Coherence in Biology

The great success of molecular biology arises from the establishment of the atomic structure of biological systems such as DNA or proteins. The activity of these systems does, however, not follow in a simple way from structure as it frequently can be switched on or off. Prom the point of view of physics this must be expressed in terms of non-linear excitations. Quite different types of excitation often have common general features which has given arise to Haken’s synergetics [l]. Establishment and maintenance of such excitations requires the supply of energy. Energy supply, in general, leads to heating. In cases which are of biological interest, however, metabolic energy supply leads to the establishment of organisation, Prigogines’s dissipative structures [2]. Whether the One or the other holds must be investigated in detail for each system. No general rule has been found, so far, which would permit a decision between the two possibilities from structure only.