This is in reply to both Joe and William.
I think we will substantially simplify and rationalize our discussion if we
concentrate on a single issue: why is the assumption "no non-expansion work"
universally made? I don't agree that this type of work can just be added in
the "fundamental equation" without destroying the logical structure of
thermodynamics - if this were so, some authors would have added it etc.
Instead, all of them unanimously forbid it but then claim that the mutilated
equation is "a combination of the first and second law". Students may
suspect that the second law may not be valid when non-expansion work is
done, and ironically they would be right.
Let us remember the polymer which, on adding H+ to the system, contracts and
lifts a weight (I gave the reference in my previous message). It is not
difficult to see that neither "fundamental" equation, with or without
mu-terms, can describe the process. The reason is simple - in the times of
J.W.Gibbs, when the "fundamental" equations were born, conformational
changes were unimaginable. Today's scientists continue to procrusteanize
these changes to the old "fundamental" bed without caring at all about the
absurd implications. Let me describe the greatest (in my view) absurdity
thermodynamics has ever given to biochemistry which can be found in any
According to thermodynamics, the maximum work extractable from the ATP
system, at constant T and P, per unit extent of reaction (ATP hydrolysis) is
Wmax = - delta G = RTlnK -
where K is the equilibrium constant. Under physiological conditions, a usual
value of Delta G is -60 KJ/mol. This means that, as one mole of ATP is
hydrolysed, the maximum work extractable is 60 KJ/mol. On the other hand,
the energy released by the ATP system as one mole of ATP is hydrolysed (-
delta H) is about 20 KJ/mol. This means that, as one mole of ATP does
maximum work, it not only uses its own energy released (20 KJ) but also
absorbs 40 KJ heat from the environment and converts it into work too!
The heat absorbed by the ATP system and converted into work has a remarkable
property: it depends on the concentrations!
For instance, as [P] approaches zero, the heat absorbed and converted into
work (as one mole of ATP does maximum work) approaches infinity!
I could have presented the example more rigorously - I would do this if
necessary. This is an absurdity I have been trying to discuss with people
for many years - so far my messages acted like to face of Medusa the Gorgon
- on seeng them everybody get petrified and never reply.