Living matter is a direct sequel of the chemical level of organization. It is not invariant to its chemical composition; the material determines key properties of life.
Chemical reactions in living systems are cyclic and autocatalytic. According to the hypothesis of S. Kauffman (1993), big chemical systems of interacting polymers, which reach a critical level of complexity, necessarily become autocatalytic and self-replicating. Their elaboration can be ordered by natural selection. As examples of autocatalytic reactions, one can consider Calvin's cycle ('propagation of sugar phosphates') or replication of ATP, also connected with photosynthesis. The cyclic chemical reactions discovered by A. Szent-Gyorgyi and represented by the famous Belousov-Zhabotinsky reaction can play the role of 'soft clocks' in living organisms.
Life is a positive connection between information molecules and proteins. The most important chemical cycle is the following: DNA produces enzymes, which, in their turn, ensure its replication.
Organic macromolecules are not thermodynamic objects; they have no aggregate state and are naturally far from a steady state. It is a prebiological stage of matter development. According to Schrodinger's simile, a living organism as well as a pendulum clock are not thermodynamic objects; because of solidity of the clock and stability of the hereditary substance of the organism, room temperature for them is practically equivalent to zero.
Polymerization as well as enzymes decrease entropy, and thereby decrease molecules' freedom to move and select their co-reactants. A principal difference of life chemistry from ordinary one is the matrix synthesis. For living matter, contrary to inanimate one, a strict order of extremely long chain of reactions is possible.
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