, also called gonadal dysgenesis), undeveloped breasts, small uterus, puffy fingers, short stature, male like characters like beared, masculinity, etc.

Biology MCQs with answers for NEET Mutation

Question 1. Rarely observed phenotype in population is called

1. Wild type
2. Mutant type
3. Variant type
4. All of the above

Answer:  2. Mutant type

The gene whose chemical structure is altered is called mutated gene and the organisms carrying this mutated gene is called mutant. It is rarely observed phenotype in population.

Question 2. One of the parents of a cross has a mutation in its mitochondria. In that cross, that parent is taken as a male. During segregation of F₂ progenies that mutation is found in

1. One-third of the progenies
2. 50% of the progenies
3. All the progenies
4. None of the progenies

Answer:  4. None of the progenies

questions about genetics

Mitochondria is an organelle present in the cytoplasm. A zygote receives its cytoplasm from the female parent gamete. Hence, in the given question, the F₂ progenies do not receive the mitochondrial genome from the male parent and mutation is not passed to progenies.

Thus, option (4) is correct.

Read And Learn More: NEET Biology Multiple Choice Question And Answers

Question 3. Assertion (A) Muton gene has fewer nucleotides than a cistron. Reason (R) Benzer coined the term muton to the smallest unit of genetic material capable of mutational change.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. Both A and R are false

Answer:  1. Both A and R are true and R is the correct explanation of A

Both A and R are true and R is the correct explanation of A. Muton has fewer nucleotides than a cistron because muton is the smallest unit in chromosome that can be changed by mutation.

NEET Biology Mutation MCQs with answers

Question 4. Mutagens are

1. Chemical agents which cause change in DNA
2. Physical agents which cause mutation
3. Cancer producing agents
4. Both 1 and 2

Answer:  4. Both 1 and 2

Mutagen may be physical or chemical agents, which causes change in DNA sequence, e.g. mutation induced by UV-radiation, acridine dye, etc. Thus, option (4) is correct

Biology MCQs with answers for NEET

Important MCQs on Mutation for NEET

Question 5. Certain mutations are not eliminated from gene pool because they are carried by

1. Homozygous individuals
2. Recessive homozygous individuals
3. Heterozygous individuals
4. Dominant heterozygous individuals

Answer:  3. Heterozygous individuals

Harmful mutation does not get eliminated from the gene pool because most of the harmful mutations are recessive and they are carried in heterozygous condition by the individual. If they (mutation) are dominant, then they easily get eliminated by the death of an organism.

Question 6. Haploids are able to express both recessive and dominant alleles/ mutations because there are

1. Many alleles for each gene
2. Two alleles for each gene
3. Only one allele for each gene in the individual
4. Only one allele in a gene

Answer:  3. Only one allele for each gene in the individual

In haploid organisms, every gene irrespective of dominant or recessive and every mutation finds expression because there is only one allele for each gene in the haploid individual. Recessive allele is able to express as there is no alternative dominant allele for producing its masking effect on recessive allele.

“which of the following is a hereditary disease “

Question 7. Mutation is

1. Recessive
2. Useful
3. Seldom useful
4. Low frequency

Answer:  1. Recessive

Mutations are normally deleterious or recessive and therefore, majority of them are of no practical value.

Biology MCQs with answers for NEET

Question 8. Which of the following statements about mutation are true?

1. Mutations are the source of new alleles for genes.
2. Organisms are able to create mutations to meet their specific needs.
3. Mutations are random events and can happen in any cell at any time.
4. Most mutations tend to be harmful or have no effect on an organism.

Chooe the correct option.

1. 1, 2 and 3
2. 1, 2, 3 and 4
3. 1, 3 and 4
4. 1 and 3

Answer:  3. 1, 3 and 4

All given statements are true about mutation except II. Incorrect statement can be corrected as Mutation occurs itself. It is the spontaneous phenomena and organisms cannot create mutations on their own. Thus, option (3) is correct.

Mutation chapter-wise MCQs for NEET

Question 9. Mark the incorrect statement about mutation?

1. Mutation is predestined
2. Major source of evaluation
3. Usually deleterious and recessive
4. It is a reversible process

Answer:  1. Mutation is predestined

Statement in option (1) is incorrect and can be corrected as Mutations are the ultimate source of all genetic variations and these are spontaneous. Rest options are correct about mutation.

Question 10. A recessive mutant is one which is

1. Not expressed
2. Rarely expressed
3. Expressed only in homozygous and hemizygous state
4. Expressed only in heterozygous state

Answer:  3. Expressed only in homozygous and hemizygous state

A recessive mutation is one in which both alleles must be mutant in order for the mutant phenotype to be observed, i.e. the individual must be homozygous recessive (rr) or hemizygous (ro) for the mutant allele to show the mutant phenotype.

Question 11. Which of the following is correct for tetrasomic aneuploids?

1. 2n + 2
2. 2n + 2 + 2 + 2
3. 2n – 1
4. 2n – 1

Answer:  1. 2n + 2

Aneuploidy is also called as heteroploidy which is the condition of having fewer or extra chromosomes than the exact multiple of the genome or whole chromosome set. In tetrasomics, chromosome is present quadruplicate (four times). Among given options 2n+2 represents tetrasomic aneuploids.

Question 12. Monosomic trisomy is represented as

1. 2n – 1 – 1
2. 2n – 1 + 1
3. 2n – 1
4. 2n + 1 + 1
5. 2n + 1

Answer:  2. 2n – 1 + 1

Monosomy is the absence of one chromosome (2n-1 )and trisomy is presence of an extra chromosome ( 2n+1) The absence of single chromosome and presence of antoher chromosome simultaneously is called monosomic trisomy (2n-1+1 ).

Biology MCQs with answers for NEET

Question 13. Find out the correct statement.

1. Monosomy and nullisomy are the two types of euploidy
2. Polyploidy is more common in animals than in plants
3. Polyploids occur due to the failure in complete separation of sets of chromosomes
4. 2n-l condition results in trisomy
5. Non-homologous chromosomal duplication results in autopolyploidy

Answer:  1. Monosomy and nullisomy are the two types of euploidy

“principles of inheritance “

Statement in option (1) is correct. Other statements are incorrect and can be corrected as 2n+1 condition results in trisomy. Polyploidy is common in plants only. Polyploidy occurs due to duplication of chromosomes and homologous chromosomes duplication results in autopolyploidy.

Question 14. A condition characterised by multiples of haploid set of chromosomes is called

1. Polyploidy
2. Symploidy
3. Aneuploidy
4. All of the above

Answer: 1. Polyploidy

Polyploidy is the condition in which the chromosome number is a higher multiple than two of the haploid number (23) of chromosomes.

NEET quiz on Mutation with solutions

Question 15. Polyploidy can result from

1. Parthenogenesis
2. Monospermy
3. Colchicine
4. All of the above

Answer:  3. Colchicine

Polyploidy is a condition in which the chromosome number is two or more times than normal haploid number found in gametes. It may occur in nature or can be induced artificially by using colchicine. This type of mutation includes all the cases in which any change in number of chromosomes in set occurs.

Biology MCQ For NEET With Answers

Question 16. Abnormal cell with random number of chromosomes is

1. Aneuploid
2. Polyploid
3. Heterokaryotic
4. Haploid

Answer:  1. Aneuploid

Aneuploidy is the condition of cells having more or less than integral multiple of typical haploid chromosome number. Thus, 22 + XXY is an extra sex chromosome due to non-disjunction of a pair of sex chromosome either in an ovum or sperm. So, abnormal cell with random number of chromosomes is aneuploid.

Question 17. An example for an allotetraploid is

1. Triticum aestivum
2. Gossypium species
3. E. coli
4. Mango

Answer:  2. Gossypium species

An example of an allotetraploid is Gossypium species of cotton. An allotetraploid is a hybrid that has a chromosome set 4 times that of a haploid organism.

Question 18. Chromosome complement with 2n -1 is called

1. Monosomy
2. Trisomy
3. Nullisomy
4. Tetrasomy

Answer:  1. Monosomy

Option (1) is correct. Monosomy occurs due to loss of a single chromosome (2n – 1). Other options are not correct and can be corrected as Nullisomy occurs due to loss of one pair of chromosomes (2n – 2). Hyperploidy may either involve addition of a single chromosome, trisomy (2n + 1) or a pair of chromosomes, tetrasomy (2n + 2).

NEET expected MCQs on Mutation 2025

Question 19. A chromosome may be lost or gained during cell division due to failure of segregation of chromatids. This condition is referred to as

1. Aneuploidy
2. Hypopolyploidy
3. Hyperpolyploidy
4. Polyploidy

Answer:  1. Aneuploidy

Chromosomal disorders are caused due to excess, absence or abnormal arrangement of one or more chromosomes. Sometimes the chromatids fail to segregate during cell division, resulting in gain or loss of a chromosome. This is called aneuploidy or heteroploidy.

Biology MCQ For NEET With Answers

Question 20. Occurrence of cells in diploid organisms containing multiples of the 2n genomes is known as

1. Aneuploidy
2. Haploidy
3. Amphidiploidy
4. Allopolyploidy

Answer:  1. Aneuploidy

Aneuploidy is the occurrence of cells in diploid organisms containing multiplies of the 2n genomes. For example, a human cell having 45 or 47 chromosomes instead of the usual 46. It does not include a difference of one or more complete sets of chromosomes.

Question 21. Trisomy and monosomy is represented by

1. 2n – 1 and 2n + 1
2. 2n + 1 and 2n – 1
3. 2n and 2n + 1
4. 2n and 2n – 1

Answer:  2. 2n + 1 and 2n – 1

Monosomy occurs due to loss of a single chromosome (2n – 1) whereas trisomy occurs due to addition of a single chromosome (2n + 1).

Question 22. Match the following column.

Answer:  1. A–5, B–1, C–4, D–2, E–3

 

Mutation Extra Questions

Question 1. Sudden and heritable change in a character of an organism is called

Mutation
Heterosis
Inbreeding
Selection
Answer: 1. Mutation

Mutations are the sudden alteration in the chemical structure of a gene or the alteration in its position on the chromosome by breaking and rejoining the chromosome.

Biology MCQ For NEET With Answers

Question 2. Errors during DNA replication, repair or recombination can lead to base-pair substitution. Such changes are

Conditional mutations
Mutagens
Spontaneous mutations
Saltatory changes
Answer: 3. Spontaneous mutations

All types of mutations are produced spontaneously, e.g. base substitutions, frame shifts, insertions and deletions. Errors during DNA replication can lead to spontaneous mutations.

Question 3. Mutations can be induced with

Infrared radiations cbse
IAA
Ethylene
Gamma radiations
Answer: 4. Gamma radiations

Mutation is the process by which genetic variations are created through changes in the base sequence within genes. It is possible to induce mutations artificially through the use of chemicals or radiations like gamma radiations.

“dihybrid cross questions “

Question 4. One of them is efficient in inducing mutations.

X-rays
Hybridisation
Colchicine
Crossing over
Answer: 1. X-rays

Two major causes of mutations are irradiation and chemical mutagens. Irradiation is exposure to radiation like X-rays and chemical mutagens are chemicals that cause changes in DNA sequences.

Thus, X-rays are efficient in inducing mutation.

Question 5. UV radiations cause

Formation of thymine dimers
Deletion of base pairs
Methylation of bases
Addition of base pairs
Answer: 1. Formation of thymine dimers

One of the major sources of DNA damage in all organisms is the UV component of sunlight. The predominant reaction induced by UV light on DNA is the dimerisation of adjacent pyrimidine bases.

Ultraviolet light induces the formation of covalent linkages localised on the C C== double bonds. In dsRNA, uracil dimers may also accumulate as a result of UV radiation.

Two common UV products are cyclobutane pyrimidine dimers (CPOs, including thymine dimers) and 6, 4 photoproducts. These premutagenic lesions alter the structure of DNA and consequently inhibit polymerases and arrest replication. So, UV radiation causes the formation of thymine dimers.

Biology MCQ For NEET With Answers

Question 6. The best chemical to induce polyploidy is

Maleic Hydrazide
ABA
Acenaphthene
Ethylene
Answer: 3. Acenaphthene

A number of chemicals are known to cause polyploidy, e.g. chloral hydrate, ethyl mercuric chloride, hexachlorocyclohexane and acenaphthene.

Question 7. The mutations are mainly responsible for

Increasing the population rate
Maintaining genetic continuity
Constancy in organisms
Variation in organisms
Answer: 4. Variation in organisms

Mutations are the sudden alteration of the chemical structure of a gene or the alteration of its position on the chromosome by breaking and rejoining of the chromosome. They rarely occur naturally but may be caused artificially by irradiation or by chemicals (mutagen), e.g. mustard gas.

They may occur in somatic cells or gametes in which case they can be inherited. They lead to variations in organisms and can be accordingly categorised into somatic mutations and gametic mutations.

Question 8. Mutations are caused by

Polyploidy
Hybridisation
Aneuploidy
All of these
Answer: 4. All of these

Mutations are caused by polyploidy, hybridisation and aneuploidy. In polyploidy, more than two paired sets of chromosomes are mutated.

In hybridisation, single-stranded DNA or RNA molecules anneal to complementary DNA or RNA.

Aneuploidy is a condition in which the number of chromosomes in the nucleus of a cell is not an exact multiple of the monoploid number of a particular species.

NEET Biology Mutation MCQs with explanations

Question 9. Change in single base pair Odisha

May change the phenotype
Quickly change the phenotype
Change the natural process
None of the above
Answer: 1. May change the phenotype

May change the phenotype change in single base pair due to mutation may or may not change the phenotype of an organism.

Question 10. Hereditary variation in plants has been obtained through the use of

X-rays or gamma rays
2, 4-D
DDT
GA
Answer: 1. X-rays or gamma rays

Radiation (X-rays or gamma rays) can increase the natural mutation rate by 1000 to 1 million fold, making the generation of genetic variation very effective.

NEET Biology Mcq

Question 11. The action of ultraviolet rays on DNA in Odisha

Induction of thymidine
Deletion of base pairs
Addition of base pairs
Methylation of base pairs
Answer: 1. Induction of thymidine

Commonly, UV radiations cause the formation of thymine dimers and induce mutation. Thus, the action of ultraviolet rays on DNA is the induction of thymidine

“pedigree questions “

Question 12. HJ Muller was awarded Nobel Prize for his

The discovery that chemicals can induce gene mutations
The discovery that ionising radiations can induce gene mutations
Work on gene mapping in drosophila
Efforts to prevent the use of nuclear weapons
Answer: 2. Discovery that ionising radiations can induce gene mutations

HJ Muller studied the effect of radiation on living organisms. He was awarded the Nobel Prize for discovering that ionising radiation can induce gene mutations.

Question 13. Which of the following is not considered a mutagen?

Uv radiation
Nuclear reaction
2-Aminopurine
Low temperature
Answer: 4. Low temperature

Mutation can be artificially induced with the help of mutagenic agents which can be broadly classified as – 1 Physical mutagens, 2 Chemical mutagens. Physical mutagens are mainly radiations like X-rays, gamma rays, beta rays and neutrons.

High temperature also causes mutations. Aminopurine is a chemical artificial base analogue of adenine. It can substitute adenine as well as can pair with cytosine.

Similarly, the nuclear reaction causes a great impact on the DNA and mutations are noticed in several generations due to nuclear reaction or explosion.

So, low temperature does not cause mutation

NEET Biology Mcq

Question 14. The mutation may result in the

Change in genotype
Change in phenotype
Change in metabolism
All of the above
Answer: 4. All of the above

In most cases, if there is a change in genotype then it ultimately leads to a change in phenotype and metabolism.

Question 15. The mutations can be induced in bacteria by Karnataka

Adding all required substances
Starving the bacteria
Exposure to high-energy radiation
Growing different strains
Answer: 3. Exposure to high-energy radiation

Mutations can be artificially induced in bacteria with the help of high-energy ionising radiation

Question 16. Chromosomal aberration is due to

Physical effects Manipal1995
Change in structure or number of chromosomes
Polyploidy
None of the above
Answer: 2. Change in structure or number of chromosomes

Chromosomal aberration (chromosome mutation) is a change in the gross structure or number of a chromosome.

The main types of chromosomal aberrations that occur due to changes in the structure are deletion, duplication, translocation, inversion and due to change in the number, i.e. euploidy and aneuploidy.

