Part 2 — Microsporogenesis, pollen structure & male gametophyte development (25 MCQs)

Q26. Microsporogenesis occurs in:

a) Megasporophyll
b) Anther pollen sacs (microsporangia)
c) Ovary
d) Stigma

Answer: b) Anther pollen sacs (microsporangia)

(b) Correct. Microsporangia in anther undergo meiosis to form microspores.
(a,c,d) Incorrect organs.

Q27. Microspores are formed by:

a) Mitosis of microspore mother cell
b) Meiosis of microspore mother cell
c) Meiosis of microspore cell giving tetrad
d) Direct differentiation from anther wall

Answer: c) Meiosis of microspore mother cell giving tetrad

(c) Correct. Diploid microspore mother cell undergoes meiosis to yield four haploid microspores (tetrad).
(a,b) Mitosis would not reduce chromosome number; meiosis is correct but (b) ambiguous — (c) precise.

Q28. Pollen grain wall inner layer that stains and is callose-like is:

a) Exine
b) Intine
c) Sporopollenin-containing layer
d) Operculum

Answer: b) Intine

(b) Correct. Intine = inner wall made of cellulose & pectin, stainable; exine = outer, sporopollenin-rich.
(c) Exine has sporopollenin.
(d) Operculum is a lid in some pollen types — not generally inner wall.

Q29. The durable, chemically inert outer layer of pollen that helps in fossilization is:

a) Cellulose
b) Sporopollenin (exine)
c) Cutin
d) Lignin

Answer: b) Sporopollenin (exine)

(b) Correct. Exine composed largely of sporopollenin, resistant to degradation.
Others are plant polymers but not pollen exine.

Q30. A mature pollen grain in most angiosperms is:

a) Unicellular vegetative only
b) Bicellular with vegetative and generative cells
c) Tricellular (vegetative + two sperms) in all species
d) Multicellular embryo sac

Answer: b) Bicellular with vegetative and generative cells

(b) Correct. Many angiosperms have bicellular pollen: vegetative cell + generative cell; generative may divide later to form two sperms (tricellular in some species).
(c) Some species are tricellular at anthesis but not all.
(d) Embryo sac is female.

Q31. The generative cell divides to produce:

a) One spermatid
b) Two sperm cells
c) Vegetative cell
d) Zygote directly

Answer: b) Two sperm cells

(b) Correct. Generative cell divides by mitosis forming two non-motile sperm (male gametes).
Others incorrect.

Q32. Tapetum layer in anther functions to:

a) Protect pollen physically only
b) Provide nourishment and materials (e.g., sporopollenin precursors) for pollen development
c) Produce microspores directly
d) Form the pollen tube

Answer: b) Provide nourishment and materials (e.g., sporopollenin precursors) for pollen development

(b) Correct. Tapetum is nutritive tissue; synthesizes sporopollenin precursors and enzymes.
(a) Partial; main role nutritional.
(c) Microspores come from microsporocytes.
(d) Pollen tube from pollen, not tapetum.

Q33. In anther, microsporocyte =:

a) Pollen mother cell (PMC)
b) Tapetal cell
c) Pollen grain
d) Pollen tube

Answer: a) Pollen mother cell (PMC)

(a) Correct. Microsporocyte or microspore mother cell undergoes meiosis to form microspores.
(b–d) Incorrect.

Q34. The wall layer which is broken down to release microspores (callose wall) is:

a) Exine
b) Intine
c) Callose wall around tetrad is degraded by callase enzyme from tapetum
d) Epidermis

Answer: c) Callose wall around tetrad is degraded by callase enzyme from tapetum

(c) Correct. Tetrads are embedded in callose wall which is enzymatically broken by callase.
Exine/intine are pollen walls, not the callose tetrad wall.

Q35. A pollen grain having one groove (colpus) or pore is described as:

a) Tricolpate
b) Monosulcate or monocolpate
c) Polycolpate
d) Apolar

Answer: b) Monosulcate or monocolpate

(b) Correct. Monosulcate = single sulcus/colpus; monocots & some groups show various aperture types.
(a) Tricolpate = three furrows (typical of eudicots).
(c) Poly = many.
(d) Apolar = not descriptive.

