NEET Biology Reproduction Flower Pre – Fertilisation Multiple Choice Question And Answers

Biology MCQs with answers for NEET Reproduction Flower Pre – Fertilisation

Question. 1 Which of the following is the reproductive organ of plants?

1. Flower
2. Pistil
3. Carpel
4. Stamen

Answer: 1. Flower

• The flower is the angiospermic reproductive organ of some plants. its main function is to reproduce.
• A flower usually reproduces by creating seeds which are then dispersed and eventually become new plants.

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Question 2. Which of the following is the part of female reproductive system?

1. Anther
2. Embryo sac
3. Stamen
4. All of these

Answer: 2. Embryo sac

Embryo sac is a sac-like structure, mostly se5en-celled and eight nucleated structure, present inside the ovule of the female reproductive system in angiosperm plants.

Question 3: The non-accessory whorls in a flower are

1. Calyx and androecium
2. Corolla and gynoecium
3. Calyx and corolla
4. Gynoecium and calyx

Answer: 3. Calyx and Corolla

• Calyx and corolla are the non-essential (non-accessory) whorls of a flower as they are not directly involved in sexual reproduction.
• Calyx is the outermost whorl of the flower consisting of sepals. Corolla consists of petals.

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Question 4.  Sexual reproduction in plants was discovered by

1. Camerarius
2. Strasburger
3. Nawaschin
4. Hofmeister

Answer: 1. Camerarius

• Camerarius first discovered sexual reproduction in plants in 1694. Other options are explained as follows Nawaschin first disco5ered triple fusion and double fertilisation in angiosperms.
• Strasburger first discovered syngamy and monosporic embryo sac in angiosperms Hofmeister discovered alteration of generation in plants.

Question 5.  Anthesis is a phenomenon which refers to

1. Development of anthers
2. Opening of flower bud
3. Stigma receptors
4. All of the above

Answer: 2. Opening of flower bud

Anthesis is a period at which the flower is fully open and functional. it includes an extension of style maturation of stamen and color change.

Question 6.  Match the following columns.

Answer: A–3, B–2, C–4, D–i

Question 7. Identify A to G respectively in the figure given below.

1. A–Sepal, B–O5ary, C–Petal, D–Filament, E–Anther, F–Stigma, G–Style
2. A–O5ary, B–Filament, C–Sepal, D–Petal, E–Style, F–Stigma, G–Anther
3. A–O5ary, B–Sepal, C–Filament, D–Petal, E–Anther, F–Stigma, G–Style
4. A–Petal, B–Sepal, C–Stigma, D–Style, E–Anther, F–O5ary, G–Filament

Answer: A–O5ary, B–Sepal, C–Filament, D–Petal, E–Anther, F–Stigma, G–Style

Question 8.  Assertion (A) In flowering plants, the structure related to sexual reproduction is flowers. Reason (R) 5arious embryological processes of plants occur in a flower.

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. The structures related to sexual reproduction in flowering plants are flowers.
• This is because embryological processes during sexual reproduction occur in the ovary, which is part of a flower.

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Structure and Events of Pre-Fertilisation-1

 

Question 1.  Proximal end of the filament of stamen is attached to the

1. Anther
2. Connective
3. Placenta
4. Thalamus or petal

Answer: 4. Thalamus or petal

Proximal end of the filament of stamen is attached to the thalamus or petal and distal end is attached to another

Question 2.  Monothecous anthers are

1. Bisporangiate
2. Monosporangiate
3. Trisporangiate
4. Tetrasporangiate

Answer: 1. Bisporangiate

The anther which contains only one lobe is called a monothecous anther. Monothecous anthers are
bisporangiate, i.e. contain two pollen sacs.

