The primary acceptor , during ` CO_(2)` fixation in ` C_(3)` plants , is

Options

A. Phosphoenolphyruvate (PEP)
B. Ribulose , 1 , 5- diposphate (RuDP)
C. Phosphoglyceric acid (PGA)
D. Ribulose monophosphate (RMP)

Answer

To determine the primary acceptor during CO₂ fixation in C₃ plants, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Process of CO₂ Fixation**:
- In C₃ plants, the process of CO₂ fixation occurs during the Calvin cycle, which is the primary pathway for carbon fixation.

2. **Know the Key Enzyme Involved**:
- The enzyme responsible for the carboxylation of CO₂ is called ribulose bisphosphate carboxylase/oxygenase (commonly known as Rubisco).

3. **Identify the Primary Acceptors**:
- The primary acceptor of CO₂ in C₃ plants is ribulose 1,5-bisphosphate (RuBP), which is a 5-carbon compound.

4. **Formation of the First Product**:
- When CO₂ combines with RuBP in the presence of Rubisco, it forms a 6-carbon intermediate that quickly splits into two molecules of 3-phosphoglycerate (PGA), which is a 3-carbon compound.

5. **Conclusion**:
- Therefore, the primary acceptor during CO₂ fixation in C₃ plants is ribulose 1,5-bisphosphate (RuBP).

### Final Answer:
The primary acceptor during CO₂ fixation in C₃ plants is **ribulose 1,5-bisphosphate (RuBP)**.

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