What is produced in the light-dependent reactions of photosynthesis?

In the light-dependent reactions of photosynthesis, the primary outputs are oxygen and ATP. These reactions take place in the thylakoid membranes of the chloroplasts and require light energy, which is absorbed by chlorophyll. When light energy strikes chlorophyll, it energizes electrons, initiating a series of reactions that lead to the splitting of water molecules (photolysis). This process releases oxygen as a byproduct.

Additionally, the energized electrons move through the electron transport chain, helping to create a proton gradient across the thylakoid membrane. As protons flow back into the stroma through ATP synthase, ATP is synthesized from ADP and inorganic phosphate. Thus, the key outcomes of the light-dependent reactions include the production of oxygen from water and the generation of ATP, both of which are crucial for the subsequent light-independent reactions (Calvin cycle) that synthesize glucose.