Question 3. During the development of anther wall layers, if inner secondary parietal layer differentiates into tapetum and the outer secondary parietal layer divides producing endothecium and middle layer, the development of anther wall layers would confirm to

1. Basic type
2. Monocot and gymnosperm type
3. Dicot type
4. None of the above

Answer: 1. Basic type

• In the basic type of wall formation, all the cells in the secondary parietal layers divide once preclinically, forming four new layers.
• These layers differentiate from outside to inside, into the endothecium, the two middle layers, and the tapetum.
• The dicotyledonous type differs from the basic type in that only the outer secondary parietal cell layer divides preclinically.
• As a consequence, only three layers are formed, the endothecium, one middle layer, and the tapetum. The endothecium and the middle layer are formed from the outer secondary parietal layer and the tapetum is formed from the inner secondary parietal layer.
• The mature anther wall comprises an epidermis, a layer of endothecium, 2 or 3 middle layers, and a single-layered tapetum.
• In monocot, the outer secondary parietal cells give rise to endothecium and the inner secondary parietal cells (layer) give rise to the middle layer during another wall de5elopment.

Question 4. Identify A and B in the diagram given below.

1. A–Pistil, B–Stamen
2. A–Stamen, B–Stigma
3. A–Anther, B–Filament
4. A–Stamen, B–Pistil

Answer: 3. A–Anther, B–Filament

Question 5.  identify A to E in the following diagram.

1. A–Tapetum, B–Microspore mother cell, C–Middle layer, D–Endothecium, E–Epidermis
2. A–Microspore mother cell, B–Middle layer, C–Epidermis, D–Tapetum, E–Endothecium
3. A–Middle layer, B–Tapetum, C–Epidermis, D–Endothecium, E–Microspore mother cell
4. A–Epidermis, B–Endothecium C–Middle layer, D–Microspore mother cell, E–Tapetum

Answer: 4. A–Epidermis, B–Endothecium, C–Middle layer, D–Microspore mother cell, E–Tapetum

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Question 6.  The following is the diagram of TS of another. identify the parts labeled A, B, and C. 

1. A–Connective tissue, B–Endothecium, C–Pollen grain
2. A–Endothecium, B–Connective tissue, C– Pollen grain
3. A–Pollen grain, B–Connective tissue, C–Endothecium
4. A–Endothecium, B–Pollen grain, C–Connective tissue

Answer: 1. A–Connective tissue, B–Endothecium, C–Pollen grains

Question 7.  Generally in the wall of the anther lobes, how many middle layers are present?

1. Seven
2. Three
3. Six
4. Nine

Answer: 2. Three

One to three layers of parenchyma cells are present surrounding each pollen sac or microsporangium. They are called middle layers.

Question 8.  The position of the middle layer in the transverse section of a young anther is between

1. Epidermis and endothecium
2. Endothecium and tapetum
3. Tapetum and sporogenous tissue
4. Cells of sporogenous tissue

Answer: 2. Endothecium and tapetum

• A very young anther in transverse section shows epidermis and archesporium. The archesporial cells divide and give rise to primary parietal cells on the outer side and sporogenous cells towards inner side.
• The cells of the parietal layer divide to form endothecium, middle layers, and tapetum. Thus, in T.S. the middle layer is present between endothecium and tapetum.

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Question 10. The function of endothecium in anther is

1. Nutritional support
2. Mechanical support
3. Dehiscence of anther
4. Protection

Answer: 3. Dehiscence of anther

The fibrous thickenings and hygroscopic nature of endothecium cells help in the dehiscence of anther at maturity.

Question 11. The fibrous bands develop from cells of the anther wall layer known

1. Epidermis
2. Endothecium
3. Middle layers
4. Tapetum

Answer: 2. Endothecium

• Microsporangial wall consists of four layers–epidermis, endothecium, middle layers, and tapetum.
• In a typical anther, the endothelial cells develop fibrous thickenings of cellulose on, the inner and radial walls and become dead Because of the presence of fibrous thickenings, the endothecium is also called fibrous layer.

Question 12.  Which part of the plant contains sporogenous tissue?

