Which DNA polymerase is most commonly employed in the Polymerase Chain Reaction (PCR) due to its ability to remain active after repeated high‑temperature denaturation steps?
Answer
Taq DNA polymerase
The correct answer is Taq DNA polymerase — Select the enzyme that matches the heat‑stability criterion, which is Taq DNA polymerase.
Step-by-step solution
- Identify the requirement for a DNA polymerase that can survive temperatures around 95 °C used in the denaturation step of PCR.
- Recall that the enzyme isolated from the thermophilic bacterium *Thermus aquaticus* (Taq) retains activity at high temperatures.
- Compare the listed enzymes: Taq polymerase is heat‑stable, whereas DNA polymerase I, Pfu polymerase, and reverse transcriptase lose activity at such temperatures.
- Select the enzyme that matches the heat‑stability criterion, which is Taq DNA polymerase.
Common mistake: Choosing DNA polymerase I, which is not heat stable
Concept tested: Heat‑stable DNA polymerase for PCR
Published · How this solution was prepared and checked
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