Cellular Transport Osmosis and Diffusion

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Membrane Transport
The job of the cell membrane is to control what
materials enter and leave the cell
These materials might include glucose, amino
acids and lipids. Also, wastes and excess
materials.
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Important vocab

• A membrane is said to be Selectively permeable
  when the plasma membrane of a cell allows some
  substances to enter the cell while keeping others
  out.

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Passive Transport Mosey on through

• Molecules pass through the membrane by diffusion
  requiring no energy from the cell.
• The molecules just slide through the membrane.

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Types of Passive TransportPart 1

• DIFFUSION movement of particles from higher
  concentration (more) to lower concentration
  (less)
• In a cell, materials always try to reach an equal
  concentration on both sides of the membrane!

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DIFFUSION
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Diffusion Example

• http//www.biosci.ohiou.edu/introbioslab/Bios170/d
  iffusion/Diffusion.html

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Types of Passive Transport..Part 2

• OSMOSIS diffusion of water across a selectively
  permeable membrane

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OSMOSIS
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What controls OSMOSIS?

• Osmosis happens when there are different
  concentrations of water inside and outside a cell

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OSMOSIS
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Gotta love the Greeks!

• ISOSequal
• HYPOunder
• HYPERover
• Remember your roots!

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ISOTONIC SOLUTIONS!

• Concentration of substances outside the cell is
  the same as concentration of substances inside
  the cell.
• Water inside cell is equal to water outside the
  cell.
• EX Immunizations are isotonic solutions so they
  do not damage the cells by gain or loss of water.

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HYPOTONIC SOLUTIONS!

• Concentration of substances is lower outside the
  cell than concentration inside the cell.
• There is more water outside the cell than inside.
• Water moves into a cell to even out the
  concentration
• Water moving into the cell causes the cells to
  swell
• In a plant cell, the cell wall prevents it from
  exploding from the pressure
• If an animal cell swells to the point that it
  bursts, this is called cytolysis

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HYPERTONIC SOLUTIONS!

• Concentration of substances outside cell is
  higher than concentration inside cell.
• There is more water inside cell than outside.
• Water moves to the outside of the cell to even
  out the concentrations.
• Cells shrivel up due to water loss, this is
  called plasmolysis

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Active Transport ENERGY REQUIRED!

• Active transport is the movement of materials
  through a membrane from lower concentration to
  higher concentration
• This requires energy from the cell

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Types of Active Transport

• ENDOCYTOSIS cells surrounds and brings in
  material from outside the cell by engulfing the
  material!
• EXOCYTOSIS cells sends out materials from cell,
  such as waste or indigestible particles.
• Both endo and exocytosis are moving large
  molecules and require energy (ACTIVE TRANSPORT!)

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Endocytosis
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Exocytosis