Plants use photosynthesis to produce their own food in the form of sugars. Photosynthesis is a complex biochemical process that occurs in chloroplasts. The process is performed by enzymes and protein complexes located in the inner membranes of chloroplasts. Energy of the sun is used by a specific protein complex (photosystem II) to split a water molecule into hydrogen ions, electrons, and oxygen. The process is called a photolysis. Oxygen is released into the atmosphere while hydrogen ions and electrons are used to form an electrochemical gradient in the chloroplast. Overall, hydrogen ions and electrons released from the water molecule are used to produce ATP and NADPH that are are further involved in the synthesis of sugars. As a result, the sun energy triggers photosynthesis and is essential for plants producing their own food.