Question

what would happen to the concentrations of atp, nadph and sugars if psi stopped working?
decrease stay the same increase
atp
nadph
sugars

Explanation:

1. ATP: Photosystem I (PSI) drives cyclic photophosphorylation, which produces additional ATP. When PSI stops, this extra ATP production ceases, though some ATP is still made by PSII. However, the overall ATP concentration will decrease over time as it is used up in the Calvin cycle without sufficient replacement.
2. NADPH: NADPH is produced directly by the electron transport chain associated with PSI, where electrons are passed to NADP⁺. If PSI stops working, no new NADPH can be generated, and existing NADPH will be consumed in the Calvin cycle, leading to a decrease in its concentration.
3. Sugars: The Calvin cycle requires both ATP and NADPH to fix CO₂ and produce sugars. With decreased levels of ATP and NADPH, the Calvin cycle cannot run effectively to synthesize new sugars, and existing sugars are not replenished, so sugar concentrations decrease.

Answer:

• ATP: Decrease (↓)
• NADPH: Decrease (↓)
• Sugars: Decrease (↓)