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

[Tom Anders]

Right fools,

The paper is:

Fast/Glycolytic muscle fiber growth reduces fat mass and
improves metabolic parameters in obese mice - Y. Izumiya, T.
Hopkins, C. Morris, K. Sato, L. Zeng, J. Viereck, J. A.
Hamilton, N. Ouchi, N. K. Lebrasseur, K. Walsh (Feb 2008);
Cell Metab. 7(2):159 [PMID 18249175]

Abstract:

"In contrast to the well-established role of oxidative muscle
fibers in regulating whole-body metabolism, little is known
about the function of fast/glycolytic muscle fibers in these
processes. Here, we generated a skeletal muscle-specific,
conditional transgenic mouse expressing a constitutively
active form of Akt1. Transgene activation led to muscle
hypertrophy due to the growth of type IIb muscle fibers, which
was accompanied by an increase in strength. Akt1 transgene
induction in diet-induced obese mice led to reductions in body
weight and fat mass, resolution of hepatic steatosis, and
improved metabolic parameters. Akt1-mediated skeletal muscle
growth opposed the effects of a high-fat/high-sucrose diet on
transcript expression patterns in the liver and increased
hepatic fatty acid oxidation and ketone body production. Our
findings indicate that an increase in fast/glycolytic muscle
mass can result in the regression of obesity and metabolic
improvement through its ability to alter fatty acid oxidation
in remote tissues."

Links (the actual papers won't be accessible to most people):

http://news.bbc.co.uk/1/hi/health/7228896.stm -- BBC news
http://www.ncbi.nlm.nih.gov/pubmed/18249175 -- PubMed
http://dx.doi.org/10.1016/j.cmet.2007.11.003 -- full text
http://dx.doi.org/10.1016/j.cmet.2008.01.003 -- review

Summary:

- They're working in mice.

- They turn on the kinase PKB aka Akt in type II muscle
fibres, which are the fast ones that you develop by liftings
weights (or sprinting), rather than the slow ones you
develop by running.

- The mice get big huge muscles - something like 50% greater
mass than controls, and it's specifically type IIb, the
fastest form, that gets increased.

- Type IIb muscle burns glucose, not fat.

- Normal mice fed a McDiet high in sugar and fat get obese;
the PKB mice don't. They still get muscular (although no
more muscular than on a 'normal' diet).

- Normal mice on the McDiet have high blood sugar, high
insulin, and insulin resistance, ie metabolic syndrome or
type II diabetes. PKB mice don't - they're healthy.

- PKB mice move less, but consume more oxygen. It's argued
that this means they're depending more on fat, but i don't
see how that follows.

- Treatment with rapamycin blocks the effect of the PKB;
rapamycin inhibits the kinase mTOR, which is downstream of
PKB on the signalling pathway that controls protein
synthesis.

The argument is that if people had more muscle, they'd lose
weight and not get diabetes. Hooray!

The trouble is that the data on humans shows that having more
muscle doesn't mean you burn more calories while at rest,
which is what seems to be happening here.

I think a lot of this might be artifactual; PKB doesn't just
promote muscle growth, it does a hell of a lot of other
things, many to do with energy metabolism. Switching it on
will also switch on lots of processes which burn energy. It's
also part of the insulin signalling pathway, so that could
explain the increased sensitivity to insulin. It's basically a
fucking stupid way of upregulating muscle size, given that
there are nice, specific things like myostatin, myoD, god
knows what else.

Except the rapamycin thing strongly points to the effect being
mediated by protein synthesis. Unless mTOR also signals to
energy metabolism. Does it? I forget.

Anyway, they need to do this again with a slightly less brutal
perturbation.

tom

--
I really don't know what any of this shit means, but it looks
impressive. -- zerolives, on YVFC

[Dz]

Tom Anderson <twic@urchin.earth.li> wrote:
> Except the rapamycin thing strongly points to the effect
> being mediated by protein synthesis. Unless mTOR also
> signals to energy metabolism. Does it? I forget.

via leptin
http://ajpendo.physiology.org/cgi/content/full/284/2/E322

Interestingly, mTOR is also activated during fasting,
http://www.jbc.org/cgi/content/full/280/16/16427

"...circulating BCAA concentrations increase in the fasted
state (25,
26). This leads to the conundrum that fasting might be
associated with mTOR activation rather than inhibition."

> Right fools,

So you gotta intermittently fast, to get huge! (told
you, fools)

[Andrzej Ro]

Tom Anderson wrote:

> - PKB mice move less, but consume more oxygen. It's argued
> that this means they're depending more on fat, but i don't
> see how that follows.

