Question

Which of the following is NOT true about Taq DNA polymerase?

Select one:

a. It can act as an exonuclease to cut single-stranded DNA

b. It adds nucleotide triphosphates to form a new DNA strand

c. It functions at extremely high temperatures

d. It requires a salt environment (buffer) to work

Answer 1

Question:

Which of the following is NOT true about Taq DNA polymerase?

Select one:

Answer:

a. It can act as an exonuclease to cut single-stranded DNA

Explanation:

Taq DNA polymerase (Taq pol) is a type of DNA polymerase which commonly used in Polymerization Chain Reaction (PCR). In the third step of PCR, Taq polymerase forms a new DNA strand by adding nucleotide triphosphates. Taq polymerase is a DNA synthesizing enzyme which can able to work at high temperature (upto 90-95 degree Celsius). In the third step of PCR the synthesis of new DNA is done at 70-72 degree Celsius which is optimal for its activity. Taq polymerase requires a salt environment (buffer) to work. Thus, option ‘b’, ‘c’ and ‘d’ are true.

As, Taq polymerase does not have the 3’ to 5’ exonuclease activity it can’t act as an exonuclease to cut single-stranded DNA. Thus, option ‘a’ is NOT true.