Question

(a) Name the raw materials required for photosynthesis. How do plants obtain these raw materials ?
(b) What are the various conditions necessary for photosynthesis ?
(c) Name the various factors which affect the rate of photosynthesis in plants.

Answer 1

Ans:- A
Essential raw materials for photosynthesis are -

• Carbon dioxide: it is a gas which is released into the atmosphere during respiration.
• Water: it is another requirement for photosynthesis which is transported upward through xylem tissue to the leaves, from where it reaches photosynthetic cells.
• Chlorophyll: it is green pigment in plants which act as a catalyst. It is responsible for absorption of sun's light by the plant. The chlorophyll pigments are photoreceptor molecules which play a key role in the photosynthesis process.
• Light: light effects photosynthesis with its intensity, duration and quality. In green light, the rate of photosynthesis is minimum, while in red or blue light the rate of photosynthesis is maximum.

Ans:- B

The conditions necessary for photosynthesis are

1. Sunlight:-photo synthetic yield varies according to the sunlight It is maximum in red and blue lights. It is zero in green light.
2. Chlorophyll:- photosynthesis takes place in chlorophyllous. It doesn't take place in albuminous plants.
3. Water: sufficient amount of water is needed for photosynthesis.
4. Carbon dioxide: an optimum amount of carbon dioxide is required for photosynthesis. When it is in low concentration photosynthetic yield is decreased. When it is in high concentration carbon dioxide photosynthetic yield is increased.
5. Oxygen: When there is a high concentration of oxygen, photorespiration takes place which leads to decrease in photosynthesis
6. Temperature: When there is high temperature, the stomata close to reduce the transpiration.

Ans:- C
Three factors can limit the speed of photosynthesis: light intensity, carbon dioxide concentration and temperature. Without enough light, a plant cannot photosynthesise very quickly, even if there is plenty of water and carbon dioxide. Increasing the light intensity will boost the speed of photosynthesis.