Amino Acids

Amino acids are organic molecules that have at least two functional groups. The diagram below is the ball and stick model for a generic amino acid:

Amino acids have two functional groups:

  • On the left-hand side of the diagram is the amino group (-NH2)
  • On the right-hand side of the diagram is the carboxylic acid group (-COOH)

There are around 20 naturally occurring amino acids, which all have the same general structure. Amino acids are polymerised in cells to form peptides, which can fold into complex shapes or combine with other peptides to form proteins.

As amino acids have two functional groups, they can react to form a condensation polymer. For example, the two glycine molecules can react to form poly(glycine) and a molecule of water. This reaction is called condensation polymerisation.

As the amino acids in this polymer are linked by peptide bonds, it is a polypeptide. We can continue to add more glycine molecules to form a longer chain of polypeptides.