One of the key factors, which makes the plasmid the vector in genetic engineering is

Options

A. It is resistant to antibiotics
B. It is resistant to restriction enzymes
C. Its ability to carry a foreign gene
D. Its ability to cause infection in the host

Answer

**Step-by-Step Solution:**

1. **Understanding Plasmids**: Plasmids are small, circular DNA molecules found in bacteria and some eukaryotic cells. They are separate from chromosomal DNA and can replicate independently.

2. **Role of Plasmids in Genetic Engineering**: In genetic engineering, plasmids serve as vectors, which are vehicles used to transfer genetic material into a host cell.

3. **Key Features of Plasmids**:
- **Low Molecular Weight**: Plasmids are generally small, which makes them easier to manipulate in the lab.
- **Origin of Replication**: They contain sequences that allow them to replicate within the host cell.
- **Selectable Markers**: Many plasmids include genes that confer resistance to antibiotics, allowing for the selection of transformed cells.

4. **Ability to Carry Foreign Genes**: The primary factor that makes plasmids effective vectors is their ability to carry foreign genes. This allows scientists to introduce specific genes into host organisms for various purposes, such as producing proteins or studying gene function.

5. **Integration into Host Genome**: The circular structure of plasmids allows them to integrate into the host genome, facilitating the expression of the foreign gene.

6. **Antibiotic Resistance**: While plasmids can confer antibiotic resistance, this feature is mainly useful for selecting successfully transformed cells rather than being the primary reason they are used as vectors.

7. **Conclusion**: The key factor that makes plasmids effective vectors in genetic engineering is their ability to carry foreign genes.

**Final Answer**: The ability to carry a foreign gene.

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