Primitive soup

Compared with the surprising variety of biochemical compounds that can be readily synthesized in Miller-type one-pot simulation experiments, the suite of organics produced under the conditions proposed by Wachtershauser is quite limited. However, the impressive demonstration that the FeS/H2S combination can reduce nitrogen to ammonia shows that considerable attention should be given to the reducing power of pyrite formation. Primordial life may have not been autotrophic, but should we hesitate to accept the idea that the primitive soup was formed from both extraterrestrial sources and endogenous synthesis in which pyrite production played a role After all, a spicy, thick bouillon is always tastier than a bland, diluted broth. 

Homogeneous Systems From Interstellar Space to Planetary Atmospheres and Primitive Soup Models... 

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

The principal building blocks of all the living entities, amino acids, can also be formed in the primitive soup model [29]. As HCN and aldehydes were produced directly from methane and ammonia, both photochemically and during electric discharge, the Strecker reaction was proposed very early as a likely pathway for the... 

Refractory dust particles not only serve as condensation nuclei for ices (see above), but are also necessary for energy dissipation during gas phase reaction between energetic atoms and molecules. Furthermore, solid inorganic particles (mostly oxides and sulphides) may play a role of photocatalysts in transformations of organic materials in both space and the primitive soup [5, 31]. 

P should also minimize distinction.s between conventionally distinct but atomic. primitives (such as space, mass, time, etc.). The vision is to take one more step along the metaphoric road remove jnan from the center of the universe —> remove all privileged frames of reference —> remove all absolutes —> remove all distinction between space and matter—r remove all distinction ( ) Start by eliminating the tacit assumption that whatever physics is self-organizing itself out of the soup of the current crop of physicists is the physics of this universe in short, go from a solipsistic phys-ics to a fundamentally relativistic physics, wherein even physics itself becomes a set (an infinite hierarchical set ) of self-consistent world-views rather than a prescribed set of exactly/uniquely prescribed laws operating independently of all observers. 

Some time after the evolution of this primitive protein-synthesizing system, there was a further development DNA molecules with sequences complementary to the self-replicating RNA molecules took over the function of conserving the genetic information, and RNA molecules evolved to play roles in protein synthesis. (We explain in Chapter 8 why DNA is a more stable molecule than RNA and thus a better repository of inheritable information.) Proteins proved to be versatile catalysts and, over time, took over that function. Lipidlike compounds in the primordial soup formed relatively impermeable layers around self-replicating collections of molecules. The concentration of proteins and nucleic acids within these lipid enclosures favored the molecular interactions required in self-replication. 

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 molecules that formed the first most primitive form of life had to self-assemble in the "primeval soup". Besides the obvious requirement of selfreproduction, there must have been an encapsulating membrane, separating inside from outside. The cubosome (a dispersed bicontinuous cubic phase, cf. Chapter 5) provides a number of remarkable properties that make it a candidate as an organisational assembly for the earliest forms of life. 

This story is remarkably similar to how Darwin s survival of the fittest is often described, at a primitive level. The monomers play the role of food, and self-copying chains or hypercycles play the role of living beings who reproduce themselves given enough food. As a result of the competition for fodder, only the most gluttonous and prolific species will siu vive. Recently, such mutual catalysis system was experimentally realized with RNA h Nevertheless, how it could have started in a primordial soup conditions remains an open question. 

Miller, Stanley L. From the Primitive Atmosphere to the Prebiotic Soup to the Pre-RNA World. Washington, D.C. National Aeronautics and Space Administration, 1996. 

In the 1950s it was assumed that the primitive Earth atmosphere consisted of methane CH4, ammonia NH3, hydrogen H2 and water H2O and S.L. Miller and H.C. Urey carried out a famous experiment at the University of Chicago. They simulated the primitive Earth atmosphere and ran continuous electric currents simulating lightning storms, which were very common on the early Earth, to this environment. After one week, 10-15 amino acids were found in this primordial soup. 

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