Burning fat for energy requires more oxygen. I though you are
goto guy when it comes to following metabolic cycles? ;-)

> The argument is that if people had more muscle, they'd lose
> weight and not get diabetes. Hooray!
>
> The trouble is that the data on humans shows that having
> more muscle doesn't mean you burn more calories while at
> rest, which is what seems to be happening here.

Well, those mice didn't get much *lighter*. From what I
gathered from the abstract, they got only slightly lighter.
They just weren't fat.

> Anyway, they need to do this again with a slightly less
> brutal perturbation.

You mean, like testosterone shots? ;-)

--
Andrzej Rosa

[Tom Anders]

On Wed, 6 Feb 2008, DZ wrote:

> Tom Anderson <twic@urchin.earth.li> wrote:
>
>> Except the rapamycin thing strongly points to the effect
>> being mediated by protein synthesis. Unless mTOR also
>> signals to energy metabolism. Does it? I forget.
>
> via leptin
> http://ajpendo.physiology.org/cgi/content/full/284/2/E322

Urgh. Yes, that would do it, wouldn't it?

> Interestingly, mTOR is also activated during fasting,
> http://www.jbc.org/cgi/content/full/280/16/16427
>
> "...circulating BCAA concentrations increase in the fasted
> state (25,
> 26). This leads to the conundrum that fasting might be
> associated with mTOR activation rather than inhibition."

Yikes. That seems kind of odd. I assume the mTOR in fat cells
is not BCAA-sensitive in the way that muscle mTOR is? Or at
least not to the same extent? Otherwise, that would really
make no sense.

> So you gotta intermittently fast, to get huge! (told
> you, fools)

If you say so!

tom

--
Science of a sufficiently advanced form is indistinguishable
from magic

[Tom Anders]

On Thu, 7 Feb 2008, Andrzej Rosa wrote:

> Tom Anderson wrote:
>
>> - PKB mice move less, but consume more oxygen. It's argued
>> that this means they're depending more on fat, but i
>> don't see how that follows.
>
> Burning fat for energy requires more oxygen. I though
> you are goto guy when it comes to following metabolic
> cycles? ;-)

It's not a big difference, though, is it? I mean, if you're
taking glucose all the way to CO2 rather than just doing
glycolysis.

Lemme work it out (ie look it up) ...

Glycolysis turns one glucose into two pyruvates, two ATPs, and
two NADH/H+; each pyruvate gets decarboxylated to an acetyl
CoA and a NADH/H+, so the overall yield is two acetyl CoA, two
ATP, and four NADH/H+. For parity with fat, i'm going to
follow half a glucose: one acetyl CoA, one ATP, two NADH/H+.

Beta-oxidation turns two carbons of a fatty acid into an
acetyl CoA plus a NADH/H+ and a FADH2.

The Krebs cycle turns an acetyl CoA into 3 NADH/H+, a GTP
(which can be exchanged for an ATP), and a FADH2.

So, the total yield for half a glucose is two ATP (one from
glycolysis, one from GTP from the Krebs cycle), 5 NADH/H+, and
a FADH2; for two carbons of fatty acid, it's one ATP, 4
NADH/H+, and two FADH2.

Right. Now the hard bit: the electron transport chain. I
thought i'd left all this behind me ten years ago, but
apparently not ...

Complex I couples NADH/H+ to UQH2, and moves four protons.

Complex II couples FADH2 to UQH2, and doesn't move any
protons.

Complex III couples UQH2 to cyt c, and moves four protons (two
by trickery).

Complex IV couples cyt c to H2O, and moves two protons (it
does two reactions at once, so moves four at a time, but it
counts as two).

So, NADH/H+ works complexes I, III and IV, and gets ten
protons moved. FADH2 works II, III and IV, and gets six
protons moved.

Half a glucose gave us 5 NADH/H+ and a FADH2, for 5*10 + 1*6 =
56 protons moved. Two carbons of fatty acid gave us 4 NADH/H+
and two FADH2, for 4*10
+ 2*6 = 52 protons moved.

It takes three protons to make an ATP in the F0/F1 ATPase.

Assuming there are no losses to leakage (which is
unrealistic), that means half a glucose gives us 18 2/3 ATPs
and two carbons of fatty acid gives us 17 1/3 ATPs. From
oxidative phosphorylation.

Adding in the ATPs we got earlier, that means half a glucose
gives you 20
2/3 ATPs, and two carbons of fatty acid gives you 18 1/3 ATPs.

