🌿 UNIT I-Post-Fertilization Events 🌿
1. The primary endosperm nucleus is formed by the fusion of:
a) Two male gametes
b) Male gamete and egg cell
c) Male gamete and polar nuclei
d) Egg cell and polar nuclei
Answer: c) Male gamete and polar nuclei
Explanation: In double fertilization, one male gamete fuses with polar nuclei to form the triploid primary endosperm nucleus (PEN).
2. The ploidy of the primary endosperm nucleus is:
a) Haploid
b) Diploid
c) Triploid
d) Tetraploid
Answer: c) Triploid
Explanation: It contains two polar nuclei (n+n) and one male gamete (n), making it 3n.
3. The type of endosperm found in coconut is:
a) Nuclear
b) Cellular
c) Helobial
d) Free-nuclear
Answer: a) Nuclear
Explanation: In coconut, free-nuclear division occurs before cell wall formation, typical of nuclear endosperm.
4. Endosperm provides:
a) Protection to seed
b) Food for embryo
c) Support for fruit development
d) Water for embryo
Answer: b) Food for embryo
Explanation: Endosperm is nutritive tissue storing starch, proteins, and oils for the developing embryo.
5. In which type of endosperm, cell walls are formed after several free-nuclear divisions?
a) Cellular
b) Nuclear
c) Helobial
d) Triploid
Answer: b) Nuclear
Explanation: Nuclear endosperm undergoes free-nuclear divisions first; cell walls appear later.
6. Helobial endosperm is found in:
a) Maize
b) Cucurbita
c) Lilium
d) Coconut
Answer: c) Lilium
Explanation: Helobial endosperm shows characteristics of both nuclear and cellular types.
7. In monocots, endosperm is:
a) Usually absent
b) Persistent
c) Diploid
d) Formed from egg cell
Answer: b) Persistent
Explanation: In monocots like maize and coconut, endosperm remains in the mature seed.
8. Coleoptile is related to:
a) Endosperm
b) Embryo
c) Seed coat
d) Fruit
Answer: b) Embryo
Explanation: Coleoptile is the sheath protecting the young shoot of the embryo in monocots.
9. Primary endosperm nucleus divides to form:
a) Embryo
b) Seed coat
c) Endosperm tissue
d) Cotyledon
Answer: c) Endosperm tissue
Explanation: PEN undergoes repeated mitotic divisions to form endosperm.
10. Endosperm may be:
a) Only diploid
b) Only triploid
c) Haploid, diploid, or triploid
d) Always haploid
Answer: c) Haploid, diploid, or triploid
Explanation: While triploid endosperm is common, in some species (like gymnosperms) it may differ.
11. In double fertilization, one male gamete fuses with the egg, the other with:
a) Synergids
b) Antipodal cells
c) Polar nuclei
d) Funiculus
Answer: c) Polar nuclei
Explanation: Fusion with polar nuclei forms triploid primary endosperm nucleus.
12. Nuclear endosperm division is initially:
a) Mitosis with cell wall formation
b) Free-nuclear mitosis without cell wall
c) Meiosis
d) Binary fission
Answer: b) Free-nuclear mitosis without cell wall
Explanation: It ensures rapid increase in number of nuclei before cellularization.
13. Function of endosperm in dicots is mostly:
a) Protective
b) Absorbed by cotyledons
c) Helps in pollination
d) Forms fruit
Answer: b) Absorbed by cotyledons
Explanation: In dicots like gram, cotyledons absorb endosperm nutrients and store them.
14. The cell walls in nuclear endosperm form:
a) Immediately
b) After several nuclear divisions
c) Never
d) Before fertilization
Answer: b) After several nuclear divisions
Explanation: Free-nuclear stage allows rapid growth before partitioning into cells.
15. In majority of flowering plants, endosperm is:
a) Diploid
b) Triploid
c) Tetraploid
d) Polyploid
Answer: b) Triploid
Explanation: Typical angiosperm endosperm is triploid (2n polar nuclei + n male gamete).
