The Basics...

What is diffusion?
Diffusion is the movement of molecules down their concentration gradient. In other words, molecules move from high concentration to low concentration (ie. spread out).

Why does diffusion happen?
Diffusion occurs due to molecular collisions. Molecules have inherent energy and are constantly in motion (as long as there is heat). When molecules collide, they bounce off each other and eventually spread out.

How much energy does it take to make diffusion happen?
This is the best part - diffusion requires NO external energy. It will happen naturally and all by itself.

What is osmosis?
Osmosis is basically just the diffusion of water. Water movement is so important to living cells that the diffusion of water was given its own name. Water will move from its own high concentration to low concentration just like anything else.

What are the types of diffusion and osmosis?
You can see an overview of diffusion and osmosis here: Diffusion Prezi

External Links

Construct a Cell Membrane - use this site to learn the parts of a cell membrane and how they fit together.
HippoCampus Cell Membranes Overview - a little long but a great animation about cell membrane transport - you should definitely watch.
Membrane Transport - another site in case you need more explanation.
Diffusion & Active Transport - and one more to really get across the point.
Phagocytosis - a different way for food to get into cells.
Osmosis Explained - water movement across the cell membrane is very important to understand.
Osmosis Practice - some practice problems for osmosis.
Osomosis Practice in Plants - some terms relating to the plant perspective.


Using the Molecular Workbench software, you will complete the class activity #10: Diffusion, Osmosis and Active Transport.

Page last modified on Sunday April 22, 2012 20:11:57 EDT