Adenosine triphosphate is a compound used by the cell to store energy. Together with NADP, ATP is responsible for carbon dioxide reduction. Carbon dioxide is said to be reduced when it loses oxygen, reacts with hydrogen or gains electrons. Carbon dioxide becomes part of Glycerate 3-phosphate. NADP and ATP further reduce GP to triose phosphate.
The process of photosynthesis involves two main phases of reactions: the light reactions, those that require light energy, and the Calvin cycle, which is the light-independent stage. The main reaction during the light-independent reaction is the conversion of carbon dioxide into organic molecules.
The electromagnetic energy from sunlight is converted to chemical energy. This process takes place in the cells containing chlorophyll. Sunlight is changed into ATP, which is the primary energy-storing molecule in living organisms. ATP provides the chemical energy that powers other metabolic reactions. One of these reactions is the reduction of carbon dioxide into sugars and other compounds. ATP is further converted into ADP + Pi, which is reverted back to ATP during the light-independent reactions.
The Calvin cycle takes place in the stroma of the chloroplasts. Three main processes take place: carbon dioxide fixation, carbon dioxide reduction and ribulose biphosphate regeneration.