And two types of atoms that work in this particular case are magnesium so, Mg and Manganese MN. And the reason we need this metal atom is because it acts as a cofactor, it increases the efficiency of this enzymes activity. Now let's take a look at the following diagram that basically describes in detail how that bond is formed. And notice this phosphodiasta bond is formed in a very similar way to how the phosphodiesta bond is formed when DNA polymerase replicates that DNA molecule. So in this particular case, this is our DNA template that the RNA polymerase molecule is actually using. So this is the three end and this is the five end.