Question

Annealing step of PCR, operates at ______°C.

• A. 90 - 98
• B. 40 - 60
• C. 70 - 75
• D. 100 - 120

Hint:

Annealing temperature is optimized based on primer sequence to ensure specific binding in PCR.

Answer 1

The Correct Option is B

Step 1: In polymerase chain reaction (PCR), the annealing step involves primers binding to the single-stranded DNA template. This occurs at 40–60°C, depending on the primer’s melting temperature. Step 2: Denaturation occurs at 90–98°C, extension at 70–75°C, and 100–120°C is too high for standard PCR steps.