Transport

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Transport

• Demo 1 Tea bag
• Predict!
• Observe!
• Explain!

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• Demo 2 Body Spray
• Predict!
• Observe!
• Explain!

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Passive Transport Diffusion Osmosis

• Concentration gradient different concentrations
  across a distance
• Molecules move from high to low concentration

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• Driven by kinetic energy (motion energy)
• Molecules constantly moving down gradient
• Equilibrium concentration same throughout

until reach
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More about water (osmosis)

• Diffuses across concentration gradient (NO energy
  required)
• High Low Concentration
• Osmotic direction depends on concentration of
  solute on both sides of membrane

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• Demo 3 raisins
• Predict!
• Observe!
• Explain!

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3 kinds of environments
Where do you think the water goes? In ? Out?
Doesnt move???

• Hypertonic concentration of solute greater
  outside cell

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• Where do you think the water goes? In ? Out?
  Doesnt move???

1. Hypotonic concentration solute greater on
   inside of cell

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• Where do you think the water goes? In ? Out?
  Doesnt move???

Equal concentrations, equilibrium
3. Isotonic equal concentration in and out of
cell molecules move at equal rate
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1. 2. 3.
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• Plasmolysis shrinking of cell membrane,
  response to hypertonic solution

Red Onion Cells Red Onion Cells
hypertonic solution
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Simple Diffusion Osmosis

• Cell membrane is selectively permeable

• Small, non-lipid soluble molecules (water)

• Look at the membrane model again. How do you
  think the following materials get in/out?

• Small, lipid soluble molecules (hydrocarbons)

• Macromolecules (starches)

• Large, nonpolar molecules (glucose)

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Facilitated Diffusion

• Non-lipid soluble molecules transported by
  carrier proteins
• High Low concentration, NO energy PASSIVE

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Ion Channels

• Proteins transport ions from high to low
  concentration
• SPECIFIC!!! Each ion has own type of channel
• Some channels always open, others gated