Question

which of the following statements accurately describes why taq polymerase is used in pcr?

• it is heat stable and can withstand the heating step of pcr.
• only minute amounts are needed for each cycle of pcr.
• it binds more readily than other polymerases to the primers.
• it has regions that are complementary to the primers.

Explanation:

To determine why Taq polymerase is used in PCR, we analyze each option:

• The first option: PCR involves a heating step (denaturation) to separate DNA strands. Taq polymerase is a thermostable enzyme (heat - stable) from a thermophilic bacterium, so it can withstand the high temperatures of the PCR heating step. This is a key characteristic for its use in PCR.
• The second option: The amount of Taq polymerase needed isn't the main reason for its use in PCR. Other polymerases also don't require large amounts, so this is not the correct explanation.
• The third option: Binding to primers is not the unique or main reason for using Taq polymerase. Other polymerases can also bind to primers, so this is incorrect.
• The fourth option: Taq polymerase does not have regions complementary to the primers. Primers are complementary to the target DNA sequence, not the polymerase, so this is incorrect.

Answer:

A. It is heat stable and can withstand the heating step of PCR.