The main factor that makes amino acids unique from one another is the R group, also known as the side chain. The R group differs in structure and composition for each amino acid, which gives them distinct properties. The carboxyl group and the amino group, while important for the chemical structure of amino acids, are common to all amino acids and do not contribute to their uniqueness. The long strands of glucose molecules are unrelated to amino acids and do not play a role in their differentiation.
