Xref: utzoo sci.bio:3841 sci.chem:2424 sci.physics:15303 sci.misc:4540
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!olivea!orc!inews!cmdnfs!bhoughto
From: bhoughto@cmdnfs.intel.com (Blair P. Houghton)
Newsgroups: sci.bio,sci.chem,sci.physics,sci.misc
Subject: Re: Osmosis - the cause at the molecular level.
Message-ID: <839@inews.intel.com>
Date: 7 Nov 90 03:32:32 GMT
References: <3703@stl.stc.co.uk> <richard.657852606@fafnir.la.locus.com> <1990Nov6.235518.8507@alchemy.chem.utoronto.ca>
Sender: news@inews.intel.com
Organization: Intel Corp, Chandler, AZ
Lines: 19

In article <1990Nov6.235518.8507@alchemy.chem.utoronto.ca> mroussel@alchemy.chem.utoronto.ca (Marc Roussel) writes:
>     This is certainly true.  You are both focussing on the wrong aspect of
>the problem however.  It is not the size of the molecules that matters,
>but their area of contact with the membrane.

If the contact plugs a hole then it plugs traffic in both directions.

All it does is reduce the effective area of the membrane.

This has no effect on the osmotic pressure.

The real question is whether diffusion itself (never mind
the osmotic case with semi-permeable membranes) is affected
by the relative size of the constituents of the system in
a manner not expressible by a set of diffusion constants.

				--Blair
				  "This has no effect on
				   the usenetic pressure..."