1 Using information stored in DNA

One important property of DNA is that it carries genetic information in the simple coding language of just four bases. These bases, which can be arranged in a huge variety of sequences, represent a vast potential store of information. In this course, we consider how this information is used by the cell. The key structural feature of complementary base pairs, which plays an important role in both stability and replication, is also the basis for how DNA functions as genetic material.

How does the simple coding language of DNA relate to the nature of the gene; that is, how do genes function? Genes, composed of DNA, specify proteins. How genes do this is the topic of this course. The essence is that the structure of DNA can be related directly to the structure of proteins, which come in a huge range of sizes and shapes, and this diversity arises from different combinations of just 20 amino acids. In the text that follows we will examine how the simple coding language of just four letters (bases) in DNA contains information for thousands of different proteins, each with its own unique sequence of amino acids.

The production of proteins is a far more complex process than the more straightforward process of DNA replication, partly because many other molecules are involved. Below we will review the overall process and then go on to examine each step in turn.