Mutation mock test for NEET preparation

Question 17. Chromosomal mutations occur due to

Deletion
Duplication
Translocation
Inversion
Choose the correct option.

1, 2 and 3
2, 3 and 4
1, 3 and 4
1, 2, 3, and 4
Answer: 4. 1, 2, 3, and 4

All the given ways are correct. The chromosomal mutation is the sudden inheritable change in the hereditary material of an organism. It is caused due to several ways like deletion, duplication, translocation, inversion, etc. Thus, option 4 is correct.

NEET Biology Mcq

Question 18. The gene mutation is UP

Mutation in the genes of DNA
Mutation in the phosphodiester linkage
Mutation in the chromosomes
Change in the sequence of nitrogenous bases
Answer: 4. Change in the sequence of nitrogenous bases

A gene mutation is a change in the sequence of the nitrogenous bases due to a change in the DNA sequence that makes up a gene

Question 19. A gene mutation which does not result in phenotypic expression is termed as

Non-sense mutation
Silent mutation
Mis-sense mutation
Frameshift mutation
Answer: 2. Silent mutation

Mutations which involve the substitution of a base by another base in such a manner that the new codon also codes for the same amino acid and thus, does not produce any faulty protein or no phenotypic changes are called silent mutations

Question 20. A non-sense mutation results into

Stoppage of transcription pm 2001
Change in protein structure
Stoppage of protein synthesis
Termination of the polypeptide chain
Answer: 2. Change in protein structure

A non-sense mutation is one which stops polypeptide synthesis due to the formation of a termination of the non-sense codon, viz. ATT(UAA), ATC (UAG), ACT(UGA)

Question 21. The creation of mutations is called

Mutagenesis
Evolution
Saltatory changes
Radiations
Answer: 1. Mutagenesis

Mutagenesis is a process by which the genetic information of an organism is changed, resulting in a mutation.

It may occur spontaneously in nature or as a result of exposure to mutagens. It can also be achieved experimentally using laboratory procedures. So, the creation of mutations is called mutagenesis.

NEET Biology Mcq

Question 22. Chemical mutagens are more dangerous than radiation. Justify from the following statements.

Exposure to them is more frequent
There is protection from radiation but no chemicals
Both 1 and 2
Chemically caused mutations are far more deleterious
Answer: 4. Chemically caused mutations are far more deleterious

A chemical mutagen is a substance that can alter a base that has already been incorporated into DNA and thereby, change its hydrogen bonding specificity.

Chemical mutagens are prevalent in the environment and a potential threat to the health of future generations.

Question 23. After a mutation at a genetic locus, the character of an organism changes due to the change in

Protein structure
DNA replication
Protein synthesis pattern
RNA transcription pattern
Answer: 1. Mutagenesis is a process by which the genetic information of an organism is changed, resulting in a mutation.

It may occur spontaneously in nature or as a result of exposure to mutagens.

It can also be achieved experimentally using laboratory procedures. So, the creation of mutations is called mutagenesis.

Question 24. Assertion 5-Bromouracil can cause mutations. Reason (R) It is called a base analogue.

Both A and R are true and R is the correct explanation of A
Both A and R are true, but R is not the correct explanation of A
A is true, but R is false
Both A and R are false
Answer: 1. Both A and R are true and R is the correct explanation of A

NEET practice test on Mutation

Question 25. Change in one base in mRNA leading to termination of the polypeptide is known as which type of mutation?

Non-sense
Mis-sense
Gibberish
Frameshift
Answer: 1. Non-sense

A non-sense mutation is one which stops polypeptide synthesis due to the formation of a termination of the non-sense codon, viz. ATT(UAA), ATC(UAG), ACT(UGA).

Other options are explained as A missense mutation is one which involves a change in a codon that produces a different amino acid at the specific site in a polypeptide, often resulting in its non-functioning.

Frame-shift or gibberish mutations are those mutations in which the reading of the frame of the base sequence shifts laterally either in the forward direction due to the insertion of one or more nucleotides or in the backward direction due to the deletion of one or more nucleotides.

Question 26. X-ray causes mutation by

Transition
Transversion
Deletion
Base substitution
Answer: 3. Deletion

High-energy radiations, such as X-rays, gamma rays, cosmic rays and UV light have been found to be mutagenic in almost all organisms. They produce mutations by causing breaks in the DNA molecule, i.e.
deletion.

Question 27. Name the type of mutation in which the cause of the mutation is not known.

Spontaneous mutation
Suppressor mutation
Non-sense mutation
Mis-sense mutation
Answer: 1. Spontaneous mutation

Spontaneous mutations are those in which the cause of the mutation is not known. These types of mutations arise due to a tautomeric shift in nitrogenous bases of DNA.

Question 28. Normally DNA molecule has A-T, G-C pairing. However, these bases can exist in alternative valency status, owing to re-arrangements called

Point mutation
Frameshift mutation
Analogue substitution
Tautomerisational mutation
Answer: 4. Tautomerisational mutation

Transitions may be tautomeric shifts (ionisation) of bases, which leads to mistaken A-C base pairing and more frequently mistaken G – T base pairing.

So, these bases can exist in alternative valency status, owing to rearrangement called tautomerization mutation.

NEET Biology Mcq

Question 29. Gibberish mutations are

Reverse
Frameshift
Transitions
Transversions
Answer: 2. Frameshift

Acridines (e.g. acriflavine, proflavine, flavine, acridine orange) enter the DNA chains in between two base pairs and cause deletion or addition of a few nucleotides.

The frame of the nucleotide sequence of DNA is thus, disturbed and read differently. It is also known as frame-shift or gibberish mutation

Question 30. Name the term given to the type of mutation which depends on the conditions of the environment.

Forward mutation
Reverse mutation
Conditional lethal mutation
Gain of function mutation
Answer: 3. Conditional lethal mutation

In conditional lethal mutation, lethality depends on the conditions of the environment, e.g. auxotrophs, temperature-sensitive mutants and suppressor mutation.

Question 31. Gene mutation occurs at the time of

DNA repair BHU 1996
RNA transcription
DNA replication
Cell division
Answer: 3. DNA replication

During replication, double strands of DNA are separated. Each strand is then copied to become another double strand.

About 1 out of every 100,000,000 times, a mistake occurs during copying, which can lead to a mutation. Mutations can also be caused by environmental foes. So, gene mutation occurs at the time of DNA replication.

Question 32. A genomic mutation involves

Change in genes am 2008
Change in chromosomal structure
Change in the number of chromosomes
All of the above
Answer: 3. Change in the number of chromosomes

The genomic mutation is the change in chromosome number due to errors in meiosis or mitosis

Question 33. The loss of a chromosomal segment is due to Kerala

Polyploidy
Deletion
Duplication
Inversion
Answer: 2. Deletion

The mutation involving the removal of one or more base pairs in the DNA sequence is called a deletion.

Question 34. Which of the following is the main category of mutation?

Somatic mutation
Genetic mutation
Heterosis
Both 1 and 2
Answer: 4. Both 1 and 2

Mutations may occur in somatic cells or gametes. In the latter case, they can be inherited. They lead to variations in organisms. So, they can be accordingly categorised into somatic mutations and genetic mutations. Thus, option 4 is correct

Question 35. Which of the following is not heritable?

Point mutation
Gene mutation
Somatic mutation
Chromosomal mutation
Answer: 3. Somatic mutation

Somatic mutations are those mutations which occur in a cell other than germ cells and are not passed to the next generations, i.e. these are not heritable.

Question 36. Point mutation may occur due to

Alteration in DNA sequence
Change in a single base pair of DNA
Deletion of a segment of DNA
Gain of a segment in DNA
Answer: 2. Change in a single base pair of DNA

Point mutation or gene mutation involves only the replacement of one nucleotide with another or a change in a single base pair of DNA.

One type of point mutation is a missense mutation. These are base changes that alter the codon for an amino acid resulting in its substitution with a different amino acid

Question 37. Which base is considered a hotspot for spontaneous point mutations?

5-bromouracil
50 methylcytosine
Guanine
Adenine
Answer: 3. Guanine

Mutations are rare events in nature and are described as spontaneous mutations. Some of these mutations originate from mistakes in the normal duplication of DNA.

Transitions may be produced by tautomeric shift or ionisation of bases which leads to mistaken, A-C base pairing and more frequently mistaken G-T base pairing.

Guanine pairs with the rare enol form of thymine and is thus, considered a hotspot for spontaneous point mutations.

Question 38. A mutation in which thymine is replaced by cytosine is called

Transition
Transversion
Mis-sense
None of these
Answer: 1. Transition

Transitions are substitution gene mutations in which a purine (say adenine) is replaced by another purine (say guanine), or a pyrimidine (say thymine) is replaced by another pyrimidine (say cytosine). Change of codon ATC to GTC or ATT or ACC is an example of a transition

Question 39. When purine is substituted by pyrimidine, the resulting mutation is

Transition mutation
Transversion mutation
Point mutation
Suppressive mutation
Answer: 2. Transversion mutation

A transversion is a substitution gene mutation in which a purine (A or G) is replaced by a pyrimidine (T or C) or vice-versa.

Question 40. Which of the following type of mutation involves the reverse order of genes in a chromosome?

Deletion Haryana
Duplication
Inversion
Reciprocal translocation
Answer: 3. Inversion

An inverse mutation is a type of intra-chromosomal modification in which the segment of chromosome separates and rejoins in the reverse position

Question 41. Frame-shift mutation and base pair substitution change the

Nucleotide structure
Nucleotide sequence
Nucleoside sequence
Sugar-phosphate sequence
Answer: 2. Nucleotide sequence

The nucleotide sequence is also called the base-pair sequence. In frame-shift mutation or base pair substitution, the nucleotide sequence gets changed.

Question 42. The mechanism that causes a gene to move from one linkage group to another is called

Inversion
Duplication
Translocation
Crossing over
Answer: 3. Translocation

Translocation is a phenomenon of transfer of a gene segment between non-homologous chromosomes, i.e. different linkage groups.

Question 43. A normal gene sequence in a chromosomal sequence is ABCDEFGH. If it is changed to ACGH, this is a case of

Frame-shift mutations
Deletions
Inversions
Duplication
Answer: 2. Deletions

In genetics, deletion is also called gene deletion or deficiency.

It is a mutation (a genetic aberration) in which a part of a chromosome or a sequence of DNA is left out during DNA replication. Any number of nucleotides can be deleted from a single base to an entire piece of chromosome.

Question 44. If the ABCDEFGH gene sequence changes to ABCABCDEFGH, then ………………. has occurred.

Deletion
Point mutation
Inversion
Duplication
Answer: 4. Duplication

A duplication consists of a piece of DNA that is abnormally copied one or more times. This type of mutation may alter the function of the resulting protein. In the given sequence, ABC duplication has occurred.

Question 45. Identify the type of mutation in the given diagram.

 

Inversion
Insertion
Deletion
Substitution
Answer: 2. Insertion

In the given diagram, there is an insertion of T in the given segment of the gene, so the diagram depicts the insertion type of mutation.

Question 46. The chromosome shown in the diagram below is broken at the points which are indicated by the arrows and the genes between these points became inverter. The resulting order of the genes will be

PQUTSRVW
WVUTSRQP
PQTURSVW
VWUTSRPQ
Answer: 1. PQUTSRVW

 

The given example represents inversion mutation in which the order of genes in a chromosome gets inverted. Thus, the resultant gene order would be PQUTSRVW

Question 47. Ochre mutations are mutations of ………… codon.

UAG
UAA
AUG
UGA
Answer: 2. UAA

Stop codons were historically given many different names, as they each corresponded to a distinct class of mutants that all behaved in a similar manner.

Amber mutations (UAG) were the first set of non-sense mutations to be discovered, isolated by Richard Epstein and Charles Steinberg and named after their friend Harris Bernstein (whose last name means ‘amber’ in German).

Ochre mutation (UAA) was the second stop codon mutation to be discovered.

Given a colour name to match the name of amber mutants, ochre mutant viruses had a similar property in that they recovered
infectious ability within certain suppressor strains of bacteria

Question 48. When a segment of chromosome breaks and later rejoins after 180° rotation, it is known as

Deletion
Duplication
Inversion
Interstitial translocation
Reciprocal translocation
Answer: 3. Inversion

In the inversion mutation, the chromosome breaks and later rejoins in an inverted (180° rotation) position.

Question 49. A transition type of gene mutation is caused when

GC is replaced by TA
AT is replaced by CG
CG is replaced by GC
AT is replaced by GC
Answer: 4. AT is replaced by GC

Transitions are substitution gene mutations in which a purine (say adenine) is replaced by another purine (say guanine) or a pyrimidine (say thymine) is replaced by another pyrimidine (say cytosine).

Change of codon ATC to GTC or ATT or ACC is an example of transition.

Question 50. Given below is a representation of a kind of chromosomal mutation. What is the kind of mutation represented?

 

Deletion
Duplication
Inversion
Reciprocal translocation
Answer: 3. Inversion

The kind of mutation represented is inversion. During inversion, a segment of the chromosome gets inverted in the process of reattachment.

Thus, a chromosome having the genes ABCDEFGH in linear order may get the segment BCD inverted. The new arrangement will be A D C B E F G H.

It is a chromosome aberration entailing two breaks in a chromosome followed by a reversal of the segment and consequently of the gene sequence in the segment.

Pericentric inversion includes the centromere in the inverted segment, whereas paracentric inversions do not include the centromere.

Question 51. Which of the following alterations of the codons ATTGCC is most serious?

ATCGCC
ATTGCA
ATTCCCGCC
ATTTGCC
Answer: 4. GC

In options 1 and 2, the given sequence is changed from ATTGCC to ATCGCC and ATTGCA respectively, by replacement of one base with another or substitution.

It changes only a single codon and thereby, replaces single amino acid with another, but the entire reading frame is not affected.

In option 3, the given sequence is changed from ATTGCC to TGCC by the addition of three bases and thus, one amino acid but there is no effect on the rest of the reading frame.

In option 4, the given sequence is changed from ATTGCC to AGC by the addition of T in 4th place.

The gene mutations that alter the base sequence of the whole genetic frame from the point of the mutation are called frame-shift mutations.

Here, the reading frame of the base sequence is shifted forward due to the insertion of one nucleotide base which in turn, changes the succeeding codon sequence from ATT- GCC to ATTTGC- C and causes the most serious alternation among the given options. Hence, option 4 is the correct answer

Question 52. The insertion or deletion of a base pair into the genetic code will cause a frame-shift mutation unless the number of base pairs inserted or deleted is

1
2
3
10
Answer: 3. 3

Frame-shift mutation occurs when one or two nucleotides are either added or deleted from DNA. The result of such mutation is the non-functioning of protein because the sequence of codons is altered.

However, when three or multiple of three base pairs are altered, frame-shift mutations do not occur

Question 53. In a mutational event, when adenine is replaced by guanine, it is a case of

Frameshift mutation
Transcription
Transition
Transversion
Answer: 3. Transition

Transitions are substitution gene mutations in which a purine (say adenine) is replaced by another purine (say guanine) or a pyrimidine (say thymine) is replaced by another pyrimidine (say cytosine).

Change of codon ATC to GTC or ATT or ACC is an example of transition.

Question 54. Translocation is a type of chromosomal aberration where

Parts of the chromosome are exchanged between homologous chromosomes
A part of one chromosome is exchanged between non-homologous counterpart
A part of one chromosome is shifted to its homologous counterpart
A part of one chromosome is shifted to another part of the same chromosome
Answer: 2. A part of one chromosome is exchanged between non-homologous counterpart

In translocations, when a portion of one chromosome is transferred to another chromosome.

There are two main types of translocations. In a reciprocal translocation, segments from two different chromosomes have been exchanged.

In a Robertsonian translocation, an entire chromosome has attached to another at the centromere; these only occur with
chromosomes 13, 14, 15, 21 and 22.

So, translocation is a type of chromosomal aberration where a part of one chromosome is exchanged between non-homologous counterparts.

Question 55. The type of chromosomal aberration indicated in the diagram is

 

Interstitial translocation
Reciprocal translocation
Pericentric inversion
Paracentric inversion
Interstitial deletion
Answer: 3. Pericentric inversion

The given diagram represents pericentric inversion as the centromere is included in it.

Question 56. Which one of the following is a wrong statement regarding mutations?

