Page 110 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key
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7. Define pollination.
Ans. Pollination: The transfer of pollen grains from the anther of a stamen to the stigma
of a pistil is called pollination. Wind, animals, insects and birds act as agents of
pollination. Pollination can take place in two different ways:
Self-pollination: When pollens from the anthers of a flower are transferred to the
stigma of the same flower or another flower of the same plant, it is called self
-pollination.
Cross-pollination: When the pollens from the anthers of a flower are transferred
to the stigma of a flower of another plant of the same species, it is called cross-
pollination.
8. Differentiate between asexual and sexual reproduction.
Ans. Asexual reproduction Sexual reproduction
1. It involves only one parent. 1. It involves male & female parent.
2. There is no fusion of 2. There is fusion of male & female
gametes. gametes.
3. Common in unicellular organisms, 3. Common in most animals & many
plants & some animals. plants.
9. What are fruits?
Ans. Fruits are the mature, ripened ovaries of flowering plants, typically containing seeds.
They develop after fertilization. Fruits are of two types – fleshy & dry.
G. Long-answer questions :
1. Name and explain different modes of asexual reproduction in microorganims.
Ans. Different modes of asexual reproduction are :
(a) Budding (b) Fragmentation,
(c) Spore Formation (d) Vegetative propagation.
Budding
The process of asexual reproduction called budding, is seen in unicellular
microorganisms like yeast. The yeast cell produces a bud which gets its own nucleus.
The bud develops to a certain size and then detaches from the mother cell to produce
a new yeast cell. The new yeast cell grows, matures and gives rise to more yeast cells.
In this way, a large number of yeast cells are produced in a short time. Sometimes, a
new bud arises from a developing bud while it is still attached to the parent cell. In
this manner, a chain of buds develops during budding in yeast cells.
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