So how much oxygen did we need? The only place oxygen is
consumed is at the end of electron transport, at a rate of one
O2 per four electrons moved, ie per two NADH/H+ or FADH2. Both
sources gave us six carriers, or twelve electrons, and so used
three oxygens.

So ...

Half a glucose: 20 2/3 ATPs per three oxygens = 6.89 ATPs per
oxygen Two carbons of fatty acid: 18 1/3 ATPs per three
oxygens = 6.11 ATPs per oxygen

In other words, glucose gives you 12.7% more ATP per oxygen
consumed than fatty acids. The difference is slightly less
when you take the glycerol in fat into account. Christ knows
what happens if some of the fat is unsaturated.

Thirteen percent doesn't seem like a lot to me. Particularly
given that
(a) presumably, both mice were burning both kinds of fuel, and
it's the ratio that's shifted, rather than going from
all-glucose to all-fat (b) the mice moved less. Both of
those would detract from the 13% signal. IME, a 13%
difference in anything biological is usually pretty hard
to detect in the first place.

I think it's more likely that the PKB activation was making
the mice waste more energy as heat.

>> The argument is that if people had more muscle, they'd lose
>> weight and not get diabetes. Hooray!
>>
>> The trouble is that the data on humans shows that having
>> more muscle doesn't mean you burn more calories while at
>> rest, which is what seems to be happening here.
>
> Well, those mice didn't get much *lighter*. From what I
> gathered from the abstract, they got only slightly lighter.
> They just weren't fat.

Yes. But the authors' (or at least some commentators')
interpretation is that it's the muscle which is burning
more energy.

>> Anyway, they need to do this again with a slightly less
>> brutal perturbation.
>
> You mean, like testosterone shots? ;-)

That did occur to me! Still not exactly specific, though ...

tom

--
Science of a sufficiently advanced form is indistinguishable
from magic

[Andrzej Ro]

Tom Anderson wrote:

> On Thu, 7 Feb 2008, Andrzej Rosa wrote:
>
>> Tom Anderson wrote:
>>
[lotsa (unnecessarily) complicated stuff]

Just a comment. You rather didn't need going through all the
cycle. There is a rule that no matter how you go from A to B,
the overall energy remains the same (under constant pressure),
so there was a simpler way to calculate all of that. Normal
combustion would work blimey.

> In other words, glucose gives you 12.7% more ATP per oxygen
> consumed than fatty acids.

And googling it up was even easier. ;-)

Here http://bja.oxfordjournals.org/cgi/reprint/91/1/120.pdf
they say, that it's even less significant difference. 213/207,
which gives less than three percent. None the less, I found
other sources where they claimed, that oxygen cost of
producing energy from fat is higher, so I repeated a wrong
statement without checking. Now I feel ashamed, as I should!

[...]
> I think it's more likely that the PKB activation was making
> the mice waste more energy as heat.

Or something. Didn't they measure respiratory exchange rate?
This is used to find the primary source of fuel for real, not
just in popular press.

>> Well, those mice didn't get much *lighter*. From what I
>> gathered from the abstract, they got only slightly lighter.
>> They just weren't fat.
>
> Yes. But the authors' (or at least some commentators')
> interpretation is that it's the muscle which is burning
> more energy.

Resting metabolic rate (RMR) is dependant on muscle mass. It's
just that this effect will not do for obese people, because
it's not huge enough.

>>> Anyway, they need to do this again with a slightly less
>>> brutal perturbation.
>>
>> You mean, like testosterone shots? ;-)
>
> That did occur to me! Still not exactly specific, though ...

Well, it will work as a remedy for McDiet. ;-)

--
Andrzej Rosa

[6packer]

ABS everybody wants them. Then why don't people do
something about it? i made a blog that i really hope will
help and motivate you to achieve this goal
www.superrippedabs.blogspot.com The key to getting abs is
through Patience and Persistence. If you put your mind to
it you can achieve anything (i know its cliche, but it's
very true!)

[Tom Anders]

On Thu, 7 Feb 2008, Andrzej Rosa wrote:

> Tom Anderson wrote:
>
>> On Thu, 7 Feb 2008, Andrzej Rosa wrote:
>>
>>> Tom Anderson wrote:
>
> [lotsa (unnecessarily) complicated stuff]
>
> Just a comment. You rather didn't need going through all the
> cycle. There is a rule that no matter how you go from A to
> B, the overall energy remains the same (under constant
> pressure), so there was a simpler way to calculate all of
> that. Normal combustion would work blimey.

No. That only works if the process is near equilibrium. These
reactions happen very far from equilibrium. If you work out
the energy liberated by the oxidation of half a glucose, and
the energy required to phosphorylate however many ADPs to ATP,
you'll find the former is a lot more than the latter. 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.

