3. Warm-up: How is osmosis related to diffusion?
Diffusion = movement of any molecules from area of high concentration to low.
Osmosis = diffusion of water molecules across a selectively permeable membrane.
Equilibrium
(equally spread out)
Red food coloring diffuses through a glass of water
Lets some things through, but not others
Water moves by osmosis from left to right

5. Station Guidelines Do NOT throw stuff!
Keep books open to bookmarked pages.
Keep video cued up for next team.
When done, clean station and reset for next group.

6. Warm-Up
Explain in terms of big and little molecules how a cell membrane is selectively permeable….

7. Cell Transportation Stations
Essential Question:
How do the materials needed for life get in and out of cells?

8. Station A: Modeling the Membrane
1. Make a sketch of a cell membrane model here and label the following: lipid bilayer, protein channels, carbohydrate chains.

9. Molecules still moving from hi to lo concentration.
Station A: Modeling the Membrane
2. What is facilitated diffusion, and how are protein channels involved in moving glucose into cells?
Facilitated diffusion = when protein channels help molecules like glucose diffuse into or out of cells. Facilitate = help.
Molecules still moving from hi to lo concentration.

10. Station B: Defining Diffusion
3. Put 2 drops of dye into a beaker of cold water. Do the same for a beaker of hot water. Shade in the pictures below to show which water changed color faster.
4. Define diffusion and explain why temperature affects the diffusion of molecules the way it does.
Diffusion = movement of molecules from area of high concentration to low.
Higher temp. makes diffusion go faster because molecules moving faster.

11. Station C: Explaining Equilibrium
5. Put 3 marbles into side A of the box, and 7 in side B. Keeping the box flat on the table, shake it gently back and forth to simulate the constant movement of molecules. Draw marbles in the box below to show what the box looks like before and after equilibrium is reached.
Before equilibrium
After equilibrium
What is equilibrium? How does the system remain in equilibrium?

12. Marbles move both directions at same rate.
Station C: Explaining Equilibrium
Put 3 marbles into side A of the box, and 7 in side B. Keeping the box flat on the table, shake it gently back and forth to simulate the constant movement of molecules. Draw marbles in the box below to show what the box looks like before and after equilibrium is reached.
Before equilibrium
After equilibrium
What is equilibrium? How does the system remain in equilibrium?
Equilibrium = equal concentration of molecules throughout, everything in balance.
Marbles move both directions at same rate.

13. Equilibrium in Nature = Balance
In order to have balanced food chain, must have more organisms at bottom of chain than at top or there won’t be enough food for everyone.

14. Station D: Understanding Osmosis
6. What is osmosis?
Osmosis = diffusion of water molecules through selectively permeable membrane (lets some things through, not others).
7. Make a sketch of the three egg specimens shown at this station. Apply your understanding of osmosis to explain what happened in each one.
A (Corn syrup)
B (pure water)
C (salt water)
More H2O diffused out of egg, making it shrink
More H2O diffused into egg, making it get bigger
H2O diffused in & out of egg at same rate (equilibrium)

15. Active transport requires energy from the cell, passive doesn’t.
Station E: Active vs Passive Transport Use the video here to answer the following question:
8. How is active transport in cells different from passive transport? How is active transport like rolling marbles up a ramp?
Active transport requires energy from the cell, passive doesn’t.
Active transport requires energy, like rolling marbles up a ramp. They don’t go that way by themselves.
Active or passive?

16. 1. Rolling ball downhill is like _________ transport. 2
1. Rolling ball downhill is like _________ transport. 2. Rolling ball uphill is like ____________transport.
passive
Concentration gradient
Low concentration
High concentration
Cell membrane

17. 1. Rolling ball downhill is like _________ transport. 2
1. Rolling ball downhill is like _________ transport. 2. Rolling ball uphill is like ____________transport.
passive
Concentration gradient
Low concentration
High concentration
Cell membrane

18. 1. Rolling ball downhill is like _________ transport. 2
1. Rolling ball downhill is like _________ transport. 2. Rolling ball uphill is like ____________transport.
passive
active
Concentration gradient
Low concentration
High concentration
Cell membrane

19. 1. Rolling ball downhill is like _________ transport. 2
1. Rolling ball downhill is like _________ transport. 2. Rolling ball uphill is like ____________transport.
passive
active
Concentration gradient
Low concentration
High concentration
Cell membrane

20. Membrane that lets some things through, but not others.
Station F: Selectively Permeable Membranes
9. What is a selectively permeable membrane?
Membrane that lets some things through, but not others.
10. Put 4 large marbles and 4 small marbles on side A of the pan. Put 8 small marbles on side B. If the marbles are always in motion, what will the pan look like after equilibrium is reached? Explain why it would look that way. A B

21. Membrane that lets some things through, but not others.
Station F: Selectively Permeable Membranes
9. What is a selectively permeable membrane?
Membrane that lets some things through, but not others.
10. Put 4 large marbles and 4 small marbles on side A of the pan. Put 8 small marbles on side B. If the marbles are always in motion, what will the pan look like after equilibrium is reached? Explain why it would look that way.
Small marbles able to pass through barrier, but not big ones. A B

22. Lets water, color and flavoring stuff through.
Station G: Diffusion Drink
11. Fill the beaker with hot water. Put a teabag in the beaker of hot water. Is the teabag a selectively permeable membrane? Explain why or why not.
Yes.
Lets water, color and flavoring stuff through.
But not tea leaves.

23. Lets little stuff through, but not bigger stuff.
Station G: Diffusion Drink
12. How is a colander (spaghetti strainer) like a cell membrane? Use bb’s and couscous to demonstrate.
Lets little stuff through, but not bigger stuff.

24. Through the protein channel.
Station H: Oil on Water
13. Drop four bb’s one at a time into the orange foam beads in the glass bowl. The bb’s represent small water molecules. Try the same thing with the green foam ball, which represents a larger glucose molecule. What part of the cell membrane do the orange foam beads represent? What does the large white foam ball with the hole in it represent? What’s the only way for glucose to get through the cell membrane?
Lipid bilayer
Protein channel
Through the protein channel.
glucose
H2O

26. Questions?

27. Active and Passive Transport animations and quiz

28. Missing? Lab: Animal Cells Lab: Plant Cells Quiz: Cell Structures
Cell Boundaries

29. Other videos….. Diffusion & osmosis Active & passive transport
Active & passive transport

30. On scratch paper:
Define the following and explain how each is involved in cell transport:
Diffusion –
Osmosis –
Equilibrium –
Active transport –
Passive transport -

31. Diffusion – Osmosis – Equilibrium –
Movement of molecules from area of high concentration to low. How things get in and out of cells.
Diffusion of water through membrane. How water gets in and out of cells.
When everything is spread out equally, everything in balance. Things diffuse until they reach equilibrium.

32. 4. Passive transport – 5. Active transport –
How cells move things in or out from high to low concentration. Doesn’t take energy.
How cells move things in or out against concentration gradient, from low to high concentration. Takes energy.

33. Passive transport: moving molecules from high concentration to low, like down hill.
Active transport: moving molecules from low concentration to high, like up hill.

34. Equilibrium: Nature always seeks balance, stability

35. Molecules still moving from hi to lo concentration.
Station A: Modeling the Membrane
2. What is facilitated diffusion, and how are protein channels involved in moving glucose into cells?
Facilitated diffusion = when protein channels help molecules like glucose diffuse into or out of cells. Facilitate = help.
Molecules still moving from hi to lo concentration.