Biochemistry is the central science because it is involved in every aspect of life. Much of what we have learned about organic chemistry thus far is related to how things work chemically, how diseases can be treated at the molecular level
with small molecules, and how we can create new compounds and materials that improve our daily lives. One of the most interesting of the many applications of organic chemistry is its ability to solve critical challenges in identification through DNA matching. Studying the structure of genes and DNA, scientists can determine genetic relationships between different species (and hence the course of evolution) or between people. They can also identify the remains of individuals through DNA matching, a valuable tool if there are no other physical means to make such an identification. In fact, DNA, the genetic material, is the key to all this work. DNA is the chemical fingerprint in every tissue of every individual. With the use of chemistry involving fluorescent dyes, radioactive isotopes, enzymes, gel electrophoresis, and a process called the polymerase chain reaction (PCR) that earned its inventor the 1993 Nobel Prize in Chemistry, it is now easy to synthesise millions of copies of DNA from a single molecule of DNA, as well as to sequence it rapidly and conveniently. To understand just how this amazing process works, we need to understand this final class of biomolecules in much more detail.