16. The first division of the zygote is:
a) Transverse
b) Longitudinal
c) Diagonal
d) Random
Answer: a) Transverse
Explanation: Transverse division produces basal and terminal cells, establishing polarity.
17. The terminal cell of zygote gives rise to:
a) Suspensor
b) Embryo proper
c) Seed coat
d) Cotyledon only
Answer: b) Embryo proper
Explanation: Terminal cell divides to form the main body of the embryo.
18. The basal cell of zygote forms:
a) Endosperm
b) Suspensor
c) Cotyledon
d) Fruit
Answer: b) Suspensor
Explanation: Suspensor anchors embryo and helps in nutrient transport.
19. In dicot embryos, cotyledons develop from:
a) Terminal cell
b) Basal cell
c) Polar nuclei
d) Antipodal cells
Answer: a) Terminal cell
Explanation: Cotyledons arise from the embryo proper derived from the terminal cell.
20. Coleorhiza protects:
a) Young shoot
b) Young root
c) Seed coat
d) Endosperm
Answer: b) Young root
Explanation: In monocots, coleorhiza surrounds the radicle.
21. The suspensor consists of:
a) Single cell
b) Multicellular structure
c) Cotyledons
d) Endosperm
Answer: b) Multicellular structure
Explanation: It may have 1–7 cells in dicots, performing anchorage and nutrient transport.
22. In dicots, embryo is:
a) Monocotyledonous
b) Dicotyledonous
c) Non-cotyledonous
d) Tri-cotyledonous
Answer: b) Dicotyledonous
Explanation: Dicots have two cotyledons which store nutrients for germination.
23. Suspensor helps in:
a) Photosynthesis
b) Nutrient transfer from endosperm to embryo
c) Fertilization
d) Pollination
Answer: b) Nutrient transfer from endosperm to embryo
Explanation: It acts like a placenta in plants.
24. The stage when embryo forms heart shape in dicots is:
a) Globular
b) Heart
c) Torpedo
d) Mature
Answer: b) Heart
Explanation: Cotyledons develop during the heart stage.
25. Torpedo stage in dicot embryo is followed by:
a) Zygote stage
b) Globular stage
c) Mature stage
d) Heart stage
Answer: c) Mature stage
Explanation: Torpedo stage elongates embryo; mature stage shows fully formed cotyledons.
26. In monocot seeds, embryo develops:
a) Two cotyledons
b) Single cotyledon
c) No cotyledon
d) Multiple cotyledons
Answer: b) Single cotyledon
Explanation: Monocots like maize have a single cotyledon called scutellum.
27. The part of the embryo that absorbs nutrients from endosperm in monocots is:
a) Coleoptile
b) Scutellum
c) Suspensor
d) Radicle
Answer: b) Scutellum
Explanation: Scutellum functions as the cotyledon and absorbs nutrients.
28. The mature embryo consists of:
a) Cotyledons, radicle, plumule
b) Endosperm only
c) Seed coat only
d) Fruit wall
Answer: a) Cotyledons, radicle, plumule
Explanation: These are the key parts visible at seed maturity.
29. Plumule develops into:
a) Root
b) Shoot
c) Cotyledon
d) Endosperm
Answer: b) Shoot
Explanation: Plumule is the embryonic shoot apex.
30. Radicle develops into:
a) Root system
b) Shoot system
c) Cotyledons
d) Endosperm
Answer: a) Root system
Explanation: Radicle is the embryonic root.
31. Seed coat develops from:
a) Zygote
b) Ovule integuments
c) Endosperm
d) Funiculus
Answer: b) Ovule integuments
Explanation: Outer integument forms testa; inner integument forms tegmen.
32. Micropyle in seed helps in:
a) Pollination
b) Water absorption during germination
c) Cotyledon formation
d) Fruit development
Answer: b) Water absorption during germination
Explanation: Small opening allows water entry.
