During gene cloning which is called 'gene taxi'

Options

A. Vaccine
B. Plasmid
C. Bacterium
D. Protozoa

Answer

### Step-by-Step Solution

1. **Understanding Gene Cloning**: Gene cloning is a process where a specific gene is isolated and replicated to produce multiple copies. This is often done to study the gene or to produce a desired product.

2. **Identifying the Role of Vectors**: In gene cloning, vectors are used to transfer the desired gene into a host organism (like bacteria or plants). Vectors act as carriers for the gene of interest.

3. **Defining 'Gene Taxi'**: The term 'gene taxi' refers to the vector because it transports the gene into the recipient organism. Just like a taxi carries passengers to their destination, a vector carries genes to the cells where they can be expressed.

4. **Types of Vectors**: Common types of vectors include plasmids, which are circular DNA molecules found in bacteria. They can replicate independently and are often used in gene cloning due to their ability to carry foreign DNA.

5. **Evaluating Options**: In the context of the question:
- **Vaccine**: Not a vector; it is used for immunization.
- **Plasmid**: Correct answer; it is a vector and referred to as 'gene taxi'.
- **Bacterium**: The entire bacterium cannot be used as a vector.
- **Protozoa**: Similar to bacteria, whole protozoa cannot be used as vectors.

6. **Conclusion**: The correct answer to the question "During gene cloning, which is called 'gene taxi'?" is **plasmid**.