And so what that does is now in step four, if we mix this molecule here with this molecule here, this carbon will be activated to form a peptide bond by the DCC molecule. And because this nitrogen will be missing that Tbag group, it will be very likely to form that peptide bond. And this nitrogen, because we still have the Tbock attached here, it will not be reactive at all. And so in step four, the activated amino acid that is also blocked by that Tbox. So the molecule we form in step number one is then mixed with amino acid attached onto that solid surface that we form in step three. And this forms a peptide bond.