Photosynthesis is a way of making organic molecules from carbon dioxide (CO2). To build organic molecules, cells use raw materials provided by the light reactions. 1,5-bisphosphate carboxylase, also known as Rubisco, is the enzyme needed for carbon fixation during the Calvin cycle. This enzyme is found in the stromal space of the chloroplast. It acts by adding CO2 to the 5-carbon sugar ribulose 1,5-bisphosphate forming 2 molecules of 3-phosphoglycerate.
