1. Aim: What is Diffusion?
Do Now: Predict what will happen with the diffusion demonstration.
Tuesday 10/21 background information for Science Project due
Wednesday 10/22; Read pages answer questions 189 #’s 1-5
Thursday 10/23 Exam
Project #1 due on 11/12.

2. Diffusion Physical Demonstration
In diffusion all substances move from a higher concentration to a lower concentration
Once the concentrations are equal on both ends we have reached “Dynamic Equilibrium”
Dynamic=Running all the time
Equilibrium=Balance

3. Sketch the beaker & contents….
Before
After
Beaker contains water and iodine.
Dialysis bag contains a starch solution.

4. Conclusions
Why did the iodine move freely across the membrane while the starch did not?
What process was demonstrated in this experiment?

5. Aim: What are some factors that affect the rate of diffusion?
Do Now: What is facilitated diffusion?
Background Information due tomorrow via turnitin.com. Worth 3 HW’s. NO LATE PAPERS WILL BE ACCEPTED! Include bibliography!
Wednesday 10/22; Read pages answer questions 189 #’s 1-5
Thursday 10/23 Exam
Project #1 due on 11/12.

6. How does Glucose enter a cell membrane?
Glucose is a big molecule
It emits a charge
Cannot readily permeate lipid bilayer
Uses Facilitated Diffusion to enter membrane
DOES NOT USE ENERGY

7. Group Activity In pairs please read “Analyzing Data” page 188.
Answer questions 1-4 on a sheet of loose leaf paper to be collected at the end of the period.
Do Not copy questions
Hand in one paper for each pair of students

8. Aim: What is Active Transport and Osmosis?
Do Now: What are some factors that affect the rate of diffusion?
Background Information due today via turnitin.com by 11:59pm! Worth 3 HW’s. NO LATE PAPERS WILL BE ACCEPTED! Include bibliography!
Tomorrow 10/22; Read pages answer questions 189 #’s 1-5
Thursday 10/23 Exam
Project #1 due on 11/12.

9. How do substances move across a cell membrane?
Diffusion and facilitated diffusion
Osmosis (water)
Active Transport: Requires ENERGY

10. Permeability of Lipid Bilayer
Hydrophobic molecules cross with ease
Why?
They are all nonpolar
Examples: Hydrocarbons
Carbon Dioxide
Oxygen
Hydrophillic Molecules and Ions cannot pass with ease
Why?
They are have charges
Examples: Glucose
Water
Na+ K+
Main Question: How will Ions and hydrophillic molecules permeate the membrane if the phospholipids won’t allow them to?

11. Active Transport: Up Close and Personal
Na+ -- K+ Pump
Moving Against the “concentration gradient”
Movement from low to high concentrations
Requires ENERGY!

12. Osmosis is… The diffusion of water
Water moves from an area of high water concentration (low solute concentration) to an area of low water concentration (high solute concentration).
Remember: Water always wants to move to a place where it can dissolve something

13. Osmosis Demonstration
Goal: To predict what will happen when eggs are placed in the following solutions:
Syrup
Tap Water
Procedure:
Egg placed in white vinegar overnight to remove shell. Membrane exposed
Tonight they will each be placed in the above solutions.
What measurement of the eggs will we need to take in order determine if osmosis occurred?

14. Aim: How can we demonstrate Osmosis?
Do Now: What is Osmosis and how does it differ from diffusion?
Have out HW questions pg 189 #’s 1-5
Test tomorrow 10/23!!!
Project #1 due on 11/12.

15. Predictions In pairs discuss the answers to the following questions…
Place the answers in your notebook
What do you predict will happen to the egg in the syrup? Why? How will you know?
What do you predict will happen to the egg in the tap water? Why? How will you know?

16. Data Table: Period 3 Substance egg submerged in
Egg’s mass (g) before placed in substance
Egg’s mass (g) after removed from substance
Syrup
56.45g
Tap Water
62.00g

17. Definitions
Solute
Solvent
Hypertonic
Hypotonic
Isotonic

18. Qualitative Data: How do the eggs look?
Egg immersed in Tap Water (Isotonic Solution?)
Egg immersed in Distilled Water (Hypotonic Solution)
Egg immersed in Syrup (Hypertonic Solution)
Egg immersed in Syrup (Hypertonic Solution)
Egg immersed in Tap Water (Hypotonic Solution)
Isotonic Solution ?

19. Compare the following solutions to each other, using the terminology we just discussed:
10% salt solution vs. distilled water
20% salt solution vs. 10% salt solution
20% salt solution vs. 20% salt solution
Distilled water vs. 20% salt solution

20. Describe the solutions in terms of concentration.
In which direction will the water move? Why?
Selectively Permeable Membrane

21. Onion Cell Plasmolysis
Onion Cell in 10% salt solution
Onion Cell Wet Mount

22. Summary What is osmosis? Where does water always want to travel?
Why doesn’t osmosis require energy?
What happens to a cell when it is placed in a hypertonic solution? Hypotonic solution? Isotonic solution?

23. REVIEW QUESTIONS
What are two ways in which substances can move across a membrane? Which requires energy?
How do these two ways differ from each other?
What types of substances rely on active transport for admission into the cell? Why?