This package is primarily aimed at medical students without 'A'-level Biology, but is also suitable for students in Biochemistry and related subjects. It may also be suitable as an introduction to gene expression for any students. The content consists of an introduction to cell structure (with diagrams and electron micrographs); an introduction to proteins, lipids and nucleic acids; DNA replication, transcription and translation (illustrated with animations of these processes). A glossary of scientific terms is provided, linked to hot words in the text, so that the user can easily jump to the glossary and then return to the tutorial.