Class 12 Biology: SEXUAL REPRODUCTION IN FLOWERING PLANTS

PYQ: SEXUAL REPRODUCTION IN FLOWERING PLANTS

1. Double fertilization is unique to angiosperms. Analyze its evolutionary advantage over gymnosperms.
2. Predict consequences if tapetum becomes prematurely degenerated.
3. How does a pistil distinguish between compatible and incompatible pollen?
4. Why is apomixis considered both beneficial and harmful in agriculture?
5. What happens if only one megaspore fails to develop into an embryo sac?
6. Explain the importance of synergids in fertilization.
7. Evaluate advantages of polyembryony in plants like Citrus.
8. Why is self-incompatibility important despite reducing fertilization chances?
9. Why is emasculation not required in some cases?
10. Compare nuclear and cellular endosperm formation.
11. Why do some pollens remain viable longer than others?
12. Why are cleistogamous flowers always autogamous?
13. Predict floral traits of wind-pollinated plants.
14. What would happen if ovule fails to produce attractant signals?
15. Explain polarity in embryo development.
16. Fruit Formation Without Fertilization: Explain parthenocarpy and its importance.
17. What is the function of callose in microsporogenesis?
18. Why is male sterility useful in hybrid seed production?
19. Why is triple fusion essential?
20. How can mutation affecting pollen formation impact plant population?
    

1. Write the difference between chasmogamous and cleistogamous flowers.
2. What is endosperm ? Describe free nuclear endosperm and cellular endosperm.
3. What is the ploidy of endosperm in angiosperms ?
4. Describe pollen-pistil interaction in detail.
5. Why do pollen grains remain preserved for long time ?
6. What are stem cells ?
7. What is endosperm ? Explain various types of endosperms.
8. What is emasculation?
9. Write down the names of post fertilization events in flowering plants. Describe the process of embryo development.
10. Explain in detail the process of development of female gametophyte. Draw diagram.
11. Define apomixis.
12. Define pollination. Explain wind and water pollination with example.
13. Define Agamospermy.
14. Describe the structure of Anatropous ovule with diagram.
15. Write the name of four flower parts.
16. Describe the structure of cellular endosperm with diagram.
17. Which of the following plant is pollinated by snails ?
    (A) Cotton (B) Arisaema (C) Mustrard (D) Tobacco
18. Microspore forms the __________gametophyte after its germination.
19. Explain double fertilization in angiosperm plants.
20. In which of the following perisperm is found ?
    (A) Beetroot (B) Pea (C) Groundnut (D) Sunflower
21. (i) Define pollination.
    (ii) Explain double fertilisation.
    (iii) Draw a labelled diagram of structure of fertilised embryo sac.
22. An example of a non-albuminous seed is
    (A) Wheat (B) Maize (C) Pea (D) Castor
23. The central cell after triple fusion becomes the____________.
24. Define apomixis.
25. Describe the structure of megasporangium.
26. Draw labelled diagram of transverse section of a pollen sac.

HOTS

1. A mutant plant shows normal anther structure but produces sterile pollen. Microscopy reveals that the tapetum degenerates very early. Explain the sequence of events leading to sterility.
2. In a species, pollen grains germinate 24 hours after pollination instead of immediately. Predict consequences on fertilization success.
3. A plant mutation prevents synergids from producing attractant chemicals. Predict the outcome.
4. In an experiment, triple fusion occurs, but endosperm fails to develop. What will happen to the embryo?
5. A mutation disables S-genes in a self-incompatible plant. Predict genetic and evolutionary consequences.
6. Normally only one megaspore survives. What if all four megaspores remain functional?
7. A chemical inhibitor blocks pollen tube guidance signals midway. What happens next?
8. A gene for apomixis is introduced into a hybrid crop. Predict long-term agricultural effects.
9. Callose wall fails to degrade during microsporogenesis. What is the effect?
10. A pollen grain forms without a vegetative cell. Can fertilization occur?
11. Antipodal cells degenerate very early in a species. Does it affect fertilization?
12. In a region with extreme humidity, pollen viability drastically reduces. Explain why.
13. A student forgets to bag a flower after emasculation. What is the likely outcome?
14. Mutation disrupts zygote polarity. Predict developmental issues.
15. Due to abnormal fertilization, embryo becomes triploid. What are consequences?
16. A wind-pollinated plant grows in a dense forest. Predict reproductive success.
17. Stigma loses receptivity before pollen arrival. Outcome?
18. Thousands of pollen grains land on stigma. How is selection ensured?
19. Hormones induce fruit formation without fertilization. What changes occur?
20. A mutation causes widespread male sterility in a plant population. Predict long-term survival.