In `C_(4)` cycle, first `CO_(2)` acceptor is

Options

A. 3C compound
B. 4C compound
C. 5C compound
D. 6C compound

Answer

To answer the question about the first carbon dioxide acceptor in the C4 cycle, we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding the C4 Cycle**: The C4 cycle, also known as the Hatch and Slack pathway, is a photosynthetic process that occurs in certain plants, known as C4 plants, which include maize and sugarcane.

2. **Identifying the First CO2 Acceptor**: In the C4 cycle, the first molecule that accepts carbon dioxide (CO2) is crucial for the pathway.

3. **Recognizing the Compound**: The first CO2 acceptor in the C4 cycle is a three-carbon compound called phosphoenolpyruvate (PEP).

4. **Location of PEP**: Phosphoenolpyruvate is found in the mesophyll cells of the plant.

5. **Enzymatic Reaction**: The enzyme responsible for facilitating the reaction where CO2 is fixed to PEP is called PEP carboxylase.

6. **Formation of Oxaloacetate**: When CO2 combines with PEP, it forms a four-carbon compound known as oxaloacetate.

7. **Conversion to Malate**: The oxaloacetate is then converted into another four-carbon compound called malate.

8. **Transport to Bundle Sheath Cells**: The malate is transported to the bundle sheath cells, where it is further processed.

9. **Recycling of PEP**: The malate is converted back into pyruvate in the bundle sheath cells, which is then sent back to the mesophyll cells, completing the cycle.

10. **Conclusion**: Therefore, the first carbon dioxide acceptor in the C4 cycle is phosphoenolpyruvate (PEP).

### Final Answer:
The first carbon dioxide acceptor in the C4 cycle is phosphoenolpyruvate (PEP).

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