II. Movement of Materials through Cell Membrane

Selectively permeable membrane- AAAAllows some materials to pass and not others

Passive Transport  Moving from high  low concentration  No energy required

Diffusion-  Molecules of a substance move from an area of higher to an area of lower concentration  High  Low

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

Osmosis-  The diffusion of water across a semi- permeable membrane

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)

Facilitated Diffusion (p 101)  Moving from high  low concentration  No energy required  Carrier molecule is required

Active Transport EEEEnergy is required TTTTwo types –1–1–1–1. low  high concentration

Movement in Vesicles (p 105)  Endocytosis- cell engulfing substance  Phagocytosis- engulfing solids Pinocytosis- engulfing liquids

Movement in Vesicles (p106)  Exocytosis-  Release of a substance from a cell  Opposite of endocytosis

Levels of Organization  Cell  Tissue  Organ  Organ System  Organism