What is the correct order for one cycle of polymerase chain reaction (PCR)?
Understanding the Steps in Polymerase Chain Reaction (PCR)
Denaturing: The first step in PCR involves denaturing the double-stranded DNA. This is done by heating the DNA to around 95°C, which separates the strands into single strands.
Annealing: After denaturation, the temperature is lowered to about 50-65°C. During this step, the primers that match the target sequence anneal or bind to the single-stranded DNA.
Extension: The final step in one cycle of PCR is extension. At a temperature of around 72°C, the enzyme Taq polymerase extends the primers by adding nucleotides to synthesize a new strand of DNA.
These three steps - denaturing, annealing, and extension - are repeated multiple times (usually 25-40 cycles) in a PCR machine to amplify the desired DNA segment exponentially.