Question

In PCR, it is important to use Taq DNA polymerase, as opposed to other DNA polymerases. This is because Taq is capable of synthesizing DNA _________.

A. at 55°C
B. at 94°C
C. from user-provided DNA and primers
D. after exposure to 94°C

Answer 1

Taq DNA polymerase is essential for PCR because it remains active after exposure to high temperatures, specifically after exposure to 94°C, which allows it to withstand the thermal cycling required for DNA amplification.

Step-by-step explanation:

In PCR (polymerase chain reaction), it is essential to use Taq DNA polymerase because it is capable of synthesizing DNA after exposure to 94°C. Taq DNA polymerase is a thermostable enzyme derived from Thermus aquaticus, a bacterium that thrives in hot springs. The enzyme remains active after being exposed to the high temperatures used in PCR, unlike other DNA polymerases which would denature under such conditions. Its optimal activity is at 72°C, within the temperature range of 22°C to 89°C.

Taq polymerase's unique thermostability allows it to synthesize new DNA strands from user-provided DNA and primers without being replaced after each cycle, significantly streamlining the PCR process.