Which is not true about PCR (Polymerase Chain Reaction) ?

Options

A. PCR can amplify very small amount of DNA
B. It can be used to detect HIV in suspects
C. Only RNA can be used as primer
D. Used to detect mutation in genes

Answer

**Step-by-Step Solution:**

1. **Understanding PCR**: The Polymerase Chain Reaction (PCR) is a technique used to amplify small amounts of DNA. It is a crucial tool in molecular biology for cloning, gene analysis, and detecting pathogens.

2. **Evaluating the Statements**:
- **Statement 1**: "PCR can amplify very small amounts of DNA."
- This statement is true. PCR is specifically designed to take a tiny amount of DNA and amplify it to a detectable level.

- **Statement 2**: "It can be used to detect HIV in suspects."
- This statement is also true. PCR can amplify viral DNA or RNA from a blood sample, allowing for the detection of HIV.

- **Statement 3**: "Only RNA can be used as a primer."
- This statement is false. In PCR, both DNA and RNA primers can be used, but typically DNA primers are used to initiate the amplification process.

- **Statement 4**: "It is used to detect mutations in genes."
- This statement is true. PCR can amplify specific regions of DNA, making it easier to study mutations.

3. **Identifying the Incorrect Statement**: Based on the evaluation, the only statement that is not true about PCR is the third one: "Only RNA can be used as a primer."

4. **Conclusion**: Therefore, the answer to the question "Which is not true about PCR?" is that only RNA can be used as a primer.

**Final Answer**: Statement 3 is not true about PCR.

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