Calvin cycle Original Scenario-Based Download PDF

Questions

1. 1.

   During an expedition inside an orbital planetary greenhouse, botanists cultivate a bioluminescent flora whose atmospheric enclosure suddenly experiences a total loss of carbon dioxide while solar lamps continue delivering uninterrupted light. Because light-dependent photophosphorylation remains fully active, the chloroplast stroma maintains high levels of ATP and NADPH. Which immediate change in stromal metabolite concentrations will occur under these specific conditions?

   • A) Both 3-PGA and RuBP concentrations drop to zero immediately because Calvin cycle enzymes denature without dissolved carbon dioxide.
   • B) 3-PGA accumulates substantially while RuBP is completely consumed because reduction reactions reverse in the absence of carbon dioxide.
   • C) RuBP levels decrease rapidly while 3-PGA levels rise because excess ATP forces RuBisCO to break down five-carbon intermediates.
   • D) RuBP levels accumulate while 3-PGA levels decrease because RuBP is no longer carboxylated but continues to be regenerated from remaining intermediates.