Tuesday, October 11, 2005

On origin of life and need of DNA for a starter

The origin of life doesn't need a system enclosed by membranes in fact it would require a system as open as possible so the probability of different chemical species meet would be greater. The origin might be of multiple different molecules being interchanged by each other in equilibrium however the presence of some of them could act as catalysts (although weak) and this process might have lead to the eventual formation of chains where the substance A catalyzed the transformation of B into C (and vice versa) and the substance C catalyzed the convertion of a substance D into A and as long as B and D are abundant there will be an increase in the amount of A and C: an autocatalytic system that can be the precursor of life itself.

The system is easier to create when there are many more susbtances in the pool so the probability of making a closed chain becomes bigger and eventually the system becomes autocatalytic. The existence of membranes might have appeared later when the control of the input and output of substances into the system became more important than the diversisty of substances available (we can imagine that there's an equilibrium between a too big number of different substances are now required to stay together and that would be scattered away without the presence of some physical limitation (after all the membranes are catalysts as well since they keep the metabolites whithin a closed region of space)).

So life might have started before the advent of DNA or RNA or any other form of information storage system as predicted by Shroedinger. An information carrier might have appeared only after a mapping code started to be used in order to better control the metabolism, in fact the advent of a mapping system in only an extension of the process of adding intermediates into a chain reaction in order to provide autocatalysis.


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