(a) List the three events that occur during the process of photosynthesis. Explain the role of
stomata in this process.
(b) Describe an experiment to show that “sunlight is essential for photosynthesis”.
Answers
Explanation:
t shirt pahana b to kya karte ho toh plese
Answer:
(a) Three most important steps of photosynthesis are:
Absorption of light energy by chlorophyll
Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen
Reduction of carbon dioxide to carbohydrates
Stomata are present in enormous amount over leafs, this tiny pores helps in the exchange of gaseous by photosynthesis. Since large amount of water can also be lost through these stomata, the plant closes these pores when it does not need carbon dioxide for photosynthesis, opening and closing of pours is regulated by guard cells, it swell up when water flows inside them, causing the stomata pore to open. Similarly the pore closes if the guard cells shrink.
(b) Experiment to prove that “sunlight is essential for photosynthes” is explained below:
(i) Select two healthy plants.
(ii) Keep them in a dark room for 3 days.
(iii) Now place them in different air tight chambers, one supplied with potassium hydroxide, which is used to absorb carbon dioxide.
(iv) Now keep the plants in sunlight for 2 hours.
(v) Pluck leaf from both plants and check the presence of starch.
(vi) Higher starch content in the jar with potassium hydroxide indicates that in the presence of light the photosynthesis have occurred so higher starch content is found.
Explanation: