Question

Which of the following steps is catalysed by Taq polymerase?

• A. Denaturation of template DNA
• B. Annealing of primers to template DNA
• C. Extension of primer end on the template DNA
• D. Maintainence of high temperature during PCR

Answer 1

Answer: (C)

Taq polymerase is used in polymerase chain reaction (PCR).

PCR is a method of amplifying DNA sequences. There are several steps involved in the process:

1. Denaturation: The two strands of the DNA are separated due to high temperature (${94}^{o}C$)
2. Annealing: Primers are annealed to the template DNA strands to initiate replication process
3. Extension: DNA polymerisation and extension of the primer end on the template strands of the DNA using Taq polymerase happen in this step

Taq polymerase is a DNA-dependent DNA polymerase which is unique in carrying out DNA polymerisation reaction at high temperatures (thermostable polymerase).