Question

C${}_4$ plants are more efficient in photosynthesis than C${}_3$ plants due to

• A. Higher leaf area
• B. Presence of large number of chloroplasts in the leaf cells
• C. Presence of thin cuticle
• D. Lower rate of photorespiration

Answer 1

The correct option is D Lower rate of photorespiration

The C4 pathway is certainly more efficient than the C3 pathway in the sense of carbon fixation. In C3 plants, carbon dioxide and oxygen are both present. This means that most of the ribulose-1,5-bisphosphate is carboxylated, but some of the ribulose-1,5-bisphosphate is oxygenated. This results in photorespiration.

So the correct option is Lower rate of photorespiration.