Physical contact between donor and recipient bacteria occur during

Options

A. Conjugation
B. Transformation
C. Transduction
D. 2 & 3

Answer

To solve the question, "Physical contact between donor and recipient bacteria occurs during," we need to analyze the options provided and understand the processes involved in each.

### Step-by-Step Solution:

1. **Understand the Options**:
- The options given are:
1. Conjugation
2. Transformation
3. Transduction
4. One and Two

2. **Define Conjugation**:
- Conjugation is a process where two bacteria come into physical contact, typically through a structure called a pilus. During this process, genetic material (usually plasmid DNA) is transferred from the donor bacterium to the recipient bacterium.

3. **Define Transformation**:
- Transformation is a process where bacteria take up free-floating DNA from their environment. This does not involve direct physical contact between the donor and recipient bacteria.

4. **Define Transduction**:
- Transduction is a process mediated by bacteriophages (viruses that infect bacteria) where genetic material is transferred from one bacterium to another. This process does not require physical contact between the bacteria.

5. **Analyze the Options**:
- From the definitions, we can conclude that:
- **Conjugation** involves physical contact.
- **Transformation** does not involve physical contact.
- **Transduction** does not involve physical contact.
- Option 4 (One and Two) is incorrect because transformation does not involve physical contact.

6. **Conclusion**:
- The correct answer is **Conjugation** because it is the only process among the options that involves direct physical contact between the donor and recipient bacteria.

### Final Answer:
**Conjugation**

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