You and your lab partner have isolated a strand of DNA which you wish to amplify. You decide to carry out a polymerase chain reaction. Describe the 3 main temperature changes that occur and what key events happen at these stages.

The polymerase chain reaction (PCR) involves many cycles of heating and cooling in order to amplify a section of DNA. You initially heat the DNA to 92C: this denatures you double-stranded DNA so that you have two single stranded templates. You then cool the DNA to 55-65C: this allows your primers to anneal to the complementary single strands. Finally you heat it to 72*C: this allows taq polymerase to extend the primers and synthesise the new DNA strands.