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TomHendricks474
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 Posted: Sun Dec 14, 2003 1:10 am Post subject: The Activation Energy Cycle |
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I have suggested that in the origin of life,
it is hard to understand how any
chemical system would be selected IF it first had to
vault a high activation energy before it became active.
Yet the reverse is true too as pointed out in this quote
from Microbiology, Nester et al.
"The activation energy barrier is crucial to life. Without it,
atoms and molecules would undergo continual rearrangement, and life could not
exist."
This suggests that my heat cycle (which I contend was the
initial energy force, and that enzymes were a replacement system
when the earth temp cycle began to cool) would have to have
a range that at times surmounted the activation energy barrier,
and at other times did not. This would set up a system of variants
for selection.
I would think that the activation energy barrier, much like the fairy tale of
Goldy and 3 bears - could not be too high, or too low, but had to be just
right.
I would also contend that this would be most important in that stage I named
the h-bond world that preceded the RNA world.
Comment?
Tom Hendricks |
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Jim Menegay
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| Posted: Mon Dec 15, 2003 1:45 am Post subject: Re: The Activation Energy Cycle |
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tomhendricks474@cs.com (TomHendricks474) wrote in message news:<brgda4$1c9u$1@darwin.ediacara.org>...
[quote]I have suggested that in the origin of life,
it is hard to understand how any
chemical system would be selected IF it first had to
vault a high activation energy before it became active.
Yet the reverse is true too as pointed out in this quote
from Microbiology, Nester et al.
"The activation energy barrier is crucial to life. Without it,
atoms and molecules would undergo continual rearrangement, and life could not
exist."
This suggests that my heat cycle (which I contend was the
initial energy force, and that enzymes were a replacement system
when the earth temp cycle began to cool) would have to have
a range that at times surmounted the activation energy barrier,
and at other times did not. This would set up a system of variants
for selection.
I would think that the activation energy barrier, much like the fairy tale of
Goldy and 3 bears - could not be too high, or too low, but had to be just
right.
I would also contend that this would be most important in that stage I named
the h-bond world that preceded the RNA world.
Comment?
Tom Hendricks
[/quote]
BRAVO!!
You have overcome one of your misconceptions. But if you hope to have
heat get you over the "activation energy barrier" then you are still
misguided IMO. However, you may be able to use DRYNESS to get you over
the barrier... That would be an indirect use of heat.
But notice! The dryness does not exactly lift you OVER the barrier. Instead,
it lowers the barrier (for the duration of the drought). So, until the
wet phase of your cycle, your molecules don>t reap the benefit of the
barrier (in terms of their own stability). When it is still dry, they
can jump right back across.
Another, issue is that the barrier will be lowered again during the next
dry phase. So, you need to have some kind of "progress" during both
the dry phase and the wet phase, in order to have any kind of increasing
stability over the course of many cycles.
(In technical terms, I am suggesting that the dryness could lower the
activation entropy. It has no effect on the activation enthalpy. The
dryness will, of course, change the equilibrium for a hydration/dehydration
reaction, and that may be a more important issue than activation, since
your proto-life seems to have no other source of free energy). |
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TomHendricks474
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| Posted: Mon Dec 15, 2003 5:39 pm Post subject: Re: The Activation Energy Cycle |
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<< BRAVO!!
You have overcome one of your misconceptions. But if you hope to have
heat get you over the "activation energy barrier" then you are still
misguided IMO. However, you may be able to use DRYNESS to get you over
the barrier... That would be an indirect use of heat.
I don>t always print it out - but my heat cycle always has a dry/wet cycle too.
But notice! The dryness does not exactly lift you OVER the barrier. Instead,
it lowers the barrier (for the duration of the drought). So, until the
wet phase of your cycle, your molecules don>t reap the benefit of the
barrier (in terms of their own stability). When it is still dry, they
can jump right back across.
Another, issue is that the barrier will be lowered again during the next
dry phase. So, you need to have some kind of "progress" during both
the dry phase and the wet phase, in order to have any kind of increasing
stability over the course of many cycles.
But that is what happens in chemical selection.
For instance a paired base is more thermally stable than a non paired one. A GC
paired base is more thermaly stable than a AU paired base. A row of GC paired
bases with stacking bases is more thermally stable than a single one. A
folded tRNA is more stable than an unfolded one. Etc. Etc. In every case in the
thermal cycle the same variants that we call life would be selected for no
other reason than suriving the heat (at this very early point in time) - thus
these first survivors would be the proto -template for the next days round.
Note that you have hear selection on a planet - not a fluke single isolated
event that turns to 2 and then 4 etc (all somehow safely outside the
environmental conditions at the time?)
(In technical terms, I am suggesting that the dryness could lower the
activation entropy. It has no effect on the activation enthalpy. The
dryness will, of course, change the equilibrium for a hydration/dehydration
reaction, and that may be a more important issue than activation, since
your proto-life seems to have no other source of free energy). >>
It is the main but not only source. We have an environment that is hot - full
of water vapor, lightning, radiation from internal earth, volcanic activity
etc. etc.
But the only cyclic heat cycle is the sun. And nothing can adapt to an
environment of ALL random changes.
TH |
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