
8
Stochastic effects in biological control systems
8.1 Introduction
At macroscopic scales, the processes o f life appear highly deterministic. At
molecular scales, however, biological processes are highly stochastic, due both
to the cellular environment and the nature of information flows in biological
networks. The effects of these stochastic variations or noise are neglected
in deterministic chemical rate equatio ns (and their corresponding differ ential
equation models) and this is reasonable, because in most cases such effects dis-
appear when they are averaged over lar ge numbers of molecules and chemical
reactions.
In the case of biological proc e s