On 23-07-2019 21:26, 'Brent Meeker' via Everything List wrote:
On 7/23/2019 12:07 PM, smitra wrote:
On 23-07-2019 04:10, 'Brent Meeker' via Everything List wrote:
On 7/22/2019 3:55 PM, smitra wrote:
This doesn't address the fundamental problems. People like Leslie
Orgel have explained why metabolism first is a non-starter.
And you think Nick Lane hasn't read Orgel?
Orgel's original arguments can be generalized into a no-go argument
that precludes all existing biochemical models for abiogenesis. This
has been pointed out by Paul Davies. However, Davies then argues that
this means that the problem lies with the fundamental laws of physics,
but one can also circumvent the problems raised by sticking to
ordinary physics and getting to the right structures within which the
conventional models can work.
He has argued on the basis of the difficulties of getting to
functional RNA, and more recently people like Paul Davies have
pointed out the fundamental nature of this problem. My suggestion is
not some new model, it simply makes conventional models such as e.g.
the protocell work better by putting these in a micro-environment
that itself has been forged in far from equilibrium conditions. The
micro-environments break the symmetry that can steer the chemistry
that takes place inside more coherently in one or the other
direction compared to whatever chemistry can go on in a macroscopic
environment.
Keep in mind that the simplest functional living organism is likely
going to be similar to a microbe, involving hundreds of thousands of
different enzymes that are then all necessary to make each other and
maintain and copy the organism. There thus exists a massive gap from
simple chemistry to the simplest self-reproducing lifeforms. The
only plausible solution is then a scenario where simpler systems
that would not function good enough to be able to reproduce with a
multiplication factor of larger than one, can reproduce with a
multiplication factor larger than 1 in a protected environment.
Which Lane and others postulate to alkaline "white smokers".
This is impossible, because you need to build structures on the
molecular scale without the enzymes that living organisms have
available. Local thermal equilibrium won't allow chemical reactions to
proceed differently a few atoms distance away at one site of a large
molecule compared to another. So, one needs to consider processes in
an environment where local thermal equilibrium will be violated on a
molecular scale. This can happen in a cryogenic environment in space
where UV radiation creates radical and ions and occasional cosmic ray
interaction causes heating allowing nearby ions and radicals to form
bonds. Such processes have been studied with the ail of getting to the
fundamental building blocks of life, but that doesn't really work
because of the random nature of the products.
But under those conditions one will also get extremely large clusters
of organics, and they can serve as the housing within which one can
have the right structures for conventional models to work. Confinement
in a small volume is essential as there will be as small number of
structures inside each such system. This means that the net effect of
all the structures inside any particular system will differ due to
statistical fluctuations. In a larger volume, the average effects of
the structures would average out to some mean effect, also the effect
the structures on the surface have on the chemistry taking place in
the entire volume would be less the larger the volume becomes.
Which is why the huge surface area and fractal-like compartments of
white-smokers are needed for the origin of life:
http://hoffman.cm.utexas.edu/courses/hydrothermal_vents.pdf
I direct your attention to Box 3.
Brent
You can't get such structures down to the molecular scale there.
Saibal
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to everything-list+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/everything-list/950cfa8fe7a52ebaaa1adda8c4391682%40zonnet.nl.
