In ` C_(3) plants , first stable product of `CO_(2)` fixation is

Options

A. 3-PGA
B. Starch
C. OAA
D. Pyruvate

Answer

To solve the question regarding the first stable product of CO₂ fixation in C₃ plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding C₃ Plants**:
- C₃ plants are a type of plant that utilizes the C₃ carbon fixation pathway, also known as the Calvin cycle, for photosynthesis.

2. **Identifying the Process**:
- The process begins with the fixation of carbon dioxide (CO₂) into an organic molecule.

3. **Role of Ribulose-1,5-bisphosphate (RuBP)**:
- The first step involves the reaction of CO₂ with a 5-carbon compound called ribulose-1,5-bisphosphate (RuBP).

4. **Carboxylation Reaction**:
- This reaction is known as carboxylation, where CO₂ is added to RuBP, catalyzed by the enzyme RuBisCO.

5. **Formation of 3-Phosphoglycerate (3-PGA)**:
- The carboxylation of RuBP results in the formation of an unstable 6-carbon intermediate that quickly splits into two molecules of 3-phosphoglycerate (3-PGA), which is the first stable product of CO₂ fixation in C₃ plants.

6. **Conclusion**:
- Therefore, the first stable product of CO₂ fixation in C₃ plants is 3-phosphoglycerate (3-PGA).

### Final Answer:
The first stable product of CO₂ fixation in C₃ plants is **3-Phosphoglycerate (3-PGA)**.

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