FACILITATED DIFFUSION A type of passive transport that does not require energy to move molecules down their concentration gradient uses membrane proteins to move molecules across the membrane that are large or charged (ions)

How does active transport differ from diffusion?

Active Transport Moves molecules from low concentration to high concentration Requires energy in the form of ATP Used to generate impulses through nerve cells & to allow cells to continue to store nutrients

Bulk Transport-Endocytosis Cells ingesting (taking in) large particles, fluid, etc. Membrane folds inward, makes a pouch, encloses material, and membrane pinches off Material is enclosed in a vesicle Transported to lysosome for digestion, or to other organelles for use (ex. WBC take in & destroy bacteria)

Types of Endocytosis Pinocytosis: solutes or fluids (cellular drinking) Phagocytosis: large particles, cells (cellular eating)

Bulk Transport-Exocytosis Reverse of Endocytosis Vesicles fuse w/membrane, releasing contents Ex: releasing proteins like insulin (animation)animation

IMPORTANT!!! Active transport & ALL forms of Bulk transport require energy!

Can you???  Distinguish between passive and active transport  Explain why facilitated diffusion is a type of passive transport  Describe the difference between a hypertonic, hypotonic and isotonic environment  Compare/Contrast endocytosis and exocytosis  Describe the structure of the cell membrane & a phospholipid