ABSTRACT
Chemical transformations that consume and liberate energy are one of the hallmarks of living systems. Living cells follow the same principles of conservation of matter and energy as do all other physical systems, though they also operate under an additional set of constraints imposed by their evolutionary history. Much of business of cellular life involves transformations of energy. Most familiar organisms make their living by eating other living or freshly dead things, thereby consuming energy-carrying organic molecules that have been generated and shepherded by other living organisms. One of the important characteristics of the cellular interior that makes it so different from the world of our everyday experience is the fact that thermal and deterministic forces are on an equal footing. A useful way to envision the energetic transformations during glycolysis is to picture each molecular species as having a characteristic energy and, as glucose goes through its series of transformations, molecule travels up and down on hilly energy landscape.
