The gene 'rop' present in pBR322 cloning vector, codes for
1) the proteins involved in the translation
2) the proteins involved in the replication of the plasmid
3) the proteins involved in the synthesis of ampicillin only
4) the proteins involved in the synthesis of tetracycline only

Options

A. 1) the proteins involved in the translation
B. 2) the proteins involved in the replication of the plasmid
C. 3) the proteins involved in the synthesis of ampicillin only
D. 4) the proteins involved in the synthesis of tetracycline only

Answer

To solve the question regarding the gene 'rop' present in the pBR322 cloning vector, we will analyze the function of the 'rop' gene and its significance in the context of the options provided.

### Step-by-Step Solution:

1. **Understand the Function of the 'rop' Gene**: The 'rop' gene in the pBR322 vector codes for a protein known as the Rop protein. This protein is crucial for the regulation of the plasmid's copy number during replication.

2. **Analyze the Options**:
- **Option 1**: "The proteins involved in the translation."
- This option is incorrect because the 'rop' gene does not code for proteins that are involved in the translation process.

- **Option 2**: "The proteins involved in the replication of the plasmid."
- This option is correct. The Rop protein plays a role in regulating the replication of the plasmid by controlling the copy number, which is essential for maintaining the plasmid's stability and function.

- **Option 3**: "The proteins involved in the synthesis of ampicillin only."
- This option is incorrect. The 'rop' gene does not code for proteins that are specifically involved in the synthesis of ampicillin.

- **Option 4**: "The proteins involved in the synthesis of tetracycline only."
- This option is also incorrect. Similar to option 3, the 'rop' gene does not code for proteins involved in the synthesis of tetracycline.

3. **Conclusion**: Based on the analysis of the options, the correct answer is **Option 2: the proteins involved in the replication of the plasmid**.