>> In other words, glucose gives you 12.7% more ATP per oxygen
>> consumed than fatty acids.
>
> And googling it up was even easier. ;-)

Pah!

> Here http://bja.oxfordjournals.org/cgi/reprint/91/1/120.pdf
> they say, that it's even less significant difference.
> 213/207, which gives less than three percent.

Ah, interesting.

> None the less, I found other sources where they claimed,
> that oxygen cost of producing energy from fat is higher, so
> I repeated a wrong statement without checking. Now I feel
> ashamed, as I should!

This would be a very quiet group if we never did that.

>> I think it's more likely that the PKB activation was making
>> the mice waste more energy as heat.
>
> Or something. Didn't they measure respiratory exchange rate?
> This is used to find the primary source of fuel for real,
> not just in popular press.

Not that i noticed.

>>> Well, those mice didn't get much *lighter*. From what I
>>> gathered from the abstract, they got only slightly
>>> lighter. They just weren't fat.
>>
>> Yes. But the authors' (or at least some commentators')
>> interpretation is that it's the muscle which is burning
>> more energy.
>
> Resting metabolic rate (RMR) is dependant on muscle mass.
> It's just that this effect will not do for obese people,
> because it's not huge enough.

Exactly.

tom

--
Next issue - Nigel and the slavegirls ... or, why capitalism
can never work!

[Curt]

On Feb 10, 9:50 pm, Andrzej Rosa <bakt...@yahoo.com> wrote:
> Dnia 2008-02-11 Andrzej Rosa napisa=B3(a):
>
>
>
> > Well, that's how it's supposedly done. Indirect
> > calorimetry, or somethi=
ng
> > like that. You measure the amount of exhaled CO2 in
> > comparison with use=
d
> > O2 and work out the relative amount of carbs and fats used
> > out of requir=
ed
> > percentages for stoichiometry to work.
>
> I just read it and got scared. That's probably one of the
> most muddy paragraphs I ever wrote. Even I can't figure out
> what I meant here. Impressive!

Impressive alcohol content? ;)

--

[Andrzej Ro]

Tom Anderson wrote:

> On Thu, 7 Feb 2008, Andrzej Rosa wrote:
>
>> Tom Anderson wrote:
>>
>>> On Thu, 7 Feb 2008, Andrzej Rosa wrote:
>>>
>>>> Tom Anderson wrote:
>>
>> [lotsa (unnecessarily) complicated stuff]
>>
>> Just a comment. You rather didn't need going through all
>> the cycle. There is a rule that no matter how you go from A
>> to B, the overall energy remains the same (under constant
>> pressure), so there was a simpler way to calculate all of
>> that. Normal combustion would work blimey.
>
> 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? For fast reactions it shouldn't matter, and in bulk of
muscle mass it shouldn't matter at all.

> These reactions happen very far from equilibrium. If you
> work out the energy liberated by the oxidation of half a
> glucose, and the energy required to phosphorylate however
> many ADPs to ATP, you'll find the former is a lot more than
> the latter.

Here you are probably right. I was thinking like a chemist,
which means that for me heat is heat, no matter if you have
useful fuel out of it, which can be converted into
mechanical energy, or just a byproduct heat, which needs to
be sweated 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. ;-))

[...]
>> None the less, I found other sources where they claimed,
>> that oxygen cost of producing energy from fat is higher, so
>> I repeated a wrong statement without checking. Now I feel
>> ashamed, as I should!
>
> This would be a very quiet group if we never did that.

And there is no police here to stop us from trying (unlike on
various forums).

>>> I think it's more likely that the PKB activation was
>>> making the mice waste more energy as heat.
>>
>> Or something. Didn't they measure respiratory exchange
>> rate? This is used to find the primary source of fuel for
>> real, not just in popular press.
>
> Not that i noticed.

Well, that's how it's supposedly done. Indirect calorimetry,
or something like that. You measure the amount of exhaled CO2
in comparison with used O2 and work out the relative amount of
carbs and fats used out of required percentages for
stoichiometry to work.

[...]
--
Andrzej Rosa

[Andrzej Ro]

Dnia 2008-02-11 Andrzej Rosa napisa³(a):
>
> Well, that's how it's supposedly done. Indirect calorimetry,
> or something like that. You measure the amount of exhaled
> CO2 in comparison with used O2 and work out the relative
> amount of carbs and fats used out of required percentages
> for stoichiometry to work.

