Answer :
Answer:
The correct function of RuBisCo (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is:
C. Convert CO₂ into sugar
RuBisCo plays a crucial role in the Calvin cycle of photosynthesis by catalyzing the carboxylation of ribulose-1,5-bisphosphate (RuBP) with carbon dioxide, leading to the production of 3-phosphoglycerate (3-PGA). This is a key step in the fixation of carbon dioxide and the synthesis of sugars during photosynthesis.
Final answer:
RuBisCo catalyzes the addition of CO₂ to RuBP during the carbon fixation stage of the Calvin cycle, leading to the production of 3-PGA and subsequent sugar synthesis, and it also helps regenerate RuBP, allowing the cycle to perpetuate.
Explanation:
The function of ribulose bisphosphate carboxylase, commonly known as RuBisCo, is essential in the process of photosynthesis. Specifically, RuBisCo is involved in the first major step of the Calvin cycle, known as carbon fixation. During this stage, RuBisCo catalyzes the addition of carbon dioxide (CO₂) to ribulose bisphosphate (RuBP), resulting in the formation of 3-phosphoglycerate (3-PGA).
In subsequent stages of the Calvin cycle, the 3-PGA molecules are reduced to glyceraldehyde 3-phosphate (G3P) using ATP and NADPH from the light-dependent reactions. Some of the G3P molecules are utilized to build glucose, which is the sugar produced in photosynthesis. Moreover, the rest of the G3P is used to regenerate RuBP, thus enabling the process of CO₂ fixation to continue. Additionally, three more ATP molecules are consumed during these regeneration reactions.
To summarize, RuBisCo fulfills a pivotal role in transforming inorganic CO₂ into an organic, usable form through the Calvin cycle, thus driving the synthesis of sugars in plants and certain microorganisms.