Deletion and insertion of base pairs cause frame-shift mutations
Cancer cells commonly show chromosomal aberrations
Uv and gamma rays are mutagens
Change in a single base pair of DNA does not cause mutation.
Answer: 4. Change in a single base pair of DNA does not cause mutation.

The statement in option 4 is wrong and can be corrected as a Change in single base pair of DNA is also a type of mutation called a point mutation.

It is a type of mutation that causes the replacement of a single base nucleotide with another nucleotide of the genetic material, DNA or RNA. For example, a point mutation is the cause of sickle cell disease. Rest all statements are correct regarding mutations.

Biology MCQ For NEET With Answers Sex Determination

Question 1. Sex-chromosomes are also called

1. Autosomes
2. Hybridisation
3. Allosomes
4. All of these

Answer:  3. Allosomes

Allosomes (also called sexchromosomes) are the chromosomes having a strong causal role in sexdetermination, usually present as a homologous pair in nuclei of one sex (homogametic sex), but occurring either singly (or with partial homologue) in those of other sex (heterogametic sex).

” pedigree analysis questions”

Question 2. The chromosomes except those associated with sex are known as

1. Heterosomes
2. Autosomes
3. Allosomes
4. Nucleosomes

Answer:  2. Autosomes

The 22 pairs of chromosomes are called autosomes, other than sex chromosome. So, autosomes are not associated with sex of organisms.

Read And Learn More: NEET Biology Multiple Choice Question And Answers

Question 3. Who discovered sex chromosome Y?

1. Robert Brown
2. MJD White
3. Nettie Stevens
4. GJ Mendel

Answer:  3. Nettie Stevens

The Y-chromosome was identified as a sex-determining chromosome by Nettie Stevens at Bryn Mawr College in 1905 during a study of the mealworm (Tenebrio molitor). Edmund Beecher Wilson independently discovered the same mechanisms in same year.

NEET Biology sex determination MCQs with answers

Question 4. Balance theory of sex-determination was proposed by

1. Calvin Bridges
2. Strassburger
3. TH Morgan
4. Waldeyer

Answer:  1. Calvin Bridges

“questions on principles of inheritance and variation “

The theory of genic balance was given by Calvin Bridges (1926). It states that instead of XY chromosomes, sex is determined by the genetic balance or ratio between X-chromosomes and autosome genomes. The theory is basically applicable to Drosophila melanogaster over which Bridges worked.

Biology MCQ For NEET With Answers

Sex determination multiple choice questions for NEET

Question 5. In which of these, the sex chromosome has been discovered for the first time?

1. Melandrium
2. Nephrolepsis
3. Pinus
4. Sphaerocarpus

Answer:  1. Melandrium

In Melandrium, the sex chromosome has been discovered for the first time.

Question 6. Sex-determination in an organism is given by, X/A=1.5, then organism will be

1. Male
2. Female
3. Super female
4. Intersex

Answer:  3. Super female

• Genic balance theory gives sexdetermination in Drosophila melanogaster. It states the ratio of number of chromosome to that of complete set of autosome determine the sex of Drosophila.
• According to this theory of sex- determination, if the ratio of X- chromosome to totalnumber of sets of autosome (X/A) is more than 1, the organism will be super female.
• If the ratio of X-chromosome to total number of sets of autosomes (X/A) falls between 1 and 0.5, the genotype will show intersex phenotype.
• The X/A value is 1.0 for normal female and 0.5 for normal male. Thus, in given condition, i.e. X/A=1.5, organism would be super female.

Biology MCQ For NEET With Answers

Question 7. For X-linkage, males are called as

1. Heterozygous
2. Hemizygous
3. Autozygous
4. Allozygous

Answer:  2. Hemizygous

inheritance and variation mcq

Hemizygosity is the condition, where only one gene pair is present that determines a particular genetic trait. Males are always hemizygous for X-linked traits, that is why, they can never be heterozygous or homozygous.

Question 8. In XX and XY chromosomal sexdetermination, females are

1. Homogametic
2. Heterogametic
3. Undetermined
4. All of these

Answer:  1. Homogametic

• XX and XY type sex-determination seen in many insect and mammals including humans. Males have X and Y-chromosomes along with autosomes and females have pair of X- chromosome along with autosomes.
• Thus, since females produce same type of gametes it is known as homogametic sexdetermination.

Question 9. Genes of sex-linked characters are located on the ………………. .

1. Chromosome 18
2. Chromosome 13
3. Chromosome 14
4. Sex chromosome

Answer:  4. Sex chromosome

The characters are said to be sexlinked if their genes are located on the sex chromosome. According to modern genetics, the X-chromosome linked character, is called sex-linked character, while Y-linked characters are called male limited characters.

Biology MCQ For NEET With Answers

Question 10. Males are haploid whereas females are diploid in

1. Drosophila
2. Amoeba
3. Honeybee
4. Neurospora

Answer:  3. Honeybee

• Haplodiploidy is a sex-determination system in which males develop from unfertilised eggs and are haploid and females develop from fertilised eggs and are diploid.
• Haplodiploidy determines the sex in all members of the insect orders– Hymenoptera (bees, ants, honeybee and wasps) and Thysanoptera (thrips).

“pedigree questions “

Question 11. In Melandrium, the sexdetermination type is

1. XX-XY type
2. XX-XO type
3. ZZ-ZW type
4. XY-XO type
5. XO-ZZ type

Answer: 1. XX-XY type

In Melandrium, staminate or male plants are XY and pistillate or female plants are XX. So, Melandrium shows XX-XY type of sex-determination

Biology MCQs with answers for NEET

Question 12. In Melandrium plants, presence of 2 pairs of autosome and an allosomal composition of XXY would make them

1. Males
2. Females
3. Sterile
4. Intersexes

Answer:  1. Males

• Melandrium album, a dioecious plant species, has two heteromorphic sex chromosomes. XY constitution is typical for male and the XX for female plants.
• This plant represents an experimental model system of sex-determination in which the Y-chromosome plays a strongly dominant male role. In Melandrium plants, presence of 2 pairs of autosome and an allosomal composition of XXY would make them males.

Question 13. Holandric genes are ones situated on

1. X-chromosome
2. Y-chromosome
3. Both 1 and 2
4. Autosomes

Answer:  2. Y-chromosome

Holandric genes are present on the differential region of the Y-chromosome. The differential regions carry completely sex-linked genes and they do not undergo crossing over.

Important sex determination questions for NEET exam

Question 14. Homologous chromosomes which are present in male and female both are known as

1. Heterosomes
2. Replosomes
3. Androsomes
4. Autosomes

Answer:  4. Autosomes

Autosomes are homologous chromosomes, i.e. chromosomes which contain the same genes (regions of DNA) in the same order along their chromosomal arms.

Biology MCQs with answers for NEET

Question 15. Which one is found in the males only?

1. X-chromosome
2. Y-chromosome
3. 2X-chromosomes
4. X+X-chromosomes

Answer:  2. Y-chromosome

The sex chromosome of male is denoted by ‘Y’. Since, males are heterogametic, the chromosome component is written as 44 + XY. They do not contian two X-chromosomes together.

“mcq on principles of inheritance and variation “

Question 16. Sex-linked characters have one distinct feature.

1. Always follow criss-cross inheritance
2. Never follows criss-cross inheritance
3. May be present on Y-chromosome
4. Only present on X-chromosome

Answer:  1. Always follow criss-cross inheritance

Criss-cross inheritance is applicable to most sex-linked disorders in humans, e.g. red-green colour blindness, haemophilia. So, sex-linked characters always follow criss-cross inheritance.

Question 17. Recessive characters are expressed

1. On any autosome
2. When they are present on X-chromosomes of male
3. On both the chromosomes of male
4. When they are present on one X-chromosome of female

Answer:  2. When they are present on X-chromosomes of male

Recessive characters are expressed when they are present in homozygous condition or when other chromosome of the chromosome pair does not possess that character, e.g. in male, the sex chromosomes are XY, as Y does not possess any recessive gene, only X is enough to express that recessive characters.

Biology MCQs with answers for NEET

Question 18. In case of birds, the females are

1. Homogametic
2. Heterogametic
3. Both 1 and 2
4. None of the above

Answer:  2. Heterogametic

In birds, females are heterogametic, i.e. ZW, whereas males are homogametic, i.e. ZZ.

Solved MCQs on sex determination for NEET Biology

Question 19. Which of the following symbols are used for representing chromosome of birds?

1. ZZ-ZW
2. XX-XY
3. XO-XX
4. ZZ-WW

Answer:  1. ZZ-ZW

• In birds, some reptiles and fishes, the females have heteromorphic (ZW) sex chromosomes and are hence they are heterogametic (A + Z, A + W).
• W-chromosome determines the female sex. The males have homomorphic sex chromosomes (ZZ) and hence, they are homogametic (A+Z).

Question 20. Genic balance theory of sexdetermination, stated by CB Bridges, is related to

1. Drosophila melanogaster
2. Rumex
3. Snapdragon
4. None of the above

Answer: 1. Drosophila melanogaster

Biology MCQs with answers for NEET

Question 21. Criss-cross inheritance means

1. X-chromosome from male will pass to a male of next generation
2. X-chromosome from a male will pass to a female of next generation
3. X-chromosome from female will pass to female of next generation
4. X -chromosome from male will pass to either male or female of the next generation

Answer:  2. X-chromosome from a male will pass to a female of next generation

• Criss-cross inheritance is a type of sex-linked inheritance, where a parent passes the traits to the grand child of the same sex through offspring of the opposite sex, that is, father passes the traits to grandson through his daughter (diagynic), while the mother transfers traits to her grand-daughter through her son (diandric).
• It was first studied by Morgan (1910) in case of eye colour in Drosophila. Thus, option (b) is correct.

Question 22. Which one of the following conditions correctly describes the manner of determining the sex in the given example?

1. XO type of sex chromosomes determine male sex in grasshopper
2. XO condition in humans as found in Turner’s syndrome, determines female sex
3. Homozygous sex chromosomes (XX) produce male in Drosophila
4. Homozygous sex chromosomes (ZZ) determine female sex in birds

Answer:  1. XO type of sex chromosomes determine male sex in grasshopper

• XO type of sex chromosomes determines the male sex in grasshopper. In grasshopper, the males lack a Y-sex chromosome and have only one X-chromosome.
• They produce sperm cells that contain either an X-chromosome or no sex chromosome, which is designated as O.

“which of the following is a hereditary disease “

Question 23. In gynandromorphs,

1. Some cells of body contain XX and some cells with genotype XY
2. All cells have XX genotype
3. All cells have XY genotype
4. All cells with genotype XXY

Answer:  1. Some cells of body contain XX and some cells with genotype XY

• Gynandromorphs arise when proper segregation of XX and XY-chromosome doe not take place in development phase of a organism.
• Therefore, some cells gets XX-chromosome, while other get XY-chromosomes. As a result, some part of the organisms appears as female and some part appeared as male. Thus, option (1) is correct.

NEET Biology Mcq

Question 24. Calvin Bridges demonstrated sex determining factor is the ratio of number of

1. X-chromosome and autosomes
2. autosome and X-chromosome
3. Y-chromosome and X-chromosome
4. Y-chromosome and autosome

Answer:  1. X-chromosome and autosomes

Calvin Bridges (1926) stated that sex in Drosophila is determined by the genic balance or ratio between X-chromosomes and autosomes.

Question 25. …………… variations are inheritable.

1. Germinal
2. Physical
3. Mental
4. Accidental

Answer:  1. Germinal

Germinal variations arise due to changes in germ cells. They may be caused due to radiations, modification of chromosome structure. These variations are inheritable.

Question 26. Example of environmental determination of sex is/are

1. Alligators
2. Turtles
3. Bonellia
4. All of these

Answer:  4. All of these

• All given options represents example of environmental sex-determination. In Bonellia, a marine worm, the swimming larva has no sex. If it settles on the bottom of the water body alone, it develops into a large (2.5 cm) female.
• If it lands on or near an existing female, a chemical from female causes the larva to develop into a tiny (1.3 mm) male.
• In turtles and alligators, a temperature below 28°C produces more males and temperature above 33°C produces more females.
• Temperature between 28°C-33°C produces males and females in equal proportion. Thus, option (4) is correct.

“which of the following is a hereditary disease “

Question 27. Haploid-diploid mechanism of sexdetermination (haplodiploidy) takes place

1. Bees
2. Wasps
3. Ants
4. All of these

Answer:  4. All of these

Haploid-diploid mechanism of sex-determination (haplodiploidy) occurs in hymenopterous insect such as bees, wasps and ants. These insects have unique phenomena in which an unfertilised egg (N) develops into male and female develops from fertilised egg (2N).

Thus, option 4. is correct.

Genetic basis of sex determination NEET MCQs with answers

Question 28. Females in haplodiploidy sex determination are

1. n
2. 2n
3. 4n
4. 3n

Answer:  2. 2n

Females in haplodiploidy sex-determination are (2n).

NEET Biology Mcq

Question 29. In haplodiploidy, determination of male sex is

1. Haploid
2. Diploid
3. Haplodiploid
4. Diplohaploid

Answer:  1. Haploid

In haplodiploidy sexdetermination, male sex is haploid (N).

Question 30. How many conditions exhibit in dissimilar sex chromosomes?

1. 2
2. 3
3. 4
4. 5

Answer:  3. 4

Four conditions exhibit in dissimilar sex chromosomes. These are

• • XX and XY
  • XX and XO
  • ZW and ZZ
  • ZO and ZZ

Question 31. Drosophila with 2A+XO are

1. Fertile female
2. Infertile female
3. Sterile male
4. Intersexes

Answer:  3. Sterile male

• If there is one X-chromosome in a diploid cell (1X:2A), the fly is male. If there are two X-chromosomes in a diploid cell (2X:2A), the fly is female (Bridges 1921, 1925).
• Thus, XO Drosophila are sterile males. In flies, the Y-chromosome is not involved in determining sex.

NEET Biology Mcq

Question 32. A fruitfly is heterozygous for sex-linked genes. When mated with a normal female fruitfly, the male specific chromosome will enter egg cells in the proportion of

1. 1: 1
2. 1: 2
3. 3: 1
4. 7: 1

Answer:  1. 1: 1

In sex-determination, the male specific chromosome will have half as much chance as the other to enter the egg cell. Hence, the proportion will be 1: 1.

Question 33. XO type of sex-determination is seen in

1. Man
2. Grasshopper
3. Drosophila
4. Birds
5. Horse

Answer:  2. Grasshopper

Insect, grasshopper, cockroaches and bugs have XX and XO type of sex determination in which XO happens to be male and XX happens to be female.

Question 34. In XO type of sex-determination,

1. Females produce two different types of gametes
2. Males produce two different types of gametes
3. Females produce gametes with Y- chromosomes
4. Males produce single type of gametes
5. Males produce gametes with Y- chromosome

Answer:  2. Males produce two different types of gametes

• In XX-XO type of sexdetermination, the females have two sex chromosomes and are designated as XX, while the males have only one sex chromosome X, therefore, they are designated as XO.
• The females are homogametic because they produce only one type of egg (A + X). The males are heterogametic with half the male gametes carrying X-chromosome (A+X), while other half being devoid of it (A + O). The sex ratio produced in progeny is 1: 1.

Thus, males produce two different types of gametes.

Best multiple choice questions on sex determination for NEET preparation

Question 35. The condition in which females lack one sex chromosome whereas males are homogametic, the sex chromosomal representation is

1. ZO-ZZ
2. XY-XX
3. XX-XO
4. ZW-ZZ

Answer:  1. ZO-ZZ

ZO and ZZ type of sexdetermination mechanism occurs in certain butterflies and moths. The female is heterogametic and produces two types of eggs, half with Z and half without Z-chromosome. The males are homogametic and forms only one kind of sperms, each with Z-chromosome.

ZO-ZZ type of sex-determination

Question 36. ZW method of sex-determination is applicable to

1. Birds
2. Fish
3. Butterfly
4. All of these

Answer:  4. All of these

ZW and ZZ-type of sex determination mechanism operates in certain insects (butterflies and moths) and in vertebrates (fishes, reptiles and birds).

