1. Hypotonic, hypertonic, and isotonic solutions
Types of solutions
Hypotonic, hypertonic, and isotonic solutions

2. Osmosis: Diffusion of Water
Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration.
In a cell, water always moves to reach an equal concentration on both sides of the membrane.

3. Osmosis: Diffusion of Water
The diffusion of water across a selectively permeable membrane is called osmosis.
Regulating the water flow through the plasma membrane is an important factor in maintaining homeostasis within a cell.

4. Osmosis: Diffusion of Water
Most cells whether in multicellular (many cells) or unicellular (only one cell) organisms, survive by osmosis because they are surrounded by water solutions.

5. Cells in an isotonic solution
(= concentrations)
the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell.

6. Cells in an isotonic solution
Molecules move into and out of the cell at the same rate, and cells retain their normal shape.

7. Cells in a hypotonic solution
hypotonic solution: dilute solution thus low solute concentration
In a hypotonic solution, water enters a cell by osmosis, causing the cell to swell.
H2O
H2O

8. Cells in a hypertonic solution
concentrated solution, thus a high solute concentration
In a hypertonic solution, water leaves a cell by osmosis, causing the cell to shrink
H2O
H2O
Water Molecule
Dissolved Molecule