Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In Polymerase Chain Reaction (PCR), a thermostable DNA polymerase is used instead of an ordinary DNA polymerase. Reason (R): The thermostable DNA polymerase denatures during the high temperature step but regains its catalytic activity during the extension step. In the light of the above statements,

Step-by-step solution

The Assertion is true. PCR requires heating the reaction mixture to a high temperature (around 94^ C ) to separate the double-stranded DNA. An ordinary DNA polymerase would be permanently destroyed by this heat, so a thermostable DNA polymerase (such as Taq polymerase) is used. The Reason is false. The thermostable DNA polymerase does not denature and then regain activity; rather, it remains active and structurally intact during the high temperature induced denaturation of double-stranded DNA. Therefore, Assertion