Question

which speeds up the reaction between carbon dioxide and rubp to restart the calvin cycle?
light energy
rubisco
3 - phosphoglycerate
glyceraldehyde 3 - phosphate

Explanation:

• Light energy is involved in the light - dependent reactions of photosynthesis, not directly in speeding up the reaction between \(CO_2\) and RuBP in the Calvin cycle.
• Rubisco (Ribulose - 1,5 - bisphosphate carboxylase/oxygenase) is the enzyme that catalyzes the reaction between \(CO_2\) and RuBP (Ribulose - 1,5 - bisphosphate) in the Calvin cycle. Enzymes speed up chemical reactions.
• 3 - phosphoglycerate is a product of the reaction between \(CO_2\) and RuBP (after catalysis by rubisco), not a catalyst for the reaction.
• Glyceraldehyde 3 - phosphate is also a product (after further reactions in the Calvin cycle) and not a catalyst for the \(CO_2\) - RuBP reaction.

Answer:

rubisco