1. Pollen
2. Microspores
3. Young anther
4. Stamen

Answer: 3. Young anther

1. The anthers are the pollen-producing structures of flowering plants that are found in the male reproductive organ known as stamen.
2. Often referred to as pollen sacs, anthers are bilobed structures that typically rest at the top of long slender stalks called filaments.
3. The young anthers are comprised of tissues that contain spore-producing cells called microsporocytes or sporogenous tissue.
4. These pollen mother cells undergo meiosis to de5elop into pollen grains. So, the correct answer is young another.

Question 13.  Center of each microsporangium is occupied by

1. Sporogenous tissue
2. Central tissue
3. Microspore mother cell
4. Spongious tissue

Answer: 1. Sporogenous tissue

In the center of each microsporangium, there is sporogenous tissue in the cells in which meiosis takes place. It leads to the formation of microspore tetrad.

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Question 14. Tapetum is a part of

1. Male gametophyte
2. Female gametophyte
3. Ovary wall
4. Anther wall

Answer: 4. Ovary wall

The cells between the middle layer and microsporogenous cells develop into tapetum. Tapetum plays an important role in pollen development by providing nutrition. It is part of another wall.

Question 15.  The tapetal nuclei in anthers of many angiosperm flowers are

1. Mostly aneuploid
2. Mostly polyploid
3. Mostly haploid
4. Not having complete haploid genome

Answer: 2. Mostly polyploid

Tapetal nuclei in anthers are mostly polyploid in nature. It is because they are multicellular in nature and the ploidy level is also manifold. This results in the tapetal layer providing nutrients and regulatory molecules adequately to the developing pollen grain.

Question 16.  Tapetal cells are characterised by the presence of

1. Dense cytoplasm and one nucleus
2. Thin cytoplasm and many nuclei
3. Dense cytoplasm and prominent nuclei
4. None of the above

Answer: 3. Dense cytoplasm and prominent nuclei

The tapetal layer is the innermost layer of another wall. It is composed of a single layer of cells characterised by the presence of dense cytoplasm and prominent nuclei.

Question 17.  Which one of the following statements is correct?

1. Sporogenous tissue is haploid
2. Endothecium produces the microspores
3. Tapetum nourishes the developing pollen
4. Hard outer layer of pollen is called intine

Answer: 3. Tapetum nourishes the developing pollen

• Statement in option (3) is correct, but other statements are incorrect, which can be corrected as Sporogenous tissue is always diploid.
• Endothecium is second layer of another wall and performs the function of protection and helps in dehiscence of another to release the pollen. The hard outer layer of pollen is called exine.

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Question 18.  Tapetum provides nourishment to young microspore mother cells by forming a plasmodium, it is

1. Amoeboid type
2. Parietal type
3. Visceral type
4. Secretory type

Answer: 1. Amoeboid type

In amoeboid type of tapetum, the radial wall of tapetum cell breaks up and releases the protoplast into the pollen chamber. All such protoplasts fuse to form the peri plasmodium.

Question 19. What happens to tapetum at maturity?

1. It persists
2. It becomes sticky
3. It is eaten up or degenerates
4. It becomes fibrous

Answer: 3. It is eaten up or degenerates

Tapetum is important for the development of pollen grains. it helps to transport the nutrients to the inner side of the anther. It is eaten up or degenerates at maturity.

Question 20. Pollen kitt substance is supplied by

1. Tapetum
2. Endothecium
3. Microspore mother cell
4. Middle layer

Answer: 1. Tapetum

Pollen kitt is an oily and sticky layer found on the surface of matured pollen grains in insect-pollinated (entomophilous) plants. it consists of lipids and carotenoids and is formed by tapetum.

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Question 21.  Assertion (A) The pollen sterility has been attributed to the malfunctioning of tapetum. Reason (R) Premature degeneration of the tapetum deprives the developing spores of its nutrition.

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. Premature tapetum degeneration is a major cause of pollen sterility.
• Tapetum surrounds and nurses the developing microspores by supplying nutrition and enzymes required for microsporogenesis and pollen development.

