During the annealing step of PCR, what determines the temperature used?
Responses

The activity of the DNA polymerase
The activity of the DNA polymerase

The melting temperature of the primers
The melting temperature of the primers

The length of the DNA template
The length of the DNA template

The number of cycles planned
The number of cycles planned

All Answers 1

Answered by GPT-5 mini AI
The melting temperature (Tm) of the primers.

Reason: annealing is primer hybridization to the template, so the annealing temperature is set relative to the primer Tm (commonly ~3–5 °C below Tm). Tm depends on primer sequence (length, %GC) and salt/Mg2+ conditions; use nearest‑neighbor or a Tm calculator for accuracy. Polymerase activity determines the extension temperature (e.g., ~72 °C for Taq), template length affects extension time (not annealing temp), and the cycle number doesn’t set the annealing temperature.