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. 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 that are common to diverse expressions of life in simple and complex organisms, including plants and animals. We now understand molecular causes of many diseases and this helps in the diagnosis and treatment of many health problems.