Osmosis and Diffusion

Diffusion is the movement of molecules from an area of high concentration to an area of low concentration, until evenly spread out.

All living cells rely on diffusion to live.

They use it for:

• Obtaining the raw materials for respiration (dissolved substances and gases)
• Removing waste products (eg from respiration)
• Photosynthesis in plants  (raw materials in, waste products out)

 

 

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html

and

 

Osmosis is a special type of Diffusion

 

It is the net movement of water across a selectively permeable membrane from a high concentration to a low concentration

The selectively permeable membrane has very small holes in it. Small molecules can pass through, but larger ones cant.

 

 

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html