Di´╗┐ffusion


Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. The molecules can be atomic, and go right through the selectively permiable/semiperiable membrane. Diffusion uses no cellular energy because it is a passive transport.

Movement of molecules is accomplished due to kinetic energy of the molecules.

Diffusion continues until the molecules are evenly distrubuted throughout the space - equilibrium. Molecules continue to move randomly during equilibrium.

Examples of molecules that move through the cell memebrane this way are: oxygen, nitrogen, water and carbon dioxide.

external image slide0012_image029.jpg
"
external image Diffusion.en.jpg
external image diffusion.gif
References:

"Augustine | Cell Membrane Transport Presentation." Cambridge Public Schools, Cambridge, MA. Web. 17 Jan. 2011. http://www.cps.ci.cambridge.ma.us/CRLS/LC_R/classrooms/AUGUSTINE/Cell_Membrane_Transport/index_files/frame.html#slide0013.html.

"Diffusion." Psychology Wiki. Web. 17 Jan. 2011. http://psychology.wikia.com/wiki/Diffusion.

"Selectively-permeable Membrane - Definition from Biology-Online.org." Life Science Reference - Biology Online. Web. 17 Jan. 2011. http://www.biology-online.org/dictionary/Selectively-permeable_membrane.

"GRAPHICS." Indiana University. Web. 17 Jan. 2011. <http://www.indiana.edu/~phys215/lecture/lecnotes/diff.html>.

Back