Final answer:
During light-dependent reactions, sunlight energy is captured by photosystems, leading to ATP and NADPH production, which are then used in the Calvin cycle to synthesize glucose.
Step-by-step explanation:
In the light-dependent reactions of photosynthesis, energy from sunlight is absorbed by pigment molecules, which initiates the process. A photon activates the antenna pigments of photosystem II (PS II), causing an electron to be excited and transferred to the electron transport chain. During this chain of events, proton gradients are created across the thylakoid membrane, leading to the synthesis of ATP through a process called chemiosmosis. Additionally, photosystem I (PS I) absorbs another photon and facilitates the creation of NADPH. Both ATP and NADPH are crucial energy carriers that power the subsequent Calvin cycle, which is the light-independent stage of photosynthesis responsible for producing glucose.