Light-dependent reactions Original Scenario-Based Download PDF

Questions

1. 1.

   In an orbital biosphere facility, researchers cultivate Phyto-Nebula, an engineered photosynthetic organism developed to regenerate atmospheric oxygen and produce biomass from artificial starlight. During an unexpected breach, a chemical contaminant inserts non-selective pore-forming channels into the thylakoid membranes, rendering them freely permeable to protons ($\text{H}^+$). Assuming the pigment complexes, electron carriers, and enzyme catalytic sites remain fully intact and operational under steady illumination, how will this membrane defect directly alter the primary products of the light-dependent reactions?

   • A) ATP production will cease due to the dissipated proton gradient, while oxygen evolution and NADPH synthesis will continue.
   • B) ATP and NADPH synthesis will both halt, while oxygen evolution continues at an accelerated rate.
   • C) Oxygen evolution and ATP synthesis will cease, while NADPH synthesis remains unaffected.
   • D) NADPH synthesis will halt due to electron transport blockage, while ATP synthesis will continue through substrate-level phosphorylation.