Are the following statements true or false? Give reason in support of your answer.

(a) The rate of photosynthesis continues to rise as long as the intensity of light rises.

(b) The outside atmospheric temperature has no effect on the rate of photosynthesis.

(c) If you immerse a leaf intact on the plant in ice cold water, it will continue to photosynthesize in bright sunshine.

(d) Destarching of the leaves of a potted plant can occur only at night.

(e) The starting point of carbon cycle is the release of CO₂ by animals during respiration.

(f) If a plant is kept in bright light all the 24 hours for a few days, the dark reaction (biosynthetic phase) will fail to occur.

(g) Photosynthesis is considered as a process supporting all life on earth.

(a) False

Explanation/Reason: The Rate of photosynthesis increase with an increase in light intensity up to a certain limit, that is till it stabilizes.

(b) False

Explanation: The outside atmospheric temperature is one of the most important determinants of the rate of photosynthesis. As the temperature increases up to 35°C, the rate of photosynthesis increases after which the rate starts to fall and stops after the temperature reaches 40°C.

(c) False

Explanation: If we immerse a leaf intact on the plant in ice cold water, the ice-cold water will hamper the photosynthesis process, even when there is enough sunshine. This is because the temperature plays an important role in determining the rate of photosynthesis.

(d) False

Explanation: For destarching, the potted plant should be kept in a dark room for 24-48 hours. Only then the starch will be removed from the leaves, to the storage organs.

(e) False

Explanation: there is no particular start point or end point in the carbon cycle. This is because the carbon is continuously being circulated between the atmosphere and all the living organisms.

(f) False

Explanation: When a plant is kept in bright light for 24 hours for a few days, the biosynthetic or dark reaction phase will continue to occur as these set of reactions are independent of light. These reactions occur simultaneously with the light dependent reactions.

(g) True

Explanation: It is considered as a process supporting all life on earth as all green plants derive food for themselves through this process. All other consumers, like animals including humans, depend on these green plants for their food. Thus, without this vital process, all living organisms would die of starvation.