33. In dicot seeds, storage tissue is:
a) Endosperm
b) Cotyledons
c) Seed coat
d) Plumule
Answer: b) Cotyledons
Explanation: Cotyledons absorb endosperm during development.
34. In monocots, storage tissue is:
a) Endosperm
b) Cotyledons
c) Seed coat
d) Plumule
Answer: a) Endosperm
Explanation: Monocots retain endosperm for storage (e.g., maize, wheat).
35. Function of seed coat:
a) Nutrition
b) Protection
c) Photosynthesis
d) Fertilization
Answer: b) Protection
Explanation: Seed coat protects the embryo from mechanical injury and desiccation.
36. In pea seed, cotyledons are:
a) Green
b) Thick and fleshy
c) Thin
d) Non-existent
Answer: b) Thick and fleshy
Explanation: Cotyledons store food and form majority of the seed.
37. Viable seeds are formed after:
a) Pollination
b) Fertilization
c) Pollination and fertilization
d) Fruit ripening
Answer: b) Fertilization
Explanation: Fertilization triggers seed development.
38. Funiculus connects:
a) Ovule to placenta
b) Seed to endosperm
c) Radicle to plumule
d) Seed to pollen tube
Answer: a) Ovule to placenta
Explanation: Funiculus forms stalk of the ovule/seed.
39. Integuments develop into:
a) Endosperm
b) Seed coat
c) Embryo
d) Fruit wall
Answer: b) Seed coat
Explanation: Outer and inner integuments form testa and tegmen.
40. Dormancy in seed is due to:
a) Immature embryo
b) Hard seed coat
c) Presence of inhibitors
d) All of the above
Answer: d) All of the above
Explanation: Seed dormancy ensures proper timing of germination.
41. Fruit develops from:
a) Ovule
b) Ovary
c) Zygote
d) Endosperm
Answer: b) Ovary
Explanation: Post-fertilization, the ovary develops into fruit.
42. Parthenocarpic fruit develops:
a) Without fertilization
b) After fertilization
c) From endosperm
d) From seed coat
Answer: a) Without fertilization
Explanation: Examples: banana, grapes; no seeds.
43. Simple fruits develop from:
a) Single ovary
b) Multiple ovaries
c) Multiple flowers
d) Only from endosperm
Answer: a) Single ovary
Explanation: Example: mango, tomato.
44. Aggregate fruits develop from:
a) One ovary
b) Multiple ovaries of single flower
c) Multiple flowers
d) Endosperm
Answer: b) Multiple ovaries of single flower
Explanation: Example: raspberry, custard apple.
45. Multiple fruits develop from:
a) Single ovary
b) Multiple flowers
c) Single flower
d) Endosperm
Answer: b) Multiple flowers
Explanation: Example: pineapple, fig.
46. The pericarp is formed from:
a) Ovary wall
b) Seed coat
c) Embryo
d) Cotyledon
Answer: a) Ovary wall
Explanation: It may be fleshy or dry depending on fruit type.
47. In fleshy fruits, pericarp is:
a) Dry
b) Fleshy
c) Hard
d) Thin
Answer: b) Fleshy
Explanation: Examples: mango, tomato.
48. In dry fruits, pericarp is:
a) Fleshy
b) Hard or dry
c) Soft
d) Juicy
Answer: b) Hard or dry
Explanation: Examples: pea, wheat.
49. Seedless fruits are:
a) Parthenocarpic
b) Fertilized
c) Non-functional
d) Integumentless
Answer: a) Parthenocarpic
Explanation: Develop without fertilization; produce no seeds.
50. Fertilization triggers fruit development because:
a) Endosperm formation
b) Hormones like auxins and gibberellins are produced
c) Seed coat formation
d) Ovule death
Answer: b) Hormones like auxins and gibberellins are produced
Explanation: These hormones induce ovary growth into fruit.
