Transport

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Transport

• How does the cell transport material?
• 9/24/07

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Cell Membrane

• Regulates what enters and leaves cell
• Cell membrane like a mosaic

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Passive TransportDiffusion

• Does not require cellular energy
• Living cells have liquid interior and its
  surrounded by liquid
• Diffusion is the tendency for molecules to move
  from high concentration to low concentration

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Diffusion

• Solution is a liquid mixture of two or more
  substances
• Solutions have equal concentrations on both sides

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Osmosis

• Diffusion of water through a selectively
  permeable membrane
• Water moves from Higher concentration to lower
  concentration

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Osmosis

• Isotonic solutionssame strength in and out of
  cell
• Hypotonic solution---below strength
• Concentration in cell is greater than out
• Hypertonic solutionabove strength
• Concentration out of cell is greater than inside
  cell

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Osmotic Pressure

• Osmosis exerts a pressure on the hypertonic side
  of a selectively permeable membrane
• Cell is filled with salts, sugars, proteins, and
  other molecules

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Facilitated Diffusion

• Doesnt use cell energy
• Uses protein channel to help molecules diffuse
  across the selectively permeable membrane
• Needs concentration difference

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Active Transport

• Requires cell energy
• Moves substances from low concentration to high
  concentration
• Example Na and K pump
• Low concentration Na in cell High concentration K
  inside cell
• Pumps Na out and K inside

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Active Transport

• Endocytosistaking material into cell by means of
  infoldings or pockets of cell membrane
• Also called phagocytosis
• Exocytosis is the removal of large amounts of
  material outside the cell

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Diversity of Cellular Life

• Unicellular organisms
• Grow
• Respond to the environment and reproduce just
  like multicellular
• Examples
• Bacteria
• Some algae

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Diversity of Cellular Life

• Multicellular Organisms
• Cells rely on one another or interdependent
• Cell specialization
• Particular function within the organism

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Levels of Organization

1. Individual Cells
2. Tissues
3. Organs
4. Organ Systems

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• www.cellsalive.com cell model