A cyclical series of biochemical reactions that occur in the stroma of chloroplasts during photosynthesis. It includes the light-independent reactions such as carbon fixation, reduction reactions and ribulose 1,5-diphosphate (RuDP) whereby sugars and starch are ultimately produced.
At this stage of photosynthesis, the energy released from ATP produced during light reactions is used to drive the conversion of carbon dioxide and other compounds into an organic molecule (e.g. glucose).
In C3 plants, the Calvin cycle is used directly to fix carbon dioxide. In C4 plants and CAM plants, a different carbon fixation precedes Calvin cycle.
Word origin: named after one of the discoverers, Melvin Calvin, a Nobel prize-winning chemist.
Variants: Calvin-Benson cycle or Calvin- Benson-Bassham cycle
See also: Photosynthesis on Tutorials for further information.