CBSE – 7th Standard Science

Question Bank – Chapter 12 – Reproduction in Plants




Q1. State the main difference between asexual and sexual reproduction.

Ans.  In asexual reproduction new plants are obtained without production of seeds or spores, while in sexual reproduction male and female gamete fuse to form seeds


Q 2. Describe the different methods of asexual reproduction.

Ans. In asexual reproduction new plants are obtained without production of seeds or spores and several methods of asexual reproduction are fragmentation, budding, spore formation and vegetative propagation.


Q 3. Explain what do you understand by sexual reproduction.

Ans. The stamens are the male reproductive part and the pistil is the female reproductive. Both the male and the female unisexual flowers may be present in the same plant or in different plants Anther contains pollen grains which produce male gametes. A pistil consists of stigma, style and ovary. The ovary contains one or more ovules. The female gamete or the egg is formed in an ovule. In sexual reproduction a male and a female gamete fuse to form a zygote. Flower is the reproductive part of plant, Sexual reproduction involves the fusion of male and female gametes.


Q4. What is pollination and self pollination?

Ans. Insects visit flowers and carry away pollen on their bodies. Some of the pollen lands on the stigma of a flower of the same kind. The transfer of pollen from the anther to the stigma of a flower is called pollination. If the pollen lands on the stigma of the same flower it is called self-pollination.


Q5. What is cross pollination?

Ans. When the pollen of a flower lands on the stigma of another flower of the same plant, or that of a different plant of the same kind, it is called cross-pollination



Q6. Explain the difference between unisexual and bisexual flowers?   

Ans. The flowers which contain either only the pistil or only the stamens are called unisexual flowers, whereas the flowers which contain both stamens and pistil are called bisexual flowers. Corn, papaya and cucumber produce unisexual flowers, whereas mustard, rose and petunia have bisexual flowers


Q 7. How does the process of fertilisation take place in flowers?

Ans. The cell which results after fusion of the gametes is called a zygote. The process of fusion of male and female The process of fusion of male and female gametes is called fertilization it takes place in the ovary of flower. gametes (to form a zygote) is called fertilisation The zygote develops into an embryo.


Q 8. Describe the various ways by which seeds are dispersed.

Ans. Seeds and fruits of plants are carried away by wind, water and animals. Some seeds are dispersed when the fruits burst with sudden jerks and seeds are scattered far from the parent plant.


Q9. How the male gamete in the pollen grain reaches the female gamete present in the ovule

Ans. Pollen grains have a tough protective coat which prevents them from drying up, they can be carried by Insects wind or water.


 Q10. Describe the process of formation of fruits and seed?

Ans. After fertilisation, the ovary grows into a fruit and other parts of the flower fall off. The fruit is the ripened ovary. The seeds develop from the ovules it contains an embryo enclosed in a protective seed coat.


Q.11  Why seed dispersal is important for plants?

Ans. Seed dispersal helps the plants to (I) prevent overcrowding,(II) avoid competition for sunlight, water and minerals and(III) invade new habitats.