Q.4 Give a brief description of the process of synthesis of food in green plants.


Answer :

(1) Leaves are the food factories of plants.
Therefore, all the raw materials must reach the leaf.

(2) Water and minerals present in the soil are absorbed by the roots and
transported to the leaves by the vessels.

(3)Carbon dioxide from air is taken in through the tiny pores present
on the surface of leaves called 'stomata'.

(4) The leaves have a green pigment called chlorophyll which helps leaves to capture
the energy of the sunlight.
This energy is used to synthesize (prepare) food from carbon dioxide and water.

(5)Since the synthesis of food occurs in the presence of sunlight, it is called photosynthesis.
So we find that chlorophyll, sunlight, carbon dioxide, and water are necessary to carry out the process of photosynthesis.

(6) During photosynthesis, chlorophyll-containing cells of leaves, in the presence of sunlight, use carbon dioxide and water to synthesize carbohydrates.
The process can be represented in an equation:

Carbon dioxide + water → Carbohydrate + oxygen

During the process, oxygen is released.
The presence of starch in leaves indicates the occurrence of photosynthesis.

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