🚀 go-pugleaf

In article <5kg5cn$1a8a@nntp6.u.washington.edu> fujimoto@u.washington.edu (Bryant Fujimoto) writes:
>
>"pparso39@swbell.net" <pparso39@swbell.net> writes:
>
>
>>john baez wrote:
>>> 
>>> In article <3369749D.3D21@midusa.net>, T. Haug <tjhaug@midusa.net> wrote:
>>> >John:
>>> >How do you define equilibrium?
>>> 
>>> In physics (and I'm posting from sci.physics), "equilibrium" is
>>> a condition in which a physical system remains in the same state
>>> as time passes.    According to this definition a sleeping dog is
>>> not in equilibrium, because while it might look static to the casual
>>> observer, it is actually breathing, metabolizing, pumping out heat
>>> into the environment, and so on, and eventually it will wake up
>>> and walk off.  By this definition, living systems are never in
>>> equilibrium; you only reach equilibrium when you die and completely
>>> decompose.
>> No.  Equillibrium is a dynamic state.  For example, we take in air,
>>water, and nutrients, which become components of our bodies, which 
>>give off waste products.  That is equillibrium.  The body stays the
>>same, more or less, but the actual materials move through the system.
>
>At equilibrium, the forward and backwards rates of all processes
>are equal.  For an living organism, this would mean that the rate
>at which it takes in air, water, and nutrients is equal to the
>rate at which it gives off air, water and nutrients.  Also the
>rate at which it gives off waste products is equal to the rate at
>which it takes in those waste products.  That would be equilibrium,
>however, that is not what occurs in any living organism.  

Your conclusion is correct, but I have to nitpick about the definition of equilibrium.
The equilibrium constant of some reaction is equal to the ratio of the forward
rate and the reverse rate of that reaction. If forward and backward rates are
equal, the equilibrium constant is 1. In which case, we'd never talk about
such-and -such a reaction is driven by ... at any rate, living organisms are
_not_ in a state of equilibrium, but they can't get too far from it, either.

Chris