In recombinant DNA technique, the term vector refers to

Options

A. Donor DNA, is identified and picked up through electrophoresis
B. Plasmid, transfers DNA into living cell
C. Collection of entire genome in the form of plasmid
D. Enzyme, cuts the DNA at specific sites

Answer

### Step-by-Step Solution:

1. **Understanding the Term 'Vector':**
- In the context of recombinant DNA technology, a vector is a DNA molecule that is used to carry foreign genetic material into another cell.

2. **Role of Plasmids as Vectors:**
- Plasmids are small, circular DNA molecules found in bacteria. They are commonly used as vectors because they can replicate independently of the chromosomal DNA in the host cell.

3. **Function of Vectors:**
- Vectors serve as vehicles to transfer the gene of interest into a host organism. For example, if we want to produce insulin, the gene coding for insulin can be inserted into a plasmid vector, which is then introduced into a bacterial cell like E. coli.

4. **Features of Effective Vectors:**
- Effective vectors possess several key features:
- **Origin of Replication:** This allows the plasmid to replicate within the host cell.
- **Selectable Markers:** These are genes that confer resistance to antibiotics, allowing for the selection of successfully transformed cells.
- **Multiple Cloning Sites (MCS):** These are regions within the plasmid that contain several restriction sites for the insertion of foreign DNA.

5. **Use of Restriction Enzymes:**
- To insert the gene of interest into the plasmid, restriction enzymes (or restriction endonucleases) are used to cut the DNA at specific sites. This creates sticky or blunt ends that can be ligated with the foreign DNA.

6. **Transformation into Host Cells:**
- After the recombinant plasmid is formed, it is introduced into the host cell through a process called transformation. The host cell then expresses the gene of interest, leading to the production of the desired protein.