TOJC: Crown Ethers
uhlerdd@plu.edu
Tue, 03 Dec 1996 00:51:00 -0800 (PST)
Good Evening Chem Kids,
I was reading section 10.22B and it discusses some crown ethers
responsible for Na and K concentrations across cell membranes. It
describes the Na/K pump as a mechanism where by certain crown ethers
(nonactin) associate more readily with K and the internal structure of the
cell (hydrophobic lipid ends) allows permeability of K ions when
associated with a transport ether. I realize it is an active mechanism by
the cell, but doesn't it still mainly rely on diffusion rates rather than
a more active form of "pumping". I don't know, but it seems a poor
analogy to describe it as pumping when it is more of an ion association to
PERMIT permeability of an ion rather than necessitate its movement.
Curiously,
Dave