Any green plant tissue is capable of photosynthesis. Chloroplasts in these cells contain the green pigment called chlorophyll which traps the light energy. However, leaves are generally the site of most food production due to their special structure. The lower epidermis of the leaf normally contains the largest percentage of stomata. This process is necessary to sustain nearly all forms of life.
Photosynthesis is divided in to two separate reactions known as the light and dark reactions.
They take place when light is present but the dark reaction does not require light. The whole process is begun by light reacting with pigments in the leaf causing the splitting of water molecules. This is called photolysis or the Hill Reaction which is not completely understood. Three products are produced in this reaction. The carbon dioxide molecules are transformed into sugars during the dark reaction using the energy that was formed during the light reaction.