Which enzyme is used in the polymerase chain reaction?

Options

A. Restriction enzymes
B. Reverse transcriptase
C. Ligase
D. DNA polymerase

Answer

**Step-by-Step Solution:**

1. **Understanding PCR**: The Polymerase Chain Reaction (PCR) is a technique used to amplify DNA, making millions of copies of a specific DNA segment.

2. **Identifying the Enzyme**: The key enzyme used in PCR is crucial for the synthesis of new DNA strands.

3. **Options Analysis**:
- **Restriction Enzymes**: These enzymes cut DNA at specific sequences but are not used in PCR for amplification.
- **Reverse Transcriptase**: This enzyme synthesizes DNA from RNA, which is not the primary function in PCR.
- **Ligase**: This enzyme joins DNA fragments together but does not amplify DNA.
- **DNA Polymerase**: This enzyme synthesizes new DNA strands by adding nucleotides to a growing DNA strand.

4. **Specific Type of DNA Polymerase**: The specific DNA polymerase used in PCR is called Taq polymerase, which is derived from the bacterium Thermus aquaticus. This enzyme is heat-stable, allowing it to withstand the high temperatures used in PCR.

5. **Conclusion**: Therefore, the enzyme used in the polymerase chain reaction is DNA polymerase, specifically Taq polymerase.

**Final Answer**: The enzyme used in the polymerase chain reaction is DNA polymerase (specifically Taq polymerase).

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