I just read it and got scared. That's probably one of the most
muddy paragraphs I ever wrote. Even I can't figure out what I
meant here. Impressive!

--
Andrzej Rosa 1127R

[Andrzej Ro]

Dnia 2008-02-11 Curt napisa³(a):
> On Feb 10, 9:50 pm, Andrzej Rosa <bakt...@yahoo.com> wrote:
>> Dnia 2008-02-11 Andrzej Rosa napisa³(a):
>>
>> > Well, that's how it's supposedly done. Indirect
>> > calorimetry, or something like that. You measure the
>> > amount of exhaled CO2 in comparison with used O2 and work
>> > out the relative amount of carbs and fats used out of
>> > required percentages for stoichiometry to work.
>>
>> I just read it and got scared. That's probably one of the
>> most muddy paragraphs I ever wrote. Even I can't figure out
>> what I meant here. Impressive!
>
> Impressive alcohol content? ;)

Just couldn't sleep (and think clearly, it seems).

--
Andrzej Rosa 1127R

[Tom Anders]

On Mon, 11 Feb 2008, Andrzej Rosa wrote:

> Dnia 2008-02-11 Andrzej Rosa napisa?(a):
>
>> Well, that's how it's supposedly done. Indirect
>> calorimetry, or something like that. You measure the amount
>> of exhaled CO2 in comparison with used O2 and work out the
>> relative amount of carbs and fats used out of required
>> percentages for stoichiometry to work.
>
> I just read it and got scared. That's probably one of the
> most muddy paragraphs I ever wrote. Even I can't figure out
> what I meant here. Impressive!

Made sense to me. But then, i've heard of this technique
before.

Surely that's not enough to work out carbohydrates, fat, and
protein, though? That's three unknowns for two measurables
(oxygen and CO2). Maybe if you measure nitrogen excretion in
the urine too you can work it out.

tom

--
Eight-bit is forever

[Tom Anders]

On Mon, 11 Feb 2008, Andrzej Rosa wrote:

> Tom Anderson wrote:
>
>> On Thu, 7 Feb 2008, Andrzej Rosa wrote:
>>
>>> Tom Anderson wrote:
>>>
>>>> On Thu, 7 Feb 2008, Andrzej Rosa wrote:
>>>>
>>>>> Tom Anderson wrote:
>>>
>>> [lotsa (unnecessarily) complicated stuff]
>>>
>>> Just a comment. You rather didn't need going through all
>>> the cycle. There is a rule that no matter how you go from
>>> A to B, the overall energy remains the same (under
>>> constant pressure), so there was a simpler way to
>>> calculate all of that. Normal combustion would work
>>> blimey.
>>
>> 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.

>> These reactions happen very far from equilibrium. If you
>> work out the energy liberated by the oxidation of half a
>> glucose, and the energy required to phosphorylate however
>> many ADPs to ATP, you'll find the former is a lot more than
>> the latter.
>
> Here you are probably right. I was thinking like a chemist,
> which means that for me heat is heat, no matter if you have
> useful fuel out of it, which can be converted into
> mechanical energy, or just a byproduct heat, which needs to
> be sweated 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?

tom

--
Eight-bit is forever

[Andrzej Ro]

Dnia 2008-02-11 Tom Anderson napisa³(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?

[...]
>>> 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. You don't lose heat to "drive the reactions fast"
either. While one can speed up a reaction with heat, it works
fairly slowly. Twice faster for every 10 degrees (iirc), by
which time a human would be well done, so my guess is that we
lose heat to actually prevent this scenario, not to drive our
reactions really fast (though one could argue, that we already
do by walking so close to the temperature of cooking
proteins).

--
Andrzej Rosa 1127R

[Andrzej Ro]

Dnia 2008-02-11 Tom Anderson napisa³(a):
> On Mon, 11 Feb 2008, Andrzej Rosa wrote:
>
>> Dnia 2008-02-11 Andrzej Rosa napisa?(a):
>>
>>> Well, that's how it's supposedly done. Indirect
>>> calorimetry, or something like that. You measure the
>>> amount of exhaled CO2 in comparison with used O2 and work
>>> out the relative amount of carbs and fats used out of
>>> required percentages for stoichiometry to work.
>>
>> I just read it and got scared. That's probably one of the
>> most muddy paragraphs I ever wrote. Even I can't figure out
>> what I meant here. Impressive!
>
> Made sense to me. But then, i've heard of this
> technique before.
>
> Surely that's not enough to work out carbohydrates, fat, and
> protein, though? That's three unknowns for two measurables
> (oxygen and CO2). Maybe if you measure nitrogen excretion in
> the urine too you can work it out.