Question 22.  Microsporangia develops into

1. Megagametes
2. Pollens
3. Microgametes
4. Pollen sacs

Answer: 4. Pollen sacs

Microsporangia are bilobed structures that develop into pollen sacs. Within it, microspores are produced that give rise to male gametophytes when they germinate.

Question 23.  The number of microsporangia present in the anther is

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

Answer: 4. Four

The anther is a bilobed and each lobe has two microsporangia, i.e., each anther contains 4 microsporangia.

Question 24.  Microsporogenesis is the

1. Development of megaspore
2. Development of pollen grain
3. Development of male gametophyte
4. Development of female gametophyte

Answer: 2. Development of pollen grain

• The formation of microspores inside the microsporangia of seed plants is called as microsporogenesis.
• A diploid microsporangium called a microsporocyte or a pollen mother cell, undergoes meiosis and gives rise to four haploid microspores. Each microspore then develops into a pollen grain.

Thus, correct answer is option (2).

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Question 25. In a flowering plant, archesporium gives rise to only the wall of the sporangium

1. Both wall and the sporogenous cells
2. Wall and the Tapetum
3. Only tapetum and sporogenous cells

Answer: 2. Both wall and the sporogenous cells

The archesporium cell divides into primary parietal cell which forms another wall and the primary sporogenous cells which form microspore mother cells (Mmc)

Question 26. In a flowering plant, the largest number of haploid cells occurs in

1. Ovule
2. Microsporangia
3. Root tip
4. Cambium

Answer: 2. Microsporangia

• In the flowering plant, the largest number of haploid cells occurs in microsporangia. it undergoes meiosis to produce microspores.
• Each microsporangium has i00 MMC, which forms 400 microspores by meiosis.

Question 27.  Pollen grains in angiosperms de5elops from MHT

1. Endothecium
2. Sporogenous tissue
3. Tapetum
4. Middle layer

Answer: 2. Sporogenous tissue

• With the development of the anther, the sporogenous cells undergo meiotic division to form microspore tetrads (pollen grains).
• Each sporogenous cell is known as pollen mother cell or microspore mother cell.

Question 28.  The pollen grain is

1. An immature male gametophyte
2. A mature male gametophyte
3. Partially developed male gametophyte
4. last stage of male gametophyte

Answer: 3. Partially developed male gametophyte

Pollen grain is partially developed male gametophyte because the rest of its development is completed on stigma when pollen grains start to germinate and produce a pollen tube having two male nuclei.

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Question 29.  The approximate diameter of a pollen grain is

1. 25-50 micrometer
2. 50-75 nanometer
3. 25-35 micrometer
4. 75-i00 nanometer

Answer: 1. 25-50 micrometer

Pollen grains are generally 25-50 mm in diameter. They have two main layers, i.e. exine, and intine.

Question 30.  Palynology deals with the study of

1. Pollen grains
2. Chromosomes
3. DNA
4. Genes

Answer: 1. Pollen grains

Study of pollen grains or microspores is called palynology. The term was given by Hyde and Williams.

Question 31: How many meiotic divisions are necessary to produce i00 pollen grains?

1. 100
2. 25
3. 50
4. 20

Answer: 2. 25

Four pollen grains are formed from one pollen mother cell by meiosis. Hence, to produce 100 pollen grains 25 meiotic divisions are required.

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Question 32.  Corn (Zea mays) has diploid number of 20 chromosomes, the number of chromosomes of microspore mother cell is

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

Answer: 2. 20

Diploid cells have the same number of chromosomes as the parent cell. Microspore mother cells are also diploid cells and are genetically identical to the parent cell. So, the number of chromosomes in microspore mother cell is 20

Question 33.  How many pollen grains are formed from i0 microspore mother cells by meiosis?

