In `C_(3)` plants, first carbon dioxide acceptor enzyme is

Options

A. `PEPCO`
B. `RuBP` carboxylase/Rubisco
C. `RuBP` oxygenase
D. Oxidase.

Answer

### Step-by-Step Solution:

1. **Understanding C3 Plants**:
- C3 plants are a type of plant that utilizes the Calvin cycle for photosynthesis. In this process, carbon dioxide is fixed into a three-carbon compound.

2. **Identifying the First Carbon Dioxide Acceptor**:
- The first step in the Calvin cycle involves the fixation of carbon dioxide. The enzyme responsible for this reaction is crucial for the process.

3. **The Role of RuBisCO**:
- The enzyme that acts as the first carbon dioxide acceptor in C3 plants is called RuBisCO, which stands for Ribulose bisphosphate carboxylase/oxygenase.

4. **Formation of Intermediate Compounds**:
- When carbon dioxide is fixed by RuBisCO, it combines with a five-carbon sugar called ribulose bisphosphate (RuBP) to form an unstable six-carbon compound.

5. **Splitting of the Six-Carbon Compound**:
- This unstable six-carbon compound quickly splits into two molecules of a three-carbon compound known as phosphoglyceric acid (PGA).

6. **Conclusion**:
- Therefore, the correct answer to the question is that the first carbon dioxide acceptor enzyme in C3 plants is RuBisCO.

### Final Answer:
The first carbon dioxide acceptor enzyme in C3 plants is **RuBisCO**.

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