Find the correct Statement .

Options

A. Ori means origin transcription
B. Some bacterial cell may have copy number of plasmids vary from 15-100
C. Vector should have many recognition sites for commonly used restriction enzyme so that alien DNA can attach to any one of the sites easily .
D. `tet^R` gene in pBR322 can be cleaved by pvu I and Pst I.

Answer

To solve the question "Find the correct Statement," we will analyze each of the provided options step by step.

### Step 1: Analyze Option 1
- **Statement**: ORI means origin of transcription.
- **Evaluation**: This statement is incorrect. ORI actually stands for the origin of replication, not transcription. The origin of transcription is referred to as the promoter region.

**Hint**: Remember that ORI is related to DNA replication, not transcription.

### Step 2: Analyze Option 2
- **Statement**: Some bacterial cells may have a copy number of plasmids that varies from 15 to 100.
- **Evaluation**: This statement is correct. The copy number of plasmids in bacterial cells can indeed vary widely, typically ranging from a few copies to several hundred copies per cell.

**Hint**: Consider how plasmids can replicate independently within bacterial cells, leading to variable copy numbers.

### Step 3: Analyze Option 3
- **Statement**: Vectors should have many recognition sites for the commonly used restriction enzyme so that alien DNA can attach to any one of the sites easily.
- **Evaluation**: This statement is incorrect. While vectors can have multiple restriction sites, it is often sufficient to have a single recognition site for a commonly used restriction enzyme to allow for the insertion of alien DNA.

**Hint**: Think about the purpose of restriction sites in cloning and how they facilitate the insertion of DNA.

### Step 4: Analyze Option 4
- **Statement**: Tetracycline arginine in PVR3-22 can be cleaved by the PVU-1 and PST-1.
- **Evaluation**: This statement is incorrect. Tetracycline is an antibiotic, and while it may be a selectable marker in plasmids, the specific enzymes mentioned (PVU-1 and PST-1) do not cleave tetracycline arginine.

**Hint**: Focus on the function of restriction enzymes and their specificity for DNA sequences rather than for antibiotics.

### Conclusion
After analyzing all the options, the correct statement is from **Option 2**: "Some bacterial cells may have a copy number of plasmids that varies from 15 to 100."

**Final Answer**: Option 2 is the correct statement.