Proteins are made from amino acids. An amino acid has three parts that are joined to a central carbon atom. Identify the three parts that create an amino acid. amino group fatty acid carboxyl group R group C group A chain of 2 carbon atoms and a nitrogen atom is shown. The middle carbon atom is bonded to a hydrogen atom and an R group. The other carbon atom is double-bonded to an oxygen atom and single-bonded to a hydroxyl group. The nitrogen atom is bonded to 2 hydrogen atoms.