Carbon fixation is a part of the photosynthesis process that occurs during the second half, also known as the Calvin cycle. Carbon fixation itself refers to a large number of different carbon-related functions that take place during the Calvin cycle. This takes place in the stoma of the plants, explains Biology Online.
Photosynthesis is the process by which some organisms, primarily plants, convert light energy into energy that can be used for biological functions. The end result of photosynthesis is hydrogen. This process can be broken up into two different parts: photolysis and the Calvin cycle. The expenditure and usage of carbon from the environment occurs during the Calvin cycle, which is why it is also known as the carbon fixation stage. This occurs after photolysis has already taken place.
Carbon fixation covers several different biological functions necessary for the finalization of photosynthesis. This includes the entry of carbon into the cycle, the breaking down of a newly formed but unstable compound, the breaking down of glycerate phosphate and the creation of triose phosphate. This process requires energy, which is obtained from light sources during the photolysis stage, so it occurs after the plant has already absorbed an adequate amount of energy from environmental light sources.