Which one is a true statement regarding DNA polymerase used in PCR

Options

A. It is used to ligate introduced DNA in recipient cell
B. It serves as a selectable marker
C. It is isolated from a virus
D. It remains active at high temperature

Answer

To determine which statement regarding DNA polymerase used in PCR is true, we will analyze each option provided in the question:

1. **Understanding PCR**:
- PCR stands for Polymerase Chain Reaction, which is a technique used to amplify (make multiple copies of) a specific segment of DNA. It involves three main steps: denaturation, annealing, and extension.

2. **Analyzing the Options**:
- **Option A**: "It is used to ligate introduce DNA in recipient cell."
- This statement is incorrect. DNA polymerase is not involved in ligating or introducing DNA into cells; it is primarily responsible for synthesizing new DNA strands during the PCR process.

- **Option B**: "It serves as a selectable marker."
- This statement is also incorrect. DNA polymerase does not function as a selectable marker; it is an enzyme that catalyzes the elongation of DNA strands during PCR.

- **Option C**: "It is isolated from a virus."
- This statement is incorrect. The DNA polymerase used in PCR, specifically Taq polymerase, is derived from the bacterium Thermus aquaticus, not a virus.

- **Option D**: "It remains active at a high temperature."
- This statement is correct. Taq polymerase is a thermostable enzyme, meaning it can withstand the high temperatures used during the denaturation step of PCR (typically around 90-94°C). This property is crucial for the PCR process.

3. **Conclusion**:
- The true statement regarding DNA polymerase used in PCR is **Option D: "It remains active at a high temperature."**