Point number one is we begin at the amino acid that is at the terminal carboxyl end, and we take this amino acid and we attach it onto a solid surface. We basically anchor our amino acid on that solid surface and we continually attach amino acids one at a time. And that entire growing polypeptide chain is attached onto a solid surface. And that's to keep that protein, the polypeptide, from actually being washed away. Because as we add each amino acid, we essentially wash our solution to basically remove all the unwanted things from that solution. And so we want to anchor that growing polypeptide and keep it in place.