So these are the four main ingredients. Now, the next question is what exactly are the steps and how many steps are there within a single cycle of PCR? So basically, if we take a single PCR cycle, we can break that cycle down into three different steps. So in one PCR cycle, we have three different steps. Step number one, we call DNA strand separation. Step number two is the hybridization of the DNA primers onto that DNA that we want to replicate.