1. Cell Membrane Review!
Each table group will be assigned a different component of the cell membrane
You need to introduce yourself, what you look like and what your role is (2-3 sentences)
Get in place as a table group as a human “cell membrane” based on your assigned component

2. Bubble Demo 2.0
Activity #4
What does this tell you about the properties of the cell membrane?
What kinds of answers did you get for the other activities?
One person from each table group
Skip the challenge section

3. Cell Transport… in a Nutshell
Passive
Transport
Diffusion
Osmosis
Facilitated Diffusion
Active
Carrier Proteins
Endocytosis
Exocytosis

4. How do molecules get inside the cell?
Directly through the phospholipid bilayer
Oxygen, CO2, water
Diffusion/osmosis
Protein channels
Charged ions like sodium, calcium, potassium or chlorine
Diffusion and osmosis
Carrier proteins
Larger molecules like glucose and amino acids
Facilitated diffusion

5. Passive Transport
SBI3C – Ms. Q
October 2nd 2018

6. On Your Own…
Read p
Make a Venn diagram with 2-3 points in each circle comparing osmosis, diffusion and facilitated diffusion
Compare answers as a class

7. Passive Transport No cell energy needed
Molecules enter or leave the cell one at a time
Molecules move with the concentration gradient due to random molecular motion
High to low
Talk about kidney dialysis as an example – passes a patient’s blood through dialysis tubing (which allows some substances but not others to get through, making it semi-permeable), surrounded by a special solution so the stuff you don’t need leaves and the stuff you need stays in – diffusion

8. Passive Transport

9. Diffusion
Even spreading of molecules from an area of high concentration to an area of low concentration across a semi-permeable membrane
Concentration: amount of a substance in a given volume
Move with the concentration gradient
Ex: In the cell membrane, small uncharged molecules and lipid molecules can pass through
Febreze or perfume or tea bag as an example
Molecules are constantly in motion
When there is no net change in the molecule movement, it’s reached equilibrium

10. What is a solution? Solutions are a mixture of:
Solvent: the part that does the dissolving (ex. water)
Solute: part that gets dissolved (eg. Sugar)
The cell is constantly trying to maintain a balance between the ECF (extracellular fluid) and the ICF (intracellular fluid/cytoplasm)
This creates homeostasis (balance)

11. Diffusion

12. Osmosis
Diffusion of water molecules across a selectively permeable membrane
Move with the concentration gradient

13. Osmosis
Water moving from an area of low concentration of solute to an area of high concentration of solute (in order to dilute them)
Water moves from where is more water to less water.
Cells want to have equal concentrations on both sides of the membrane!

14. Solution Tonicity ISOTONIC
[Solute] inside cell = [Solute] outside cell
No net water movement occurs
This means homeostasis is achieved

15. Solution Tonicity HYPERTONIC [Solute] greater outside cell
Water moves out of cell, into extracellular fluid

16. Solution Tonicity HYPOTONIC [Solute] less outside cell
Water moves into cell from extracellular fluid

21. Water flows from hypotonic to hypertonic

22. Application of Osmosis
Store fresh vegetables in fresh water to keep them crisp
Intravenous (IV) drips must be ISOTONIC to a patient’s blood otherwise red blood cells could gain or lose fluid
Reverse osmosis can desalinate ocean water and make it drinkable
Osmosis is why your fingers “prune” when you go swimming

23. This week Tomorrow: Egg Demo + Facilitated Diffusion
Thursday: Dialysis Tubing Lab
Friday: Active Transport