Final answer:
The enzyme responsible for carboxylation in photosynthesis is called ribulose bisphosphate carboxylase, or RuBisCO. It catalyzes the first major step of the Calvin cycle, which is integral for carbon fixation and glucose production.
Step-by-step explanation:
The enzyme that catalyzes carboxylation during photosynthesis is called ribulose bisphosphate carboxylase, commonly abbreviated as RuBisCO. Carboxylation is a crucial step in the Calvin cycle, where carbon fixation takes place. RuBisCO facilitates the addition of carbon dioxide to ribulose bisphosphate (RuBP), resulting in a 6-carbon compound that quickly splits into two molecules of 3-phosphoglycerate (3-PGA). Subsequently, these molecules go through a series of reactions, using energy from ATP and NADPH produced in the light-dependent stages, to eventually form carbohydrates like glucose.
Plants predominantly follow the C3 pathway for carbon fixation, wherein the first organic product of this process is a three-carbon compound, hence the name 'C3'. There are modifications in some plants, like those following the C4 pathway, which can efficiently fix carbon under conditions of limited CO2 availability. RuBisCO's role in the light-independent reactions, or Calvin cycle, illustrates the cyclical nature of the photosynthesis process that interconnects with cellular respiration.