From: the_thompsons@earthlink.net   
      
   sticks wrote:   
   > On 8/23/2025 8:06 AM, MarkE wrote:   
   >> On 22/08/2025 11:19 pm, RonO wrote:   
   >>> On 8/21/2025 6:26 PM, MarkE wrote:   
   >>>> A perspective on OoL from Dr. Edward T. Peltzer. Quotes following   
   >>>> are interview excerpts.   
   >>>> _______   
   >>>>   
   >>>> I did have many discussions with Miller and Bada on many subjects,   
   >>>> but the issues of pre-biotic chemistry and the origin of life were   
   >>>> the most common. Both were excellent chemists. You could ask them   
   >>>> about almost anything and they would have an answer or know where   
   >>>> one could look to find out. In some cases, I suspected they already   
   >>>> knew, but wanted to give me the experience of scouring the library   
   >>>> to find out. One could say that they taught me everything I new   
   >>>> about prebiotic chemistry at the time.   
   >>>>   
   >>>> During his doctoral studies at the Scripps Institution of   
   >>>> Oceanography (SIO), he was mentored by two luminaries in prebiotic   
   >>>> chemistry: Stanley Miller, renowned for the Miller-Urey experiment   
   >>>> simulating early Earth conditions, and Jeffrey Bada, an expert in   
   >>>> the field of amino acid racemization and a prominent figure in the   
   >>>> study of organic compounds in meteorites.   
   >>>>   
   >>>> As for the various individual [OoL] theories, here are a few of the   
   >>>> fatal errors. Hydrothermal vents do not make organic compounds, they   
   >>>> destroy them.   
   >>>>   
   >>>> Surface based synthesis might yield a few useful compounds, but many   
   >>>> compounds with a diverse range of functionality are needed for the   
   >>>> first organism. RNA is too unstable outside a living cell to offer   
   >>>> much hope of it doing anything in the pre-biotic soup if somehow it   
   >>>> was formed (which is exceptionally unlikely).   
   >>>>   
   >>>> My least favorite theory among all the options is the lipid world.   
   >>>> Assuming that one could get a collection of similar chain length   
   >>>> fatty acids bonded to glycerol to make triglycerides (which itself   
   >>>> is highly unlikely in the pre-biotic soup of randomly generated   
   >>>> compounds), then one could form an artificial vesicle (alternatively   
   >>>> called a coacervate or liposome) with a lipid bilayer film. What you   
   >>>> then have is not much more than a “soap bubble.” There is no   
   >>>> interior metabolism, no ion- transport pathways in the “membrane”;   
   >>>> it is nothing more than a film- coated droplet. How it would acquire   
   >>>> an internal metabolism, etc., is anyone’s guess. But guesses, as   
   >>>> entertaining as they might be, are not a scientific explanation of   
   >>>> how life arose abiotically.   
   >>>>   
   >>>> Random undirected chemistry does not yield biopolymers. Organisms   
   >>>> need proteins, DNA &/or RNA, polysaccharides, etc. These polymers   
   >>>> are uniform in that they are composed of a monomeric class of   
   >>>> compounds bound together in very specific ways: proteins are chains   
   >>>> of amino acids linked by peptide bonds; DNA & RNA are chains of   
   >>>> nucleotides linked by phosphate bridges; polysaccharides (e.g.,   
   >>>> starch & cellulose) are chains of glucose molecules linked by   
   >>>> α-(1,4) glycosidic bonds in starch (amylose) and β-(1,4) glycosidic   
   >>>> bonds in cellulose. Random, undirected chemical reactions do not   
   >>>> yield these pure polymers. Instead, they yield polymers formed by   
   >>>> random condensations of whatever compounds are at hand, producing   
   >>>> high molecular weight compounds without a well-defined structure.   
   >>>> Examples of this are fulvic and humic acids, melanoids, etc. Their   
   >>>> structures are complex, involve monomers from a variety of compound   
   >>>> classes and without a common bonding pattern. As such, they exhibit   
   >>>> little to no biological activity and store no information.   
   >>>>   
   >>>> The biggest challenge of all will be to convince the folks who dream   
   >>>> up the various theories for the origin of life to include the impact   
   >>>> of competing reactions on their pathways as opposed to writing “just   
   >>>> so stories.”   
   >>>>   
   >>>> The origin of homochirality (D-sugars, L-amino acids, etc.) has   
   >>>> proved to be a difficult problem to solve. The goal needs to be   
   >>>> chiral purity otherwise just a single wrong isomer can completely   
   >>>> foul the functionality of the biopolymer (protein, DNA/RNA, etc.).   
   >>>> Homochirality is always up against racemization, the process by   
   >>>> which chiral molecules get mixed with their mirror images   
   >>>> (enantiomers). Any such lack of purity among chiral molecules is   
   >>>> deadly to life. All three of the proposed processes to achieve   
   >>>> homochirality fail for such reasons. First, they are slow and only   
   >>>> achieve a partial enrichment of the desired form. Second,   
   >>>> racemization reactions work faster to undo this enrichment. What   
   >>>> little progress is made is quickly lost. Third, the racemization   
   >>>> rate increases with temperature. So, the condition needed to   
   >>>> speed-up other synthesis processes works against homochirality. The   
   >>>> source of homochirality remains an unsolved mystery.   
   >>>>   
      
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