In the PCR technique, the heat resistant polymerase used is :

Options

A. primer
B. Taq polymerase
C. ethidium bromide
D. alkaline phosphatase

Answer

**Step-by-Step Solution:**

1. **Understanding PCR**: The Polymerase Chain Reaction (PCR) is a technique used to amplify or make multiple copies of a specific segment of DNA.

2. **Role of Polymerase in PCR**: In PCR, an enzyme called DNA polymerase is essential for synthesizing new DNA strands. This enzyme adds nucleotides to the growing DNA strand, using the original DNA as a template.

3. **Need for Heat Resistance**: During the PCR process, the reaction mixture is subjected to high temperatures (around 94-98°C) to denature the DNA, separating the two strands. Therefore, the DNA polymerase used must be heat-resistant to function effectively at these elevated temperatures.

4. **Identifying the Correct Polymerase**: The most commonly used heat-resistant DNA polymerase in PCR is Taq polymerase, which is derived from the bacterium Thermus aquaticus. This polymerase remains active and stable at high temperatures, making it ideal for PCR.

5. **Evaluating Other Options**:
- **Primers**: These are short sequences of nucleotides that initiate DNA synthesis but are not polymerases themselves.
- **Ethidium Bromide**: This is a dye used for staining DNA in gel electrophoresis and does not play a role in the PCR process.
- **Alkaline Phosphatase**: This enzyme is used to remove phosphate groups from nucleotides and is not involved in PCR.

6. **Conclusion**: Based on the above evaluations, the correct answer to the question is Taq polymerase, as it is the heat-resistant polymerase used in the PCR technique.

**Final Answer**: Taq Polymerase

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