When sunlight is absorbed by one of many pigments present in photosystem II the light energy is distributed from pigment to pigment until it reaches the reaction center. The electrons present in the reaction center jumps to higher energy state on receiving light energy. Each high energy electron is passed to an acceptor molecule (plastoquinone) and replaced with an electron produced by splitting of water. The splitting of water produces oxygen and electrons. The high energy electrons are transferred to electron transport chain. The energy present in these electrons is used to create a gradient in the thylakoid membrane of chloroplast. The gradient facilitates the flow of H⁺ ions across thylakoid membrane and which lead to the production of ATP by enzyme ATP synthase.
