The Calvin cycle is also known as the dark reactions, C3 cycle, Calvin-Benson-Bassham (CBB) cycle, or reductive pentose phosphate cycle. The cycle was discovered in 1950 by Melvin Calvin, James Bassham and Andrew Benson.
The Calvin cycle is part of photosynthesis. The cycle is done in two stages. In the first stage, chemical reactions use light energy to produce adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADP) in its reduced state, or NADPH. The second stage is called the Calvin cycle. During this phase carbon dioxide and water are converted into organic molecules, such as glucose. The Calvin cycle is also called a dark reaction. The reactions require reduced NADP, which comes from a light-dependent reaction. The overall chemical equation for the Calvin cycle is: 3 CO2 + 6 NADPH + 5 H2O + 9 ATP yields glyceraldehyde-3-phosphate (G3P) + 2 H+ + 6 NADP+ + 9 ADP + 8 Pi (Pi = inorganic phosphate).