Which of the following statements about RuBisCO is true?

Question

Which of the following statements about RuBisCO is true?

1. A. It is active only in the dark
2. B. It has higher affinity for oxygen than carbon dioxide
3. C. It is an enzyme involved in the photolysis of water
4. D. It catalyzes the carboxylation of RuBP (Correct answer)

Correct Answer

Option D — It catalyzes the carboxylation of RuBP

Detailed Solution & Explanation

The correct answer is It catalyzes the carboxylation of RuBP.

Key Points

• RuBisCO (RuBP carboxylase-oxygenase) catalyses the carboxylation of RuBP — the most crucial step of the Calvin cycle where CO$_2$ is fixed.
• It has a higher affinity for CO$_2$ than O$_2$, and it is not involved in photolysis of water nor restricted to the dark.