Question 37. Heterogamety is the term where an individual produces two types of gametes. The most appropriate answer is

1. Male Drosophila fly
2. Female Drosophila fly
3. Female bird
4. Both 1 and 3

Answer:  4. Both 1 and 3

• Heterogamety is the term used where an individual produces two types of gametes. Depending upon the sex-determination mechanism in the species, either males or females can be heterogametic sex, producing two different types of gametes.
• In Drosophila, female has XX genotype and male has XY genotype. In birds, female has ZW genotype and males have ZZ genotype. Thus, option (4) is correct.

Question 38. Match the following columns.

Answer:  1. A–2, B–4, C–1, D–3

NEET Biology Mcq

Question 39. The traits which are not expressed due to a particular gene, but are expressed by products of sex hormones are

1. Sex influenced traits
2. Autosomal traits
3. Allosomic traits
4. Sex-linked traits

Answer:  1. Sex influenced traits

• The traits are not expressed due to particular genes, but are expressed by products of sex hormones are sex influenced traits, e.g. low pitched voice, bearding moustaches.
• In males, pattern baldness is related to both autosomal genes as well as excessive secretion of testosterone.

Question 40. An unfertilised human egg contains

1. Two X-chromosomes
2. One X-and one Y-chromosome
3. One Y-chromosome only
4. One X-chromosome only

Answer:  4. One X-chromosome only

An unfertilised human egg contains only one X-chromosome. A human sperm contains either an X or a Y-chromosome, thereby determining the sex of the offspring after fertilisation (XX = female, XY = male).

NEET Biology X and Y chromosome sex determination MCQs

Question 41. If the expression of a trait is limited to one sex, it is sex ……………. trait.

1. Linked
2. Influenced
3. Expressed
4. Limited

Answer:  4. Limited

Sex limited genes are those which express characters in only one sex and are located on allosomes or autosomes. For example, beard in man due to testosterone and breast development in female.

Question 42. In human sex-determination, the key factor is

1. Y-chromosome
2. X-chromosome
3. Both 1 and 2
4. None of these

Answer:  1. Y-chromosome

The Y-chromosome carries a gene that encodes a testis determining factor. Unlike the situation in Drosophila, the mammalian Y-chromosome is a crucial factor for determining sex in humans.

Question 43. Human females have

1. 46 autosomes
2. 44 autosomes
3. 2 pairs of allosomes
4. 23 pairs of autosomes

Answer:  2. 44 autosomes

• In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. 22 of these pairs, called autosomes, look the same in both males and females.
• The 23rd pair, the sex chromosomes, differs between males and females. Thus, human female has 22 pairs or 44 autosomes and one pair or 2 allosomes

Question 44. As per Denver Convention, the autosomes of man have been classified in …….. groups.

1. 7
2. 4
3. 3
4. 16

Answer:  1. 7

• The Denver system of classification divide human chromosomes including sex chromosomes into 7 groups from A to G in order of decreasing length.
• Group A includes chromosomes pairs 1, 2, 3 group, B has pairs of 4 and 5 chromosomes, group C has pairs of 6 to 12 chromosomes, group D has pairs of 13 to 15 chromosomes, group E has pairs of 16 to 18 chromosomes, group F has pairs of 19 and 20 chromosomes and group G has pairs of 21 and 22 chromosomes.

Question 45. In man, sperms contain autosomes and

1. Both X and Y-chromosomes
2. Either X or Y-chromosomes
3. Only Y-chromosome
4. Only X-chromosome

Answer:  4. Either X or Y-chromosomes

XX and XY type of sexdetermination is seen in many insect and mammals including humans. Males have X and Y-chromosome along with autosome and females have pair of X- chromosome along with autosome. In man, sperm contains autosomes and either X or Ychromosomes.

Question 46. There are five daughters and no son in a family. It may be due to

1. Father produced only X containing sperms
2. Father produced no sperms at all
3. Y type sperms are weaker and not effective
4. By chance each time X sperm fertilised the egg

Answer:  4. By chance each time X sperm fertilised the egg

There are five daughters and no son in a family because by chance, each time X sperm fertilised the egg.

Question 47. Sex-limited and sex-linked genes are located on

1. Autosomes
2. X-chromosome
3. Y-chromosome
4. Both 2 and 3

Answer:  2. X-chromosome

The traits which are carried on sex chromosomes are called sex linked traits. The genes for the traits are only located on X-chromosomes (sex-linked and sex-limited) of both male and female organisms. X-chromosome is large and contains more genes, whereas Y-chromosomes are small.

Question 48. A couple has 6 children, 5 of which are girls and 1 is boy. The percentage of having a girl child on next time is

1. 10%
2. 20%
3. 50%
4. 100%

Answer:  3. 50%

Probability of child being boy or girl is 50% during each pregnancy.

Thus, option 3. is correct.

Question 49. Find out A, B and C in the diagram given below.

1. A–Male gamete, B–Female, C–Gametes
2. A–Male, B–Female, C–Sperm
3. A–Female, B–Male, C–Gametes
4. A–Gametes, B–Female, C–Male

Answer:  4. A–Gametes, B–Female, C–Male

A–Gametes, B–Female, C–Male

Question 50. A mother in a family of five daughters is expecting her sixth baby. The chance of this being a son is

1. 0%
2. 25%
3. 50%
4. 100%

Answer:  3. 50%

Humans has 22 pairs of autosomes and 1 pair of sex chromosome which are XX in females and XY in males. So, every time, the chance of son or daughter is 50% depending upon which sex chromosome from male fertilises the ovum.

Question 51. Gamete mother cells of the chromosome 44 + XY suffers from non-disjunction at first meiotic division. Identify the set of gametes in which this condition would occur

1. 22 + XX, 22 + YY and 22, 22
2. 22 + XY, 22 + XY and 22, 22
3. 22 + X, 22 + Y and 22+Y, 22
4. 22 + X, 22 +X and 22+Y, 22+Y

Answer:  2. 22 + XY, 22 + XY and 22, 22

• Non-disjunction is the condition in which the separation of chromosome does not take place during cell division. In 44+XY gametes there is non-separation of XY gene.
• It leads to the formation of sperm having genotypes, 22 + XY and 22. In such condition, XY would be inherited together due to non-disjunction of XY chromosome.

Question 52. Mr. Kapoor has Bb autosomal gene pair and d allele sex-linked. What shall be proportion of Bd in sperms?

1. zero
2. 1/2
3. 1/4
4. 1/8

Answer:  3. 1/4

Genotype of Mr. Kapoor will be Bb, hence one fourth of the sperms will have Bd.

Question 53. Probability of four sons to a couple is

1. 1/4
2. 1/8
3. 1/16
4. 1/32

Answer:  3. 1/16

In each pregnancy, there is 1/2 probability of having either sex, i.e. male or female. Hence, probability of four sons to a

(\(\frac{1}{2}\))⁴ = \(\frac{1}{2}\)×\(\frac{1}{2}\)×\(\frac{1}{2}\)×\(\frac{1}{2}\)

=\(\frac{1}{16}\)

Biology MCQ For NEET With Answers – Chromosomal Basis Of Inheritance

Question 1. The word chromosome simply refers to

1. Painted body
2. Coloured body
3. Doubling body
4. Thread-like body

Answer:  2. Coloured body

The word chromosome is derived from Chrom-coloured; some- body. Therefore, the meaning of chromosome is the coloured body.

Question 2. Chromosome theory of inheritance was proposed by

1. Sutton and Boveri
2. Bateson and Punnett
3. TH Morgan
4. Watson and Crick

Answer:  1. Sutton and Boveri

Read And Learn More: NEET Biology Multiple Choice Question And Answers

The chromosomal theory of inheritance proposed by Sutton and Boveri. It states that chromosomes are the vehicles of genetic heredity. Neither Mendelian genetics nor gene linkage is perfectly accurate, instead, chromosome behaviour involves segregation, independent assortment, and occasionally, linkage.

Question 3. Chromosome theory states that

1. Genes are located on chromosome
2. Chromosome is made up of DNA
3. Chromosome is made up of RNA
4. All of the above

Answer:  1. Genes are located on chromosome

inheritance and variation mcq

Chromosome theory states that genes are located on specific locations on chromosome. According to chromosomal theory of inheritance, the behaviour of chromosomes and its location can explain Mendel’s law of inheritance.

Biology MCQ For NEET With Answers

NEET Biology Cancer MCQs with Answers

Question 4. Sometimes chromosome number increases or decreases due to

1. Mutagenic change
2. Non-disjunction of chromosome
3. Genetic repeats
4. All of the above

Answer:  2. Non-disjunction of chromosome

Sometimes chromosome number increases or decreases due to non-disjunction of chromosome. It refers to condition of failure of homologous chromosomes or sister chromatids to separate during cell division.

Question 5. For the preparation of genetic maps, the recombination frequencies between genes are additive over short distances but not over long distances, due to

1. Multiple crossover
2. Lethal mutation
3. Epistasis
4. Synaptonemal complex

Answer:  1. Multiple crossover

• The frequency of crossing over and hence recombination between two genes is directly proportional to the physical distance between the two.
• In other words, two genes which are nearest to each other in the chromosomes will have least crossing over or recombination between them. On the other hand, two genes which have the maximum distance between them on the chromosome will have the maximum percentage of crossing over or recombination.
• Thus, the recombination frequencies between genes are additive over short distances but not over long distances due to multiple crossover for the preparation of genetic maps.

inheritance and variation mcq

Question 6. Normally, all genes occur in pairs occupying position on the Xchromosome and not on Ychromosome. This indicates that

1. Y-chromosome is larger than X-chromosome
2. entire set of genes on X is different from those on Y-chromosome
3. X-chromosome is larger than Y-chromosome
4. X-chromosome is dominating with Y-chromosome

Answer:  3. X-chromosome is larger than Y-chromosome

Normally, all genes occur in pairs on the

• X-chromosome and not on
• Y-chromosome. This indicates that
• X-chromosome is larger than
• Y-chromosome. Y-chromosome is much shorter than the X-chromosome.

Biology MCQ For NEET With Answers

Question 7. Crossing over in diploid organism is responsible for

1. Segregation of alleles
2. Recombination of linked alleles
3. Dominance of genes
4. Linkage between genes

Answer:  2. Recombination of linked alleles

Exchange of chromatid segments between the non-sister chromatids of a bivalent is called crossing over. It occurs during pachytene of prophase-I and it is responsible for recombination of genes.

Question 8. Alleles of different genes that are on the same chromosome may occasionally be separated by a phenomenon known as

1. Pleiotropy
2. Epistasis
3. Continuous variation
4. Crossing over

Answer:  4. Crossing over

Crossing over is separation of alleles of different genes that are present on the same chromosome.

Important MCQs on Cancer for NEET Biology

Question 9. Genetic traits are often carried on separate chromosomes. Which of the following genotype represents a heterozygous dihybrid organism?

1. TTRR
2. TtRr
3. Ttrr
4. TtRr

Answer:  2. TtRr

Dihybrid organism is heterozygous for two particular factors. It is obtained by a cross between parents that are homozygous for two factors in consideration. A cross between TTRR and ttrr results into heterozygous dihybrid TtRr. Genetic traits are often carried on separate chromosomes.

Question 10. Recombination of alleles of two genes, A and B following crossing over will hypothetically result in four allelic recombinations. In the absence of crossing over, the two parental combinations would be formed as

1. AB and ab type
2. AB and Ab type
3. ab and aB type
4. AB, ab, Ab and aB

Answer:  1. AB and ab type

• In normal conditions, there are chances of crossing over and four types of gametes are formed. These gametes show linkage in 50% of the gametes and 50% of the gametes are of recombination type.
• The crossing over occurs in between the two non-sister chromatids of a homologous chromosome pair only and the other two chromatids are not involved. If there is no crossing over then, only two types of gametes will be formed. So, the parental combination would be AB and ab as 1:1 in the absence of recombination.

Biology MCQ For NEET With Answers

Question 11. Linkage was discovered by

1. Miller
2. Morgan
3. De Vries
4. Mendel

Answer:  2. Morgan

• The hypothesis that linked genes tend to remain in their original combinations because of their location in the same chromosome was given by TH Morgan in 1991.
• Morgan stated that the pairs of genes of homozygous parent tend to enter in the same gametes and to remain together, whereas same genes from heterozygous parent tend to enter in the different gametes and remain apart from each other.

inheritance and variation mcq

Question 12. The unit of linkage map is

1. Map unit
2. Morgan
3. CentiMorgan
4. Both 1 and 3

Answer:  4. Both 1 and 3

In genetics, a centiMorgan (abbreviated cM) or map unit (mu) is a unit for measuring genetic linkage. It is defined as the distance between chromosome positions (also termed loci or markers) for which the expected average number of intervening chromosomal crossovers in a single generation is 0.01.

Thus, option (4) is correct.

Question 13. Coupling and repulsion hypothesis was given by

1. Bateson and Morgan
2. Morgan and Punnett
3. Bateson and Punnett
4. Morgan and Muller

Answer:  3. Bateson and Punnett

Bateson and Punnett (1906) proposed that dominant alleles as well with recessive alleles tend to remain together due to gametic coupling. If dominant and recessive alleles are present in different parents, they tend to separate due to repulsion.

Causes and Types of Cancer MCQs for NEET

Question 14. The functional unit of gene is

1. Cistron
2. Muton
3. Recon
4. Exon

Answer:  1. Cistron

The functional unit of gene has been called cistron by Benzer because it is a chromosomal segment within which the cis-trans effect operates. The cistron represents a segment of the DNA molecule and consists of a linear sequence of nucleotides which controls some cellular functions.

Biology MCQ For NEET With Answers

Question 15. Linkage was first suggested by

1. Sutton and Boveri
2. Morgan
3. De Vries
4. Pasteur

Answer:  1. Sutton and Boveri

Linkage was first suggested by Sutton and Boveri when they formulated the famous ‘chromosomal theory of inheritance’. Betason and Punnett (1906) while working on sweet pea also noticed that some factors remain together and do not show recombination or segregation.

Question 16. Linkage and crossing over are

1. Same phenomena
2. Different phenomena
3. Opposite phenomena
4. Identical phenomena

Answer:  3. Opposite phenomena

• Strength of linkage between two genes is inversely proportional to the distance of two genes. This means, if two genes are closely placed then they have high percentage of linkage and if, they are placed far then there is low percentage of linkage.
• Linkage and recombination are two opposite phenomena. In linkage, two genes remain united and in recombination, the two genes go apart due to crossing over during gametogenesis (meiosis).

NEET Biology Mcq

Question 17. Which of the following banding group is used in staining both plant and animal chromosomes?

1. C-group
2. G-group
3. R-group
4. N-group

Answer:  1. C-group

inheritance and variation mcq

• Group banding is used in staining both plant and animal chromosomes. Chromosomes are stained with special fluorescent dyes that have differential affinity for difficult parts of chromosomes.
• There are many types of staining techniques, which show different banding patterns. C-banding is common to both plants and animals. It stains region having constitutive heterochromatin.

Question 18. Frequency of crossing over will be relatively more if

1. Distance between the two genes is less
2. Distance between the two genes is more
3. Linked genes are more
4. Both 2 and 3

Answer:  2. Distance between the two genes is more

• Frequency of actual crossing over is always proportional to the distance between the two genes. If two genes (mutations or markers) are far apart, the chance of crossing over between them and producing recombinant chromosomes is large.
• If two genes are close together, the chance of crossing over between them is small.

Question 19. After crossing two plants, the progenies are found to be male sterile. This phenomenon is found to be maternally inherited and is due to some genes which reside in

1. Mitochondria
2. Cytoplasm
3. Nucleus
4. Chloroplast

Answer:  1. Mitochondria

• In several crops like maize cytoplasmic control of male sterility is known. In such cases, if female parent is male sterile, F1 progeny would also be male sterile because cytoplasm is mainly derived from egg obtained from male sterile female parent.
• Many experiments have proved that factors responsible for cytoplasmic male sterility are located in mitochondrial DNA. A particular phenotype arises because of dominant mutations in the mitochondrial genome.

Topic-wise Cancer MCQs for NEET with Explanation

Question 20. Failure of the two homologous chromosomes to separate and move towards opposite poles during anaphase-I is called

1. Crossing over
2. Non-disjunction
3. Linkage
4. Recombination

Answer:  2. Non-disjunction

Non-disjunction is the condition in which the separation of chromosome does not take place
during cell division.

Question 21. Which of the following statements is not true about homologous recombination?

