The Activation Energy Cycle

[email hidden] (TomHendricks474) wrote in message news:<[email hidden]>...

Quoted message said:

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

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).

<< 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