1. Cell Membrane: Osmosis
SC.912.L.14.2 Relate structure to function for the components of plant and animal cells. Explain the role of cell membranes as a highly selective barrier (passive and active transport)

2. EQ: How does water move through the cell?
C.M. Osmosis
Objective: explain how materials pass through a semipermeable membrane
EQ: How does water move through the cell?

3. Structure and Function
Phospholipid bilayer
Polar head, 2 fatty acid tails
Protein, cholesterol, carbohydrate chains
Functions:
Controls what enters and exits the cell to maintain an internal balance (semipermeable)
Provides protection and support for the cell

4. Active Transport
Drives molecules against the concentration gradient from low to high concentration with ENERGY (ATP)
Ex- up a slide
ATP

5. Passive Transport
Movement of molecules from high to low concentration without energy
Movement of molecules high to low
Movement of water from high to low

6. Osmosis
Osmosis is the movement of water across a membrane from a region of high water concentration to a region of low water concetration
This generally means from a region with very few dissolved materials to a region with lots of dissolved materials (like salt)
How is this different from Diffusion?
Diffusion = movement of materials across the membrane form high to low concentration
osmosis =movement of WATER across the membrane from high to low concentration

7. REVIEW!!! What are the properties of water?
What behaviors of water allow these properties to exist?
Why is water a universal solvent?

8. Osmosis Jones?
Super hero and goes on adventures through the cells in the body
Why is he blue?
WATER!!
Osmosis = movement of water

9. Activate Your Prior Knowledge!
What do the following prefixes mean?
Hyper: more; above
Hypo: less; below
Iso: the same; equal

10. Compared to the conditions in the cell:
Osmosis
Compared to the conditions in the cell:
Hypertonic: has a higher concentration of dissolved substances
Hypotonic: has a lower concentration of dissolved substances
Isotonic: has the same (equal) concentrations of dissolved substances

11. Think, Pair, Share
We’ve learned that osmosis is water moving across the membrane of a cell. What do you think would happen to the size of the cell if it was exposed to:
A hypertonic solution?: The cell will shrink/ shrivel up as water flows out; the cell could die
A hypotonic solution?: The cell will swell as water moves in; could eventually rupture (burst)
An isotonic solution?: The size of the cell will not change

12. Label the following on your notes page.
Solution Type
Cell shape

13. How do different solutions affect cells?
The concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell.
10%
Isotonic
10%
No change

14. How do different solutions affect cells?
In a hypertonic solution, water leaves a cell by osmosis, causing the cell to shrink.
20%
Hypertonic
10%
shrinks

15. How do different solutions affect cells?
In a hypotonic solution, water enters a cell by osmosis, causing the cell to swell.
10%
Hypotonic
20%
swells

16. Osmosis

17. H2O molecules diffusing INTO a cell.

18. Osmosis
Where would the water go?
(hint: where is there more FREE water molecules?)

20. Check for Understanding
Based on your understanding of osmosis, which direction will the water molecules move? Identify whether the exterior conditions are hypo/hyper/isotonic:
Outside
Inside
On osmosis practice sheet- label some beakers just with solution (math)

21. Check for Understanding
There were equal concentrations of dissolved substances inside and outside of the cell, so no net movement will occur (water will go in and out equally). The conditions outside the cell were ISOTONIC.
Outside
Inside

22. Check for Understanding
Based on your understanding of osmosis, which direction will the water molecules move? Identify whether the exterior conditions are hypo/hyper/isotonic:
Outside
Inside

23. Check for Understanding
There were more dissolved substances outside the cell, so water will move OUT of the cell. The conditions outside the cell were HYPERTONIC. (this means the conditions inside were hypotonic)
Outside
Inside

24. Check for Understanding
Based on your understanding of osmosis, which direction will the water molecules move? Identify whether the exterior conditions are hypo/hyper/isotonic:
Outside
Inside

25. Check for Understanding
There were more dissolved substances inside the cell, so water will move INTO of the cell. The conditions outside the cell were HYPOTONIC. (this means the conditions inside were hypertonic)
Outside
Inside

26. How Osmosis Works?
Your observations should only take up half of the page or less.
/student_view0/chapter39/how_osmo sis_works.html
During the video record the 4 following observations in your notes:
The types of molecules that can cross a lipid membrane.
The types of molecules that cannot cross a lipid membrane.
The reaction of the water molecules when Urea is added to the right side.
The water level changes.

27. Gummy Bears Which gummy was in tap water and which was in salt?
Use science terms to explain what happened to each bear:
Hypertonic
Hypotonic
Isotonic
Osmosis
Passive transport
Energy (ATP)
Tap water swells- hypotonic solution (water enters the gummy because there is less dissolved material – so more free water molecules- outside of the cell) osmosis is the movement of water from high WATER to LOW water trying to balance the amount of free water.
Salt water shrinks- hypertonic solution (water leaves the gummy because there is more dissolved material- so less free water molecules- outside the cell)

28. Osmosis Practice
Answer the analysis questions based on your observations/data of the gummy bears in salt and tap water. Then, complete the activity to label the solutions and cells on the back. C- level 2 voice H- ask three before me A- gummy questions and osmosis practice sheet M- remain seated in your assigned seat, walking around will be a strike P- work with your pod to complete your questions Success!