Polymerase chain reaction employs

Options

A. Primers and DNA ligase
B. DNA ligase only
C. DNA polymerase only
D. Primers and DNA polymerase

Answer

**Step-by-Step Solution:**

1. **Understanding PCR**: The Polymerase Chain Reaction (PCR) is a widely used technique in molecular biology to amplify specific DNA sequences. It allows researchers to create millions of copies of a particular DNA segment in vitro (outside a living organism).

2. **Components of PCR**: The main components required for PCR include:
- **DNA Polymerase**: This enzyme synthesizes new DNA strands by adding nucleotides to the growing DNA chain. It is crucial for the amplification process.
- **Primers**: Short sequences of nucleotides that provide a starting point for DNA synthesis. They are designed to bind to specific regions of the target DNA.

3. **Temperature Cycling**: PCR involves repeated cycles of temperature changes:
- **Denaturation**: The double-stranded DNA is heated to separate it into two single strands.
- **Annealing**: The temperature is lowered to allow primers to bind to their complementary sequences on the single-stranded DNA.
- **Extension**: The temperature is raised again to allow DNA polymerase to extend the primers, synthesizing new DNA strands.

4. **Conclusion**: Based on the components and the process described, PCR employs both primers and DNA polymerase to amplify the target DNA sequence. DNA ligase is not involved in the PCR process, as it is used for joining DNA fragments rather than amplifying them.

**Final Answer**: Polymerase chain reaction employs primers and DNA polymerase.

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