Class 12 Biology – Long Answer Questions
Chapter: Sexual Reproduction in Flowering Plants
Q1. Describe the process of sexual reproduction in flowering plants.
(Full detailed answer already provided above in structured format.)
Q2. Explain the structure and development of male gametophyte in
angiosperms.
1. Introduction:
The male gametophyte of angiosperms is the pollen grain which develops from
microspores inside the anther.
2. Structure of Anther:
- Anther is bilobed and tetrasporangiate.
- Each anther has 4 microsporangia which form pollen sacs.
3. Microsporogenesis:
- Microspore mother cells (MMC) undergo meiosis → 4 haploid microspores
(tetrad).
- Each microspore → a pollen grain
4. Pollen Grain Development:
- Immature pollen grain is 2-celled:
- Vegetative cell: Large, rich in food
- Generative cell: Small, floats in vegetative cytoplasm
- At maturity, pollen is released and carried to stigma.
5. Pollen Wall:
- Exine: Tough, with sporopollenin
- Intine: Thin, cellulose and pectin
Conclusion:
The male gametophyte carries male gametes and initiates fertilisation.
Q3. Describe the development and structure of female gametophyte in
flowering plants.
1. Introduction:
The female gametophyte is the embryo sac, formed inside the ovule of the ovary.
Chapter: Sexual Reproduction in Flowering Plants
Q1. Describe the process of sexual reproduction in flowering plants.
(Full detailed answer already provided above in structured format.)
Q2. Explain the structure and development of male gametophyte in
angiosperms.
1. Introduction:
The male gametophyte of angiosperms is the pollen grain which develops from
microspores inside the anther.
2. Structure of Anther:
- Anther is bilobed and tetrasporangiate.
- Each anther has 4 microsporangia which form pollen sacs.
3. Microsporogenesis:
- Microspore mother cells (MMC) undergo meiosis → 4 haploid microspores
(tetrad).
- Each microspore → a pollen grain
4. Pollen Grain Development:
- Immature pollen grain is 2-celled:
- Vegetative cell: Large, rich in food
- Generative cell: Small, floats in vegetative cytoplasm
- At maturity, pollen is released and carried to stigma.
5. Pollen Wall:
- Exine: Tough, with sporopollenin
- Intine: Thin, cellulose and pectin
Conclusion:
The male gametophyte carries male gametes and initiates fertilisation.
Q3. Describe the development and structure of female gametophyte in
flowering plants.
1. Introduction:
The female gametophyte is the embryo sac, formed inside the ovule of the ovary.
