The polymerase chain reaction cycle is a three-step process that includes denaturation, annealing and elongation. This cycle is used to amplify a specific gene from a copy of DNA. It is used in forensics to isolate blood at crime scenes to determine if suspects were present during the crime.
The first step of the cycle is denaturation. This step heats and separates the strands of DNA. The second step is annealing. This step is used to attach primers and polymerase to strands of DNA. The third step is elongation. This step continuously adds a base after each primer to completely synthesize a new DNA strand. The steps in this cycle are repeated up to 35 times to produce a large quantity of DNA samples. Although there is an initialization step before denaturation and a final elongation step after elongation, these steps are not repeated during the cycle.