Prelude
One of the most fascinating and well-known stories in science is that of the discovery of the structure of DNA, which was accomplished by James Watson and Francis Crick in 1953, when both were young men working at Cavendish Laboratory in Cambridge, England. Watson's autobiographical book, The Double Helix, describes that period of accomplishment, but it retains its popularity because it deals directly with a more general theme. It might be the best description for modern readers of the magical quality of science and its appeal for young people seeking adventure, mystery, and fame. In this way, the story of DNA, beginning with its unveiling, has been linked to romance, celebrity, and power.
DNA, the most famous of the family of biological polymers called nucleic acids, is worthy of this glamour. Nucleic acids are the key information storage molecules of life. Genetic information is encoded within the nucleic acids of almost every cell in our body, where it is capable of being inherited from one cell to the next, generation after generation. The study of nucleic acids is multifaceted: It involves examination of the structure and function of nucleic acid polymers, the capacity of these molecules to hold information, the changes in information content that happen upon modifications of nucleic acids, the diverse roles of nucleic acids in the life of a cell, and the characteristics that make them useful tools in biomedical engineering. In fact, as in many other areas of science and technology, the use of the nucleic acids DNA and RNA is becoming central to the work of biomedical engineers. The biological polymers called nucleic acids were introduced in Chapter 2; this chapter will expand on that introduction, showing how nucleic acids work to store genetic information and perform other essential biochemical functions.
DNA is intimately involved in human health. Many diseases result from failures at the DNA level.