The overall chemical reaction involved in photosynthesis is: 6CO2 + 6H2O (+ light energy) C6H12O6 + 6O2. This is the source of the O2 we breathe, and thus, a significant factor in the concerns about deforestation.
he chemical process by which green plants synthesize organic compounds from carbon dioxide and water in the presence of sunlight. It occurs in the chloroplasts (most of which are in the leaves) and there are two principal types of reactions. In the light-dependent reactions, which require the presence of light, energy from sunlight is absorbed by photosynthetic pigments (chiefly the green pigment chlorophyll) and used to bring about the photolysis of water:
H2O ? 2H++2e-+½O2.
The electrons released by this reaction pass along a series of electron carriers (see electron transport chain); as they do so they lose their energy, which is used to convert ADP to ATP in the process of photophosphorylation. The electrons and protons produced by the photolysis of water are used to reduce NADP:
2H++2e-+NADP+ ? NADPH+H+
. The ATP and NADPH produced during the light-dependent reactions provide energy and reducing power, respectively, for the ensuing light-independent reactions (formerly called the 'dark reaction'), which