Re: weight loss and respiration

[Joel Rauber <Joel_Rauber@SDSTATE.EDU>]

John Denker wrote in part:

> > I breath in O2 and exhale CO2.
>
> That's true as far as it goes, but it's not the whole story.

Precisely one of my points.

> >  If this
> > happens on a one for one basis than that part of the process is
> a net loss
> > of mass, therefore the act of breathing can't produce a weight gain.
>
> The conclusion is true, but it does not follow from the argument given.

I believe it follows from the premise.  I later questioned the premise.

> > I do have relatives with significant knowledge in medicine and
> biochemistry
> > and posed the question to them.  The response is that this isn't a simple
> > question.  There is no one reaction to which you can assign the
> incoming O2,
> > so the above isn't necessarily happening on a one for one basis.
>
> The metabolism of carbohydrates is particularly easy to understand.  The
> name tells the tale:  they are all of the formula C_m (H2O)_n --- so it
> takes m molecules of O2 to metabolize them.  The result is m molecules of
> CO2 and n molecules of water.  Virtually all of the CO2 (and perhaps much
> of the H2O) is lost by respiration.
>
> <snip>
>
> Trying to figure "weight gain" by simply auditing the weight of inputs and
> outputs is a pointless exercise unless you are prepared to do a _really_
> meticulous audit.  The level of detail being discussed in this thread is
> not nearly meticulous enough.

I believe that is the point I was making above.

<snip again>
> Or are we trying to conduct a case study in bad experiment
> design?  Why?  Isn't there enough of that already?

My contribution was intended to merely suggest reasons why someone might be
asking these questions.  I'm in no way suggesting this as an excercise in a
classroom, high school, college or otherwise; as a case study or design
study.  Hence there is no need to respond to the above rhetorical questions.

Joel Rauber
Joel_Rauber@sdstate.edu