Describe the role of `CaCl_2` in the preparation of competent cells ?

Explanation

**Step-by-Step Solution:**

1. **Understanding Competent Cells**: Competent cells are bacterial cells that have been treated to allow them to take up foreign DNA more easily. This is an essential step in molecular biology for cloning and transformation processes.

2. **Role of Calcium Chloride (CaCl2)**: Calcium chloride is commonly used in the preparation of competent cells. Its primary role is to facilitate the uptake of DNA by the bacterial cells.

3. **Binding with DNA**: Calcium ions (Ca²⁺) from CaCl2 interact with the negatively charged phosphate groups present in the DNA. This interaction reduces the electrostatic repulsion between the DNA and the negatively charged lipopolysaccharides on the surface of the bacterial cell membrane.

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