1. 80
2. 40
3. 20
4. 10

Answer: 2. 40

One microspore mother cell produce four pollen grains by undergoing single meiotic division. Thus, 10 MMC produce (i0 4× ) 40 pollen grains.

Question 34.  The number of pollen grains produced by each head inflorescence of family–Asteraceae which has 10 actinomorphic flowers and if each anther produces 20 pollen grain, are

1. 300
2. 800
3. 500
4. 1000

Answer: 4. 1000

Each flower has 5 stamens. The number of stamens in an inflorescence will be 10×5 = 50. Each anther has 20 pollen grains, the total number of pollen grains will be 50×20 =1000

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Question 35.  If 400 pollen grains are produced from a single monoecious anther from its components equally, what is the number of pollen grain mother cells in each of the sporangia?

1. 200
2. 100
3. 50
4. 25

Answer: 2. 100

Monothecous anther means anther having only one theca or lobe. I pollen mother cell undergoes meiosis to form four haploid microspores each of which develops into pollen grain.

Hence, for 4 pollen grains, i pollen mother cell is required. So, for 400 pollen grains, pollen mother cells required = =400 4 100. So, the correct answer is 100.

Question 36. In angiosperm, all four microspores of tetrad are co5ered by a layer that is formed by

1. Pectocellulose
2. Callose
3. Cellulose
4. Sporopollenin

Answer: 2. Callose

• Callose wall surrounds the sporocytes during the meiotic stage. it provides an isolation barrier, sealing off one meiotic cell from another.
• Hence, it acts as a molecular filter, isolating the developing microspores from the influence of the surrounding diploid tissue.

Question 37.  The ‘isobilateral type’ of microspores arrangement in tetrad is present in

1. Solanum nigrum
2. Zea mays
3. Cassia fistula
4. Signa radiata

Answer: 2. Zea mays

All four spores are formed in one plane because the spindles of first and second meiotic division remain at right angle to one another, it forms isobilateral tetrad, e.g. Zea mays.

Question 38. In dicots, the most common type of pollen tetrad is

1. Isobilateral
2. linear
3. Tetrahedral
4. Decussate

Answer: 3. Tetrahedral

Tetrad is a group of four haploid and immature pollen grains in tetrahedral fashion produced by meiotic division. in dicots, the most common type of pollen tetrad is tetrahedral.

Question 39.  The intine of a pollen grain is made up of

1. Cellulose and pectin
2. lipid and protein
3. Pectin and lignin
4. lignin and cutin

Answer: 1. Cellulose and pectin

The intine is the inner wall of pollen grain. it is made of cellulose and pectins. intine surrounds the pollen grain protoplasm.

Question 40.  Exine of pollen grains is composed of

1. Pectocellulose
2. lignocellulose
3. Sporopollenin
4. Pollen kitt

Answer: 3. Sporopollenin

The outer layer of pollen is exine. It is cuticularised and the cutin is of special type called sporopollenin.

Question 41.  Which one of the following is resistant to enzyme action?

1. Pollen exine
2. Leaf cuticle
3. Cork
4. Wood fibre

Answer: 1. Pollen exine

Pollen exine is made up of sporopollenin which is resistant to enzyme actions leading to chemical and biological decomposition. It preser5es pollen grains during fossilisation.

Question 42.  Sporopollenin is a constituent of pollen exine. it can be degraded by the action of

1. Enzymes
2. High temperature
3. Trong acids
4. Cannot be degraded

Answer: 4. Cannot be degraded

The outer layer of pollen grain is called exine. it is thick, smooth, and cuticularised. The cutin is called sporopollenin. It is not affected by high temperatures, strong acids, or strong alkalis.

Thus, it is resistant to chemical and biological decomposition can not be degraded.

Question 43.  Which of the following has proved helpful in preserving pollen as fossils?

1. Pollen kitt
2. Sporopollenin
3. Oil content
4. Cellulosic intine

Answer: 2. Sporopollenin

Sporopollenin cannot be degraded by enzymes, strong acids, and alkalis, therefore it is helpful in preserving pollen as a fossil. Pollen kitt help in insect pollination.

