The member "real life" is asserting that replicating molecules could not have formed in the oceans. (And as usual, on no external authority, simply making a statement from authority, which is an authority we have no reason to assume he possesses.) However, it has long been known that certain clays, many of which form on the floors of oceans, both in inshore areas, and on continental shelf floors and on deep ocean floors, can bind prebiotic amino acids, and form peptide chains. The following is from an article in the
Scientific American from April, 1974. Unfortunately, i cannot link it.
Quote:Recent research has shown that a number of organic substances formed by a combination of two or more molecules can be bonded to the surface of clay minerals. A number of investigators think the adsorptive properties of certain clays may have played a crucial role in the origin of life. The hypothesis arises as a result of the effort to simulate the conditions under which amino acids may form proteins within the human body. Experiment showed simple amino acids formed into the longer chains called peptides on the surface of clay particles. It is thought that clay acts a catalyst for the information of long peptide chains, or proteins.
The hypothesis was tested experimentally in America and abroad. Scientist added one amino acid in solution to various clay minerals. Then they exposed the clay to temperature and moisture variations. The main findings were that more peptides were produces at various temperatures when clay was present than when it was absent, and that production of peptides was a significant advantage in the presence of protein conversion.
The passage below is comprised of the two opening paragraphs and the final paragraph of an article entitled "Synthesis of Glycine Oligomers under Simulated Prebiotic Conditions on the Surface of Layered Silicate Clay Minerals."
Quote:There are still many unanswered questions regarding the synthesis of the first complex biological molecules needed for the emergence of life. From the simplest organic molecules, amino acids may be formed. Peptides and polypeptides are then constructed from amino acid units. These polypeptides then form the proteins necessary for living entities. The simplest organic molecules were formed by natural means in many different ways. Amino acids, the building blocks of polypeptides, are known to be synthesized from simple components through the action of heat, electrical discharge, UV radiation, and other mechanisms. It is likely that many amino acids were found in abundance on the prebiotic Earth. Amino acids have also been identified in extraterrestrial sources such as comets and meteorites. How did these abundant amino acids come together to form polypeptides or proteins?
In 1951, Bernal proposed that simple clay minerals may have played a role in the prebiotic formation of polypeptides. Many clay minerals are known to adsorb or intercalate organic molecules. Exchangeable metal cations in the inner regions or on the surface of the clays may then act to catalyze the reactions to form peptides and polypeptides from the adsorbed amino acids. Indeed, many groups have shown that clay minerals in the presence of amino acids do produce peptide oligomers.
**********************************************
In conclusion, clay minerals may have indeed played a major role in the prebiotic formation of the first peptides or polypeptides. We have directly observed the condensation of the amino acid glycine into glycine oligomers. These reactions occur at surface step edges and micro-pore sites, where access to interlayer metal cations is made possible. We are currently studying the site specific prebiotic polymerization of nucleosides on clay mineral surfaces, as well as the condensation of amino acids of varying sizes and reactivities at step edges and micro-pores.
The author is Tim Porter, who has a PhD in Surface Physics from Arizona State University, and the page is maintained by the Physics and Astronomy department of Northern Arizona University, where Mr. Porter is a faculty member. The home page of the Phsyics and Astronomy department at Northern Arizona Unversity describes his area of specilization as:
Quote:Study of inorganic/organic composite materials, the interaction of biological molecules with layered silicate minerals, atomic and molecular structure of surfaces, microsensor design and fabrication.
The article from which those three paragraphs were taken
can be read here.
The home page of Northern Arizona University's Physics and Astronomy department
can be viewed here.
The properties of silicate and aluminate clays in fixing prebiotic amino acids to form peptide chains has long been known, and has been the subject of careful study for nearly 40 years. I'm not at all surprised that this is completely unknown to the member "real life."
