Homeostasis

All cells must maintain an internal balanceFor animal cells:Allow glucose, oxygen and water inExport wastes and carbon dioxide out

Selectively Permeable

The ability of a membrane to allow some substances to pass through while keeping others outStrainerFilterScreen door???

Structure of the Plasma Membrane

Phospholipid

Phosphate

Lipids

http://telstar.ote.cmu.edu/biology/downloads/membranes/

Phospholipid Bilayer

Meaning that there is two layers of the phospholipid molecule

http://www.wiley.com/college/pratt/0471393878/student/animations/membrane_transport/index.html

Protein Molecules

Are embedded throughout the bilayer, serve as channels for materials to pass through the membrane

http://home.earthlink.net/~shalpine/anim/Life/memb.htm http://www.wisc-online.com/objects/index_tj.asp?objid=AP1101

Fluid Mosaic Model

The phospholipids are not bonded to each other and can freely move sideways throughout the bilayer

http://www.stolaf.edu/people/giannini/flashanimat/lipids/membrane%20fluidity.swf http://telstar.ote.cmu.edu/Hughes/tutorial/cellmembranes/bil.swf

Diffusion

The movement of particles from areas of high concentration to areas of low concentration

http://www.stolaf.edu/people/giannini/flashanimat/transport/diffusion.swf

http://www.wisc-online.com/objects/index_tj.asp?objid=AP1903

Movement occurs until dynamic equilibrium is reached – continuous movement with no overall change Smells, dyes, ??

Osmosis

The diffusion of water molecules through a membrane from a high to low concentration

http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Osmosis.htm

Active Transport

Movement of materials against the concentration gradient

Requires energy!!!

http://programs.northlandcollege.edu/biology/Biology1111/animations/transport1.html http://www.stolaf.edu/people/giannini/flashanimat/cellstructures/phagocitosis.swf http://www.wisc-online.com/objects/index_tj.asp?objid=AP11203