Question

Which part of the Calvin cycle would be affected if a cell could not produce the enzyme RuBisCO?

a) Carbon fixation
b) Reduction
c) Regeneration of RuBP
d) Photolysis

Answer 1

Without the enzyme RuBisCO, the carbon fixation stage of the Calvin cycle would be directly impacted, disrupting the entire cycle's ability to produce glucose from CO₂.

Step-by-step explanation:

If a cell cannot produce the enzyme RuBisCO, the part of the Calvin cycle that would be affected is the carbon fixation stage. During carbon fixation, RuBisCO catalyzes the addition of CO₂ to ribulose bisphosphate (RuBP), resulting in the production of 3-phosphoglycerate (3-PGA). Without RuBisCO, carbon fixation cannot occur, which prevents the production of 3-PGA and ultimately affects the entire Calvin cycle's ability to synthesize glucose. This enzyme is fundamental as it initiates the process of incorporating atmospheric CO₂ into an organic molecule. Other stages of the Calvin cycle, including reduction and regeneration of RuBP, would also be unable to proceed because they depend on the successful completion of the carbon fixation stage.