II. Movement of Materials through Cell Membrane

1. II. Movement of Materials through Cell Membrane

2. Selectively permeable membrane- Allows some materials to pass and not others

3. Passive Transport Moving from high ? low concentration No energy required

4. Diffusion- Molecules of a substance move from an area of higher to an area of lower concentration High ? Low

5. Equilibrium-  Concentration of the molecules will be the same throughout the space they occupy

6. Osmosis- The diffusion of water across a semi-permeable membrane

7. Direction of Osmosis a. Equal water concentration inside and outside cell, cell remains the same (p 99) b. High water concentration outside cell, water diffuses in, cell swells (p 99) c. High water concentration inside cell, water diffuses out, cell shrinks (p 99)

8. Facilitated Diffusion (p 101) Moving from high ? low concentration No energy required Carrier molecule is required

9. Active Transport Energy is required Two types 1. low ? high concentration

10. Movement in Vesicles Endocytosis- cell engulfing substance Phagocytosis- engulfing solids Pinocytosis- engulfing liquids

11. Movement in Vesicles Exocytosis- Release of a substance from a cell Opposite of endocytosis