Talk:Protobiont
From Wikipedia, the free encyclopedia
 |
This article is within the scope of the Molecular and Cellular Biology WikiProject. To participate, visit the WikiProject for more information. The current monthly improvement drive is Signal transduction. | ||
|
Article Grading: The article has not been rated for quality and/or importance yet. Please rate the article and then leave comments here to explain the ratings and/or to identify the strengths and weaknesses of the article.. |
|||
Here I had started an exension, if it could be of any help for anyone, here it is.
Prebiotic selection
Under this hypothesis, a series of selections comparable to those of natural selection, among molecules which evolved to more complex macromolecules. It was suggested that proteins apparition preceded those of nucleic acids, since they exerts catalytic activities precipitating molecular reactions and that amino acids from which they are build are more simple than nucleotides.
Some researchers such as G. Shramm and S. W. Fox and their team have been able to build experimentally peptidic polymers very similar to those which are synthesised by living organism. It was thosefor proposed that since complex organic molecules could be recreated, nature could have done just the same in a series of molecular evolution. This hypothesis was tested on laboratory when experimental syntheses have produced various pairs of nucleotides, even though still less than in bacterias DNA. Oparin proposed that the precipitation in aqueous environments of organic molecules could have very well been the origin of the living cells.
From precipitation of molecules to the formation of protobiontes
The size and the nature of the molecules created in aqueous environment forces their agglomeration which causes the formation of coacervates (product of the aggregation). The macromolecules formed and brought by water reacts just the same way. Various hypotheses have been proposed to explain the evolutions of protobiontes from the simple agglomeration of macromolecules to the apparition of primitive life form which would be capable of autoconservation, autoregulation and autoreproduction.
The problem of autoconservation
Autoconversation is primordial in the apparition of life, the process under which the problem of energy must be resolved. The total energy of a system must include a part which could be usable to maintain the system and another part, “degraded” which should correspond with the increase of entropy. According to the second law of thermodynamic, the entropy of a closed system can only increase which would decrease the level of organisation. It was this same law which caused an incompatibility between the notions of evolution in physics and those under which life form have evolved. Fad (ix) 17:15, 9 April 2007 (UTC)
