NEET Biology Molecular Basis Of Inheritance Multiple Choice Question And Answers

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NEET Biology Molecular Basis Of Inheritance

Question 1. Broad-spectrum antibiotics like streptomycin bind to smaller subunits of ribosomes of prokaryotes, thereby

  1. Inhibiting protein synthesis
  2. Blocking the action of peptidyl transferase
  3. Misleading of genetic code
  4. Causing point mutation

Answer: 1. Inhibiting protein synthesis

Streptomycin is a broad-spectrum antibiotic that acts as an inhibitor of protein synthesis.

Question 2. Synthesis of DNA can be stopped by incorporating artificial

  1. Ddatp
  2. Ddgtp
  3. Ddctp
  4. All of these

Answer: 4. All of these

Dideoxynucleotides like dd ATP, ddGTP, ddCTP, etc., lack the 3′ — OH group. They would stop DNA synthesis because the 3′–OH group is required for the functioning of the DNA polymerase enzyme.

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Question 3. Which of the following is the correct sequence of units of genetics arranged in descending order of size?

  1. Gene → cistron → muton → recon
  2. Gene → muton → cistron → recon
  3. Gene → recon → cistron → muton
  4. Gene → cistron → recon → muton

Answer: 4. Gene → cistron → recon → muton

Studies have proved that a gene is not a unit of either function recombination or mutation. Benzer in view of his work, coined the terms cistron (unit of function), recon (unit of recombination), and muton (unit of mutation).

Recon consists of one, two, or more nucleotide pairs. Muton consists of a single nucleotide pair. Cistron, on the other hand, is the length of DNA that codes for a specific polypeptide chain or a functional RNA molecule.

It may be several base pairs long. On arranging these in descending order of their size, a distinct hierarchy is developed with the gene at the top, muton at the base, and cistron and recon in between. Thus, the correct sequence is genes, cistron, recon, and muton.

Question 4. Nucleotide sequence changes in DNA are not passed to offspring in

  1. Egg and sperm cells
  2. Non-sexual cells
  3. Diploid and haploid cells
  4. All of the above

Answer: 4. All of the above

If the mutation or change in nucleotide sequences does not occur in the germ cells or if the mutation occurs in a non-sexual cell, then it will not pass on to the next generation. The non-germinal mutations are also called somatic mutations

Question 5. Below is a list of a few processes.

  1. Transcription (eukaryotic)
  2. Transcription (prokaryotic)
  3. Replication (eukaryotic)
  4. Translation (prokaryotic)
  5. Translation (eukaryotic)

Choose the correct site of occurrence of the processes

  1. 1–Nucleus, 2–cytoplasm, 3–nucleus, 4–cytoplasm, 5–cytoplasm
  2. 1–Nucleus, 2–nucleus, 3– cytoplasm, 4–cytoplasm, 5–cytoplasm
  3. 1–Cytoplasm, 2–cytoplasm, 3–nucleus, 4–cytoplasm, 5–nucleus
  4. 1–Nucleus, 2–cytoplasm, 3–nucleus, 4–cytoplasm, 5–cytoplasm

Answer: 1. 1–Nucleus, 2–cytoplasm, 3–nucleus, 4–cytoplasm, 5–cytoplasm

As there is no defined nucleus in prokaryotes, all three process (replication, transcription, and translation) takes place in their cytoplasm. In eukaryotes, transcription and replication occur in the nucleus, but translation occurs in the cytoplasm. Thus, option 1 is correct.

NEET Biology Molecular Basis Of Inheritance Multiple Choice Question And Answers

Question 6. Mitochondrial DNA is advantageous for evolutionary studies as

  1. It is inherited only through the female parent and thus evolves in a way that allows the trees of relationships to be easily constructed
  2. It is present in the X-chromosome
  3. It first appeared in humans and is not found in other animals
  4. It has evolved very fast

Answer: 1. It is inherited only through the female parent and thus evolves in a way that allows the trees of relationships to be easily constructed.

Mitochondrial DNA is advantageous for evolutionary studies because it is inherited only through the female parent and thus, evolves in a way that allows trees of relationship to be easily constructed.