They assume that during training (where it was primarily
used) proteins don't matter. They know it from some other
study (iirc).

--
Andrzej Rosa 1127R

[Jim Janney]

Tom Anderson <twic@urchin.earth.li> 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

[Tom Anders]

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.

> You don't lose heat to "drive the reactions fast" either.
> While one can speed up a reaction with heat, it works fairly
> slowly. Twice faster for every 10 degrees (iirc), by which
> time a human would be well done, so my guess is that we lose
> heat to actually prevent this scenario, not to drive our
> reactions really fast (though one could argue, that we
> already do by walking so close to the temperature of cooking
> proteins).

No, that's not what i'm talking about. I don't mean the effect
of temperature on reaction rate (which is more complicated in
biological systems anyway, as temperature affects protein
folding, even small changes, which affects the catalysis,
which counteracts the increase in rate from increased thermal
motion of the molecules). The temperature of the cells doesn't
vary much, i think.

What i mean is that if there isn't energy given up to heat, ie
if chemical potential energy is conserved across the reaction
(eg if you put 100 kJ of glucose in, you get 100 kJ of ATP
out), then a reaction won't go forward - it is, by definition,
at equilibrium. It's *only* when a reaction loses energy to
heat that it proceeds. It doesn't have to be a lot, but the
more it loses, the faster it will tend to go. The apparent
inefficiency of metabolism is there because we'd rather have
less energy more quickly.

I appreciate that i'm explaining this really badly. I did
thermodynamics about this time in 1999, so i'm rusty on the
terminology and nuances. I was a biochemist, so i came away
with what i needed to know for biochemistry, which was not a
lot more than some rules of thumb.

tom

--
quick good

[Tom Anders]

On Tue, 12 Feb 2008, Jim Janney wrote:

> Tom Anderson <twic@urchin.earth.li> 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:
>>>>>
>>>>>> 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?

Very good!

tom

--
No hay banda

[Andrzej Ro]

Dnia 2008-02-12 Tom Anderson napisa³(a):
> On Tue, 12 Feb 2008, Andrzej Rosa wrote:
[...]
>>>>> 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.

That's what made me cringe. ;-) How come you can write that
entropy is heat while you know full well that it has
different unit?

Now, my point. If you introduce some heat into the system, its
entropy will go up by at least Q per T, that is true (of
course). The problem is that by increasing entropy we are
_lowering_ the thermodynamical potential of the system. At
equilibrium entropy is at maximum, so nothing can happen, by
definition.

If you treat entropy as a measure of how many things can
happen spontaneously until all is done, there is no point of
increasing it artificially, because the higher entropy is, the
less can happen.

(And you could increase it by absorbing heat, not by radiating
it out. If we radiate a lot of heat out, the entropy of the
system will go down and hell will freeze, both figuratively
and literally. ;-))

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

Heat is a way of exchanging energy. Heat, energy and work
aren't the same thing, even if they are closely related.

>> You don't lose heat to "drive the reactions fast" either.
>> While one can speed up a reaction with heat, it works
>> fairly slowly. Twice faster for every 10 degrees (iirc), by
>> which time a human would be well done, so my guess is that
>> we lose heat to actually prevent this scenario, not to
>> drive our reactions really fast (though one could argue,
>> that we already do by walking so close to the temperature
>> of cooking proteins).
>
> No, that's not what i'm talking about. I don't mean the
> effect of temperature on reaction rate (which is more
> complicated in biological systems anyway, as temperature
> affects protein folding, even small changes, which affects
> the catalysis, which counteracts the increase in rate from
> increased thermal motion of the molecules). The temperature
> of the cells doesn't vary much, i think.
>
> What i mean is that if there isn't energy given up to heat,
> ie if chemical potential energy is conserved across the
> reaction (eg if you put 100 kJ of glucose in, you get 100 kJ
> of ATP out), then a reaction won't go forward - it is, by
> definition, at equilibrium. It's *only* when a reaction
> loses energy to heat that it proceeds.

Not true. There are plenty of endothermic reactions which will
go on as long as there are substrates available.

You can see it as if two substrates meet, and let's say that
they have activation energy (which normally will be higher
than average). Then they can go either their own ways without
forming products, or form products. Products can have both
higher or lower internal energy than substrates, no matter.
They will have lower energy than two substrates at activation
energy, so it will still work fine.

> It doesn't have to be a lot, but the more it loses, the
> faster it will tend to go.

That's often the case, but not always, so one should be at
least aware of making a simplification here.

