The bacterial cell which is able to uptake plasmid DNA is called __________.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term used to describe a bacterial cell that can take up plasmid DNA.

2. **Defining Plasmid DNA**: Plasmid DNA is a small, circular piece of DNA that is separate from the chromosomal DNA and can replicate independently. It often carries genes that provide bacteria with genetic advantages, such as antibiotic resistance.

3. **Competence in Bacteria**: For a bacterial cell to take up plasmid DNA, it must be in a specific state known as "competence." This means the bacterial cell is capable of taking up foreign DNA from its environment.

4. **Methods to Induce Competence**:
- One common method to make bacteria competent is by treating them with divalent cations, such as calcium ions. This treatment increases the permeability of the bacterial cell membrane, allowing plasmid DNA to enter.
- Another method is the heat shock technique, where bacteria are subjected to a sudden increase in temperature (e.g., 42 degrees Celsius) followed by a return to a lower temperature (ice). This also enhances the uptake of plasmid DNA.

5. **Conclusion**: Based on the understanding of competence and the methods to induce it, the bacterial cell that can uptake plasmid DNA is called a "competent" cell.

**Final Answer**: The bacterial cell which is able to uptake plasmid DNA is called **competent**.

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