What is the role of RuBisCO in the Calvin cycle?

RuBisCO, or ribulose bisphosphate carboxylase/oxygenase, plays a crucial role in the Calvin cycle by catalyzing the fixation of carbon dioxide. This enzyme facilitates the first major step of carbon fixation where it catalyzes the reaction of carbon dioxide with ribulose bisphosphate (RuBP), resulting in a 3-carbon compound called 3-phosphoglycerate (3-PGA). This reaction is essential for converting inorganic carbon into an organic form that can eventually lead to the synthesis of glucose and other carbohydrates, which plants utilize for energy and growth.

The significance of RuBisCO in the Calvin cycle underscores its role as the key enzyme that makes it possible for photosynthetic organisms to assimilate carbon dioxide from the atmosphere and incorporate it into their metabolic processes.