Which of the following statements is incorrect?

Options

A. Plasmids have the ability to replicate within the bacterial cells independent of the control of chromosomal DNA
B. Some plasmids have only one or two copies per cell whereas, the others may have 15-100 copies per cell
C. Bacteriophages have the ability to replicate within the bacterial cell independent of the control of chromosomal DNA
D. Transformation is a procedure of separation and isolation of DNA fragments

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks us to identify which of the provided statements is incorrect regarding plasmids, bacteriophages, and transformation.

2. **Analyzing Statement 1**: "Plasmids have the ability to replicate within the bacterial cells, independent of the control of chromosomal DNA."
- **Explanation**: Plasmids are indeed extra-chromosomal DNA that can replicate independently within bacterial cells. This statement is correct.

3. **Analyzing Statement 2**: "Some plasmids have only 1 or 2 copies per cell whereas others may have 15 to 100 copies per cell."
- **Explanation**: This statement is also correct as plasmids can vary in copy number within bacterial cells.

4. **Analyzing Statement 3**: "Bacteriophage have the ability to replicate within the bacterial cell independent of the control of chromosomal DNA."
- **Explanation**: Bacteriophages are viruses that infect bacteria and can replicate within them. This statement is correct as well.

5. **Analyzing Statement 4**: "Transformation is a process to separate DNA."
- **Explanation**: This statement is incorrect. Transformation refers to the uptake of foreign DNA by a bacterial cell, which is a form of horizontal gene transfer. The process used to separate and isolate DNA fragments is gel electrophoresis.

6. **Conclusion**: The incorrect statement among the options provided is Statement 4.

**Final Answer**: The incorrect statement is: "Transformation is a process to separate DNA."

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