Mitochondrial DNA is contributed by ova at the time of fertilization.

Question 7. The genome of Caenorhabditis elegans consists of

  1. 3 Billion base pairs and 30,000 genes
  2. 180 Million base pairs and 13,000 genes
  3. 4.7 million base pairs and 4000 genes
  4. 97 Million base pairs and 18,000 genes
  5. 12 Million base pairs and 6000 genes

Answer: 4. 97 Million base pairs and 18,000 genes

Caenorhabditis elegans is a species of soil-dwelling nematode (roundworm) used as a model organism in molecular genetics and developmental biology.

The C. elegans genome is about 97 million base pairs long and consists of six chromosomes and a mitochondrial genome. The genome contains an estimated 18,000 protein-coding genes.

Question 8. How many times, DNA can replicate in the life of a cell?

  1. Only once
  2. Twice
  3. Several times
  4. Depends on the ploidy level

Answer: 1. Only once

The preparation for DNA replication initiation is tightly linked to cell cycle progression, ensuring that replication occurs only once per cycle.

Question 9. A mechanism that can cause a gene to move from one linkage group to another is

  1. Translocation
  2. Inversion
  3. Crossing over
  4. Duplication

Answer: 1. Translocation

Translocation refers to a change in the location of genes from one linkage group to another. It is the separation of a chromosome segment and its union with a non-homologous chromosome.

Question 10. Read the following four statements.

  1. In transcription, adenosine pairs with uracil.
  2. Regulation of lac operon by a repressor is referred to as positive regulation.
  3. The human genome has approximately 50,000 genes.
  4. Haemophilia is a sex-linked recessive disease.

How many of the above statements are right?

  1. Two
  2. Three
  3. Four
  4. One

Answer: 1. Two

In the given statements, only two statements are correct. Statements I and IV are correct, but statements 2 and 3 are incorrect.

Incorrect statements can be corrected In the presence of an inducer, such as lactose or allolactose, the repressor is inactivated by interaction with the inducer.

This allows RNA polymerase to access the promoter and transcription proceeds. Hence, regulation of lac operon by repressor is referred to as negative regulation.

The human genome is said to have approximately 3 × 109 bp and approximately 20,000-25,000 genes

Question 11. The compound rifampicin is very

  1. Potent inhibitors of bacterial RNA polymerases
  2. Potent inhibitors of bacterial DNA polymerases
  3. Weak inhibitors of bacterial RNA polymerases
  4. Weak inhibitors of bacterial DNA polymerases

Answer: 1. Potent inhibitors of bacterial RNA polymerases

Rifampicin is an effective antibiotic against tuberculosis. It can inhibit bacterial RNA polymerase and thus halts protein synthesis at the transcription level

Question 12. Which of the following has a thymine base in its composition?

  1. Nodoc
  2. Codon
  3. Anticodon
  4. Codogene

Answer: 4. Codogene

Codogene is the smallest possible sequence (triplet) of nucleotides present on the DNA strand which can specify one particular amino acid. Thus, cologne has thymine, whereas no-doc, codon, and anticodon have uracil, adenine, and guanine.

Question 13. The antibiotic not associated with the inhibition of protein synthesis is

  1. Chloromycetin
  2. Tetracycline
  3. Puromycin
  4. Penicillin

Answer: 4. Penicillin

All the listed broad-spectrum antibiotics except penicillin inhibit protein synthesis.

Question 13. Assertion of the expression of cellular genetic information is unidirectional. Reason (r) cancer virus goes topsy-turvy, therefore reverse transcription allows a sequence of RNA to be retrieved and used as genetic information.

  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

Question 14. Telomerase is an enzyme that is a

  1. Simple protein
  2. RNA
  3. Ribonucleoprotein
  4. Repetitive DNA

Answer: 3. Ribonucleoprotein

Telomerase is a ribonucleoprotein that adds specific DNA sequence repeats (TAG in all vertebrates) to the 3′ (three prime) end of DNA strands in the telomere regions.

The enzyme is a reverse transcriptase that carries its own RNA molecule, which is used as a template when it elongates telomeres, which are shortened after each replication cycle.

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