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. Now, what our RNA polymerase does is it binds onto that DNA molecule and it reads the DNA template from the three to the five end and that means it builds it from the five to three end. So this is the RNA chain that the RNA polymerase already built. So let's imagine that inside this chain we have N number of nucleotides and this is the N plus one nucleotide that is being added onto that growing RNA chain.