Re: MFW journal club - lifting weights makes you thin, cures diabetes?

Tom Anderson <twic@xxxxxxxxxxxxxxx> writes:

On Tue, 12 Feb 2008, Andrzej Rosa wrote:

Dnia 2008-02-11 Tom Anderson napisa?(a):
On Mon, 11 Feb 2008, Andrzej Rosa wrote:

Tom Anderson wrote:

No. That only works if the process is near equilibrium.

Which means, that there should be enough time for changes of temperature
to not result in changes of pressure. It works like that by default in
condensed phase.

Or do you mean, that a cell can't be considered a closed system?

That.

Well, actually, i meant something else entirely, but i've realised i was
talking nonsense, so i'm going with that instead.

For fast reactions it shouldn't matter, and in bulk of muscle mass it
shouldn't matter at all.

On the contrary! A *lot* of heat escapes the cell.

And enters another one, doesn't it?

It may do, but it gets to the bloodstream, and is then transported to
your skin. At the cell and tissue level, heat is flowing out.

For this process, the amount of energy 'lost' to entropy (really,
the amount of energy given up to drive the reactions forward quickly)
is fixed by the stoichiometries of the enzymes, which is what i looked at.
Except i didn't account for the 'clutch slip' by leakage of protons across
the mitochondrial membrane, which can be a significant amount.

I managed to never learn biochemistry on this level (which wasn't all that
easy), so I can't comment here. (But your wording regarding entropy, energy
and kinetics makes me cringe a bit. ;-))

My apologies! What's wrong with it?

You don't lose energy to entropy. Entropy is an information about
energy distribution in the system, so one doesn't drive the other.

So what's that T - delta - S term in the formula for Gibbs free
energy, then?

Entropy is heat. And as i'm sure you're aware, heat is work and work
is heat.

Is that a hat I hear dropping?

--
Jim Janney
.

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