Question

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

Explanation:

PSII (Photosystem II) is involved in the light - dependent reactions of photosynthesis. It is responsible for splitting water molecules, which provides electrons for the electron transport chain. The electron transport chain is crucial for the production of ATP (through chemiosmosis) and NADPH (by reducing NADP+). If PSII stops working:

• ATP: The electron transport chain that leads to ATP synthesis (via the proton - motive force) is disrupted. Since PSII is the source of electrons for the non - cyclic electron flow (which is a major contributor to ATP production in photosynthesis), ATP production will decrease.
• NADPH: NADPH is produced when electrons from PSII (via the electron transport chain) are used to reduce NADP+. Without PSII functioning, there are no electrons available for this reduction reaction, so NADPH levels will decrease.
• Sugars: Sugars are produced in the Calvin cycle (light - independent reactions) which requires ATP and NADPH. Since both ATP and NADPH levels decrease, the Calvin cycle cannot proceed efficiently, and sugar production (and thus sugar concentrations) will decrease.

Answer:

ATP: Decrease, NADPH: Decrease, Sugars: Decrease