PCR steps: denaturation, annealing, extension
What happens during the annealing step of PCR?
Answer C: explanation for every choice
A
Strand separation is the denaturation step.
B
Extension by Taq polymerase is the extension step.
C
Correct. The temperature is lowered, typically to about 50–65 °C, so primers can bind the template.
D
Reverse transcription is the first step of RT-PCR, not a step of each PCR cycle.
TakeawayDenature (~95 °C) → anneal (~50–65 °C) → extend (~72 °C).
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb48.