Students should be able to describe the structure of DNA and define genome. • The genetic material in the nucleus of a cell is composed of a chemical called DNA. DNA is a polymer made up of two strands forming a double helix. The DNA is contained in structures called chromosomes. • A gene is a small section of DNA on a chromosome. Each gene codes for a particular sequence of amino acids, to make a specific protein. • The genome of an organism is the entire genetic material of that organism. The whole human genome has now been studied and this will have great importance for medicine in the future. • Students should be able to discuss the importance of understanding the human genome. This is limited to the: search for genes linked to different types of disease; understanding and treatment of inherited disorders; use in tracing human migration patterns from the past.