The approach of viewing complex biochemical phenomena as autocatalytic relaxation processes has been introduced previously (Liquori & Tripiciano, 1980; Liquori & Florio, 1985). In the present work this formalism is extended from its original framework regarding cell growth, to the problem of genetic expression. The case of the heat-shock response in organisms ranging from man to bacteria is discussed. Finally, we give some biochemical examples in which the new approach underlines evident temporal co-operativity.