Which is not correct about plasmid

Options

A. Host chromosome can be integrated with plasmid
B. Transfer of plasmid can occur from one cell to another with the killing of former
C. It is extrachromosomal DNA in bacteria
D. It is not an integral part but inert genetic material

Answer

To determine which statement about plasmids is not correct, let's analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding Plasmids**:
- Plasmids are small, circular pieces of DNA that are separate from the chromosomal DNA in bacteria. They can replicate independently and often carry genes that provide advantages, such as antibiotic resistance.

2. **Evaluating the First Statement**:
- The first statement claims that "host chromosome can be integrated with our plasmid."
- This statement is **correct**. Plasmids can integrate into the host chromosome through a process called recombination.

3. **Evaluating the Second Statement**:
- The second statement states that "the transfer of plasmids can occur from one cell to another with the killing of the former cell."
- This statement is **incorrect**. The transfer of plasmids typically occurs through processes like conjugation, transformation, or transduction, and does not involve the killing of the donor cell. The donor cell remains alive after transferring the plasmid.

4. **Evaluating the Third Statement**:
- The third statement mentions that "it is extra chromosomal DNA in bacteria."
- This statement is **correct**. Plasmids are indeed extra chromosomal, meaning they exist outside the main chromosomal DNA.

5. **Evaluating the Fourth Statement**:
- The fourth statement claims that "it is not an integral part but it is genetic material."
- This statement is also **correct**. While plasmids are not integral parts of the chromosomal DNA, they are still considered genetic material.

6. **Conclusion**:
- The only statement that is not correct about plasmids is the second one: "the transfer of plasmids can occur from one cell to another with the killing of the former cell."

### Final Answer:
The statement that is not correct about plasmids is: "the transfer of plasmids can occur from one cell to another with the killing of the former cell."

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