A radioactive labeled carbon entering the Calvin cycle as ¹⁴CO₂ A)would be removed from the cycle as various carbohydrate side products in the first round of the cycle. B)could be identified only in the triose intermediates within the cycle. C)would only be observed in intermediates following three rounds of the cycle. D)could be observed in any of the intermediates within the cycle during the first or subsequent rounds of the cycle. E)would be rapidly removed by transketolase catalyzed reactions.

Question

Quizplus · Accepted Answer

The radioactive labeled carbon can be found in any of the intermediates within the Calvin cycle during the first or subsequent rounds because it can be incorporated into any of the sugars synthesized during the cycle. Therefore, the best choice is D.Option A is incorrect because the labeled carbon won't be removed as carbohydrate side products in the first round of the cycle. B is incorrect because the triose intermediates are where the labeled carbon reroutes to form glucose. C is illogical because labeled carbon can be identified even following a single round of the cycle. E is incorrect because transketolase catalyzed reactions play no significant role in the labeling of carbon in the Calvin cycle.

A Radioactive Labeled Carbon Entering the Calvin Cycle as 14CO2

A Radioactive Labeled Carbon Entering the Calvin Cycle as ¹⁴CO₂