Which DNA polymerase is most commonly employed in the Polymerase Chain Reaction (PCR) because it remains active after repeated cycles of high‑temperature denaturation?
Answer
Taq DNA polymerase
The correct answer is Taq DNA polymerase — Select the remaining option, Taq DNA polymerase, as the correct answer.
Step-by-step solution
- Identify the requirement that the polymerase must withstand repeated heating to ~95 °C.
- Recall that Taq polymerase, isolated from Thermus aquaticus, is thermostable and therefore used in PCR.
- Eliminate enzymes that are not thermostable (DNA polymerase I, DNA polymerase III, reverse transcriptase).
- Select the remaining option, Taq DNA polymerase, as the correct answer.
Common mistake: Confusing Taq polymerase with DNA polymerase I, which is heat‑labile.
Concept tested: PCR enzyme selection
Published · How this solution was prepared and checked
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