Ch5 p94

Types of Transport Passive Transport Diffusion Osmosis Facilitated diffusion Active Transport Cell membrane pumps Endocytosis Exocytosis Movement across a membrane depends on BOTH the concentrations of particles AND their size, shape and if they dissolve in lipids!

Passive Transport Diffusion – the movement of particles from an area of high concentration to an area of low concentration Movement down its concentration gradient Happens naturally due to kinetic energy of molecules Dye in a glass of water (where would it happen faster – hot water or cold water?) Movement of particles happens until EQUILIBRIUM is reached as long as the particles… …can move thru the substance or across the membrane

Passive Transport Osmosis – the movement of WATER from an area of high concentration to low concentration Hypertonic: get your energy OUT Hypotonic: Hypo the Hippo Isotonic: equal

Passive Transport Facilitated Diffusion – the movement of particles is assisted by carrier proteins in the cell membrane.

Active Transport Cell Membrane pumps Sodium (Na)-potassium (K) pumps “Na Na NAAA Na, Na Na NAAA Na HEY HEY Good bye” Our cells need the potassium in them. It doesn’t care if there isn’t a lot outside the cell, it just wants to bring in as much as it can. Sodium sneaks in the cell, and isn’t needed. SO…the cell uses energy to kick out the Na and bring in the K

Active Transport

Endocytosis: endo=in cyto=cell Pinocytosis “to drink” brings in fluid Phagocytosis “to eat” brings in large particles or cells The cell membrane forms a divit and wraps around until it connects on the other side, forming a vessicle.

Active Transport Exocytosis: Exo=exit cyto=cell When a vesicle that has formed in the cell, attaches to the cell membrane and opens up, releasing its contents out of the cell.