Question

The above diagram depicts the graphic relationship between influence of light intensity and carbon dioxide concentration on the rate of photosynthesis of green algae. Which of the following statement justifies the diagram?

• A. At low intensity,the light dependent reaction is rate limiting but at high light,$C{O}_2$ is rate limiting
• B. The number of chlorophyll molecules limits the rate of photosynthesis
• C. Photosynthesis is independent of light intensity provided there is no total darkness
• D. Chlorophyll responds equally to light intensities and $C{O}_2$ concentrations, thereby limiting the rate of photosynthesis

Answer 1

The correct option is D Chlorophyll responds equally to light intensities and $C{O}_2$ concentrations, thereby limiting the rate of photosynthesis

Light intensity and carbon dioxide are considered as one of the factors affecting the rate of photosynthesis. When the light intensity is lowered, the rate of photosynthesis becomes slow. Higher light intensity is preferred for photosynthesis to occur at the normal rate. They affect the activity of chlorophyll molecules and the rate of photosynthesis. Since, both the factors when increased, causes the rate of reaction to increase, the chlorophyll molecules respond similarly to both the factors. The response is equal and hence, the rate of reaction is limited after sometime.

Thus, the correct answer is option D.