How do plants convert sunlight into energy through photosynthesis?

Photosynthesis occurs in two main stages within plant cells. In the light-dependent reactions, chlorophyll and other pigments in the thylakoid membranes of chloroplasts absorb sunlight, using that energy to split water molecules and generate ATP and NADPH while releasing oxygen as a byproduct. In the second stage, the Calvin cycle, these energy carriers power the conversion of carbon dioxide from the air into glucose in the chloroplast stroma. The enzyme RuBisCO fixes CO2 into organic molecules, which are then processed using the ATP and NADPH from the first stage. The resulting glucose serves as the plant's primary energy source and building material, storing the sun's energy in chemical bonds that can be released later through cellular respiration.