Biochemists study the chemistry of life. Living things exhibit a large varitey of activities: eating; sleeping; moving; talking; thinking . The unique chemical reactions behind these activities are due to biomolecules which contain specific functional groups.

A functional group is a group of atoms within a molecule, which makes it react in a certain way - gives it its chemical character. Biological molecules often have more than one functional group.

Proteins are of extreme importance in living things. Like carbohydrates and fats, they can be used as a source of energy, but they are much more complex molecules. As well as carbon, hydrogen and oxygen, proteins also contain nitrogen; many also contain sulphur; some contain other elements.

There is a wide variety of proteins and they differ in many ways, however they all have one thing in common. They all contain amino acids. They contain two functional groups; the carboxylic acid group:

and the amine functional group:

The simplest amino acid is glycine:

Bibliography

Martin, D. & Sampugna, J. Molecules in Living Systems (New York: Harper & Row, 1973).