Topic outline

    • Reproduction in Plants

      Q20. What are the vegetative parts of plants?

      Ans. In vegetative propagation new plants are produced from different vegetative parts such as leaves, stems and roots.


      Q21. Explain what you understand by sexual reproduction.

      Ans. Sexual reproduction produces offspring by the fusion of gametes, resulting in offspring genetically different from the parent or parents.


      Q22. State the main difference between asexual and sexual reproduction.

      Ans. In asexual reproduction plants can give rise to new plants without seeds, whereas in sexual reproduction, new plants are obtained from seeds.


      Q23. What will happen if all seeds of a plant were to fall at the same place and grow there?

      Ans. There would be severe competition for sunlight, water, minerals and space. As a result the seeds would not grow into healthy plants.

      Q24. What is the function of flowers in plants?

      Ans. The flowers perform the function of reproduction in plants. Flowers are the reproductive parts of a plant. A flower may have either the male part or the female part or both male and female parts.


      Q25. How are plants benefited by seed dispersal?

      Ans. Plants benefit by seed dispersal. It prevents competition between the plant and its own seedlings for sunlight, water and minerals. It also enables the plants to invade new habitats for wider distribution.


      Q26. What types of seeds are dispersed by animals?

      Ans. Some seeds are dispersed by animals, especially spiny seeds with hooks which get attached to the bodies of animals and are carried to distant places. Examples are Xanthium and Urena.


      Q27. How do potatoes reproduce?

      Ans. Potatoes can be grown asexually by vegetative reproduction. This can be done by planting a part of potato with an eye and watering it regularly for few days. The new stem start on the eyes of the potato and a potato plant will develop.

      Q28. How do plants reproduce?

      Ans. There are several ways by which plants produce their offspring. These are categorised into two types: (i) asexual  and (ii) sexual reproduction. In asexual reproduction plants can give rise to new plants without seeds, whereas in sexual reproduction, new plants are obtained from seeds.


      Q29. How does sexual reproduction take place in flowering plants?

      Ans. Anther contains pollen grains which produce male gametes. A pistil consists of stigma, style and ovary. 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.


      Q30. Explain the difference between self-pollination and cross-pollination.

      Ans. If the pollen lands on the stigma of the same flower it is called self-pollination. 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.


      Q31. How can we grow a new rose plant from the parent plant?

      Ans. A new rose plant can be grown by cutting off a part of the stem of an existing plant, with two or more nodes, and planting it in the ground. A node is a part of the stem from where a leaf grows. This stem grows into a new rose plant.

      Q32. How fruits and seeds are formed?

      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. The seed contains an embryo enclosed in a protective seed coat.

      Some fruits are fleshy and juicy such as mango and orange. Some fruits are hard like almonds and walnuts.


      Q33. How do algae reproduce?

      Ans. Slimy green patches are seen in ponds, or in other stagnant water bodies. These are the algae. When water and nutrients are available algae grow and multiply rapidly by fragmentation. An alga breaks up into two or more fragments. These fragments or pieces grow into new individuals. This process continues and they cover a large area in a short period of time.


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