College

Which compound is produced during carbon fixation?

A. PGA
B. G3P
C. RuBP
D. C6H12O6

Answer :

During the process of carbon fixation in photosynthesis, carbon dioxide is incorporated into a stable intermediate. This occurs in the Calvin Cycle. The first compound that is produced during carbon fixation is 3-phosphoglycerate (PGA). Here's a step-by-step explanation:

1. Carbon Fixation Step: The Calvin Cycle begins with carbon fixation, where carbon dioxide (CO2) is captured from the atmosphere.

2. Role of Enzyme: The enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase, commonly known as RuBisCO, facilitates this reaction.

3. Formation of 3-Phosphoglycerate (PGA): Carbon dioxide is combined with a 5-carbon sugar molecule known as RuBP (ribulose bisphosphate). This reaction results in an unstable 6-carbon compound which immediately splits into two 3-carbon molecules.

4. The 3-Carbon Product: These 3-carbon molecules are known as 3-phosphoglycerate (PGA). It's the first stable product in the Calvin Cycle.

Therefore, the compound produced during carbon fixation is PGA.