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Osmosis & Diffusion. Diffusion. * The movement of molecules from an area of HIGH concentration to an area of LOW concentration. Examples of Diffusion. Tea Perfume Flatulence. Diffusion. Diffusion does NOT use energy .
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Diffusion * The movement of molecules from an area of HIGHconcentration to an area of LOWconcentration.
Examples of Diffusion • Tea • Perfume • Flatulence
Diffusion • Diffusion does NOT use energy. • When the particles are balanced on both sides of a membrane, EQUILIBRIUM has been reached.
Osmosis • The diffusion of water across a selectively permeable membrane.
Osmosis • Osmosis does NOT use energy. Ex. Top of page 101 “Why does the side with more sugar molecules rise?” • Osmotic pressure will force the water to move from an area of low water concentration to an area of high water concentration.
Blood example: Bottom of p. 101 • Hypotonic (LOW)-Refers to the solution outside the cell. • Hypertonic (HIGH)-Refers to the solution outside the cell. • Isotonic (EQUAL)-Refers to the solution outside the cell.
Facilitated Diffusion • A carrier protein helps to move another particle across the cell membrane. • Energy is NOT used. But can only work if there is a concentration gradient .
Active Transport • DOESrequire energy. • A protein channel, pushes certain molecules across the cell membrane. • Examples: Calcium, potassium and sodium ions are pushed across. They usually cannot diffuse across by themselves.
Endocytosis • “endo= in & cytosis =cell” So, this word means “into the cell”. • A form of active transport, so does use energy • Phagocytosis= “Cell Eating” • Pinocytosis= “Cell Drinking”
Exocytosis • “exo=OUTcytosis=CELL • Getting rid of excess water or waste.