1. Tonicity
The affects of Osmosis

2. But what effect would that have on a cell?
We know that osmosis is the movement of water from an area of high water concentration to an area of low water concentration.
But what effect would that have on a cell?

3. Create a 3 tab foldable like the one shown below.
Step 1
Step 2
Fold a sheet of paper from side to side. Make the back edge about 2cm longer than the front.
Fold into thirds and cut only the top layer along both folds to make 3 tabs
Isotonic
Solution
Hypotonic
Hypertonic
How osmosis affects cells in . . .
Step 3
Label as shown on the right.

4. Read about Osmosis on pages & 77 of your Holt textbook, and use the information to complete your foldable.

5. Describe what is happening in an isotonic solution and the affect it has on a cell
Describe what is happening in an hypotonic solution and the affect it has on a cell
Describe what is happening in an hypertonic solution and the affect it has on a cell
Use 4 arrows to indicate the direction water is moving into and out of a cell.
Diagram of an cell in an isotonic solution
Diagram of an cell in an hypotonic solution
Diagram of an cell in an hypertonic solution

6. Isotonic Solution cells in a . . . H 0 H 0 2 2 H 0 2 H 0 2 H 0 H 0 2 2
10% NaCl
90%H2O
H 0 2
H 0 2
NO NET MOVEMENT - cell stays the same
H 0 2
H 0 2
10% NaCl
90%H2O
H 0 2
H 0 2

7. Hypotonic Solution cells in a . . . H 0 2 H 0 2 H 0 2 H 0 2 H 0 2
10% NaCl
90%H2O
More water moves into the than leaves the cell causing it to swell.
H 0 2
H 0 2
H 0 2
H 0 2
20% NaCl
80%H2O
H 0 2

8. Hypertonic Solution cells in a . . . H 0 H 0 2 2 H 0 2 H 0 2 H 0 H 0 2
15% NaCl
85%H2O
More water moves out of the cell than into the cell causing it to shrink.
H 0 2
H 0 2
H 0 2
H 0 2
5% NaCl
95%H2O
H 0 2
H 0 2

10. An osmosis investigation was conducted using chicken eggs to represent cells with semipermeable membranes. The mass of each egg was measured to determine how much water diffused into or out of the eggs. The eggs were first soaked in vinegar to dissolve the shell. Each egg was then placed in one of three different solutions for 24 hours.
Distilled Water
100% water
Vinegar
85% water
Corn Syrup
5% water

11. Based on your knowledge of osmosis and the way water molecules move in various solutions, what would happen if you took a fish from the ocean (salt water) and placed it in a fresh water lake?

12. Because it would be going from an environment high in solute to an environment much lower in solute, the fish would swell and die.

13. What is a Isotonic Solution?
In an isotonic solution, the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell.

14. What happens to a cell when placed in a isotonic Solution?
The cell remains unchanged

15. What is a Hypotonic Solution?
In an hypotonic solution the concentration of dissolved substances is lower in the solution outside the cell than the concentration inside the cell.

16. What happens to a cell when placed in a Hypotonic Solution?
The cell will swell

17. What is an Hypertonic Solution?
In an hypertonic solution the concentration of dissolved substance outside the cell is higher than the concentration inside the cell.

18. What happens to a cell when placed in aq Hypertonic Solution?
The cell will shrink