  Recently, the bond lengths of the molecular components of nucleic acids and
of caffeine and related molecules were shown to be sums of the appropriate
covalent radii of the adjacent atoms. Thus, each atom was shown to have its
specific contribution to the bond length. This enabled establishing their
atomic structures for the first time. In this work, the known bond lengths for
amino acids and the peptide bond are similarly shown to be sums of the atomic
covalent radii. Based on this result, the atomic structures of all the twenty
essential amino acids and a tripeptide have been presented.
