Encyclopedia of Physical Science and Technology - Biochemistry - 3rd Ed

BIOENERGETICS, an amalgamation of the term biological energetics, is the branch of biology and biochemistry that is concerned with how organisms extract energy from their environment and with how energy is used to fuel the myriad of life’s endergonic processes. Organisms may be usefully divided into two broad groups with respect to how they satisfy their need for energy. Autotrophic organisms convert energy from nonorganic sources such as light or from the oxidation of inorganic molecules to chemical energy. As heterotrophic organisms, animals must ingest and break down complex organic molecules to provide the energy for life.