Question

Why is the enzyme RuBP carboxylase-oxidase (Rubisco) so important in the photosynthetic assimilation of carbon?

a) It fixes carbon dioxide during the Calvin cycle
b) It releases oxygen during the light reactions
c) It synthesizes glucose during the dark reactions
d) It reduces NADP+ during photosystem II
e) It converts ATP to ADP during the light reactions

Answer 1

Rubisco is crucial in photosynthesis as it catalyzes the fixation of CO₂ to RuBP in the Calvin cycle, leading to the production of sugars needed for plant growth and energy. Option number a is correct.

Step-by-step explanation:

The enzyme RuBP carboxylase-oxidase, also known as Rubisco, is critically important in the photosynthetic assimilation of carbon because it catalyzes the first step of the Calvin cycle, known as carbon fixation.

During carbon fixation, Rubisco fixes atmospheric carbon dioxide (CO₂) to ribulose bisphosphate (RuBP), resulting in the production of 3-phosphoglycerate (3-PGA), which is then used to produce glyceraldehyde 3-phosphate (G3P). Some of the G3P is utilized to synthesize glucose while the rest regenerates RuBP, enabling continuous CO₂ fixation and the overall production of carbohydrates essential for plant growth and energy storage.