An 'Anatomy' Lesson An 'Anatomy' Lesson Amino acids are the molecular units that make up proteins .
All proteins are various compositions of twenty specific naturally occurring amino acids.
Let's investigate what chemical groups constitute an amino acid. Firstly, click here to acquire a picture of the amino acid called alanine . Towards the left of the amino acid image is the amine group . This is also attached to the alpha carbon, and is protonated in solution as conveyed in the image. Towards the right of the amino acid image is the carboxylic acid group .