And one other important property of the polymerase chain reaction is the fact that it takes within a given beaker, within a given closed container. So what that means is after the first cycle takes place, we don't actually have to add anything into that mixture because the mixture has all the ingredients from the beginning. So after one cycle takes place, all we have to do is we have to bump up the temperature back to 95 degrees Celsius to restart cycle number two. So what that means is if cycle number one took place and we form these two double stranded DNA molecules, all we have to do to restart the cycle is to increase the temperature to 95, and then these two DNA will begin separation. And then all we have to do is change the temperature to 54. So cool the solution to go to step number two of cycle two, and then to get to step three, we have to bump the temperature back up to 72 Celsius to basically make sure that DNA synthesis takes place.