Hypotonic, Hypertonic
and Isotonic
How diffusion works in different solutions.
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
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
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
Hypertonic Solution
 Water particles are going to move OUT of the cell to
even out the concentration.
 This causes the cell to shrivel.
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
Hypotonic Solution
 Water molecules are going to move into the cell, to
even out the concentrations.
 The causes the cell to get larger.
You Try
1. What is the % of water inside the cell?
2. What is the % of water outside the cell?
3. Will osmosis occur? If so, in what direction?
4. Will the cell shrink or swell?
5. This picture shows a cell
in a ______________ solution.
10%
glucose
20%
glucose
You Try
1. What is the % of water inside the cell?
2. What is the % of water outside the cell?
3. Will osmosis occur? If so, in what direction?
4. Will the cell shrink or swell?
5. This picture shows a cell
in a ______________ solution.
20%
glucose
20%
glucose
You Try
1. What is the % of water inside the cell?
2. What is the % of water outside the cell?
3. Will osmosis occur? If so, in what direction?
4. Will the cell shrink or swell?
5. This picture shows a cell
in a ______________ solution.
40%
glucose
20%
glucose
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
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