Why is a heat-stable DNA polymerase used in the polymerase chain reaction (PCR)?

Answer and explanation

Correct answer: D. It survives the heat used to separate the strands

  1. Step 1: PCR heats DNA to about 95 °C to break hydrogen bonds between strands.
  2. Step 2: An ordinary polymerase would be denatured, so a heat-stable one is used.
Answer
It survives the heat used to separate the strands.
Why not the others: It works only at 20 °C: it works at about 72 °C. It separates the strands without heat: the strands are separated by heating to about 95 °C. It copies RNA into DNA: this is reverse transcriptase.

Practise more Cell Biology, Metabolism and Genetics.

Free questions with an explanation for every one, and full timed Scottish Highers mock tests.

All Cell Biology, Metabolism and Genetics questionsTake a mock test

More Cell Biology, Metabolism and Genetics questions