Answer :
Final answer:
RuBisCO is the enzyme that catalyzes carbon fixation in photosynthesis, enabling the conversion of CO2 into organic compounds during the Calvin cycle. So, the correct answer is option c) RuBisCO.
Explanation:
The substance that catalyzes carbon fixation is the enzyme ribulose-1,5-bisphosphate carboxylase, commonly abbreviated as RuBisCO. This enzyme plays a crucial role in the process of photosynthesis, specifically within the Calvin cycle, which is the sequence of reactions that make up the light-independent part of photosynthesis.
Carbon fixation itself is the term used to describe the conversion of inorganic CO2 from the atmosphere into organic compounds by living organisms. In the context of the Calvin cycle, RuBisCO facilitates the reaction between CO2 and another molecule called ribulose bisphosphate (RuBP), leading to the production of 3-phosphoglycerate (3-PGA). This process is vital for the synthesis of glucose and other carbohydrates that plants use for energy and growth.
In summary, RuBisCO catalyzes the reaction between CO2 and RuBP, forming two molecules of 3-PGA. The series of reactions that follow, including the reduction of 3-PGA using ATP and NADPH, and the eventual regeneration of RuBP, perpetuate the cycle of carbon fixation.