Peptide Bond formation between successive amino acids

Note that the amino end on the second (R2) amino acid is added to the carboxyl end of the first (R1) amino acid. The amino terminus of the R1 amino acid remains unchanged, and polypeptide grows in the NC direction.
The repeating N - C(R) - C subunit remaining after the dehydration reaction is an amino acid residue.

Figure after © 2010 PJ Russell, iGenetics 3rd ed.; all text material © 2011 by Steven M. Carr