In the light-independent reactions, ribulose-bisphosphate and carbon dioxide react together in the process known as carbon fixation, the reaction is catalyzed by the enzyme Rubisco. In the process, two three-carbon molecules of glycerate-3-phosphate are produced.
Further, the molecule of glycerate -3-phosphate is reduced to produce triose phosphate by using ATP and NADPH generated during the light-dependent reactions. Some of the triose phosphates are used to reproduce ribulose-bisphosphate, while some are used to generate starch or glucose.