1. Exchange of homologous segments
2. Exchange takes place between two homologous DNA molecules
3. It is also termed as general recombination
4. It involves a direct exchange of sequences of DNA

Answer:  4. It involves a direct exchange of sequences of DNA

Statement in option (4) is not true and can be corrected as Homologous recombination involves
a reciprocal exchange of sequences of DNA. Rest other statements are true about homologous recombination.

Question 22. The cytoplasmic units of inheritance are called as

1. Genome
2. Lethal gene
3. Plasmagenes
4. All of these

Answer:  3. Plasmagenes

Cytoplasmic inheritance or non-chromosomal (extranuclear) inheritance is the passage of traits from parents to offspring through structures present inside the cytoplasm of contributing gametes. Plasmagenes occur in plastids, mitochondria, plasmids and some special particles like Kappa particles, sigma particles, etc. So, the cytoplasmic units of inheritance are called as plasmagenes.

NEET Biology Mcq

Question 23. A set of genes will be in a complete linkage when the progeny phenotypes for parental (P) and recombinant (R) types are

1. P = 0%, R = 100%
2. P = 50%, R = 50%
3. P < 50%, R> 50%
4. P = 100%, R = 0%

Answer:  4. P = 100%, R = 0%

• In complete linkage, the progeny phenotypes are P = 100%, R = 0%. Here, P refers to parental type and R refers to recombinant type.
• The genes located on the same chromosome do not separate and are inherited together over the generations due to the absence of crossing over.
• It allows the combination of parental traits to be inherited and recombinant types are absent.

Question 24. The number of linkage group in E.coli is/are

1. 4
2. 2
3. 1
4. 5

Answer:  1. 1

• Linkage group refers to the genes linked together in a single chromosome. Number of linkage groups in an organism is equal to its haploid number of chromosomes.
• For example, in Drosophila, the haploid number (n) is 4 so linkage group is 4. But the number of linkage group in prokaryotes like E. coli is one. This is because bacteria being prokaryotes have a single circular chromosome only.

Question 25. Physical association of genes on a chromosome is called

1. Repulsion
2. Linkage
3. Aneuploidy
4. Duplication
5. Polyploidy

Answer:  2. Linkage

Linked genes are present close together on a chromosome, making them likely to be inherited together. It refers to the physical association of genes on a chromosome. Thus, option (b) is correct.

inheritance and variation mcq

Question 26. In a test cross involving F1 dihybrid flies, more parental type offspring were produced than the recombinant type offspring. This indicates

1. The two genes are linked and present on the same chromosome
2. Both of the characters are controlled by more than one gene
3. The two genes are located on two different chromosomes
4. Chromosomes failed to separate during meiosis

Answer: 1. The two genes are linked and present on the same chromosome

If in a test cross involving F1 dihybrid flies more parental combinations appear as compared to the recombinants in F₂ -generation, then it is indicative of involvement of linkage.

Linkage is the tendency of two different genes on the same chromosome to remain together during the separation of homologous chromosomes at meiosis.

Biology MCQ For NEET With Answers

Question 27. What is pseudoallele?

1. Allele with similar function
2. Allele with similar structure
3. Alleles with similar function and structure
4. Alleles with similar function and different structure

Answer:  4. Alleles with similar function and different structure

When two types of allele have similar functions, but different structures, these are called pseudoalleles. These are located in close proximity.

Question 28. In sweet pea, genes C and P are necessary for colour in flowers. The flowers are white in the absence of either or both the genes. What will be the percentage of coloured flowers in the offspring of the cross Ccpp × ccPp?

1. 75%
2. 25%
3. 100%
4. 50%

Answer:  2. 25%

It is a dihybrid cross, Ccpp x ccPp (both are white). We know that in Ccpp x ccPp, Male gametes are Cp, cp Female gametes are cP, cp Hence, ratio = l (coloured): 3 (white), i.e. 25% coloured flowers.

Question 29. Recombination of genes occur at

1. Prophase-1 in mitosis
2. Prophase-1 in meiosis
3. Prophase-2 in meiosis
4. Metaphase-2 in meiosis

Answer:  2. Prophase-1 in meiosis

Recombination occurs when two molecules of DNA exchange pieces of their genetic material with each other. It occurs during pachytene stage of prophase-1, of meiosis-1.

Question 30. Assertion (A) The linked genes tend to get inherited together. Reason (R) The link between them fails to break.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. Both A and R are false

Answer:  1. Both A and R are true and R is the correct explanation of A

Both A and R are true and R is the correct explanation of A. When two genes are close together on the same chromosome, they do not assort independently and are said to be linked. The linked gene tends to get inherited together as the link between them fails to break.

Biology MCQ For NEET With Answers

Question 31. Distance between two linked genes upon a chromosome is measured in crossover units. It is

1. Ratio of crossing over between them
2. Crossover value
3. Number of other genes between them
4. None of the above

Answer:  2. Crossover value

• Distance between two linked genes upon a chromosome is measured in crossover units or the crossover value. Crossover unit is the percentage of recombinant in an organism.
• In diploid organisms, most easily measured method is by crossing the double heterozygote to the double recessive. The percentage can never exceed 50%. This value gives the map distance between the two loci, used in chromosome mapping.

Question 32. Neurospora is widely used in genetic studies. Pick out the false statement.

1. They can be cultured easily in the lab
2. Being haploid the recessive gene can express themselves
3. Crossing over is rare phenomenon and it cannot be detected
4. They have short life cycle of 10 days

Answer:  3. Crossing over is rare phenomenon and it cannot be detected

Statementin option (3) is false and can be corrected as Neurospora follow Mendelian genetics which means that even closely placed genes are segregated independently and do not show linkage, but follow crossing to form new genetic combination. Rest statements are true.

Question 33. Neurospora is useful in genetics because Uttaranchal

1. 8 ascospores are arranged linearly in ascus
2. 4 ascospores are arranged linearly in ascus
3. Of formation of ascospores
4. Of formation of sac-like fruit body

Answer:  1. 8 ascospores are arranged linearly in ascus

• Neurospora is an ascomycete fungus, haploid and grows as a mycelium. It has two mating types and fusion of nuclei of two opposite types leads to meiosis followed by mitosis.
• The resulting 8 nuclei generate eight ascospores, arranged linearly in an ordered fashion in a pod-like ascus so that the various products of meiotic division can be identified.

Biology MCQ For NEET With Answers

Question 34. Both chromosome and gene (Mendelian factors) whether dominant or recessive are transmitted from generation to generation in which form?

1. Changed
2. Unaltered form
3. Altered form
4. Disintegrated

Answer:  2. Unaltered form

Both genes and chromosomes (Mendelian factors) whether dominant or recessive are transmitted
from generation to generation in the pure or unaltered form. It is also called law of purity of gametes.

Question 35. A condition where a certain gene is present in only a single copy in a diploid cell is called

1. Heterozygous
2. Monogamous
3. Homozygous
4. Hemizygous

Answer:  4. Hemizygous

inheritance and variation mcq

• A condition where only one gene or allele of allelic pair is present is called hemizygous condition. Other options are explained as Homozygous or pure organism have two similar genes or alleles for a particular character in a homologous pair of chromosomes, e.g. TT or tt.
• Heterozygous or hybrid organism contains two different alleles or individuals contain both dominant and recessive genes of an allelic pair, e.g. Tt. Monogamy is the relationship of spending complete life with single partner

Question 36. If a gamete has 16 chromosomes, what will be the number of chromatids before anaphase-1?

1. 8
2. 16
3. 32
4. 64

Answer:  1. 8

After anaphase-I, the chromosome number doubles. As after anaphase-I, the number of chromosomes is 16. So, before anaphase-I, the number of chromosome would be n = 16/2 = 8 So, the cell has progressed from having 8 chromosomes to 16 chromosomes after anaphase-I.

Question 37. Chromosomes as well as genes occur in …A…. The two alleles of a gene pair are located on homologous sites on …B… chromosomes. Choose the correct choice for A and B.

1. A-single, B-analogous
2. A-pair, B-analogous
3. A-pair, B-homologous
4. A-single, B-heterozygous

Answer:  3. A-pair, B-homologous

Chromosome always occur in pair (A) and when located on homologous sites, they are called homologous (B) chromosome.

NEET Biology Oncogenes and Tumor Suppressor Genes MCQs

Question 38. Number of linkage groups in Pisum sativum

1. 2
2. 4
3. 7
4. 8

Answer:  3. 7

Number of linkage groups in Pisum sativum is 7 because it contain 14 chromosomes.

Question 39. The commonly used animal in genetics is

1. Escherichia coli
2. Drosophila
3. Neurospora
4. Chlorella

Answer:  2. Drosophila

• A wide variety of animals have previously been used for animal testing including mice, flies and monkeys.
• A particularly useful model organism is Drosophila melanogaster, a type of fruitfly. This fly has become the main invertebrate model used to study developmental genetics.

Question 40. Select the correct statement from the ones given below with respect to dihybrid cross.

1. Tightly linked genes on the same chromosome show higher recombinations
2. Genes far apart on the same chromosome show very few recombinations
3. Genes loosely linked on the same chromosome show similar recombinations as the tightly linked
   ones
4. Tightly linked genes on the same chromosome show very few recombinations

Answer:  4. Tightly linked genes on the same chromosome show very few recombinations

• Statement in option (4) is correct with respect to dihybrid cross. When two genes are close together on the same chromosome, they do not assort independently and are said to be linked tightly.
• They show less frequency of recombination. Whereas gene located on different chromosomes assort independently and have a recombination frequency of 50% .

Question 41. Name the sites of DNA, which have a high probability of crossing over?

1. Cold spots
2. Hot spots
3. Covalent bond
4. Hydrophobic bond

Answer:  2. Hot spots

There are certain sites on DNA, which have a high probability of crossing over. These are called hot spots. Those sites which have a low probability of crossing over are called cold spots.

Question 42. Determination of linkage and percentage of crossing over between two linked genes is important because

1. It helps in the fixation of heterosis in the organism
2. It helps in maintaining the heterozygosity in a given population
3. It explains coupling and repulsion
4. None of the above

Answer:  3. It explains coupling and repulsion

• Coupling refers to the linkage of two dominant or two recessive alleles, whereas repulsion indicates that dominant alleles are linked with recessive alleles.
• So, determination of linkage and percentage of crossing over between two linked genes is important because it explains coupling and repulsion.

Question 43. Which of the following is suitable for experiment on linkage?

1. AaBB × aaBB
2. AABB × aabb
3. AaBb × AaBb
4. AAbb × AaBB

Answer:  2.  AABB × aabb

AABB × aabb is suitable for experiment on linkage. Linkage is the tendency for certain genes to be inherited together, because they are on the same chromosome.

Thus, parental combinations of characters are found more frequently in offspring than non-parental characters..

Question 44. Which of the following statement is not true regarding linkage group?

1. Group of physically linked genes
2. Represent a haploid number of chromosomes
3. Shown by linkage map
4. Linkage groups are not correlated with each other

Answer:  4. Linkage groups are not correlated with each other

Statement in option (4) is not true and can be corrected as The number of linkage group can be
correlated as the number of homologous pairs. Rest statements are true regarding linkage group.

Question 45. The transference of genes from one chromosome to another during synapsis is termed as

1. linkage
2. dominance
3. over
4. Independent assortment

Answer:  3. C over

• Crossing over is the reciprocal exchange of segments between non-sister chromatids of a pair of homologous chromosomes.
• It results in recombination of genes. The non-sister chromatids in which exchange of segments take place, are known as crossovers or recombinants, while other chromatids not involved in exchange of segments are called non-crossovers or parental types.

Question 46.

Linked gene pair – Cross Value (COV)

T and U – 25

T and V – 5

V and U – 30

V and W – 10

In the table above, COV are mentioned for different linked gene pair. Find out the sequence of genes T, U, V, W on the chromosome.

VTWU

TVWU

BTWVU

VWTU

Answer:  1. VTWU

The genes which have higher COV (Cross Over Value) are placed farthest and genes which have lowest COV are placed close to each other. V and U have highest COV = 30, T and V have lowest COV = 5. After gathering the other COV, the sequence of genes will be VTWU. It can be understood by the linkage map given below.

NEET Exam Cancer Detection and Treatment Most Repeated MCQs

Question 47. The distance between the genes a, b, c, and d in mapping units are a-d = 3.5, b-c = 1, a-b = 6, c-d = 1.5, a-c = 5 Find out the sequence of arrangement of these genes.

1. Acdb
2. Abcd
3. Acbd
4. Abdc
5. Adcb

Answer:  5. Adcb

inheritance and variation mcq

Chromosome mapping is based on the fact that genes are linearly arranged in the chromosome and frequency of crossing over is directly proportional to the distance between two genes. So, the sequence of arrangement of given genes is adcb as shown below

Question 48. Two genes R and Y are located very close on the chromosomal linkage map of maize plant. When RRYY and rryy genotypes are hybridised, the F₂ segregation will show

1. Segregation in the expected 9 : 3 : 3: 1 ratio
2. Segregation in 3:1 ratio
3. Higher number of the parental types
4. Higher number of the recombinant types

Answer:  3. Higher number of the parental types

• The closely located gene show the tendency of linkage and they are transmitted together to the next generation.
• If two closely located genes show linkage, they do not show crossing over and result in formation of higher number of the parental type.

Question 49. The total number of progeny obtained through dihybrid cross of Mendel is 1280 in F₂-generation. How many of them are recombinants?

1. 240
2. 360
3. 480
4. 720

Answer:  3. 480

The total number of progeny obtained through dihybrid cross of Mendel is 1280 in F₂-generation. Out of these, 480 will be recombinant. In a dihybrid cross, the ratio of pure to recombinant is 10: 6. So, when total progeny is 1280, 800 would be pure and rest are recombinant.

Pure =  \(\frac{10}{16}\)× 1280

=  800

Recombinant =  \(\frac{6}{16}\)× 1280

= 480

Question 50. How many linkage groups are present in man?

1. 23 linkage groups
2. 46 linkage groups
3. 22 linkage groups
4. 44 linkage groups

Answer:  1. 23 linkage groups

Number of linkage groups in a species corresponds to its haploid number of chromosomes. Therefore, 23 linkage groups are present in man.

Question 51. Two linked genes, a and b show 20% recombination. The individuals of a dihybrid cross between ++/ ++ ab/ab shall show gametes

1. + + 80 : ab: 20
2. + + 50 : ab: 50
3. + + 40 : ab 40: + a 10 : + b: 10
4. + + 30 : ab 30: + a 20: + b: 20

Answer:  3. + + 40 : ab 40: + a 10 : + b: 10

The combined linkage frequency between parental combination ++ and ab is 80%. The combined recombination frequency between recombinant combination + a and + b is 20%. The individual frequencies would be half of combined frequency, i.e. ++ 40: ab 40: + a 10: +b: 10.

Question 52. Which of the following statements is not true for two genes that show 50% recombination frequency?

1. The genes are tightly linked
2. The genes show independent assortment
3. If genes present on same chromosome, they undergo many crossover in every meiotic division
4. The genes may be on different chromosomes

Answer:  1. The genes are tightly linked

• Statement in option (1) is not true for two genes that show 50% recombination frequency and can be corrected as Tightly linked genes show more linkage than crossing over.
• The genes that show 50% recombination frequency would undergo crossing over. Rest statements are true.

Question 53. Which of the following is site specific recombination?

1. Modification
2. Transposition
3. Holiday junction
4. Retrotransposons

Answer:  2. Transposition

Transposition is the process of recombination, which allows one DNA sequence to inserted in another without taking care of sequence homology.

Question 54. Bateson and Punnett (1909) discovered linkage while working on

1. Pisum sativum
2. Lathyrus odoratus
3. Drosophila melanogaster
4. Lychmis alba

Answer:  2. Lathyrus odoratus

Linkage was 1st discovered by Bateson and Punnett while experimenting on sweet pea, Lathyrus odoratus.

Question 55. Which of the following is not a recombination system?

1. RecBCD
2. RecE
3. RecF
4. DnaF

Answer:  4. DnaF

Homologous recombination was first described in bacterial systems. The three different recombination systems are RecF, RecE, and RecBCD. So, DNA F is not a recombination system.

