Difffusion

Protect cell

Control incoming and outgoing substances

4.Selectively permeable - allows some molecules in, others are kept out

Cell Membrane and Cell Wall:

• ALL cells have a cell membrane made of proteins and lipids 

•Cell membranes and cell walls are porous allowing water, carbon dioxide, oxygen and nutrients to pass through easily

“Gatekeeper” of the cell—regulates the flow of materials into and out of cell—selectively permeable

•Cell membrane helps cells maintain homeostasis—stable internal balance

•Movement of molecules from an area of high concentration to an area of low concentration.

•Movement from one side of a membrane to another, un-facilitated

Diffusion: random movement of particles from an area of high concentration to an area of low concentration