NCERT Class 7 Science Twelfth Chapter Reproduction in Plants Exercise Solutions
Reproduction in Plants
Inside Questions with Answers:
What is called reproduction?
Ans. The production of new individuals from their parents is known as reproduction.
Define vegetative parts of a plant.
Ans. Most plants have roots, stems and leaves. These are called the vegetative parts of a plant.
Name the two ways by which plants produce their offspring.
Ans. (i) asexual, and (ii) sexual reproduction.
Give the difference between asexual and sexual reproduction in plants.
Ans. In asexual reproduction plants can give rise to new plants without seeds,
whereas in sexual reproduction, new plants are obtained from seeds.
What is vegetative propagation.
Ans. It is a type of asexual reproduction in which new plants are produced from roots, stems, leaves and buds. Since reproduction is through the vegetative parts of the plant, it is known as vegetative propagation.
Give example of Roots of plants can give rise to new plants.
Ans. Sweet potato and dahlia.
What is called bud?
Ans. The small bulb-like projection coming out from the yeast cell is called a bud.
What is called algae.
Ans. Slimy green patches in ponds, or in other stagnant water bodies are the algae.
Name the male reproductive part of plant.
Ans. Stamen.
Name the female reproductive part of plant.
Ans. Pistil.
Define unisexual flowers.
Ans. Flowers which contain either only pistil or only stamens are called unisexual flowers.
Example: Corn, papaya and cucumber.
Define bisexual flowers.
Ans. Flowers which contain both stamens and pistil are called bisexual flowers.
Example: mustard, rose and petunia.
What does the pistil consist?
Ans. A pistil consists of stigma, style and ovary.
What is called Stamens?
Ans. Flowers are the reproductive parts of a plant called Stamen.
What is called zygote.
Ans. The cell which results after fusion of the gametes is called a zygote.
What is called pollination?
Ans. The transfer of pollen from the anther to the stigma of a flower is called pollination.
What is ca]led fertilisation ?
Ans. The process of fusion of male and female gametes (to form a zygote) is called fertilisation.
How many types of Pollination? Explain them.
Ans. Pollination is of two types, self-pollination and cross-pollination. In self-pollination, pollen grains are transferred from the anther to the stigma of the same flower. In cross-pollination, pollen grains are transferred from the anther of one flower to the stigma of another flower of the same kind.
What is the benefit of seed dispersal.
Ans. Seed dispersal helps the plants to (i) prevent overcrowding, (ii) avoid competition for sunlight, water and minerals and (iii) invade new habitats.
Exercises Questions with Answers:
(1) Fill in the blanks:
(a) Production of new individuals from the vegetative part of parent is called_____________.
Ans. (a) vegetative reproduction
(b) A flower may have either male or female reproductive parts. Such ba flower is called_____________.
Ans. (b) unisexual flower
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as _____________.
Ans. (c) pollination
(d) The fusion of male and female gametes is termed as _____________.
Ans. (d) fertilization
(e) Seed dispersal takes place by means of _____________, _____________ and _____________.
Ans. (e) wind, water and animals.
(2) Describe the different methods of asexual reproduction. Give examples.
Different methods of asexual reproduction are following:
Vegetative propagation: It is a type of asexual reproduction in which new plants are produced from roots, stems, leaves and buds. Since reproduction is through the vegetative parts of the plant, it is known as vegetative propagation.
Spore Formation: Fungi on a bread piece grow from spores which are present in the air.
Budding: Tiny organisms like yeast can be seen only under a microscope. These grow and multiply every few hours if sufficient nutrients are made available to them.
Fragmentation: Green patches 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.
(3) Explain what you understand by sexual reproduction.
Ans. Sexual reproduction involves the fusion of male and female gametes. There are several methods of sexual reproduction such as FRUITS AND SEED FORMATION, SEED DISPERSAL etc.
(4) State the main difference between asexual and sexual reproduction.
Ans. Check Inside Questions and Answers.
(5) Sketch the reproductive parts of a flower.
(6) Explain the difference between self-pollination and cross-pollination.
If the pollen lands on the stigma of the same flower or another flower of the same plant, it is called self-pollination. Whereas, When the pollen of a flower lands on the stigma of a flower of a different plant of the same kind, it is called cross-pollination.
In self-pollination, pollen grains are transferred from the anther to the stigma of the same flower. Whereas In cross-pollination, pollen grains are transferred from the anther of one flower to the stigma of another flower of the same kind.
Self pollination takes place in plants like wheat, peas etc. whereas Cross pollination takes place in plants like lady-finger, tomato, brinjal etc.
(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 gametes (to form a zygote) is called fertilisation. The zygote develops into an embryo. This is the process of fertilisation take place in flowers.
(8) Describe the various ways by which seeds are dispersed.
Ans. Seeds of grasses or hairy seeds of aak (Madar) and hairy fruit of sunflower get blown off with the wind to far away places.
Some seeds are dispersed by water. These fruits or seeds usually develop floating ability in the form of spongy or fibrous outer coat as in coconut.
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.
Some seeds are dispersed when the fruits burst with sudden jerks. The seeds are scattered far from the parent plant. This happens in the case of castor and balsam.
(9) Match items in Column I with those in Column II:
Column I Column II
(a) Bud >>>>>(i) Maple
(b) Eyes >>>>>(ii) Spirogyra
(c) Fragmentation >>>>>(iii) Yeast
(d) Wings >>>>>(iv) Bread mould
(e) Spores >>>>>(v) Potato
(vi) Rose
Ans:
Column I | Column II
|
(a) Bud | (iii) Yeast |
(b) Eyes | (v) Potato |
(c) Fragmentation | (ii) Spirogyra |
(d) Wings | (i) Maple |
(e) Spores | (iv) Bread mould |
- Tick the correct answer:
(a) The reproductive part of a plant is the
(i) leaf
(ii) stem
(iii) root
(iv) flower
Ans. (iv) flower
(b) The process of fusion of the male and the female gametes is called
(i) fertilisation
(ii) pollination
(iii) reproduction
(iv) seed formation
Ans. (i) fertilisation
(c) Mature ovary forms the
(i) seed
(ii) stamen
(iii) pistil
(iv) fruit
Ans. (iv) fruit
(d) A spore producing organism is
(i) rose
(ii) bread mould
(iii) potato
(iv) ginger
Ans. (ii) bread mould
(e) Bryophyllum can reproduce by its
(i) stem
(ii) leaves
(iii) roots
(iv) flower
Ans. (ii) leaves
Important Pictures
how to Pollination in flower