Lesson eLearning

Which DNA polymerase is most commonly employed in PCR due to its ability to remain active after repeated high‑temperature denaturation steps?

easy MCQ 1 mark Class 12 · Biology · Biotechnology and Its Applications
  1. T4 DNA polymerase
  2. Taq DNA polymerase
  3. DNA polymerase I
  4. Pfu DNA polymerase
Answer
Taq DNA polymerase

The correct answer is Taq DNA polymerase — Answer: Taq DNA polymerase.

Step-by-step solution

  1. Identify the requirement for a thermostable DNA polymerase that can withstand the denaturation step of PCR.
  2. Recognise that *Taq* DNA polymerase from *Thermus aquaticus* is naturally thermostable and can be repeatedly activated at 94–95°C.
  3. Note that *Taq* also has high processivity and is commercially available at low cost.
  4. Conclude that *Taq* is the enzyme most frequently used in standard PCR protocols.
  5. Answer: Taq DNA polymerase.
Common mistake: Thinking of T4 DNA polymerase or DNA polymerase I

Concept tested: PCR polymerase selection

Published · How this solution was prepared and checked

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