Question 56. Percentage of recombination between A and B is 9%, A and C is 17%, B and C is 26%. Then the arrangement of genes is

1. ABC
2. ACB
3. BCA
4. BAC

Answer:  4. BAC

By manipulating the three possibilities of gene arrangements A-B-C, A-C-B and B-A-C, it was found that the three genes must be arranged in the order B-A-C with the distance between B-A being 9 cm and A-C being 17 cm and the distance between B-C being 26 cm. Order of genes is shown below

Thus, option (4) is correct.

inheritance and variation mcq

Question 57. Assertion (A) The percentage frequency with which a gene successfully manifests its phenotypic effect is called expressivity. Reason (R) The extent or intensity of phenotypic expressions of certain genes may vary in different individuals due to environmental influences.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. Both A and R are false

Answer:  2. Both A and R are true, but R is not the correct explanation of A

• Both A and R are true, but R is not the correct explanation of A. Expressivity is a measure for describing the range of phenotypic expression.
• It measures the extend to which a given phenotype is expressed at the phenotypic level. Different degrees of expression in different individual may be due to variation in the allelic constitution of the rest of the genome or due to environmental factors.

Question 58. If you cross a white eyed female, Drosophila with a red eyed male, Drosophila what will be the colour of eyes for their male and female offspring?

1. Both red eyed
2. Both white eyed
3. Red eyed daughter and white eyed son
4. Red eyed son and white eyed daughter

Answer:  3. Red eyed daughter and white eyed son

• Eye colour is a sex-linked trait. In this case, the F₁ male progeny was red eyed, as the father only gave the Y-chromosome and not X which determines eye colour.
• Then similarly, the F2 sons would be white eyed by allele from their mother, female will be red eyed as they get both alleles.

Question 59. Fruitfly is excellent model for genetics because of

1. Small life cycle (two weeks).
2. Can be bred on simple synthetic medium.
3. Single mating produces large number of progeny.
4. Clear differentiation of sexes.
5. Many heredity variations can be seen with low power microscopes.

Choose the correct option.

1. 1, 2 and 3
2. 3, 4 and 5
3. 1, 4 and 5
4. 1, 2, 3, 4 and 5

Answer:  4. 1, 2, 3, 4 and 5

All given statements are correct in describing fruitfly as an excellent model for the genetics. Thus, option (4) is correct.

Biology MCQ For NEET With Answers

Question 60. Walter Sutton is famous for his contribution to

1. Genetic engineering
2. Totipotency
3. Quantitative genetics
4. Chromosomal theory of inheritance

Answer:  4. Chromosomal theory of inheritance

Chromosomal theory of inheritance was given by Walter Sutton. He worked with grasshopper chromosomes and showed that chromosomes occur in distinct pairs which segregate during meiosis.

Question 61. Out of 8 ascospores formed in Neurospora the arrangement is 2a: 4a: 2a showing

1. No crossing over
2. Some meiosis
3. Second generation division
4. First generation division

Answer:  3. Second generation division

In Neurospora, after crossing over between the gene and centromere, the paired arrangement of ascospores is AAaaaaAA or 2a: 4a: 2a. This is called second division segregation.

Immunotherapy and Chemotherapy MCQs for NEET

Question 62. Depending upon the distance between any two genes which is inversely proportional to the strength of linkage, crossovers will vary from

1. 50-100%
2. 0-50%
3. 75-100%
4. 100-150%

Answer:  2. 0-50%

• Depending upon the distance between any two genes which is inversely proportional to strength of linkage, non-crossover will vary from 50-100%.
• 100% non- crossover is a state where no crossing over takes place as in male Drosophila. The crossover will similarly vary from 0-50% and will never exceed 50 %.

Question 63. Which of the following shows linkage group in coupling phase?

Answer:  Diagram in option (1) shows linkage group in coupling phase. The two alleles A and B are located on same gene and are inherit together. In other three diagrams, the alleles A and B are located on different genes.

Biology MCQ For NEET With Answers

Question 64. Fusion of homologous chromosomes from the same parent is known as

1. Auxesis
2. Autosyndesis
3. Wading
4. None of the above

Answer:  2. Autosyndesis

Autosyndesis is the fusion of pair of homologous chromosomes from the same parent during meiosis in polyploids.

Question 65. Which of the following is true about linkage?

1. It is phenomenon in which more recombinants are produced in F₂ -generation.
2. More parental combinations are produced in F₁ -generation.
3. Genotypes which are present in F₁ hybrid reappear in high frequency in F₂-generation.
4. It is a phenomenon in which two chromosomes are linked.

Choose the correct option.

1. Only 1
2. Only 2
3. 1 and 3
4. 3 and 4

Answer:  2. Only 2

Only statement II is correct, while other three are incorrect. In linkage, two alleles of a gene are linked. So that the number of recombinants produced in F₂-generation are very less or negligible.

inheritance and variation mcq

Question 66. The frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes was explained by

1. TH Morgan
2. Gregor J Mendel
3. Alfred Sturtevant
4. Sutton Boveri

Answer:  3. Alfred Sturtevant

Alfred Sturtevant explained chromosomal mapping on the basis of recombination frequency which is directly proportional to distance between two genes on same chromosome.

Question 67. Incomplete linkage is …A… whereas complete linkage is …B… . Choose correct option for A and B.

1. A-common, B-rare
2. A-rare, B-common
3. A-impractical, B-practical
4. A-practical, B-impractical

Answer:  1.  A-common, B-rare

Question 68. Study the given test cross and choose the correct option for F₂-generation.

1. Hybrid cross (9:3:3:1)
2. Hybrid cross (3:1)
3. Dihybrid cross (12:4)
4. Dihybrid linked gene cross (3:1)

Answer:  4. Dihybrid linked gene cross (3:1)

Option (4) is correct for F₂ -generation. The linked genes do not show independent assortment but remain together and are inherited enblock producing only parental type of progeny. They give a dihybrid ratio of 3: 1 and a test cross ratio of 1: 1.

Question 69. Cytological basis of crossing over was first established by

1. TH Morgan Chandigarh
2. Correns
3. Castle and Mendel
4. CB Bridges

Answer:  1. TH Morgan Chandigarh

Cytological basis of crossing over was described in theory by Thomas Hunt Morgan. The physical basis of crossing over was first demonstrated by Harriet Creighton and Barbara McClintock in 1931.

Biology MCQ For NEET With Answers

Question 70. When the number of recombinant progeny is usually less than the number expected in independent assortment it is called

1. Complete linkage
2. Incomplete linkage
3. Complete recombination
4. Complete independent assortment

Answer:  2. Incomplete linkage

In incomplete linkage, some recombinant progenies are produced, but their percentage is very less as expected in independent assortment.

Question 71. Mendel conducted a number of crosses and studies but could never discover linkage. What could be the reason for this?

1. Some genes are linked but they are too far apart for crossing over to be distinguished from
   independent assortment.
2. Linked genes were never tested for the same time in same cross.
3. The seven genes were present on the 7 chromosomes.
4. The genes underwent mutations during subsequent crossings.

Choose the correct option.

1. 1 and 2
2. 2 and 3
3. and 4
4. Only 4

Answer:  1. 1 and 2

• Statement 1 and 2 are correct while 3 and 4 are incorrect. Mendel could not find out linkage because all of his experimental characters of pea were not linked.
• They were present far apart from each other on four different chromosomes. Thus, option (a) is correct.

Question 72. Mendel did not observe linkage due to

1. Mutation
2. Synapsis
3. Crossing over
4. Independent assortment

Answer:  4. Independent assortment

Principle of law of independent assortment is applicable to only those factors or genes which are present on different chromosomes. Mendel did not observe linkage due to independent assortment of alleles.

Role of Carcinogens and Mutations in Cancer MCQs for NEET

Question 73. The linkage map of X chromosomes of fruitfly has 66 units, with yellow body gene (y) at one end and bobbed hair (b) gene at other end. The recombination progeny between these two genes (y and b) should be

1. <50%
2. 100%
3. 66%
4. >50%

Answer: 1. <50%

• X -chromosome has 66 crossover units with yellow and bobbed genes at two extreme ends of the map.
• Recombination frequency never exceeds 50% (< 50%) between any two loci, but these 66 units will actually be obtained by making use of a mapping function.

Question 74. If the genes are located in a chromosome as A—B—C—D—E— O—-T. Which of the gene pairs will have least probability of being inherited together?

1. C and D
2. A and T
3. A and B
4. O and T

Answer:  2. A and T

Longer is the distance, lesser will be the probability of the two genes being inherited together as there will be a greater chance of recombination. Thus, A and T would not inherit together.

Question 75. Bateson used the term coupling and repulsion for linkage and crossing over. Choose the correct coupling and repulsion combination. Coupling Repulsion

1. AABB, aabb AAbb, aaBB
2. AABB, aabb AABB, AAbb
3. AAbb, aaBB AaBb, aabb
4. aaBB, aabb AABB, aabb

Answer: 1. AABB, aabb AAbb, aaBB

• Bateson gave the coupling and repulsion hypothesis for linkage and crossing over. Similar genes remain together and do not undergo crossing over.
• Bateson called them coupling genes. While on the other hand, dissimilar genes segregate and crossing over takes place. Bateson called them repulsion parent’s gene. The correct coupling and repulsing combination is AABB, aabb and AAbb aaBB, respectively.

Question 76. Number of linkage groups in Drosophila are

1. 4
2. 8
3. 6
4. 10

Answer:  1. 4

The number of linkage groups present in an individual corresponds to the number of chromosomes in its haploid genome. Fruitfly, Drosophila melanogaster has four linkage groups (4 pairs of chromosomes).

Question 77. The jumping gene in maize was discovered by

1. HG Khorana
2. Barbara McClintock
3. Beadle and Tatum
4. TH Morgan

Answer:  2. Barbara McClintock

Transposons or jumping genes was discovered by Barbara McClintock (1951) in maize.

Question 78. A diagram of the chromosomes of a fruitfly is given below. Labels A, B, C and D are marked to various chromosomes. Choose the correct option that indicates an autosome labelled.

1. C
2. A
3. B
4. D

Answer:  3. B

Drosophila have 3 pairs of autosome and one pair sex chromosome. Sex-determination in Drosophila is exactly similar to the human beings, i.e. female is homogametic and male is heterogametic.

In the given diagrams, first diagram belongs to the female Drosophila and second diagram belongs to the male Drosophila.

• Indicates X-chromosomes in female, Drosophila.
• Indicates Autosome
• Indicates X-chromosome in male, Drosophila.
• Indicates Y-chromosome in male, Drosophila.

Thus, option (3) is correct.

Question 79. Maize has ten pairs of chromosomes. How many linkage groups will be present, if all the genes are mapped?

1. 20
2. 5
3. 40
4. 10

Answer:  4. 10

The number of linkage groups present in an individual corresponds to number of chromosomes in its haploid genome (all the chromosomes, if haploid or homologous pairs, if diploid). Maize has 10 linkage groups, as it has 10 pairs of chromosomes (haploid set is 10).

Question 80. A and B genes are linked. What shall be genotype of progeny in a cross between AB/ab and ab/ab?

1. AAbb and aabb
2. AaBb and aabb
3. AABB and aabb
4. None of the above

Answer:  2. AaBb and aabb

• The tendency of potential combinations to remain together, which is expressed in terms of low frequency of recombinations (new combinations) is called linkage.
• Genes present on same chromosomes show linkage. These genes are called linked genes. Since, A and B genes are linked they will be passed on together in the progeny. Thus, the genotype of progeny would be AaBb and aabb.

Question 81. Which one of the following information is essential to determine the genetic map distance between two genes located on the same chromosome?

1. Length of the particular chromosome
2. Number of genes present in the particular chromosome
3. Number of nucleotides in the particular chromosome
4. Percentage of crossing over or recombinant frequency between the two genes

Answer:  4. Percentage of crossing over or recombinant frequency between the two genes

A genetic map is a linear, graphic representation of the sequence and relative distances of various genes present in a chromosome. The distance between two genes located on the same chromosome is directly proportional to percentage of crossing over or recombination frequency between the two genes.

Question 82. Two dominant non-allelic genes are 50 map units apart. The linkage is

1. Cis type
2. Trans type
3. Complete
4. Absent/ incomplete

Answer:  4. Absent/ incomplete

When two dominant non-allelic genes are 50 map units apart, the linkage is absent or incomplete. At or above this distance, crossing over and formation of recombinants is favoured.

Question 83. In sex linkage, the speciality is

1. Atavism
2. Criss-cross inheritance
3. Reversion
4. Gene flow

Answer:  2. Criss-cross inheritance

• Sex linkage or sex-linked gene (X-linked gene) has a characteristic inheritance pattern which is called ‘criss -cross inheritance’. In this case, the X-linked gene is transmitted from father to grandsons through its carrier daughters.
• It was first studied by Morgan (1910) in case of eye colour in Drosophila. This type of inheritance is applicable to most sex-linked disorders in humans, e.g. colour blindness, haemophilia, etc.

Question 84. If 5% is the strength of linkage between two genes, then they are 5 map units apart on same chromosome. This statement is

1. False
2. Controversial
3. True
4. Either 1 or 3

Answer:  2. Controversial

Given statement is controversial. One Linkage Map Unit (LMU) is 1% recombination. Thus, the linkage map distance between two genes is the percentage of recombination (crossover) between these genes. Thus, percentage of strength of linkage does not express as map unit.

Question 85. Crossing over that results in genetic recombination in higher organisms occurs between

1. Two different bivalents
2. Sister chromatids of bivalent
3. Non-sister chromatids of bivalent
4. Two different nuclei

Answer:  3. Non-sister chromatids of bivalent

Crossing over takes place between non-sister chromatids of bivalent.In sisters chromatids, the crossing over does not take place.

Question 86. What map unit (centiMorgan) is adopted in the construction of genetic maps?

1. A unit of distance between two expressed genes representing 10% cross over
2. A unit of distance between two expressed genes representing 100% crossover
3. A unit of distance between genes on chromosomes, representing 1% crossover
4. A unit of distance between genes on chromosomes, representing 50% crossover

Answer:  3. A unit of distance between genes on chromosomes, representing 1% crossover

1 map unit represents 1% crossover. Map unit is used to measure genetic distance. This genetic distance is based on average number of cross over frequency. Thus, option (c) is correct.

Question 87. There are three genes a, b, c. Percentage of crossing over between a and b is 20%, b and c is 28% and a and c is 8%. What is the sequence of genes on chromosome?

1. b, a, c
2. a, b, c
3. a, c, b
4. None of these

Answer:  1. b, a, c

inheritance and variation mcq

Percentage of crossing over between a and b is 20%, so they are 20 map distance apart, b and c are 28 map distance apart and a and c are 8 map distance apart.

So, that the correct sequence of genes on chromosomes will be b, a, c.

Question 88. In sex linkage, reciprocal cross yields

1. Cross results
2. Identical results
3. Distinct results
4. None of the above

Answer: 1. Cross results

In the case of sex linkage, reciprocal cross does not yield identical results, but it shows a criss-cross inheritance pattern, i.e. male transmits its sex-linked genes to all daughters, who in turn transmit them to half of their male progeny.

 

Biology MCQ For NEET With Answers Principles Of Inheritance And Variation  Miscellaneous

Question 1. Which of the following is true regarding human genetics?

1. Most characters are controlled by one gene
2. Human skin colour is controlled by more than two genes
3. Same characters are not inherited according to Mendel’s law
4. All of the above

Answer:  2. Human skin colour is controlled by more than two genes

All statements are correct. In human, most characters are controlled by one gene, but some characters like human skin colour is controlled by more than one gene. These characters are not inherited according to Mendel inheritance pattern.

Read And Learn More: NEET Biology Multiple Choice Question And Answers

Question 2. Match the following columns

“pedigree analysis questions “

Answer:  1. A–2, B–3, C–1, D–4

Question 3. Assertion (A) Polytene chromosomes have a high amount of DNA. Reason (R) Polytene chromosomes are formed by repeated replication of chromosomal DNA without separation of chromatids.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R false
4. Both A and R are false

Answer: 1. Both A and R are true and R is the correct explanation of A

Both A and R are true and R is the correct explanation of A. Polytene chromosomes are giant chromosomes. They begin as normal chromosomes, but through repeated rounds of DNA replication without any cell division (called endoreplication) or separation of chromatids, they become large, banded chromosomes having large amount of DNA.

Biology MCQ For NEET With Answers

NEET Biology Principles of Inheritance and Variation MCQs with answers

Question 4. Which of the following match is correct?

