The light-dependent reactions of photosynthesis take place in the thylakoid membranes of chloroplasts. These membranes contain chlorophyll and other pigments that absorb sunlight to initiate the process. During these reactions, light energy is converted into chemical energy in the form of ATP and NADPH, and water molecules are split to release oxygen
. Specifically, the thylakoid membrane hosts photosystems I and II, where light absorption excites electrons that travel through an electron transport chain, leading to the synthesis of ATP and NADPH. The splitting of water (photolysis) also occurs in the thylakoid membrane, providing electrons to replace those lost by photosystem II
. Thus, the thylakoid membrane within the chloroplast is the site of the light-dependent reactions.
