Sexual Reproduction in Flowering Plants
1. What is sexual reproduction in flowering plants?
Answer:
Sexual reproduction in flowering plants involves the formation of male and female gametes, their fusion (fertilization), and the formation of seeds and fruits.
2. Name the male and female reproductive organs of a flower.
Answer:
- Male reproductive organ: Androecium (Stamen)
- Female reproductive organ: Gynoecium (Carpel/Pistil)
3. What is anther? Mention its function.
Answer:
The anther is the terminal part of the stamen.
Function: It produces pollen grains which contain male gametes.
4. What is microsporogenesis?
Answer:
Microsporogenesis is the process by which microspore mother cells undergo meiosis to form haploid microspores (pollen grains).
5. What is a pollen grain?
Answer:
A pollen grain is the male gametophyte of flowering plants that carries male gametes.
6. Mention the structure of a mature pollen grain.
Answer:
A mature pollen grain has:
- Exine (outer thick wall)
- Intine (inner thin wall)
- A vegetative cell
- A generative cell
7. What is megasporogenesis?
Answer:
Megasporogenesis is the process by which the megaspore mother cell undergoes meiosis to form haploid megaspores inside the ovule.
8. How many megaspores are formed and how many remain functional?
Answer:
Four megaspores are formed, but only one remains functional.
9. Describe the structure of the embryo sac.
Answer:
The embryo sac is 7-celled and 8-nucleate, consisting of:
- 1 egg cell
- 2 synergids
- 3 antipodal cells
- 2 polar nuclei
10. What is pollination? Name its types.
Answer:
Pollination is the transfer of pollen grains from anther to stigma.
Types:
- Self-pollination
- Cross-pollination
11. What is double fertilization?
Answer:
Double fertilization is the process where one male gamete fuses with the egg cell (syngamy) and the other fuses with polar nuclei (triple fusion).
12. Name the products of double fertilization.
Answer:
- Zygote
- Primary endosperm nucleus
13. What is endosperm? Mention its function.
Answer:
Endosperm is a nutritive tissue formed after fertilization.
Function: It provides nourishment to the developing embryo.
14. What is embryo?
Answer:
The embryo is the young sporophyte formed from the zygote after fertilization.
15. What changes occur after fertilization in a flower?
Answer:
- Ovule → Seed
- Ovary → Fruit
- Zygote → Embryo
- Ovary wall → Pericarp
16. What is apomixis?
Answer:
Apomixis is the formation of seeds without fertilization.
17. Mention one significance of sexual reproduction in plants.
Answer:
It produces genetic variation, which helps in evolution and adaptation.
18. What is pollen tube? State its function.
Answer:
The pollen tube is a tubular outgrowth of pollen grain.
Function: It carries male gametes to the embryo sac.
19. What is stigma?
Answer:
Stigma is the receptive part of the carpel where pollen grains germinate.
20. Why is cross-pollination beneficial?
Answer:
Cross-pollination increases genetic variation and produces healthier offspring.
Exam Tips for Students
✔ Focus on definitions + diagrams
✔ Remember key terms: 7-celled, 8-nucleate, double fertilization
✔ Practice 3–5 mark answers neatly
No comments:
Post a Comment