How does photosynthesis turn sunlight into energy?

Photosynthesis converts sunlight into chemical energy through two main stages. In the light-dependent reactions, chlorophyll in the thylakoid membranes absorbs sunlight, which energizes electrons. This energy splits water molecules, releasing oxygen as a byproduct and generating ATP and NADPH, which are energy-carrying molecules. In the second stage, the Calvin cycle, those energy carriers power the conversion of carbon dioxide from the air into glucose. Enzymes in the chloroplast stroma use ATP and NADPH to assemble CO2 molecules into sugar through a series of chemical reactions. The glucose produced stores chemical energy in its molecular bonds, which the plant can later break down for fuel or use as building material for growth.