Cellulosic intine is inner sporoderm layer of pollen grain that is made up of cellulose and pectin.

Question 44. Sporopollenin is formed by polymerisation of

1. Fat and phenols
2. Carotenoids and fat
3. Fat and esters
4. Carotenoids and esters

Answer: 1. Fat and phenols

• Sporopollenin is composed of carbon, hydrogen, and oxygen though the exact chemical composition is not known.
• Due to its unusual chemical stability, it is resistant to degradation. Analysis has revealed
  that it is composed of a mixture of biopolymers, containing mainly long-chain fatty acids, phenyl propanoids, phenolics, and traces of carotenoids.

Question 45.  Which of the following statements is/are wrong?

1.  Pollen grains remain viable for several months because their outer co5ering is made of sporopollenin
2.  No enzyme can degrade sporopollenin
3.  Pollen grains are well represented in fossil strata due to sporopollenin
4. Pollen wall has cavities containing proteins

Answer: 4. Pollen wall has cavities containing proteins

• Statement given in option (4) is wrong, which can be corrected as Pollen wall comprises two principal layers, the inner intine and outer exine.
• The intine is pectocellulosic in nature. A special feature of intine is the presence of beads, ribbons, or plates of enzymatic proteins particularly in the vicinity of germ pores.
• The exine is composed of sporopollenin, which is derived from carotenoids by oxidative polymerization. Thus, pollen walls have no cavities containing proteins. Rest all options are correct.

Question 46. ‘Which one of the following statements is not true?

1. Tapetum helps in the dehiscence of anther
2. Exine of pollen grains is made up of sporopollenin
3. Pollen grains of many species cause severe allergies
4. Stored pollen in liquid nitrogen can be used in the crop breeding programs

Answer: 1. Tapetum helps in the dehiscence of anther

Statement in option (1) is not true because Dehiscence of anther occurs due to stomium cells of endothecium. Tapetum nourishes the developing pollen grains. Rest all options are correct.

Question 47.  Which of the following statements about sporopollenin is false?

1. Exine is made up of sporopollenin
2. Sporopollenin is one of the most resistant organic materials
3. Exine has apertures called germ pores where sporopollenin is present
4. Sporopollenin can withstand high temperatures and strong acids
5. So far no enzyme is known to degrade sporopollenin

Answer: 3. Exine has apertures called germ pores where sporopollenin is present

• Statement in option (3) is false. The covering of pollen grain is called sporoderm. it has two layers, outer exine, and inner intine. Exine is made of a highly resistant fatty substance called sporopollenin.
• At certain places, sporopollenin is absent. They are called germ pores (if rounded) or germinal furrows (if elongated). This is the region through which the pollen tube emerges during pollination. Rest all statements are correct.

Question 48.  Ubisch bodies are present in

1. Pollen tube
2. Pollen grain
3. Microspore
4. Tapetum

Answer: 4. Tapetum

• Ubisch bodies are small, granular structures that are found in the extracellular matrix of cells of the secretory tapetal layer that surrounds developing pollen grains.
• Ubisch bodies have a sporopollenin coat, these are attached to the peritapetal wall and may play a role in pollen development.

Question 49.  The ubisch bodies found in tapetal cells help in the formation of

1. Pollen kitt and pollinia
2. Exine
3. Sporopollenin
4. Intine and pollen kitt

Answer: 2. Exine

Ubisch bodies secreted by tapetum help in forming the external thickening of exine as these bodies get coated with sporopollenin.

Question 50.  Gametogenesis refers to the process

1. Fusion of two gametes
2. Fusion of two gametangia
3. Formation of two types of gametes
4. Formation of male gamete only

Answer: 3. Formation of two types of gametes

Gametogenesis refers to the process of formation of two types of gametes, i.e. male and female. Gametes are haploid in nature.

