In `C_(3)` plants, the first stable product of photosynthesis during dark reaction is

Options

A. Malic acid
B. Oxaloacetic acid
C. Phosphoglyceric acid (PGA)
D. Phosphoglyceraldehyde (PGAL)

Answer

To answer the question regarding the first stable product of photosynthesis during the dark reaction in C3 plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**: Recognize that C3 plants utilize the C3 pathway for photosynthesis, which includes both light and dark reactions. The dark reaction is also known as the Calvin cycle.

2. **Identify the Process**: In the Calvin cycle, carbon dioxide (CO2) is fixed and reduced to form carbohydrates. This process occurs in the stroma of chloroplasts.

3. **Recognize the Role of Enzymes**: The enzyme ribulose bisphosphate carboxylase/oxygenase (RuBisCO) catalyzes the first step of the Calvin cycle, where CO2 is combined with ribulose bisphosphate (RuBP).

4. **Determine the First Stable Product**: The immediate product of the reaction between CO2 and RuBP is a 6-carbon compound that quickly splits into two molecules of 3-phosphoglycerate (3-PGA), which is a 3-carbon compound.

5. **Conclude the Answer**: Therefore, the first stable product of photosynthesis during the dark reaction in C3 plants is **3-phosphoglyceric acid (3-PGA)**.

### Final Answer:
The first stable product of photosynthesis during the dark reaction in C3 plants is **3-phosphoglyceric acid (3-PGA)**.

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