Question

Which of these statements about Taq polymerase used during PCR is not correct?

• A. It is used for primer extension to synthesise a new DNA strand
• B. It is a thermostable enzyme and can survive temperatures up to $125^{\circ }$
• C. It is obtained from Thermus aquaticus
• D. Its addition eliminated the need to add fresh polymerase in every PCR cycle

Answer 1

Answer: (B)

Taq polymerase is a thermostable DNA polymerase found in thermophilic bacteria Thermus aquaticus. Its optimum temperature for activity is approx. $75^{\circ }$-$80^{\circ }C$. Taq polymerase is well-suited for PCR because it is able to withstand the temperature of up to 95°C required for DNA strand separation without denaturing.