Question 51.  Male gametes in angiosperms are formed by the division of

1. Generative cell
2. Vegetative cell
3. Microspore mother cell
4. Microspore

Answer: 1. Generative cell

Each pollen grain contains vegetative cells and a generative cell. in flowering plants, the vegetative tube cell produces the pollen tube and the generative cell divides to form two sperm cells or male gametes.

Question 52.  Generative cell of a microspore undergoes which type of division?

1. Mitosis
2. Meiosis
3. Endomitosis
4. Either (1) or (3)

Answer: 1. Mitosis

The haploid generative cell of a microspore or pollen grain undergoes mitosis division to form two haploid male gametes

Question 53. The larger nucleus in a pollen grain is

1. Tube nucleus
2. Sperm nucleus
3. Generative nucleus
4. None of the above

Answer: 1. Tube nucleus

Pollen grain is the mother cell of male gametophyte. Development of male gametophyte begins inside the microsporangium. The microspore nucleus divides mitotically to form smaller generative cells and much larger vegetative cells called tube cells or nuclei.

Question 54.  At the time of shedding, the number of nuclei present in an angiosperm pollen grain is

1. One
2. One or two
3. Two or three
4. Only two

Answer: 3. Two or three

• In majority of angiosperms, the pollen grains are shed from the anther at the bicelles (2-celled) stage.
• But in some genera (both the monocots and dicots), the generative cell divides prior to the dehiscence of the anther, and pollen grain is shed at 3-celled stage.
• Approximately 70% of species shed their pollen at the 2-celled stage and 30% at 3-celled stage.

Question 55.  Male gametophyte in angiosperms produces

1. Single sperm and two vegetative cells
2. Three sperms
3. Two sperms and a vegetative cell
4. Single sperm and a vegetative cell

Answer: 3. Two sperms and a vegetative cell

The protoplast of the male gametophyte divides mitotically to produce two unequal cells; a small generative cell and a large vegetative cell.

The generative cell divides into two non-motile male gametes (or sperms). Thus, the male gametophyte in angiosperms produces two sperms and a vegetative cell. The vegetative cell, later on, grows to produce pollen tube.

Question 56.  Pollen grains ofCycas are liberated at ……………….. stage.

Three celled

Two celled

Single-celled

None of these

Answer: 1. Three celled

Pollination in Cycas is anemophilous and takes place at 3-celled stage, i.e. prothalial cell, generative cell, and tube cell.

Question 57. In angiosperms, the formation of two male gametes from a pollen grain involves ………….. divisions.

1. One meiotic and one mitotic
2. Two meiotic and two mitotic
3. Only two mitotic
4. Only two meiotic

Answer: 3. Two meiotic and two mitotic

• In angiosperms, the diploid pollen mother cell undergoes meiosis-i followed by meiosis-2 to form a tetrad having 4 haploid microspores.
• This tetrad separates to form 4 haploid pollen grains. Each pollen grain undergoes two mitotic divisions to give rise to 2 male gametes.

Thus, the correct answer is option (3).

Question 58.  An immature male gametophyte differs from a mature male gametophyte in that it

1. Has not yet left the pollen sac
2. Has not yet germinated and its generative cell has not divided into two male gametes
3. Is a microspore that has not yet divided by mitosis
4. Still consists of microsporocyte

Answer: 2. Has not yet germinated and its generative cell has not divided into two male gametes

• An immature male gametophyte differs from a mature male gametophyte as immature male gametophyte has not yet germinated and its generative cell has not divided into two male gametes.
• When the pollen grain is mature generative cell divide mitotically to form two sperm cells.

Question 59.  Which one of the following statements is wrong?

