This means that DNA polymerases rarely make mistakes and when they do, they can fix the mistakes on their own. So let's take a look at the following diagram which basically describes how we form the phosphor diaster body. And as we discuss this, we can imagine that the DNA polymerase molecule hovers about this position and catalyzes the formation of this phosphodiastor bond. So here we have the DNA template that we're going to use to basically pair up the correct complementary basis. And this template is needed to actually form that polynucleotide chain correctly. So this is the DNA template, this is the three end and this is the five end.