what groups of atoms are common to all amino acids?

Answer 1

In every amino acid, the central asymmetric carbon is bonded to an amino group, a hydrogen atom, and a carboxylic acid group; only the side group is variable, and each of the 20 amino acids has its own distinctive side group that confers on the molecule its identity and much of its uniqueness of chemical reactivity.

Answer 2

the amine and carboxyl groups