University of Central Florida (UCF) Biomedical Exit Practice Exam

A peptide bond covalently links amino acids in proteins. It forms by a condensation reaction between the carboxyl group of one amino acid and the amino group of the next, releasing a molecule of water. This creates a -CO-NH- linkage along the backbone, giving the polypeptide its directional sequence from N-terminus to C-terminus. The peptide bond has partial double-bond character from resonance, making it planar and limiting rotation, which helps determine the protein’s overall shape. Other types of bonds—like hydrogen bonds, ionic interactions, or glycosidic linkages—do not serve as the main linkage between amino acids in the polypeptide chain.