1. Transport
Demo 1: Tea bag
Predict!
Observe!
Explain!

2. Demo 2: Body Spray
Predict!
Observe!
Explain!

3. Passive Transport: Diffusion & Osmosis
Concentration gradient – different concentrations across a distance
Molecules move from high to low concentration

4. Driven by kinetic energy (motion energy)
Molecules constantly moving “down gradient”
Equilibrium – concentration same throughout
until reach

5. 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

6. Demo 3: raisins
Predict!
Observe!
Explain!

7. Where do you think the water goes? In ? Out? Doesn’t move???
3 kinds of environments
Where do you think the water goes? In ? Out? Doesn’t move???
Hypertonic – concentration of solute greater outside cell

8. Where do you think the water goes? In ? Out? Doesn’t move???
Hypotonic – concentration solute greater on inside of cell

9. Where do you think the water goes? In ? Out? Doesn’t move???
Equal concentrations, equilibrium
3. Isotonic – equal concentration in and out of cell; molecules move at equal rate

12. Plasmolysis – shrinking of cell membrane, response to hypertonic solution
Red Onion Cells Red Onion Cells – hypertonic solution

13. 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)

14. Facilitated Diffusion
Non-lipid soluble molecules transported by carrier proteins
High Low concentration, NO energy: PASSIVE

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