Resistance genes present in pBR322 are

Options

A. Penicillin and ampicillin
B. Ampicillin and tetracycline
C. Tetracycline and erythromycin
D. Erythromycin and ampicillin.

Answer

To solve the question regarding the resistance genes present in the plasmid pBR322, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding pBR322**:
- pBR322 is a well-known plasmid vector used in molecular biology for cloning purposes. It is important to know its structure and components.

2. **Identifying Key Features**:
- The plasmid contains an origin of replication (ORI) which allows it to replicate independently within a host cell.
- It also contains selectable markers, which are crucial for identifying successfully transformed cells.

3. **Resistance Genes**:
- pBR322 contains two specific antibiotic resistance genes:
- **Ampicillin Resistance Gene (amp)**: This gene provides resistance to the antibiotic ampicillin.
- **Tetracycline Resistance Gene (tet)**: This gene provides resistance to the antibiotic tetracycline.

4. **Evaluating Options**:
- The options given are:
- A) Penicillin and Ampicillin
- B) Ampicillin and Tetracycline
- C) Tetracycline and Erythromycin
- D) Erythromycin and Ampicillin
- From our knowledge of pBR322, we can eliminate options A, C, and D because:
- Penicillin is not a resistance gene in pBR322.
- Erythromycin is not present as a resistance gene in pBR322.

5. **Conclusion**:
- The correct answer is **B) Ampicillin and Tetracycline** as these are the resistance genes present in pBR322.