And notice that this oxygen is actually lost and that's because we also form a molecule known as dicyclohexyluria. And so what happens is this entire molecule is essentially broken off to form this stabilized molecule that is resonance stabilized between this nitrogen, this nitrogen and this oxygen. And so this is the first peptide bond that is formed in our polypeptide chain. Now, if we repeat step number three and step number four many times, we essentially can add many of these amino acids onto our growing polypeptide chain. So each time we essentially want to remove the TBA group and then we want to add this molecule here. So for instance, in the next step here, we say repeat many times.