Q36. Pollen grains adapted to insect pollination usually have:

a) Sticky, sculptured exine and abundant cytoplasm (large)
b) Smooth, dry exine and small size for wind transport
c) Extremely reduced exine
d) Flagella for motility

Answer: a) Sticky, sculptured exine and abundant cytoplasm (large)

(a) Correct. Entomophilous pollen often sticky, ornamented, heavy, nutritious.
(b) Describes anemophilous (wind) pollen.
(c,d) Incorrect.

Q37. Pollen grains of gymnosperms differ because they:

a) Have motile sperm with flagella
b) Lack pollen wall
c) Are always bicellular only
d) Are formed in the ovule

Answer: a) Have motile sperm with flagella

(a) Correct for many gymnosperms (e.g., cycads, Ginkgo) which have flagellated sperm; but conifers have non-flagellate sperm delivered by pollen tube.
(b) Gymnosperm pollen has wall.
(c) Not universally true.
(d) Pollen formed in male cones.

Q38. The pollen tube nucleus originates from:

a) Vegetative nucleus
b) Generative nucleus
c) Both
d) Synergid

Answer: a) Vegetative nucleus

(a) Correct. Vegetative nucleus directs pollen tube growth; generative produces sperms.
(b) Generative divides into sperms; does not direct tube growth.
(d) Synergids are female cells in embryo sac.

Q39. In angiosperms, the male gametophyte is represented by:

a) Pollen grain and pollen tube
b) Generative cell only
c) Sperm only
d) Microsporocyte

Answer: a) Pollen grain and pollen tube

(a) Correct. Male gametophyte includes vegetative cell, generative/sperm cells, and the pollen tube during fertilization.
(b–d) Partial components only.

Q40. Which of the following is NOT a role of tapetum?

a) Providing nutrition to developing microspores
b) Secretion of callase to dissolve callose wall
c) Forming pollen exine components
d) Differentiating into pollen tubes

Answer: d) Differentiating into pollen tubes

(d) Correct (not a role). Tapetum does not become pollen tubes. All others are tapetum functions.

Q41. Microspore tetrads are often arranged as:

a) Tetrahedral or isobilateral forms depending on species
b) Only linear
c) Only radial but never tetrahedral
d) No consistent arrangement

Answer: a) Tetrahedral or isobilateral forms depending on species

(a) Correct. Tetrad arrangement varies (tetrahedral in many dicots, isobilateral in some).
(b–d) Incorrect.

Q42. A pollen grain matured before anther dehiscence and ready to fertilize is called:

a) Immature pollen
b) Viable pollen at anthesis
c) Sterile pollen
d) Microspore mother cell

Answer: b) Viable pollen at anthesis

(b) Correct. Anthesis = flower opening; pollen released often already mature.
Others incorrect.

Q43. Which structure carries male gametes to ovule?

a) Style only
b) Pollen tube
c) Stigma alone
d) Anther filament

Answer: b) Pollen tube

(b) Correct. Pollen tube grows through style and transmits sperms to embryo sac.
(a,c,d) Not direct carrier.

Q44. A biporate or triporate pollen means:

a) Two or three apertures for germination
b) Two or three pollen nuclei
c) Two anthers per flower
d) Two carpels per ovary

Answer: a) Two or three apertures for germination

(a) Correct. Apertures allow pollen tube emergence.

Q45. The thickened area on pollen grain where exine is absent and pollen tube emerges is called:

a) Germ pore or aperture
b) Operculum
c) Colpus
d) Exine lacuna

Answer: a) Germ pore or aperture

(a) Correct. Germ pore (aperture) is thinner region for tube emergence.
(b) Operculum is a lid on some pollen types.
(c) Colpus is a groove-type aperture.

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Part 2 — Microsporogenesis, pollen structure & male gametophyte development (25 MCQs)