Which enzyme is crucial for fixing CO2 in the Calvin cycle?

The enzyme that is crucial for fixing CO2 in the Calvin cycle is RuBisCO, which stands for Ribulose bisphosphate carboxylase/oxygenase. RuBisCO catalyzes the first major step of carbon fixation, which is the primary conversion of inorganic carbon dioxide into an organic molecule. In this process, RuBisCO facilitates the reaction of carbon dioxide with ribulose bisphosphate (RuBP) to produce 3-phosphoglycerate (3-PGA), a three-carbon compound that is further processed in the Calvin cycle to ultimately produce glucose and other carbohydrates.

This function is essential for photosynthesis, as it helps create the organic compounds that plants use for energy and growth. Without RuBisCO, the Calvin cycle would not be able to initiate, and CO2 would not be converted into forms that can be used by the plant to form glucose and other vital biomolecules. The presence and efficiency of RuBisCO are central to the productivity of photosynthetic organisms and thus play a crucial role in the global carbon cycle.

In contrast, ATP synthase is involved in synthesizing ATP during the light-dependent reactions, while PEP carboxylase plays a role primarily in C4 photosynthesis, and NADP+