What separates the strands of $DNA$ in the Polymerase Chain Reaction ($PCR$) technique?

• A. Helicase enzyme
• B. High temperature
• C. RNA primer
• D. DNA ligase

Answer: (B)

Verified step by step guidance

1. Understand the Polymerase Chain Reaction (PCR) process: PCR is a technique used to amplify specific DNA sequences, making millions of copies of a particular segment of DNA.
2. Identify the role of strand separation in PCR: The separation of DNA strands is crucial for the replication process, allowing primers to bind to the single-stranded DNA and initiate synthesis.
3. Recognize the method used for strand separation in PCR: Unlike cellular DNA replication, which uses helicase enzymes to separate strands, PCR relies on high temperatures to denature the DNA.
4. Explain the denaturation step in PCR: During the denaturation step, the reaction mixture is heated to a high temperature (usually around 94-98°C), causing the hydrogen bonds between the DNA strands to break, resulting in two single strands.
5. Clarify why high temperature is used instead of enzymes: High temperature is a practical method for strand separation in PCR because it is efficient and can be easily controlled in a laboratory setting, unlike enzymatic processes which require specific conditions and additional components.