II. Movement of Materials through Cell Membrane

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II. Movement of Materials through Cell Membrane
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Selectively permeable membrane-

• Allows some materials to pass and not others

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Passive Transport

• Moving from high ? low concentration
• No energy required

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Diffusion-

• Molecules of a substance move from an area of
  higher to an area of lower concentration
• High ? Low

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Equilibrium-

• Concentration of the molecules will be the same
  throughout the space they occupy

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Osmosis-

• The diffusion of water across a semi-permeable
  membrane

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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)

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Facilitated Diffusion (p 101)

• Moving from high ? low concentration
• No energy required
• Carrier molecule is required

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Active Transport

• Energy is required
• Two types
• 1. low ? high concentration

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Movement in Vesicles (p 105)

• Endocytosis- cell engulfing substance
• Phagocytosis- engulfing solids
  Pinocytosis- engulfing liquids

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Movement in Vesicles (p106)

• Exocytosis-
• Release of a substance from a cell
• Opposite of endocytosis

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Levels of Organization

• Cell
• Tissue
• Organ
• Organ System
• Organism