Biochemistry is the study of the molecules and chemical reactions of life.
The defining feature of biochemistry is that it uses the principles of chemistry to explain biology at the molecular level. Biochemistry is a relatively new area, less than a hundred years old, but advances are occurring at a remarkable rate for several reasons. We now understand many central processes of life. These discoveries include the structure of DNA and the flow of information, the unraveling of central metabolic pathways, and the structure and function of many proteins. We now understand molecular patterns which are common to diverse expressions of life in simple and complex organisms, including plants and animals.