Crossing the Membrane,

Facilitated Diffusion and Active Transport

Day 3

Facilitated Diffusion – Transport of substances from high concentration to low with aid of proteins

Remember, diffusion is ALWAYS high to low.

Molecules are ‘allowed’ to pass through membrane with help of Carrier Proteins

No energy needed

Facilitated Diffusion

http://www.youtube.com/watch?v=s0p1ztrbXPY

Active Transport – Movement of substances across a cell membrane from an area of low to high concentration WITH the use of energy.

Against the Concentration Gradient

Low -> High concentration

Endocytosis - Exocytosis

Active Transport

Endocytosis – when the cell membrane surrounds a particle, encloses it, and brings it into the cell.

Endo – take in

White blood cells use this process to exterminate threats in our body

Two Types:

Exocytosis – The cell releases a substance within it through its membrane.

Exo - release

Two Types:

Low to high concentration, in one of two ways:

Higher outside<-Exocytosis

Higher inside Endocytosis

http://www.youtube.com/watch?v=1w10R9lv7eQ

Endocytosis / Exocytosis Animation

Slug http://www.youtube.com/watch?v=PiQkebrC

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REVIEW!!