Question

Which of the following statements about RuBisCO is true?

• A. It has higher affinity for oxygen than carbon dioxide.
• B. It is an enzyme involved in the photolysis of water.
• C. It catalyzes the carboxylation of RuBP.
• D. It is active only in the dark.

Hint:

RuBisCO = Calvin cycle = CO2 fixation.

Answer 1

The Correct Option is C

RuBisCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is the key enzyme in the Calvin cycle (dark reactions of photosynthesis). It catalyzes the fixation of CO2 by adding it to RuBP (ribulose-1,5-bisphosphate). While it can also react with oxygen (photorespiration), its affinity for CO2 is higher under normal conditions. It is not involved in the photolysis of water, which occurs in the light-dependent reactions.