1. Hypotonic, Hypertonic and Isotonic
How facilitated diffusion (osmosis) works in different solutions.

2. Isotonic Solution Latin: “Iso” means equal. So…
Isotonic means that it has the same solute concentration on the inside of the cell as the outside of the cell.
Inside the Cell:
20% solute, 80% water
Outside the Cell:
20% solute, 80% water

3. Isotonic
As a result, there is no net movement of water molecules. The concentration on both sides of the membrane remains the same.
Inside the Cell:
20% solute, 80% water
Outside the Cell:
20% solute, 80% water

4. Hypertonic Solution Latin: “Hyper” means over or above. So…
Hypertonic means there is a higher solute concentration on the outside of the cell, than on the inside of the cell.
Inside the Cell:
20% solute, 80% water
Outside the Cell:
40% solute, 60% water

5. Hypertonic Solution
Water particles are going to move OUT of the cell to even out the concentration.
This causes the cell to shrivel.

6. Hypotonic Solution Latin: “Hypo” means low or below. So…
Hypotonic means that it has the lower solute concentration on the outside of the cell, than on the inside of the cell.
Inside the Cell:
20% solute, 80% water
Outside the Cell:
10% solute, 90% water

7. Hypotonic Solution
Water molecules are going to move into the cell, to even out the concentrations.
The causes the cell to get larger.

8. You Try What is the % of water inside the cell?
What is the % of water outside the cell?
Will osmosis occur? If so, in what direction?
Will the cell shrink or swell?
This picture shows a cell
in a ______________ solution.
10% glucose
90% water inside cell
80% water outside cell
Yes – water will move out of cell
Shrink
Hypertonic
20% glucose

9. You Try What is the % of water inside the cell?
What is the % of water outside the cell?
Will osmosis occur? If so, in what direction?
Will the cell shrink or swell?
This picture shows a cell
in a ______________ solution.
20% glucose
80% water inside cell
80% water outside cell
Yes – both
Neither
Isotonic solution
20% glucose

10. You Try What is the % of water inside the cell?
What is the % of water outside the cell?
Will osmosis occur? If so, in what direction?
Will the cell shrink or swell?
This picture shows a cell
in a ______________ solution.
40% glucose
60% water inside the cell
80% water outside the cell
Yes – inwards
Swell
Hypotonic
20% glucose

11. Real World Examples Why does my skin wrinkle in the bath?
We are sitting in a hypotonic solution
So water rushes in, causing our skin cells to swell
Our swollen cells are too large to fit on our bodies, causing wrinkles to occur
Why does a slug die when you pour salt on it?
The slug is put in an intense hypertonic solution
So water rushes out of the slug, causing it to lose water rapidly – thus, the slug dies

12. Real World Examples
If I’m stranded on a desert island, why can’t I drink salt water?
Salt water is hypertonic to your blood plasma and cells
So water rushes out of your cells (and red blood cells), causing them to shrivel  making you more dehydrated
What do my kidneys have to do with this?
Your kidneys are constantly regulating the concentration of your blood plasma and therefore your cells
Keeps excess water out, keeps needed water in
The color of pee is related to hydration

13. Real World Examples
Why can’t you put a salt-water fish in a fresh-water aquarium?
The fish is put in a hypotonic solution.
So water rushes in, causing the fish to gain too much water, which rupture’s the fish’s cells, causing it to die
How can a fish even live in salt-water?
Fish live in a hypertonic solution, so ordinarily water wants to rush out
Fish have to drink lots of salt water to make the concentrations even – then they pump out the salt using active transport