For example there is quite a lot of energy difference
between graphite and diamond. According to your model
transformation of graphite into diamonds should be
spontaneous and fairly fast. ;-)

> The apparent inefficiency of metabolism is there because
> we'd rather have less energy more quickly.

This I don't get. Maybe you are right here, but I don't "see"
it.

> I appreciate that i'm explaining this really badly. I did
> thermodynamics about this time in 1999, so i'm rusty on the
> terminology and nuances. I was a biochemist, so i came away
> with what i needed to know for biochemistry, which was not a
> lot more than some rules of thumb.

I had nothing to do with thermodynamics even longer than you,
and I tend to fumble a bit while trying to explain what I
(almost) remember, but I think that you do confuse several
things here. I mean for real, not just by using very rough
simplifications.

--
Andrzej Rosa 1127R

[Andrzej Ro]

Dnia 2008-02-12 Tom Anderson napisa³(a):
> On Tue, 12 Feb 2008, Jim Janney wrote:
>
>> Tom Anderson <twic@urchin.earth.li> 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:
>>>>>>
>>>>>>> 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?
>
> Very good!

I don't get it. There is this saying "at the drop of the
hat", but I somehow can't make it fit here. So, what is so
good here?

--
Andrzej Rosa 1127R

[Charles]

On Wed, 13 Feb 2008 06:58:06 +0100, Andrzej Rosa
<bakters@yahoo.com> wrote:

>Dnia 2008-02-12 Tom Anderson napisa?(a):
>> On Tue, 12 Feb 2008, Jim Janney wrote:
>>
>>> Tom Anderson <twic@urchin.earth.li> 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:
>>>>>>>
>>>>>>>> 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?
>>
>> Very good!
>
>I don't get it. There is this saying "at the drop of the
>hat", but I somehow can't make it fit here. So, what is so
>good here?

It is apparent that someone is mixing their metaphors.

The penny will drop in a moment I suspect! ;o)

[Tom Anders]

On Wed, 13 Feb 2008, Andrzej Rosa wrote:

> Dnia 2008-02-13 DZ napisa?(a):
>> Andrzej Rosa <bakters@yahoo.com> wrote:
>>> Entropy is an information about energy distribution in the
>>> system
>>
>> The question that's been puzzling me for years is: if you
>> put a plugged-in iron into a freezer, who will win?
>
> Lawyers.

No. The electricity company.

tom

--
Me ant a frend try'd to WALK the hole unterrgrand but was
putting off - sometime we saw a trane! -- Viddler Sellboe

[Tom Anders]

On Wed, 13 Feb 2008, Andrzej Rosa wrote:

> Dnia 2008-02-13 Tom Anderson napisa?(a):
>> On Wed, 13 Feb 2008, Andrzej Rosa wrote:
>>
>>> Dnia 2008-02-13 Charles napisa?(a):
>>>> On Wed, 13 Feb 2008 06:58:06 +0100, Andrzej Rosa
>>>> <bakters@yahoo.com> wrote:
>>>>
>>>>>>>> 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?
>>>>>>
>>>>>> Very good!
>>>>>
>>>>> I don't get it. There is this saying "at the drop of the
>>>>> hat", but I somehow can't make it fit here. So, what is
>>>>> so good here?
>>>>
>>>> It is apparent that someone is mixing their metaphors.
>>>>
>>>> The penny will drop in a moment I suspect! ;o)
>>>
>>> I wasn't easy to google an explanation. I search in
>>> English, but I found an answer on Polish page. Some
>>> translators are trying to be serious, or what? ;-)
>>
>> It's a joke that there is essentially no way you could
>> possibly get unless you knew the thing it was referring to
>> already. Charles, i think, does not.
>>
>> What you need to know is that these chaps:
>>
>> http://en.wikipedia.org/wiki/Flanders_and_Swann
>>
>> Wrote and performed comic songs, including this one:
>>
>> http://www.uky.edu/~holler/CHE107/media/first_second_law.m-
>> p3 http://www.nyanko.pwp.blueyonder.co.uk/fas/anotherhat_f-
>> irst.html
>
> Intro was quite funny, but the song made me cringe a
> little. ;-)
>
> Heat is work and work's a curse And all the heat in the
> universe Is gonna cool down, 'Cos it can't increase Then
> there'll be no more work And there'll be perfect peace
> Really? Yeah, that's entropy, Man.
>
> Universe will cool down because it *is* increasing, so
> density of energy will be lower in the future. Which has
> nothing to do with entropy. Entropy would increase even
> without cooling down effect.

