Re: Irony

On 17/12/2024 5:50 am, Ernest Major wrote:

On 16/12/2024 06:10, MarkE wrote:

I've raised Steven Benner's "tar paradox" in a recent post; it subsequently occurred to me that the Miller-Urey experiment is, ironically, a demonstration of this (I've mentioned this in a another thread, but thought it deserved a separate post). Miller-Urey produced only unusable small/trace amounts of amino acids in a "tar" mixture:
>
Breakdown of products:
* Carboxylic Acids (e.g., formic acid, acetic acid, and succinic acid): These dominated the product mix, typically making up 80-90% of the total organic compounds.

 Not tar. I found a Miller & Urey paper.
 

* Hydroxy Acids (e.g., lactic acid and glycolic acid): Accounted for 5-10% of the total.

 Not tar.
 

* Amino Acids: Typically contributed about 1-2% of the total organic product yield.

 Not tar. Also the numbers you give below add up to ~4.5%. The number from a Miller and Urey paper I found give an every larger proportion (by mole) of amino acids, and carboxylic acids in the 50-60% range.
 

* Other Organic Molecules: Small amounts of urea, nitriles, aldehydes, and hydrocarbons were also formed, constituting the remainder of the products.

 Not tar.

>
Relative concentrations of amino acids produced:
- Glycine: Approximately 2.1% of the total yield
- Alanine: Around 1.7%
- β-Alanine: About 0.76%
- Aspartic Acid: Approximately 0.024%
- Glutamic Acid: Around 0.051%

 I had thought that the Miller-Urey experiment did produce appreciable quantities of tar. Was I mistaken?
 

I think so.
"Miller’s experiment did produce the amino acids, but only by continuously circulating the reaction mixture and isolating products as they were formed. The quantities were still tiny and not in the same proportions as found in nature. One of the causes of the low yield has been identified by Peltzer who worked with Miller. As the amino acids were formed they reacted with reducing sugars in the Maillard reaction, forming a *brown tar* around Miller's apparatus. Ultimately, Miller was producing large compounds called mellanoids, with amino acids as an intermediate product."
Or this:
"Little discussed by anyone outside the origins of life scientific community was that the experiment also produced a lot of a dark, sticky substance, a gooey tar that covered the beaker’s insides. It was dismissed as largely unimportant and regrettable then, and in the thousands of parallel origins of life experiments that followed.
Though they do offer this glimmer:
"Today, however, some intrepid researchers are looking at the tarry residue in a different light."
https://manyworlds.space/2017/09/21/messy-chemistry-a-new-way-to-approach-the-origin-of-life/