It is believed that the ratio of cyclic electron transport to Z-scheme photosynthesis changes in response to metabolic demands. If a plant were using the C₄ Hatch-Slack pathway, how would it alter these processes compared to a plant just performing the standard C₃ Calvin cycle to produce glucose? A) More cyclic photophosphorylation, less Z-scheme. B) More Z-scheme photosynthesis, less cyclic photophosphorylation. C) No significant difference. D) Impossible to predict from the information provided.

Question

Quizplus · Accepted Answer

Plants using the Hatch-Slack pathway (C4 photosynthesis) often operate under conditions where efficient energy use is critical, such as high temperatures. Cyclic electron transport can generate additional ATP without producing NADPH, which is beneficial for the ATP-demanding reactions of the C4 pathway. Thus, compared to plants using only the Calvin cycle (C3 photosynthesis), C4 plants might increase cyclic photophosphorylation to meet the higher ATP demands, while reducing reliance on the Z-scheme, which produces both ATP and NADPH in equal amounts.

It Is Believed That the Ratio of Cyclic Electron Transport