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Regina Bailey

What Is Diffusion?

By August 31, 2012

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Diffusion of water and other molecules across a semipermeable membrane.
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Diffusion is the tendency of molecules to spread into an available space. Without other outside forces at work, substances will diffuse from a more concentrated environment to a less concentrated environment.

Passive transport is the diffusion of substances across a membrane. This is a spontaneous process and cellular energy is not expended. Molecules will move from where the substance is more concentrated to where it is less concentrated. The rate of diffusion for different substances is affected by membrane permeability. For instance, water diffuses freely across cell membranes but other molecules can not. They must be helped across the cell membrane through a process called facilitated diffusion.

Osmosis is a special case of passive transport. In osmosis, water diffuses from a hypotonic (low solute concentration) solution to a hypertonic (high solute concentration) solution. Generally speaking, the direction of water flow is determined by the solute concentration and not by the "nature" of the solute molecules themselves.


October 12, 2013 at 4:16 am
(1) pogi says:

some concepts and terminology are not explained very well u have to think for a moment and look for another source..bit scientific tnx.

October 17, 2013 at 5:35 pm
(2) Connor Spencer Harries says:


If you don’t have to think about it you aren’t learning anything new really, the internet is a wonderful resource for learning from but not if you just expect everyone to give you a dead straight answer without having to do a bit of understanding.

- Connor

October 23, 2013 at 12:56 pm
(3) Kalifala m.sheriff says:

It is proven by scientific experiment.we can’t regard it as rubbish.

January 25, 2014 at 12:52 am
(4) muhazull says:

Dat is gud

February 4, 2014 at 3:03 pm
(5) Bobarian Mcgillian says:

I think it is explained okay.

February 27, 2014 at 11:00 am
(6) koketso says:

i love it it make senes

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