Sunday, 12 June 2011

Chance and Necessity - Jacques Monod II

The curve showing the variation of activity as dependent upon concentration of an effector (including the substrate) is almost always S-shaped. In other words the effect of the ligand at first increases faster than its concentration. This behaviour is the more remarkable in that it appears to be characteristic of allosteric enzymes.In ordinary "classic" enzymes, on the contrary, the effect increases more slowly than the concentration p68.
Foundation of the S-systems idea of Voit.

 For example: in state R the protein will be able to recognize and therefore to bind compound alpha at one site (but not compound beta), whereas in state T it will recognize and bind compound beta but not alpha. It follows that either compound will have the effect of stabilizing the protein in this or that of its two states, R or T, at the expense of the other; and that alpha and beta will be mutually antagonistic, since their respective interactions with the protein are mutually exclusive p70.
This might be a way of getting an XOR relationship.
There is no chemically necessary relationship between the fact that beta-galactosidase hydrolyzes beta-galatosides, and the fact that its biosynthesis is induced by the same compounds. Physiologically useful or "rational" this relationship is chemically arbitrary - "gratuitous" one might say. This fundamental concept of gratuity i.e. the independence, chemically speaking, between the function itself and the nature of the chemical systems controlling it  - applies to allosteric enzymes... enabling an interaction, positive or negative, to come about between compounds without chemical affinity, and thereby eventually subordinating any reaction to the intervention of compounds that are chemically foreign and indifferent to this reaction. p77.
This implies the generation of a hierarchy of levels of cybernetic control. It also suggests lots of possibilities for co-evolution of processes and regulation.
only failure awaits attempts to reduce the properties of a very complex organisation to the "sum" of the properties of its parts. A most foolish and wrongheaded quarrel it is, merely testifying to the "holists" profound misappreciation of scientific method and of the crucial role analysis plays in it. If a Martian engineer were trying to understand one of our earthling computers, how far could he conceivably get were he, on principle, to refuse to dissect the basic electronic components which in the machine execute the operations of propositional algebra? If any one branch of molecular biology illustrates better than others the sterility of holist theses as against the cogency of analytical method, it is indeed the study of these microscopic cybernetic systems.. p 79.
Monod is partly right and partly wrong the point is that the arrangement of the microscopic components is not embedded in the components themselves.
And even though these analyses are not yet near to furnishing us with a complete description of the cybernetic system of the simplest cell, they tell us that, without exception, all the activities that contribute to the growth and multiplication of that cell are interconnected and intercontrolled directly or otherwise. On such a basis, but not that of a vague "general theory of systems," does it become possible for us to grasp in what very real sense the organism does effectively transcend physical laws - even while obeying them - this achieving at once the pursuit and fulfilment of its own purpose.   
This is just an attack on Bertalanffy who is referenced for General Systems Theory. It is not actually presenting any kind of alternative framework and it is also contradictory.

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