This document summarizes plant photosynthesis and the key protein complexes involved. It describes oxygenic photosynthesis which takes place in plants, algae and cyanobacteria, producing oxygen from water and carbohydrates from carbon dioxide. It also discusses anoxygenic photosynthesis which occurs in some bacteria and does not produce oxygen. The key complexes involved in oxygenic photosynthesis are photosystem I, photosystem II, the cytochrome b6f complex, and plastocyanin. Photosystem II uses light energy to split water, releasing protons, electrons, and oxygen. The cytochrome b6f complex transfers electrons between photosystem II and photosystem I. Plastocyanin then transfers electrons from cytochrome b6f to photos