ABSTRACT
This chapter describes the structure of deoxyribonucleic acid (DNA). It presents a broad overview of DNA and how it is packaged into chromosomes. The discovery of the structure of the DNA double helix was a landmark in twentieth-century biology because it immediately suggested answers to both questions, thereby providing a molecular explanation for the problem of heredity. The genomes of eucaryotes are divided up into chromosomes, and in this section we see how genes are typically arranged on each chromosome. The packaging of selected regions of eucaryotic genomes into different forms of chromatin makes possible a type of cell memory mechanism that is not available to bacteria. The chapter examines the structure of the DNA molecule and explain in general terms how it is able to store hereditary information. It discusses the specialized proteins that make this type of packaging possible.
