So if we use this special heat resistant DNA polymerase, we place it into our mixture and we bump the temperature back up to about 72 degrees Celsius. This is the optimal temperature for this special heat resistant thermosilic DNA polymerase that is called TAC DNA. Now, what the polymerase does, like any polymerase, it uses those primers, it begins at the primers and it moves from the five to the three end to basically synthesize and replicate that DNA molecule. So that is shown in the following diagram. So, once again, step three. The cooled solution at 54 degrees Celsius is heated to a temperature of 72 degrees Celsius.