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

During the light-dependent reactions of photosynthesis, ATP and NADPH are produced as a result of the absorption of light energy by chlorophyll and other pigments in the thylakoid membranes of the chloroplasts. This process begins when light hits these pigments, leading to the excitation of electrons. As these energized electrons move through the electron transport chain, their energy is used to pump hydrogen ions across the thylakoid membrane, creating a proton gradient. This gradient drives ATP synthesis via ATP synthase, and the process also leads to the reduction of NADP+ to NADPH.

Additionally, water molecules are split (a process known as photolysis) to release oxygen as a byproduct. Thus, while oxygen is indeed produced during the light-dependent reactions, the primary focus is on the production of ATP and NADPH, which are essential for the subsequent light-independent reactions (Calvin cycle) where carbon fixation occurs to form glucose. Chlorophyll itself is not produced during these reactions; it's a pigment already present that facilitates the light-absorbing process.