If we ligate a foreign, DNA at the Barn HI site of tetracycline resistance gene in pBR322 the recombinant plasmid u ill:

Options

A. A. show ampicillin resistance only
B. B. show tetracycline resistance
C. C. grow well on tetracycline containing medium
D. D. not grow on ampicillin containing medium

Answer

To solve the question regarding the ligation of foreign DNA at the BamHI site of the tetracycline resistance gene in the pBR322 plasmid, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Plasmid pBR322**:
- pBR322 is a commonly used plasmid vector that contains genes for antibiotic resistance, specifically for ampicillin (Amp^R) and tetracycline (Tet^R). These resistance genes serve as selectable markers.

2. **Identifying the BamHI Site**:
- The BamHI site is a specific location on the plasmid where the foreign DNA can be inserted. In this case, it is located within the tetracycline resistance gene (Tet^R).

3. **Ligation of Foreign DNA**:
- When foreign DNA is ligated into the BamHI site of the Tet^R gene, it disrupts the function of this gene. This means that the tetracycline resistance gene will no longer be functional because the foreign DNA interrupts its coding sequence.

4. **Consequences of Disruption**:
- Since the Tet^R gene is disrupted, the transformed bacteria will lose their ability to grow in the presence of tetracycline. They will not be able to survive on tetracycline-containing media.

5. **Ampicillin Resistance**:
- The ampicillin resistance gene (Amp^R) remains intact and functional. Therefore, the bacteria will still be able to grow on media containing ampicillin.

6. **Conclusion**:
- Based on the above analysis, the recombinant plasmid will show resistance only to ampicillin and not to tetracycline. Therefore, the correct answer to the question is option A: "show ampicillin resistance only."

### Final Answer:
- The recombinant plasmid will **show ampicillin resistance only**.