Photosynthesis takes place in the chloroplasts of plant cells. Photosynthesis is the process by which carbon dioxide, water and light energy are used to produce oxygen and glucose:6CO2 + 6H2O (+ light energy) --> C6H12O6 + 6O2Photosynthesis only takes place in chloroplasts as they contain chlorophyll - the pigment that absorbs light energy. The oxygen produced by the chloroplast is either released into the atmosphere or used by the plant's mitochondria for respiration.The rate of photosynthesis therefore depends on many factors, including the availability of CO2, H2O and light, as well as the temperature.