> On Fri, 31 Mar 2000, David Wheeler went:
>
> >
> > The most important electrochemical effects come from the ions within
> > a few nanometers of the cell membrane; so, all those big negative
> > proteins deep in the cell have little immediate effect.
>
And David Epstein replies:
> This _still_ baffles me.
Me too but I'll add something anyway. I didn't mention the Big
Negatives because they just complicated what I was hoping was a simple
explanation. They are necessary, though. But, like Sherlock Holmes'
dog in the night, more for what they don't do than for what they do.
Think what would happen if they were small'uns. As positive potassium
moves out as law-abiding citizens obeying the Law of Diffusion, they
make the interior more negative. If the negative proteins were small,
they'd follow along (since negative hates negative and is attracted to
positive). The result would be that for every positive potassium
charge delivered to the outside, there would be a negative protein
charge accompanying it. Result: no charge.
But if the proteins are big guys, they can't leave, and the interior
gets more negative.
Once again, QED (free translation: Yo dude, I think I nailed it). Or
maybe not.
-Stephen
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Department of Psychology fax: (819) 822-9661
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