Photosystem II is a protein complex found in the thylakoid membranes of plant chloroplasts. It plays a crucial role in the process of photosynthesis by capturing light energy and using it to split water molecules into oxygen, protons, and electrons. This reaction generates oxygen as a byproduct and provides the electrons needed for the next steps in photosynthesis. The electrons released from Photosystem II are transferred through a series of proteins in the thylakoid membrane, known as the electron transport chain. This process helps create a proton gradient that ultimately drives the production of ATP and NADPH, which are essential energy carriers used in the later stages of photosynthesis.