Hypotonic, Hypertonic and

IsotonicHow facilitated diffusion (osmosis) works in different

solutions.

Isotonic SolutionLatin: “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

IsotonicAs 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 SolutionLatin: “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 SolutionWater particles are going to move OUT of the

cell to even out the concentration.

This causes the cell to shrivel.

Hypotonic SolutionLatin: “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 SolutionWater molecules are going to move into the cell,

to even out the concentrations.

The causes the cell to get larger.

You Try1. 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 Try1. 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 Try1. 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 ExamplesWhy does my skin wrinkle in the bath?

We are sitting in a hypotonic solutionSo water rushes in, causing our skin cells to swellOur 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 solutionSo water rushes out of the slug, causing it to lose

water rapidly – thus, the slug dies

Real World ExamplesIf I’m stranded on a desert island, why can’t

I drink salt water?Salt water is hypertonic to your blood plasma and

cellsSo 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 inThe color of pee is related to hydration

Real World ExamplesWhy 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 outFish have to drink lots of salt water to make the

concentrations even – then they pump out the salt using active transport