1. Independent assortment – Separation of factor
2. Lamarck – Natural selection
3. Hatch and Slack – Chemiosmotic theory
4. Peter Mitchell – Proposed Z scheme

Answer:  1. Independent assortment – Separation of factor

• Option (1) is correctly matched. According to law of independent assortment, the two factors of each character assort or separate, independent of the factors of other characters at the time of gamete formation and get randomly rearranged in the offspring.
• Other options are incorrect and can be corrected as Darwin–Natural selection Peter Mitchell – Chemiosmotic theory Hatch and Slack –C 4 pathway

“principles of inheritance and variation pyq neet “

Question 5. Branching habit of sunflower plant is a …… character.

1. Recessive
2. Dominant
3. Both 1 and 2
4. None of these

Answer:  2. Dominant

• Branching habit of sunflower is a dominant character over unbranching habit. Single copy of gene of branched habit is sufficient to express itself.
• Since, the allele for branched habit can express itself in heterozygous condition, it is not a recessive character. When both recessive and dominant traits are expressed in a heterozygous genotype, it is codominance, but only branching habit of this plant is expressed in heterozygous condition.

Question 6. A plant with same genotype has different phenotype. Yes or No?

1. No, because identical genotype give identical phenotype
2. No, because of mutation
3. Yes, due to environment affects on the phenotype
4. Yes, because phenotype and genotype are depended on the area of growth

Answer:  3. Yes, due to environment affects on the phenotype

Environment can influence the phenotype of an organism due to which plant with same genotype can have different phenotype, e.g. human skin colour.

Question 7. Match the Column I with Column II and select the correct option.

Answer:  2. A–3, B–4, C–1, D–2

Important MCQs on Principles of Inheritance and Variation for NEET

Question 8. Match the name of scientist given in Column I with the contribution given in Column II.

“inheritance and variation mcq “

Answer:  2. A–1, B–2, C–3, D–4

Question 9. A nutritionally wild type of organism, which does not require any additional growth supplement, is known as

1. Phenotype
2. Holotype
3. Autotroph
4. Prototroph

Answer:  4. Prototroph

• Prototroph is the nutritionally wild strain which is unable to grow in the minimal medium unless additional nutrients were added to the medium.
• Phenotype is the kind of organism produced by the reaction of a given genotype with the environment. Holotype is one of the original types used to describe a new species. Autotroph are organism who make their own food.

Biology MCQ For NEET With Answers

Question 10. Match the following columns.

Answer:  1. A–3, B–4, C–1, D–2

Question 11. The number of genotypes produced when individual of genotype YyRrTt are crossed with each other?

1. 4
2. 64
3. 28
4. 27

Answer:  4. 27

• Number of genotypes produced when individuals of genotype ‘YyRrTt’ are crossed with each other is 27. The number of genotypes produced can be calculated by n × n × n, where ‘n’ is the number of alleles in the given genotype.
• In the given question, there are three types of alleles which shows that n = 3. Therefore, the number of genotypes produced when YyRrTt = 3 × 3 × 3 = 27.

“monohybrid test cross ratio “

Question 12. A normal, green male maize plant is crossed with albino female. The progeny is albino because

1. Trait for albinism is dominant
2. The albinos have biochemical to destroy plastids derived from green male
3. Plastids are inherited from female parent
4. Green plastids of male must have mutated

Answer:  3. Plastids are inherited from female parent

Besides nucleus, some genes are 3, 1, 2. also present in the cytoplasm of the female, parent and these genes are called plasmogens. In the given example, the progeny is albino because of inheritance of plastids from female parent.

Biology MCQs with answers for NEET

Question 13. What is the correct sequence of the following events?

1. Formation of the chromosome theory of heredity.
2. Experiments which proved that DNA is the hereditary material.
3. Mendel’s laws of inheritance discovery.

Choose the correct answer

1. 1, 3 and 2
2. 1, 2 and 3
3. 3, 1 and 2
4. 2, 1 and 3

Answer:  3. 3, 1 and 2

• Correct sequence of statements are 3, 1 and 2. Mendelian inheritance is a type of biological inheritance that follows the principles originally proposed by Gregor Mendel in 1865 and 1866, re-discovered in 1900 and popularised by William Bateson.
• Chromosome Theory of Heredity was proposed in 1902. The HersheyChase experiments were a series of experiments conducted in 1952 by Alfred Hershey and Martha Chase that helped to confirm that DNA is genetic material. Thus, option (3) is correct.

NEET quiz on Inheritance and Variation with solutions

Question 14. One of the following is the correct statement.

1. Mendel’s laws were not postulated by Mendel himself
2. Mendel simply gave theortical and statistical explanation of his research work
3. Correns represented the findings of Mendel into ‘laws of heredity’
4. All of the above

Answer:  4. All of the above

All given statements are correct.

“monohybrid cross ratio “

Question 15. Preformation theory concerning transmission of characters was given by

1. Swammerdam
2. Aristotle
3. Wolf
4. Pythagoras

Answer:  1. Swammerdam

Preformation theory was proposed by two Dutch biologists, Swammerdam and Bonnet (1720-1793). This theory states that a miniature humen called homunculus was already present in the egg and sperm. In other words, a miniature human was preformed in the gametes.

Biology MCQs with answers for NEET

Question 16. ‘Law of filial regression’ was postulated by

1. Mendel
2. Morgan
3. Watson and Crick
4. Galton

Answer:  4. Galton

• Law of filial regression is the principle that inherited traits such as tallness may revert to the mean of the population meaning offspring would be tall, but closer to the population mean.
• Galton’s law of filial regression is another name for filial regression. Named after the English explorer and scientist Sir Francis Galton (1822–1911) who first drew attention to it.

Question 17. The phenomenon of ‘like begets like’ is due to

1. Genetics
2. Heredity
3. Germplasm
4. Variation

Answer:  2. Heredity

• The phenomenon of genetic transfer of characteristics from one generation to the next, where an offspring expresses characteristics similar to that of the parent is like begets like.
• This phenomenon is best understood when the offspring of a mango plant is a mango plant and that of a human is a human and not a monkey or a lion. So, the correct answer is heredity.

Question 18. Hypertrichosis is an example of which inheritance?

1. Incomplete sex-linked
2. Sex-limited
3. Holandric
4. Sex-influenced

Answer:  3. Holandric

Hypertrichosis is the excessive growth of hair on the body. It is an example of holandric inheritance. Genes responsible for this are located on Y-chromosomes only which are also known as holandric genes. Y-linked holandric genes are transmitted directly from father to son.

NEET Biology Mcq

Question 19. The longest chromosome is seen in

1. Allium
2. Lilium
3. Trillium
4. Zea mays

Answer:  3. Trillium

The size of chromosome is variable (0.25 – 30) and can be measured at metaphase during mitosis. The smallest chromosome is of 0.2 m observed in fungi and birds and the largest in some plant like Trillium (30).

Question 20. Match the following columns.

Answer:  1. A–4, B–1, C–2, D–3

NEET expected MCQs on Principles of Inheritance and Variation 2025

Question 21. Phenocopies have

1. Different genotypes
2. Different phenotypes
3. Both of 1 and 2
4. None of the above

Answer: 1. Different genotypes

“principles of inheritance and variation class 12 “

A phenocopy is a condition where the phenotype of an individual is altered because of an environmental factor and thus, the individual appears to have an altered genotype, though in
fact it does not.

NEET Biology Mcq

Question 22. Match the following columns.

Answer:  2. A–2, B–1, C–4, D–3

Question 23. Match the following columns.

Answer:  1. A–4, B–2, C–1, D–5

NEET Biology Inheritance and Variation MCQs with explanations

Question 24. Which of the following is incorrectly paired?

1. ‘SRY’ gene–X chromosome
2. 2n–2–Nullisomic
3. Nucleoid Prokaryote
4. Polytene chromosome–Drosophila
5. Trisomy–Down’s syndrome

Answer:  1. ‘SRY’ gene–X chromosome

Option (1) is incorrectly paired and can be corrected as ‘SRY’ is the sex reversal gene which is found on Y- chromosome. Rest all options are correct.

Question 25. Mixing of paternal and maternal chromosomes is called

1. Amphimixis
2. Mutation
3. Apogamy
4. Apomixis

Answer:  1. Amphimixis

A synonymous term for sexual reproduction is amphimixis. However, the more precise definition of amphimixis is the union or the fusion between the male and the female gametes in sexual reproduction.

Biology MCQs with answers for NEET Sexually Transmitted Infections (STIs)

Question 1. Disease transmitted from an infected person during unprotected vaginal, anal and oral contact is called

1. Sexually transmitted disease
2. Waterborne disease
3. Pathogenic disease
4. Communicable disease

Answer:  1. Sexually transmitted disease

Sexually transmitted diseases transmit through body fluid discharge like vaginal secretion, semen, etc., during unprotected intercourse.

Read And Learn More: NEET Biology Multiple Choice Question And Answers

Question 2. Identify the correct match.

1. STDs – Sexually Transmitted Diseases
2. VD – Venereal Disease
3. RTI – Reproductive Tract Infection

Choose the correct answer

1. 1 and 2
2. 2 and 4
3. 1 and 3
4. 1, 2 and 3

Answer: 4. 1, 2 and 3

All the given matches are correct. Thus, option (4) is correct.

“neetprep reproductive health “

Question 3. Incidents of STD are usually very high among people belonging to the age group of

1. 15 to 35 years
2. 15 to 30 years
3. 15 to 24 years
4. 15 to 45 years

Answer:  3. 15 to 24 years

Incidents of STDs are very high in the population of 15 to 24 years of age group due to active sexual interests.

NEET Biology sexually transmitted infections MCQs with answers

Question 4. Early stage symptoms of most STDs include

1. Itching
2. Fluid discharge
3. Slight pain
4. Swelling

Choose the correct option.

1. 1, 2 and 4
2. 1, 2 and 3
3. 1, 3 and 4
4. 1, 2, 3 and 4

Answer:  4. 1, 2, 3 and 4

All given symptoms, i.e. swelling, itching, fluid discharge, slight pain etc are the early symptoms of most STDs. Thus, option (d) is correct.

Biology MCQs with answers for NEET

Sexually transmitted diseases (STDs) multiple choice questions for NEET

Question 5. Which of the following statements is/are incorrect about STDs?

1. STDs are called silent infection
2. STDs lead to changing pattern of sexual behaviour
3. Abstinence results into STD infection
4. Pathogens of STDs develop resistance to antibiotics

Answer: 3. Abstinence results into STD infection

Statement in option 3 is incorrect and can be corrected as Abstinence means abstain from sexual intercourse, thus it can help in preventing STD infections. Rest statements are correct about STDs

“mcq reproductive health “

Question 6. Which one of the following statements is correct regarding Sexually Transmitted Diseases (STDs)?

1. A person may contact syphilis by sharing food with person suffering from disease
2. Haemophilia is one of the STDs
3. Genital herpes and sickle-cell anaemia both are STDs
4. The chance of a 5-year-old boy contacting a STD is rare

Answer: 4. The chance of a 5-year-old boy contacting a STD is rare

Statement in option 4 is correct. The chance ofa 5- old -year- boy contacting STD is very rare, since he is unlikely to have sex at this age. Rest statements are incorrect and can be corrected as

• A person may contact syphilis by direct contact with a syphilitic sore, known as chancre.
• Haemophilia is a X-linked recessive disorder.
• Genital herpes is sexually transmitted infection, but sickle-cell anaemia is an inherited group of disorder.

Question 7. Later stage complications of STDs are

1. Pelvic inflammation disease
2. Abortion
3. Still birth
4. Ectopic pregnancies
5. Infertility
6. Cancer

Choose the option containing correct combinations.

1. 1, 2, 3, 4 and 5
2. 1, 2, 3. 5 and 6
3. 1, 3, 4, 5 and 6
4. 1, 2,3, 4, 5 and 6

Answer: 4.  1, 2,3, 4, 5 and 6

Consequences of delayed treatment of STDs are threatening. If proper and timely treatment is not given, STDs may lead to complications such as Pelvic Inflammatory Disease (PID), abortions, still birth, ectopic pregnancies, infertility or even cancer of the reproductive tract. Thus, option (4) is correct.

Biology MCQs with answers for NEET

Question 8. Select the option including all sexually transmitted diseases.

1. Gonorrhoea, malaria, genital herpes
2. AIDS, malaria, filaria
3. Cancer, AIDS, syphilis
4. Gonorrhoea, syphilis, genital herpes

Answer:  4. Gonorrhoea, syphilis, genital herpes

Gonorrhoea, syphilis and genital herpes, all are sexually transmitted diseases.

• Gonorrhoea is caused by a bacterium, Neisseria gonorrhoeae. It is a Sexually Transmitted Disease (STD) that can infect both men and women.
• It can cause infections in the genitals, rectum and throat. Syphilis is caused by a bacterium, Treponema pallidum. It starts as painless sore, typically on the genitals, rectum or mouth.
• Genital herpes is caused by a virus type-II herpes simplex virus. It causes herpetic sores or painful bilsters (fluid-filled bumps) that can break open and ooze fluid.

“questions about reproductive health “

Question 9. STDs caused by viruses are

1. AIDS
2. Hepatitis-B
3. Genital herpes
4. Chancroid

Choose the correct answer

1. 1, 2, 3 and 4
2. 1 and 3
3. 2, 3 and 4
4. 1 and 2

Answer: 1. 1, 2, 3 and 4

All the given STDs are caused by viruses. Viral STDs are as follows:

Important STI and STD questions for NEET Biology exam

Question 10. All the listed pathogens cause STD, except

1. Bacteria
2. Parasite
3. Fungi
4. Virus

Answer: 3. Fungi

STDs are caused by bacteria parasites and viruses. Fungi do not cause STDs.

Biology MCQs with answers for NEET

Question 11. A bacterial infection that cause genital inflammation and discharge is

1. Treponema
2. Syphilis
3. Urethritis
4. Gonorrhoea

Answer:  4. Gonorrhoea

• Gonorrhoea is a bacterial infection that may result in yellowish discharge from the genitals accompanied by itching and burning.
• Other options are explained as Treponema is responsible for diseases such as syphilis, bejel and yaws. Urethritis is the inflammation of urethra.

Question 12. Common STD in India is

1. Syphilis
2. Gonorrhoea
3. AIDS
4. Herpes

Answer: 2. Gonorrhoea

Gonorrhoea is the common sexually transmitted disease in India.

Question 13. It is a disease which mainly affects mucous membrane of urinogenital tract. In males, burning feeling on passing urine, after a yellow discharge occurs, that is accompanied by fever, headache and feeling of illness. The STD is

1. Syphilis
2. Gonorrhoea
3. AIDS
4. None of these

Answer: 2. Gonorrhoea

Gonorrhoea results in inflammed mucous membrane of urinogenital tract. Due to this, person experience burning senstation while urinating yellow discharge, fever, headache, etc.

Biology MCQ For NEET With Answers

Question 14. The sexually transmitted disease that can affect both the male and the female genitals and may damage the eyes of babies born of infected mothers is Karnataka

1. AIDS
2. Syphilis
3. Gonorrhoea
4. Hepatitis

Answer: 3. Gonorrhoea

Gonorrhoea affects the genital mucous membranes of both sexes. If a pregnant woman has gonorrhoea, her baby’s eyes may become infected during the passage through the birth canal at the time of delivery.

Solved MCQs on sexually transmitted diseases for NEET

Question 15. The gonorrhoea infection observed in girls prior to attaining puberty is

1. Gonococcalophthalmia
2. Gonococcal urethritis
3. Gonococcal vulvovaginitis
4. Gonococcal arthritis

Answer: 3. Gonococcal vulvovaginitis

Gonococcal vulvovaginitis is the most frequent gynecologic pathology among prepubertal females.

“reproductive health bank of biology “

Question 16. Gonorrhoea is caused by

1. Treponema pallidum
2. Neisseria gonorrhoeae
3. Candida utilis
4. Streptococcus gonorrhoea

Answer: 2. Neisseria gonorrhoeae

Gonorrhoea is an infection caused by the bacterium, Neisseria gonorrhoeae. Is is also known as gonococcus. It is a Gram negative diplococci bacterium.

Question 17. In gonorrhoea, incubation period is about ……… days.

1. 1-5
2. 6-9
3. 2-5
4. 10-20

Answer:  3. 2-5

In gonorrhoea, the incubation period, i.e. the time from exposure to the bacteria until symptoms develop is usually 2 to 5 days. But sometimes symptoms may not develop for up to 30 days.

