What is the primary product of the light-dependent reactions of photosynthesis?

Core Concept

Thylakoid pigment complexes absorb photons and drive electrons through an electron transport chain. That electron flow pumps protons into the thylakoid lumen, and the returning proton current powers ATP synthase while the final acceptor NADP+ receives electrons to become NADPH. No sugar is made in this stage. ATP and NADPH simply stockpile convertible energy that the Calvin cycle will spend when fixing carbon.