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Karnataka State Syllabus Class 7 Science Chapter 12 Reproduction in Plants
Class 7 Science Reproduction in Plants Textbook Exercise Questions and Answers
Question 1.
Fill in the blanks
(a) Production of new individuals from the vegetative part of parent is called Vegetative propagation.
(b) A flower may have either male or female reproductive parts. Such a flower is called 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 Pollination.
(d) The fusion of male and female gametes is termed as fertilisation.
(e) Seed dispersal takes place by means of wind, water and animal.
Question 2.
Describe the different methods of asexual reproduction. Give examples.
Answer:
The different methods of asexual reproduction in plants are as follows:
(a) Vegetative propagation: It is the reproduction in plants through the vegetative parts like stem, leaf, roots, and buds.
Examples:
- Rose, money plant, hibiscus, etc. produce new plants from their branches. The piece of branch is termed as cutting.
- Potato, ginger, or turmeric reproduce from their stems when burned in soil.
- Bryophyllum leaf has buds in the margins of the leaf. Each bud can give rise to a new plant when falls on moist soil.
- Roots of sweet potato and dahlia give rise to new plants when planted in soil.
(b) Budding: It involves the formation of a new individual from a bulb-like projection called a bud. The bud gradually grows and gets detached from the parent cell and forms a new cell which grows, matures, and produces more cells. Example: This reproduction is seen in yeast.
(c) Fragmentation: In this type of. reproduction, the parent body breaks up into two or more fragments. These fragments grow into new individuals. Example: It is seen in algae.
(d) Spore formation: Spores are asexual reproductive bodies covered by hard protective coat to withstand unfavourable conditions. Spore germinates and develops into a new individual in favourable conditions. Example: Plants such as moss, fungi, and ferns reproduce by means of spores.
Question 3.
Explain what you understand by sexual reproduction.
Answer:
Sexual reproduction is a process which requires two parents. Each parent produces gametes which fuse to form the zygote. This zygote develops into a new individual.
Question 4.
State the main difference between asexual and sexual reproduction.
Answer:
Asexual reproduction | Sexual reproduction |
In this kind of reproduction, only one parent is required. New plants are obtained without seeds. |
In this kind of reproduction two parents are required. New plants are obtained from seeds. |
Question 5.
Sketch the reproductive parts of a flower,
Answer:
Question 6.
Explain the difference between self-pollination and cross-pollination.
Answer:
Self-pollination | Cross-pollination |
(a) It is the transfer of pollen grains from the anther to the stigma of the same flower or another flower of the same plant. (b) Offsprings are genetically similar. |
(a) It is the transfer of pollen grains from the anther of one flower to the stigma of another flower of the different plant of tire same kind. (b) Offsprings show variation in characters from their parents. |
Question 7.
How does the process of fertilization take place in flowers?
Answer:
After pollination, pollen grain gives rise to a pollen tube that passes through the style and reaches the ovary. When the pollen tube enters an ovule, it releases the male gametes. The male gamete fuses with the female gamete. This process is called fertilization. The cell which is formed after the fertilisation is known as a zygote. The zygote develops into an embryo.
Question 8.
Describe the various ways by which seeds are dispersed?
Answer:
Seeds are dispersed by the following ways;
(a) Wind: Seeds of some plants are very light and have wings or hairy. They are dispersed by wind. Example; Wing seed of maple and drumstick, hairy seeds of aak (Madar).
(b) Water: Some fruits or seeds develop floating ability in the form of the spongy or fibrous outer coat. Example: Coconut fruit is carried away by water to distant places.
(c) Animals: Some seeds are carried by animals. Example: Seeds of Xanthium and Urena have hooks which get attached to the bodies of animals and are carried to distant places. Some animals eat fruits but the seeds in the fruit are not digested and they pass out along with faeces of animals. These seeds later germinate under favourable conditions like the seeds of guava, fig, and benies.
(d) Sudden burst: Some seeds are dispersed when the fruits burst with sudden jerks. These seeds are scattered far from the parent plant. Example: Castor and balsam.
Question 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 |
Answer:
(a) – (iii);
(b) – (v);
(c) – (ii);
(d) – (i);
(e) – (iv).
Question 10.
Tick (✓) the correct answer
(a) The reproductive part of a plant is the
(i) leaf
(ii) stem
(iii) root
(iv) flower
Answer:
(iv) flower
(b) The process of fusion of the male and female gametes is called
(i) fertilisation
(ii) pollination
(iii) reproduction
(iv) seed formation
Answer:
(i) fertilisation
(c) Mature ovary forms the
(i) Seed
(ii) Stamen
(iii) pistil
(iv) fruit
Answer:
(iv) fruit
(d) A spore-producing organism is
(i) rose
(ii) bread mould
(iii) potato
(iv) ginger
Answer:
(ii) bread mould
(e) BryoDyllum can reproduce by its:
(i) stem
(ii) leaves
(iii) roots
(iv) flower
Answer:
(ii) leaves