Biology MCQ For NEET With Answers

Question 18. Non-gonococcal urethritis is caused by

1. Neisseria gonorrhoeae
2. Chlamydia trachomatis
3. Treponema pallidum
4. Trichomonas vaginalis

Answer:  2. Chlamydia trachomatis

Non-gonococcal urethritis is caused by Chlamydia trachomatis. It infects the columnar epithelium of cervix, urethra and rectum.

Question 19. Ceftriaxone is most effective against

1. Chlamydiosis
2. Gonorrhoea
3. Syphilis
4. AIDS

Answer: 2. Gonorrhoea

The drugs used in the treatment of gonorrhoea are ceftriaxone, ampicillin and penicillin.

Question 20. Match the following sexually transmitted diseases (Column I) with their causative agent (Column II) and select the correct option

Answer: 1. A–2, B–3, C–4, D–1

Question 21. STDs caused by bacteria is/are

1. Syphilis
2. Chancroid
3. AIDS
4. Both 1 and 2

Answer:  4. Bacterial STDs are

Question 22. Which of the following pairs represents correct pairing?

1. Syphilis – Treponema pallidum
2. AIDS – Bacillus conjugalis
3. Gonorrhoea – Leishmania donovani
4. Typhoid – Mycobacterium leprae

Answer:  1. Syphilis – Treponema pallidum

• Option 1 represents correct pairing. Syphilis is bacterial disease caused by a spirochaete bacterium, Treponema pallidum.
• Other options represent incorrect pairings and can be corrected as AIDS is a viral disease caused by Human Immuno Deficiency Virus HIV).
• Gonorrhoea is a sexually transmitted disease and its causative organism is Neisseria gonorrhoeae. Typhoid is an acute infection caused by Gram (– ve) anaerobic flagellated bacillus bacterium, Salmonella typhi.

Biology MCQ For NEET With Answers

Question 23. A sexually transmitted disease symptomised by the development of chancre on the genitals is caused by the infection of

1. Treponema pallidum
2. Neisseria gonorrhoeae
3. Human immunodeficiency virus
4. Hepatitis-B virus.

Answer: 1. Treponema pallidum

Syphilis is caused by a spirochaete, Treponema pallidium. It is characterised by the development of chancre at the site of infection, e.g. genitals.

Symptoms and prevention of STIs NEET MCQs with answers

Question 24. Which statement is not correct about syphilis?

1. Primary stage of disease shows the appearance of chancre on genitalia and lips
2. During latent stage, syphilis, bacteria show severe symptoms and the person is contagious
3. Secondary stage of disease shows the appearance of multiple lesions on mucous membrane of lips, mouth and genitalia
4. Tertiary stage of disease shows the appearance of gumma on the skin

Answer:  2. During latent stage, syphilis, bacteria show severe symptoms and the person is contagious

• Statement in option 2 is not correct. Syphilis is a bacterial infection usually spread by sexual contact.
• The first stage involves a painless sore on the genitals, rectum or mouth. After the initial sore heals, the second stage is characterised by a rash.
• Then, there are no symptoms until the final stage which may occur years later, it is called the latent stage.
• Patient does not show any symptoms and is not contagious during this phase. The final stage can result in damage to the brain, nerves, eyes or heart.

Question 25. AIDS is Haryana

1. Characterised by reduction in number of killer cells
2. An autoimmune disease
3. Characterised by reduction in number of helper T-cells
4. The resist of inability of the body to produce interferon

Answer:  3. Characterised by reduction in number of helper T-cells

During AIDS, the virus replicates inside and kills T-helper cells, which are required for almost all adaptive immune responses. Thus, number of helper T-cells reduces significantly.

NEET Biology Mcq

Question 26. AIDS disease was first reported in

1. Russia
2. USA
3. Germany
4. France

Answer:  2. USA

AIDS was first reported in the United State of America (USA) in 1981 and has since became a major worldwide epidemic.

Question 27. The common means of transmission of AIDS is

1. Sexual intercourse
2. Blood transfusion
3. Placental transfer
4. All of the above

Answer: 4. All of the above

All given options are common means of transmission of AIDS. HIV (Human Immunodeficiency Virus) causes AIDS (Aquired Immuno Deficiency Syndrome) disease.

The most efficient means of transmission of AIDS is blood transfusion (60%), sexual intercourse (25%) and placental transmission (10%). Thus, option (d) is correct.

Question 28. Which of the following is correct regarding HIV, hepatitis-B, gonorrhoea, trichomoniasis?

1. Trichomoniasis is a STD whereas others are not
2. Gonorrhoea is a viral disease whereas others are bacterial
3. HIV is a pathogen whereas others are diseases
4. Hepatitis-B is eradicated completely whereas others are not

Answer:  3.  HIV is a pathogen whereas others are diseases

• Option 3 is correct regarding HIV. HIV is a retrovirus that causes AIDS whereas hepatitis-B, gonorrhoea and trichomoniasis are categorised as STDs.
• Other options are incorrect regarding HIV, hepatitis-B, gonorrhoea, trichomoniasis.
• Gonorrhoea is a bacterial disease, hepatitis-B still affects chronically and can only be eradicated with vaccination.

Question 29. Match the name or diseases under the Column 1 with the name or causal organisms given under Column 2.

Choose the correct option from the codes given below.

Answer:  A–5, B–3, C–2, D–4

Question 30. Detection technique for AIDS is

1. PCR
2. ELISA
3. Both 1 and 2
4. Clinical culture

Answer:  3. Both 1 and 2

Generally, AIDS detection is done by ELISA (Enzyme Linked Immuno Sorbent Assay). But sometime the results of this technique are not accurate.

So, by combining it with PCR (Polymerase Chain Reaction), the reliability of the detection of AIDS increases. Thus, option (c) is correct.

NEET Biology Mcq

Question 31. NACO stands for

1. National Acid Control Organisation
2. National AIDS Comprehending Organisation
3. National AIDS Control Organisation
4. National AIM for Control Organisation

Answer:  3. National AIDS Control Organisation

NACO stands for National AIDS Control Organisation. It was established in 1992 in India.

Best multiple choice questions on sexually transmitted infections for NEET preparation

Question 32. World AIDS Day and World Earth Day are celebrated on AIDS Day

1. 22nd April 1st December
2. 2nd December 24th April
3. 1st December 22nd April
4. 2nd December 24 th April

Answer: 3. 1st December 22nd April

World AIDS Day – 1st December World Earth Day – 22nd April

Question 33. Match the following columns.

Answer:  A–2, B–1, C–3

Question 34. Which of the following STDs are not curable?

1. Genital herpes, hepatitis-B, HIV infection
2. Chlamydiasis, syphilis, genital warts
3. HIV, gonorrhoea, trichomoniasis
4. Gonorrhoea, trichomoniasis, hepatitis-B

Answer:  1. Genital herpes, hepatitis-B, HIV infection

Hepatitis-B, genital herpes and HIV infections are not curable. Other sexually transmitted diseases are completely curable, if detected early and treated properly.

NEET Biology Mcq

Question 35. Hepatitis-B and HIV are contacted through

1. Sharing used needles
2. Transfusion of contaminated blood
3. Transfer of infection from infected mother to child
4. All of the above

Answer:  4. All of the above

Mode of Infection of AIDS and hepatitis are same. Hepatitis-B and HIV is contacted through sharing used needles, transfusion of contaminated blood and transfer of infection from infected mother to child.

Thus, option 4 is correct.

Question 36. Which of the following diseases is not transmitted through contaminated water?

1. Typhoid
2. Cholera
3. Amoebiasis
4. Hepatitis-B

Answer:  4. Hepatitis-B

• Hepatitis-B is caused by hepatitis-B virus which enters the body mainly by sexual contacts and from mother to child.
• It cannot be transmitted through air or water. All the other diseases given in options are transmitted through contaminated water.

Question 37. Hepatitis-B virus is

1. Double-stranded DNA virus
2. Double-stranded RNA virus
3. Single-stranded DNA virus
4. Single-stranded RNA virus

Answer:  1. Double-stranded DNA virus

HBV abbreviated Hepatitis-B virus is a partially double-stranded DNA virus. It is a species of the genus Orthohepadnavirus and a member of the Hepadnaviridae family of viruses.

Question 38. Which of the following symptoms are observed in person suffering from hepatitis-B?

1. Fatigue and nausea
2. Abdominal pain and arthritis
3. Jaundice
4. All of the above

Answer: 4. All of the above

• All given symptoms are observed in person suffering from hepatitis-B. Person suffering from hepatitis-B has acute illness with symptoms that last for several weeks, including yellowing of the skin and eyes (jaundice), dark urine, extreme fatigue, nausea, vomiting and abdominal pain.
• Sometimes a person with acute hepatitis can develop acute liver failure, which can lead to death.

Thus, option 4 is correct.

NEET Biology Mcq Chapter Wise

Question 39. Which of the following sexually transmitted diseases do not specifically affect reproductive organs?

1. Genital warts and hepatitis-B
2. Syphilis and genital herpes
3. AIDS and hepatitis-B
4. Chlamydiasis and AIDS

Answer: 3. AIDS and hepatitis-B

• AIDS and hapatitis-B are sexually transmitted diseases which do not specifically affect reproductive organs.
• AIDS affects the overall immune system of the individual and hepatitis-B affects the liver. These are called STDs because these spread through unsafe or unprotected sex.

Question 40. Hepatitis-B is transmitted through

1. Blood transfusion
2. Intimate physical contact
3. Sexually
4. All of the above

Answer: 4. All of the above

Hepatitis-B virus is transmitted through intimate physical contact, blood transfusion and from mother to child. Thus, option (d) is correct.

Question 41. HBSAg test is performed to diagnose

1. AIDS
2. Herpes
3. Hepatitis-B
4. Syphilis

Answer: 3. Hepatitis-B

• HBSAg (Hepatitis-B surface antigen A) ‘positive’ or ‘reactive’ test result means that the person is infected with hepatitis-B.
• This test can detect the actual presence of the hepatitis-B virus (called the ‘surface antigen’) in the blood

NEET Biology HIV, AIDS, and other STDs MCQs

Question 42. Which of the following sexually transmitted diseases is not completely curable?

1. Gonorrhoea
2. Genital warts
3. Genital herpes
4. Chlamydiasis

Answer:  2. Genital warts

Genital herpes is caused by type-2 herpes simplex virus. At present, there is no cure for type-2 herpes simplex virus. Other non-curable STIs are hepatitis-B and HIV.

Question 43. Recurrence of watery blisters on the genitalia and swollen lymph nodes in groin are the symptoms of

1. Genital warts
2. Genital herpes
3. Genital lesions
4. Genital hepatitis

Answer:  2. Genital herpes

• Genital herpes is a Sexually Transmitted Disease (STD).
• This STD causes swollen lymph nodes and herpetic sores, which are painful blisters (fluid-filled bumps) that can break open and ooze fluid.

NEET Biology Mcq Chapter Wise

Question 44. Acyclovir is used in the treatment of

1. HIV
2. Hepatitis-B
3. Genital herpes
4. Gonorrhoea

Answer: 3. Genital herpes

Acyclovir is a drug used in the treatment of genital herpes. It inhibits the formation of new sores and interferes with the replication of viruses.

Question 45. Genital warts are caused by

1. Human papilloma virus
2. Human immunodeficiency virus
3. Hepatitis-B virus
4. Herpes simplex virus

Answer:  1. Human papilloma virus

• Genital warts are soft growths that appear on the genitals. It is a Sexually Transmitted Infection (STI) caused by certain strains of the Human Papilloma Virus (HPV).
• HPV infection is especially dangerous in women because some types of HPV can cause cancer of the cervix and vulva.

Question 46. Cancer of cervix, vulva, vagina and anus are caused by

1. HBV
2. HIV
3. HSV
4. HPV

Answer:  4. HPV

Cervical cancer is caused by sexually acquired infection with certain types of HPV. Two HPV types (16 and 18) cause 70% of cervical cancers and pre-cancerous cervical lesions.

There is also evidence linking HPV with cancers of the anus, vulva, vagina, penis and oropharynx.

1. Genital herpes
2. Genital warts
3. Pubic lice
4. AIDS

Answer:  2. Genital warts

Alpha interferons are used in the treatment of genital warts. Other treatments include condylox drug, freezing with liquid nitrogen, laser surgery, etc.

Question 48. Find the correct match.

1. Trichomoniasis – Trichomonas vaginalis
2. Genital warts – Herpes simplex virus
3. Pubic lice – HBV virus
4. Vaginal candidiasis – Candida utilis

Answer:  1. Trichomoniasis – Trichomonas vaginalis

• Option (1) is correct match as Trichomonas vaginalis is a protozoan which causes trichomoniasis.
• Other options are incorrect matches and can be corrected as Genital warts are caused by human papilloma virus.
• Pubic lice is infested through sexual activity or through unhygenic way of living. Vaginal candidiasis can be caused by yeast, Candida albicans.

NEET Biology Mcq Chapter Wise

Question 49. Profuse, yellowish, greenish frothy smelling discharge from vagina is due to infection of

1. Troponema pallidum
2. Chlamydia
3. Trichomonas vaginalis
4. Neisseria

Answer: 3. Trichomonas vaginalis

• Trichomoniasis is a common sexually transmitted infection caused by a parasite, Trichomonas vaginalis.
• In women, trichomoniasis can cause a foul-smelling vaginal discharge, genital itching and painful urination. Men who have trichomoniasis typically have no symptoms.

Question 50. Which of the following antibiotic is used in the treatment of trichomoniasis?

1. Miconazole
2. Ceftriaxone
3. Aureomycin
4. Tetracycline

Answer:  3. Aureomycin

Trichomoniasis is treated using various drugs like aureomycin, terramycin and meteronidazole.

Question 51. Match the following columns.

Answer:  2. A–1, B–2, C–3, D– 4, E–5

Question 52. Which one of the following pairs is not correctly matched?

1. Syphilis – Treponema
2. Sleeping sickness –Trypanosoma Gambiense
3. Dengue fever – Arbovirus
4. Plague – Entamoeba

Answer:  4. Plague – Entamoeba

Option 4 is not correctly matched pair and can be corrected as Plague is an infectious disease caused by the bacterium, Yersinia pestis and amoebiasis is an infection of the intestines caused by a parasite called Entamoeba.

Question 53. Phthirus pubis causes

1. Vaginitis
2. Pubic lice
3. Syphilis
4. Chlamydiasis

Answer:  2. Pubic lice

The most common way to acquire pubic lice is through sexual intercourse. Its causative agent is Phthirus pubis.

Question 54. Untreated chlamydiasis may lead to

1. Pelvic Inflammatory Disease (PID)
2. Urethra Inflammatory Disease (UID)
3. Kidney Inflammatory Disease (KID)
4. None of the above

Answer:  1. Pelvic Inflammatory Disease (PID)

• Pelvic Inflammatory Disease (PID) leads to sterility in person suffering from untreated chlamydiasis.
• Other options are explained as Urethra Inflammatory Diseases (UIDs) are caused by bacteria that enter the urethra from the skin around the urethra’s opening. Kidney Inflammatory Disease (KID) is caused by bacterial infection.

Question 55. Transmission of STDs can be prevented by

1. Avoiding sex with unknown people
2. Having multiple partner
3. Following protected sex
4. Avoiding sharing of any kind of syringes.

Choose the correct option.

1. 1, 2 and 4
2. 1, 2 and 3
3. 1, 3 and 4
4. 1, 2, 3 and 4

Answer: 3. 1, 3 and 4

Transmission of STDs can be prevented by avoiding sex with multiple or unknown partners, using condoms, disposal of syninges after single use, etc. Thus, option (3) is correct.

Question 56. Which of the following is an effective antibiotic for STDs?

1. Tetracycline
2. Erythromycin
3. Rifampicin
4. All of these

Answer:  4. All of these

• All given options are effective antibiotics for STDs. Tetracycline is used to treat many different bacterial infections of the skin, intestines, respiratory tract, urinary tract, genitals, lymph nodes, and other body systems.
• It is often used in treating severe acne or sexually transmitted diseases such as syphilis, gonorrhoea or chlamydia.
• Erythromycin is used against against Chlamydia. Rifampin and its analogues are the most active of all antibiotics against Chlamydia trachomatis. Thus, option (d) is correct.