1. When pollen is shed at two-celled stage, double fertilisation does not take place
2. Vegetative cell is larger than generative cell
3. Pollen grains in some plants remain 5iable for months
4. Intine is made up of cellulose and pectin

Answer: 1. When pollen is shed at two-celled stage, double fertilisation does not take place

• Statement in option (1) is wrong. In 60% of flowering plants, the pollen grains are shed at two-celled stages, i.e. tube cell and generative cell. Further, de5elopment of male gametophyte (pollen grain) occurs on stigma.
• Pollen grain gives rise to pollen tube which absorbs nourishment from the cells of style for its growth. Generative cell divides to give rise to two male gametes. Rest all options are correct.

Question 60.  Even after killing the generative cell with a laser beam, the pollen grain of a flowering plant germinates and produces normal pollen tube because

1. laser beam stimulates pollen germination and pollen tube growth
2. The laser beam does not damage the region from which pollen tube emerges
3. The contents of killed generative cell permit germination and pollen tube growth
4. The vegetative cell has not been damaged

Answer: 4. The vegetative cell has not been damaged

• During microspore formation cellular differentiation occurs and generative and vegetative cells are formed.
• The generative cell produces two sperm cells whereas the vegetative cell produces the pollen tube which
  helps to deliver the male gametes to the embryo sac. Therefore, if the laser beam kills the generative cell, it will not affect the normal pollen tube formation. Thus, the correct answer is option (4).

Question 61.  Pollinia are found in which plant family?

1. Asteraceae
2. Malvaceae
3. Myrtaceae
4. Asclepiadaceae

Answer: 4. Asclepiadaceae

The presence of pollinium is a characteristic feature of family– Asclepiadaceae.

Question 62. In orchids and milkweeds, all pollen grains of an anther lobe remain united in a sac called

1. Compound pollen grain
2. Pollinia
3. Caudicles
4. Translator

Answer: 2. Pollinia

• Pollinia is a mass of pollen grains typically transferred as a unit during pollination. it is found in the flowers of certain plants such as orchids and milkweeds.
• These are connected to one or two elongated stripes, which in turn are attached to a sticky viscidium, a disc-shaped structure that sticks to a 5isiting insect.

Question 63. The pollen grains of rice and wheat lose their 5iability in …….. minutes of their release.

1. 30
2. 10
3. 60
4. 90

Answer: 1. 30

• Pollen Viability is the period for which pollen grains retain the ability to germinate. it is little in flowers which are pollinated in bud condition.
• it is 30 minutes in rice and wheat. it depends upon environmental conditions like temperature and humidity.

Question 64.  Pollen grains can cause

Bronchial afflictions

Asthma

Bronchitis

All of the above

Answer: 1. Bronchial afflictions

• Pollen grains of many species cause severe allergies and bronchial afflictions. in some people, it often leads to chronic respiratory disorders, i.e. asthma, bronchitis, etc.
• Parthenium or carrot grass gained entry into India along with imported wheat and has now become ubiquitous in the occurrence and causes of pollen allergy.

Question 65. Which part of the pollen causes pollen allergy?

1. Exine
2. Intine
3. Pollen cytoplasm
4. Both (1) and (2)

Answer: 3. Pollen cytoplasm

1. Pollen allergy is an allergy caused when contact with specific pollens. Allergens in the pollen are concentrated in the cytoplasm.
2. When allergens from an inhaled pollen grain are released and bind with antibodies, they produce a
   number of symptoms like runny or stuffy nose, sneezing, red, itchy, and watery eyes, and swelling around the eyes.

Question 66.  Pollen tablets are available in the market for in vitro fertilisation

1. For breeding programs
2. As food supplements
3. For ex-situ conservation

Answer: 3. As food supplements

• Pollen grains are believed to be rich in nutrients (protein 7-26 %, carbohydrates 24-48%, fats 0.9- i4.5%).
• They are taken as tablets or syrups to improve health. They also enhance the performance of athletes and racehorses.

Thus, option (3) is correct.

Question 67. Endothecium and tapetum in anther are derived from

1. Primary sporogenous layer
2. Primary parietal layer
3. Both (a) and (b)
4. None of the above

Answer:  2. Primary parietal layer