Question

Virus-mediated transfer of host DNA from one cell to another cell is known as:

• A. Transduction
• B. Integration
• C. Transformation
• D. Transcription

Hint:

Transduction is the virus-mediated transfer of genetic material between bacterial cells, often involving bacteriophages.

Answer 1

The Correct Option is A

Step 1: Understanding transduction. Transduction is a process in which a bacteriophage (virus) transfers genetic material from one bacterial cell to another. This occurs when a phage accidentally packages host DNA instead of viral DNA and injects it into another bacterium. 

Step 2: Types of transduction. 
- Generalized transduction: Any bacterial gene can be transferred. 
- Specialized transduction: Only specific bacterial genes near the phage integration site are transferred. 

Step 3: Why other options are incorrect. 
- (B) Integration: Refers to viral DNA integrating into the host genome, not transferring host DNA. 
- (C) Transformation: Involves uptake of free DNA from the environment by bacteria, not virus-mediated. 
- (D) Transcription: The process of RNA synthesis from DNA, unrelated to gene transfer.

Answer 2

The question describes a process where a virus carries host DNA from one cell into another cell. Let's check each term against that description.

1. Transduction: This is the process where a bacteriophage accidentally packages a piece of its host bacterium's DNA instead of its own viral DNA, then injects that host DNA into the next bacterial cell it infects. This is a virus-mediated gene transfer, matching the question exactly.
2. Integration: This term describes viral DNA inserting itself into the host cell's genome, which is the virus's own genetic material entering the host, the reverse direction of gene flow compared to what the question describes.
3. Transformation: This is the uptake of free, naked DNA from the surrounding environment directly by a bacterial cell, with no virus involved at any step.
4. Transcription: This is the process of copying a DNA sequence into RNA inside a cell, a normal step in gene expression that has nothing to do with moving DNA between cells.

Only transduction involves a virus physically carrying host genetic material from one cell to another, which is exactly what the question is describing.

So the correct answer is Transduction.