I think they're referring to the Heat Death of the Universe:

http://en.wikipedia.org/wiki/Heat_death_of_the_universe

Which is entirely about entropy. You're thinking of the
Big Freeze:

http://en.wikipedia.org/wiki/Big_Freeze

tom

--
Orange paint menace

[Dz]

Tom Anderson <twic@urchin.earth.li> wrote:
> Andrzej Rosa wrote:
>> Dnia 2008-02-13 DZ napisa?(a):
>>> Andrzej Rosa <bakters@yahoo.com> wrote:
>>>> Entropy is an information about energy distribution in
>>>> the system
>>>
>>> The question that's been puzzling me for years is: if you
>>> put a plugged-in iron into a freezer, who will win?
>>
>> Lawyers.
>
> No. The electricity company.

But the freezer door would be closed, so that's a closed
system.

If our universe is closed, the total energy is zero, because
the matter and the gravitaional energies cancel. I suspect
something like that would happen in the freezer.

[Andrzej Ro]

Dnia 2008-02-14 DZ napisa³(a):
> Tom Anderson <twic@urchin.earth.li> wrote:
>> Andrzej Rosa wrote:
>>> Dnia 2008-02-13 DZ napisa?(a):
>>>> Andrzej Rosa <bakters@yahoo.com> wrote:
>>>>> Entropy is an information about energy distribution in
>>>>> the system
>>>>
>>>> The question that's been puzzling me for years is: if you
>>>> put a plugged-in iron into a freezer, who will win?
>>>
>>> Lawyers.
>>
>> No. The electricity company.
>
> But the freezer door would be closed, so that's a
> closed system.

That's what she says. Guys just wonder what happens with all
the money they bring in and never see them again.

> If our universe is closed, the total energy is zero, because
> the matter and the gravitaional energies cancel. I suspect
> something like that would happen in the freezer.

Good theory. Lawyers will love it.

(I'm not divorcing anyone. Just kidding. But seriously,
freezer is also a heater, because net energy effect of
refrigerator is heating the environment. If you put something
hot in the freezer this energy is radiated out the back of the
fridge. Energy remains constant in isolated systems; closed
systems can draw energy from the outside or perform work on
the environment.)

--
Andrzej Rosa 1127R

[Andrzej Ro]

Dnia 2008-02-14 Tom Anderson napisa³(a):
> On Wed, 13 Feb 2008, Andrzej Rosa wrote:
>
>> Intro was quite funny, but the song made me cringe a
>> little. ;-)
>>
>> Heat is work and work's a curse And all the heat in the
>> universe Is gonna cool down, 'Cos it can't increase Then
>> there'll be no more work And there'll be perfect peace
>> Really? Yeah, that's entropy, Man.
>>
>> Universe will cool down because it *is* increasing, so
>> density of energy will be lower in the future. Which has
>> nothing to do with entropy. Entropy would increase even
>> without cooling down effect.
>
> I think they're referring to the Heat Death of the Universe:
>
> http://en.wikipedia.org/wiki/Heat_death_of_the_universe
>
> Which is entirely about entropy.

The penny dropped for me now. Finite amount of energy
distributed over infinite universe (by entropy) will cool
everything down, and because energy can't be created, there is
no escape from cooling everything down to zero.

I didn't factor in, that at the time the "obvious" assumption
about universe was that the space is probably infinite, but
the text actually makes sense.

> You're thinking of the Big Freeze:
>
> http://en.wikipedia.org/wiki/Big_Freeze

Well, I wasn't really thinking about what will be as much as
what is already known. Big Bang radiation is microwaves now,
so the space had to grow a bit. Microwaves carry less energy
than shorter wavelengths, so things also cooled down by now.

--
Andrzej Rosa 1127R

[Lucas Buck]

On Wed, 13 Feb 2008 18:32:19 +0000 (UTC), DZ
<674@91893380.147857489.16579.21734.27027> wrote:

>Andrzej Rosa <bakters@yahoo.com> wrote:
>> Entropy is an information about energy distribution in
>> the system
>
>The question that's been puzzling me for years is: if you put
>a plugged-in iron into a freezer, who will win?

"For my birthday I got a humidifier and a de-humidifier... I
put them in the same room and let them fight it out."
(Steven Wright)

[Lucas Buck]

On Wed, 13 Feb 2008 18:32:19 +0000 (UTC), DZ
<674@91893380.147857489.16579.21734.27027> wrote:

>Andrzej Rosa <bakters@yahoo.com> wrote:
>> Entropy is an information about energy distribution in
>> the system
>
>The question that's been puzzling me for years is: if you put
>a plugged-in iron into a freezer, who will win?

Most modern freezers are permanent-press anyway.