Question

A PCR machine can raise the temperature up to 100°C but after that, it is not able to lower the temperature below 70°C automatically. Which step of PCR will be hampered first in this faulty machine? Explain why?

Answer 1

i. If a PCR machine fails to lower the temperature below 70°C then the annealing step (in which primers attach to the respective ends of the DNA template) would be affected.

ii. The annealing step of PCR requires a temperature ranging between 40°C to 60°C therefore if a PCR machine fails to lower the temperature below 70°C, primers will not attach to the DNA templates.