Re: The tar paradox

On Sat, 14 Dec 2024 16:37:58 +0000, erik simpson wrote:

On 12/14/24 7:35 AM, LDagget wrote:

On Sat, 14 Dec 2024 10:22:43 +0000, MarkE wrote:
>

On 14/12/2024 5:25 pm, erik simpson wrote:

On 12/13/24 9:51 PM, MarkE wrote:

On 14/12/2024 3:31 pm, erik simpson wrote:

Without reproduction tar is what you get for sure.  Nitrogen is high
enough concentration cause death by asphyxiation.

>
No reproduction prebiotically, therefore you're agreeing that the tar
paradox is an OoL showstopper?
>

I misprinted.  It's not a showstopper if the prebiotic reproduction is
present. It might be very slow or fail at some point.  The important
thing is that it's happening in many places.
>

>
What do you mean by "prebiotic reproduction"? Self-replicating naked
RNA? An autocatalytic set containing informational polymers?
>
In either case, these are disallowed if the tar paradox is unresolved.
And it appears to not only be unresolved, but largely unacknowledged.
>
Your statement "The important thing is that it's happening in many
places", is a vague, unsupported assertion, not an argument.

>
This is a pretty goofy thread.
The initial assertion about adding energy means you produce tar is
the vague and insufficiently correct thing. Let's break it down.
>
If you start with a soup of organic molecules and add in some high
energy reactants, you'll get a great deal of non-specific reactions.
I'm referring to, for example molecules prone to produce, for example,
free radicals or epoxides. These are so energetic that they will react
with the first thing they hit. That's somewhat exaggerated, but the
key point is that they won't show much discrimination so the reactions
that are "enabled" highly varied, not specific.
>
With even a very modest understanding of biochemistry, you should see
that this is unlike biochemical reactions. Biochemical reactions,
especially the sorts involved with biopolymers are vastly more
specific, and require much less activation energy than exists with
free radicals and epoxides. You attach molding around a door with
finishing nails and a small hammer, not a wrecking ball.
>
So the naked statement about "when you put energy into organic material
it turns into asphalt" is not very useful. In fact, the rest of that
quote runs rough over the facts as well.
>
But beyond this, it presses an absurdity: it presses the idea that
scientists think abiogenesis involved strictly random chemical
processes.
I'll grant there are astrobiologists, and even some ill-informed
biologists
that might speculate that way. But serious scientists all invoke
catalysis
early. And even basic knowledge of catalysis says that the chemistry
being done is a lower activation energies and is highly specific.
>
So the core question at hand is, why are you indulging in this
irrelevant aside about high energy, uncatalyzed reactions, when your
supposed focus in on OoL research?
>
Establishing ways to fail doesn't mean much. Visit an undergraduate
O-chem lab. All those kids with written directions failing to produce
the correct products doesn't mean the reactions don't work. It might
mean the search for intelligent life is difficult.
>

"Tar" in this context doesn't have any real meaning or definition.  It's
any sticky goo that comes from mixing random organic compounds and
cooking it, provided it doesn't blow up.  Don't try this at home, kids.

Having worked some on analytical chemical characterization of organic
polymers, including on products of attempts to synthesize chemical
libraries, including trying to figure out what went wrong when things
go wrong, I'll agree that the definitions of "tar" are inexact. However,
the sort of "tar" that people refer to from things akin to Miller-Urey
type experiments do include polymers with constituents that have bonding
patterns which indicate reaction patterns indicative of free radical
catalytic pathways.
Chemists are always trying to make their processes run faster and
adding heat is a common strategy --- up until doing so opens up multiple
additional reaction pathways. Then, things metaphorically overflow the
dam. The most common sort of problems involve free radicals. Vinyl
groups,
epoxides, and peroxides are common culprits, along with a few
problematic
heterocyclics in the pyrimidine family.
Of course one can't get a complete analysis of a "tar" because its so
heterogeneous but you can play some interesting tricks to test for the
parent molecules of things that fragment into some of the usual suspect
monomeric constituents. And that's how we can relate the composition
of really ugly tars with less muddled samples from reactions that were
pushed a bit too hard.