Basic Biology - Molecules of life - Small Molecules

Small molecules - amino acids

These can be the building blocks of the macromolecules or they can have independent roles, such as signal transmission or a source of energy or material for a cell. Some important examples besides water are sugars, fatty acids, amino acids and nucleotides.

For instance, biological cell membranes are constructed from fatty acids, into which macromolecules are embedded. There are 20 different amino acid molecules, which are the building blocks for proteins.

The above image shows the basic composition of all amino acids. The amino acids differ by R side chain molecules which define the interaction properties of the amino acid. The amino acids link together in a specific order to form a protein. The order in which these amino acids are linked and the properties of each of these amino acids determines the 3D structure of the protein.

There is a convention that each amino-acid is denoted by a letter in the Latin alphabet, for instance arginine is denoted by R, histidine by H, lysine by L and there are 20 such letters.

General information about amino acid and nucleotide properties.


Next we will look at protein molecules >>>