Prebiotic soup

Thus, the estimates for the rates of the prebiotic synthesis of biomolecules also need a drastic downward correction the hypothetical primeval soup then becomes much thinner ... 

The prebiotic primeval soup, i.e., the oft-cited mixture of organic molecules in the primordial ocean, or in ponds which could have arisen in many ways, e.g., in the atmosphere or the hydrosphere the substances concerned could also have been delivered from outer space. 

Lazcano, an evolutionary biologist, and Miller, an experienced prebiotic chemist, believe that the most important bottlenecks in the biogenesis process leading from the primeval soup to the RNA world, and thence to cyanobacteria, are the following ... 

The pH of the oceans forming the primordial soup is important in controlling the charged nature, or otherwise, of the amino and carboxylic acid species and hence their chemistry. Generating reaction schemes for the prebiotic synthesis of molecules requiring basic conditions will not be relevant if the oceans are acidic. Consider dissolving CO2 into water, simply written as ... 

This was about the same time that Darwin himself thought of a naturalistic view of the origin of life remember his little warm pond full of salts and other good ingredients, which later on would become the famous prebiotic soup However, Darwin didn t think too much about the origin of life. Some of the contemporary scientists who popularized his views, however, did it for him, most notably Ernst Hackel, who stressed that there is no difference in quality between the inanimate and the animate world Anorgane and Organismen) and that therefore there is a natural and continuous flux from the one to the other (Hackel, 1866). This very continuity principle was also advocated clearly by Friedrich Rolle (Rolle, 1863 Fryer, 1880). 

The author also makes a strong point to indicate the difference between this approach and the prebiotic soup approach, and argues (Wachtershauser, 2000) ... 

In the case of proteins or nucleic acids we do not have two, but several comonomers furthermore we are not dealing with the simple case of radical polymerization, but with the more complex polycondensation. Very little is known about the kinetics of the copolymerization of polycondensates - for example analysis of ta and re has not been done systematically for amino acids. However, a few general points can still be made on the basis of the general principles of copolymerization. One has been already mentioned that the initial composition of amino acids in the prebiotic soup may not correspond to the amino-acid composition in the chain. Thus, the fact that one given amino acid has a very small frequency of occurrence in protein chains may not necessarily mean that this amino acid was not present under prebiotic conditions the low frequency in the chains can simply be the result of the kinetics of polycondensation. Conversely, the presence of preferred residues or short sequences in protein chains might be due to the interplay of kinetic parameters, and have little to do with the initial biological constraints. 

Bada, J. L. and Lazcano, A. (2003). Prebiotic soup - revisiting the Miller experiment. Science, 300, 745-6. 

Creation of prebiotic soup, including nucleotides, from components of Earth s primitive atmosphere... 

With these kinds of experiments in mind, Beck3311 has elegantly deduced some of the important simple coordination chemistry of the prebiotic soup. He suggests a primary ligand set of H20, NH3, CO, CN, (CN)2C22, S2, H, N2 and C02. Some of these species are of importance in reactions to form complex organic molecules, as discussed below. Cyanide complexes were possibly important in the primitive oceans, and experiments on extraction of elements from powdered rock samples have shown that significant concentrations of Fe, Co, Cu, Mn and Mo... 

This discussion. .. has, in a sense, focused on a straw man the myth of a self-replicating RNA molecule that arose de novo from a soup of random polynucleotides. Not only is such a notion unrealistic in light of our current understanding of prebiotic chemistry, but it should strain the credulity of even an optimist s view of RNA s catalytic potential...Without evolution it appears unlikely that a self-replicating ribozyme could arise, but without some form of self-replication there is no way to conduct an evolutionary search for the first, primitive self-replicating ribozyme. 

The location. In the past, the suggestions have varied from Darwin s warm little pond to the global ocean as a gigantic prebiotic soup. Three sites have received special attention recently hydrothermal deep-sea vents51 and mounds52 and the ocean-atmosphere interface.53,54... 

Figure 8.9 Aldol condensation of formaldehyde as a source of carbohydrates in the prebiotic primitive soup...

Beck MT, ling J (1977) Transition-metal complexes in the prebiotic soup. Naturwissenschaften 64 91... 

There are several favorite notions of the site of the origin of life (Nisbet, 1987). The best known is the Marxist hypothesis of the primaeval soup — that the early ocean was a soup of organic molecules that had fallen in from meteorites (which frequently contain complex carbon-chain compounds organic chemicals, but made by prebiotic inorganic processes). In this soup, lipid blobs somehow evolved into living cells. The discovery of hydrothermal systems led to the realization that early oceans would have pervasively reacted with basalt, both in hydro-thermal systems and also with basalt ejecta after impacts. Thus, the late Hadean ocean was most unlikely to be a festering broth, but more likely a cool clean ocean not greatly dissimilar to the modem ocean exit the primaeval soup. 

Even so, as has been pointed out, silicon may have had a part to play in the origin of life on Earth. A curious fact is that terrestrial life forms utilize exclusively right-handed carbohydrates and left-handed amino acids. One theory to account for this is that the first prebiotic carbon compounds formed in a pool of "primordial soup" on a silica surface having a certain handedness. This handedness of the silicon compound determined the preferred handedness of the carbon compounds now found in terrestrial life. An entirely different possibility is that of artificial life or intelligence with significant silicon content. 

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