What makes amino acids unique from one another

An amino acid is an organic molecule that is made up of a basic amino group (−NH2), an acidic carboxyl group (−COOH), and an organic R group (or side chain) that is unique to each amino acid. ... Each molecule contains a central carbon (C) atom, called the α-carbon, to which both an amino and a carboxyl group are attached.

The R-groups are different and unique

italy's population growth rate is almost at zero, the national statistics agency, istat, said on monday, mainly due to a dwindling birth rate.