In a experiment , in pBR322 an alien DNA is introduced using sal I. The transformant will grow on

Options

A. Ampicillin
B. Tetracycline
C. Both (a) and (b)
D. None of these

Answer

To solve the question regarding the growth of transformants after introducing alien DNA into the plasmid pBR322 using the restriction enzyme Sal I, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding pBR322**:
- pBR322 is a plasmid that contains two antibiotic resistance genes: one for ampicillin and one for tetracycline.
- It also has multiple restriction sites, including Sal I, which is located within the tetracycline resistance gene.

**Hint**: Remember that plasmids like pBR322 are often used in genetic engineering due to their ability to replicate independently and carry foreign DNA.

2. **Insertion of Alien DNA**:
- When alien DNA is introduced using Sal I, it is inserted into the tetracycline resistance gene.
- This insertion disrupts the function of the tetracycline resistance gene, making it non-functional.

**Hint**: Inserting DNA into a gene often disrupts that gene's function, which is crucial for understanding how antibiotic resistance is affected.

3. **Effect on Antibiotic Resistance**:
- The ampicillin resistance gene remains intact and functional because the insertion did not affect it.
- Therefore, the bacteria containing the recombinant plasmid will still be resistant to ampicillin.

**Hint**: Identify which antibiotic resistance genes are affected by the insertion of foreign DNA to determine where the bacteria can grow.

4. **Growth Conditions**:
- When the transformed bacteria are grown on media containing ampicillin, they will survive and grow because they are resistant to ampicillin.
- Conversely, when grown on media containing tetracycline, they will not survive because they have lost the ability to resist tetracycline due to the disruption of the tetracycline resistance gene.

**Hint**: Consider the survival of bacteria based on their resistance to antibiotics present in the growth media.

5. **Conclusion**:
- The transformants will grow on ampicillin medium but will not grow on tetracycline medium. Therefore, the correct answer to the question is that the transformants will grow on ampicillin medium.

**Hint**: Summarize the effects of the genetic modifications on the bacteria's ability to withstand specific antibiotics.

### Final Answer:
The transformant will grow on **ampicillin medium**.