Extrachromosomal self replicating double stranded circular DNA in bacterial cell is called

Options

A. plasmid
B. cosmid
C. phasmid
D. all of these

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks for the term that describes extrachromosomal, self-replicating, double-stranded circular DNA found in bacterial cells.

2. **Analyzing the Options:**
The options provided are:
- Plasmid
- Cosmid
- Phasmid
- All of these

3. **Defining Plasmid:**
A plasmid is a small, circular, double-stranded DNA molecule that is distinct from a chromosomal DNA and can replicate independently within a cell. Plasmids are commonly found in bacteria and can carry genes that provide beneficial traits, such as antibiotic resistance.

4. **Identifying Other Options:**
- **Cosmid:** A cosmid is a hybrid vector that contains features of both plasmids and phage lambda DNA, used in cloning.
- **Phasmid:** A phasmid is a type of vector that combines features of plasmids and bacteriophages, but it is not a naturally occurring form of DNA in bacterial cells.

5. **Conclusion:**
Since the question specifically asks for the type of DNA that is extrachromosomal and self-replicating in bacterial cells, the correct answer is **plasmid**.

**Final Answer:**
The extrachromosomal self-replicating double-stranded circular DNA in bacterial cells is called **plasmid**.

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