The formation of PGA in dark reactions is called as

Options

A. carboxylation
B. photorespiration
C. oxygenation
D. reduction

Answer

To answer the question regarding the formation of PGA (3-Phosphoglycerate) in dark reactions, we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding Dark Reactions**:
- Dark reactions, also known as the Calvin Cycle, occur in the stroma of chloroplasts and do not directly require light. They utilize the products of light reactions (ATP and NADPH) to convert carbon dioxide into glucose.

2. **Identifying the Key Process**:
- The formation of PGA is a crucial step in the Calvin Cycle. It is important to note that this process involves the fixation of carbon dioxide.

3. **Carboxylation**:
- The first step in the Calvin Cycle is called carboxylation. During this step, carbon dioxide (CO2) is fixed by combining with Ribulose 1,5-bisphosphate (RuBP), which is the CO2 acceptor.

4. **Formation of PGA**:
- The reaction catalyzed by the enzyme Ribulose 1,5-bisphosphate carboxylase/oxygenase (commonly known as Rubisco) leads to the production of 3-Phosphoglycerate (PGA). This is the first stable product formed in the Calvin Cycle.

5. **Conclusion**:
- Therefore, the formation of PGA in dark reactions is specifically referred to as **Carboxylation**.

### Final Answer:
The formation of PGA in dark reactions is called **Carboxylation**.

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