Question

The C₄ plants are photosynthetically more efficient than C₃ plants because

• A. the CO₂ efflux is not prevented
• B. they have more chloroplasts
• C. the CO₂ compensation point is more
• D. CO₂ generated during photorespiration is trapped and recycled through PEP carboxylase.

Answer 1

Answer: (D)

Explanation:
Due to high rate of photosynthesis and reduced rate of photorespiration, $C_4$ plants are more efficient than $C_3$ plants. $C_4$ plants have special leaf anatomy called 'Kranz anatomy'. It have less $C{O}_2$ compensation points and chlorophyll concentration is more than in $C_3$ plants.
Atmospheric $C{O}_2$ is fixed by $PEP$ carboxylase in mesophyll cells and is accepted by phosphoenolpyruvate (PEP) in the mesophyll cells to produce 4 carbon organic oxaloacetic acid.