A team of botanists aboard a deep-space research vessel discovers that exposing an engineered photosynthetic organism to a membrane-active agent makes its thylakoid membranes freely permeable to hydrogen ions. Although light-driven electron transport continues uninterrupted, resulting in the steady photolysis of water and normal reduction of NADP+, the cells completely stop generating ATP. Which statement best explains why this alteration halts ATP production during the light-dependent reactions?

A) It dissipates the proton gradient across the thylakoid membrane, eliminating the proton-motive force required by ATP synthase.

B) It blocks the photolysis of water molecules at photosystem II, preventing electrons from entering the electron transport chain.

C) It directly inhibits ferredoxin-NADP+ reductase, halting the reduction of terminal electron carriers in the stroma.

D) It degrades chlorophyll pigments in the antenna complexes, preventing photon absorption and resonance energy transfer.

Light-dependent reactions Original Scenario-Based Practice

Biology · Cellular Energetics · Biology · Photosynthesis

1 Biology practice questions on Light-dependent reactions. Questions built around original scenarios.

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Cellular Energetics · Biology

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