Question

In which condition do the leaves of a green plant respire?

	Bright light	darkness
	right	right
	right	wrong
	wrong	right
	wrong	right

Answer 1

Hint: In the case of plants, intake of carbon dioxide and release of oxygen depends upon the amount of light received. The sunlight acts as a foundation of photosynthesis and plays a vital role in the synthesis of food.

Complete answer-Plants respire all the time i.e. during day and night. But the rate of photosynthesis depends upon the amount of sunlight because sunlight provides the initial energy to start the cycle and convert the energy into chemical energy. It is a biological process in which the energy contained within the light is converted into chemical energy such as ATP and NADPH that helps to power the processes within the cell.
In bright light, photosynthesis utilizes carbon dioxide and produces oxygen and its rate is faster than respiration. During day time, photosynthesis produces oxygen and carbohydrates at a faster rate than it is consumed by respiration. It also utilizes carbon dioxide at a faster rate than respiration produces it. This process results in the production of extra oxygen and carbohydrates.
Hence, the correct option is B Bright light-right, darkness-wrong.

Note: In the dim light, the rate of respiration and photosynthesis is equal. A plant consumes all the oxygen that is produced during photosynthesis. The photosynthesis utilizes all the carbon dioxide released during respiration. Therefore, there is no net gain of oxygen and carbon dioxide in the atmosphere.