The branch of pharmacology concentrating on drug biotransformation and the biochemical aspects of drug metabolism and drug action at a cellular or subcellular level.

A reference to the career field of science that deals with the chemical substances that occur in living organisms, the processes by which these substances enter in living organisms, the processes by which these substances enter into or are formed in the organisms and react with each other and the environment, and the methods by which the substances and processes are identified, characterized, and measured.

An electrochemical energy source in which electricity is generated chemically by the oxidation of biological substances.

1. The amount of dissolved oxygen (DO) consumed by micro-organism in the biochemical oxidation of organic and inorganic matter; a commonly used measurement to determine water quality, since the amount of oxygen used is an indicator of the level of organic waste that is present.
2. The standard measurement for determining the level of organic pollution in a sample of water.
3. The oxygen required by aerobic organisms; such as, those in sewage, for metabolism.

It is the amount of oxygen used by micro-organisms feeding on the organic material over a given period. Sewage effluent must be diluted to comply with the statutory BOD before it can be disposed of into "clean" rivers.

The use of chemical characteristics to help classify organisms; for example, the Asteroideae and Cichorioidae, which are the two main divisions of the plant family Compositae, are separated by the presence or absence of latex.

The area of taxonomy has increased in importance with the development of chromatography, electrophoresis, serology, and other analytical techniques.