This is Glycine the simplest Amino Acid. It has two hydrogens attached to its central carbon. Is is the only Amino Acid that does not have stereo isomers. On one end is an Amine group, consisting of a nitrogen (in blue) and two hydrogens (yellow). On the other end is a Carboxyl group. Carboxyl groups are characterized by a carbon attached double bonded to a oxygen and single bonded to a hydroxyl group. The Caboxyl group releases hydrogens and therefore is acidic.
Amino Acids engage in condensation reactions with each other forming peptide bonds. Chains of many Amino Acids are called Polypeptides because of these bonds. Amino Acids are the building blocks of Proteins