1. The “bouncers” of the cell
Cell Boundaries
The “bouncers” of the cell

2. Diffusion All living cells exist in a liquid environment
the cell membrane regulates the movement of dissolved molecules from one side of the membrane to the other.

3. Measuring Concentration
Mass of solute (stuff that is dissolved) in a given volume of solution.
In other words mass of solute/volume of solution.
A 12 L salt water solution that contains 2 grams of salt - What is the concentration of this solution

4. Hands ON! The AVERAGE mass of a human body is 70 Kg
What would be the concentration of human tissue in this classroom?

5. Diffusion
Process where solutes in a solution move from an area of high concentration to lower concentration
Diffusion will occur until an equal concentration is obtained (equilibrium)
If substances can cross the cell membrane they will move into/out of the cell due to diffusion
This process does not require energy

6. Diffusion
When equilibrium is reached diffusion does not cease to occur, it just happens equally
Food coloring demo!

7. Passive Transport

8. Osmosis
The diffusion of water (and water ONLY) through a selectively permeable membrane
Two solutions can be compared using the following terms:
Hypotonic (hypo = under) lower concentration of solutes
Hypertonic (hyper = above) higher concentration of solutes
Isotonic (iso = same) equal concentration
Hint: tonic = strength