The second phase of the photosynthesis process is the light independent reaction where glucose is produced by fixing ${\mathrm{C}\mathrm{O}}_2$ . This process occurs in the stroma of the chloroplast and utilizes the products of the light reaction. $\mathrm{C}{\mathrm{O}}_2$ fixation is brought about by Calvin cycle or ${\mathrm{C}}_3$ pathway. This cycle involves three mains steps of carboxylation, reduction and regeneration. Even plants with adaptation for glucose synthesis make use of Calvin cycle. ${\mathrm{C}}_4$ plants and CAM plants also run Calvin cycle for ${\mathrm{C}\mathrm{O}}_2$ fixation with little variation. In C4, 4C compound intermediate forms before splitting and entering the Calvin cycle. In CAM, plants gather sunlight in day time and run the Calvin cycle in night time to avoid water loss.