1. Tonicity
Day 1

2. Main Ideas: Need to move things in/out of cell; 3 ways to do this
Things always move from high to low concentration
Because membrane is selectively permeable, can choose whether to do this or not
hyPERtonic – higher inside than should be
hyPOtonic – lower inside than should be

3. What NEEDS to move Nutrients Meet energy demands Growth & repair Water
Chemical reactions!
Waste
Maintain normal functioning

4. 3 General Ways to Move Diffusion ** Transport Proteins
Endocytosis/Exocytosis

5. Diffusion HIGH concentration to LOW concentration MOLECULES are moving
Passive (no energy required)

6. Diffusion
Constant back/forth until equal concentration

7. Factors affecting Diffusion Rate
Concentration Gradient
Size & shape of molecules
Temperature
Concentration gradient: a greater difference in concentration increases the rate of diffusion
Size & shape of molecules: smaller molecules diffuse more quickly
Temperature: heating speeds up diffusion

8. Osmosis Same ideas as diffusion, but WATER is moving
Water easily moves across membrane

9. Osmosis Words Solute: particles dissolved in water Solvent: the water!
Solution: combination of solute and solvent
Osmotic Pressure: pressure to due osmosis movement
Mr. Solute

10. Examples (don’t write!)

11. OSMOSIS
Where is the solute concentration higher?
Higher concentration of solute
Lower concentration of solute

12. OSMOSIS
Where is the water concentration higher?
Higher concentration of solute
Lower concentration of solute
Lower concentration of WATER
Higher concentration of WATER

13. Higher concentration of solute Lower concentration of solute
OSMOSIS
Where will the water go?
Water movement
Water movement
Higher concentration of solute
Lower concentration of solute
Lower concentration of WATER
Higher concentration of WATER

14. Tonicity (write!) ALWAYS comparing two areas Isotonic: same [ ]
No net movement of water
Hypertonic: more [ solute ]
Hypotonic: less[ solute ]

15. Tonicity in a solution Solution Cell Isotonic No change Hypertonic
Water rushes out; Cell SHRINKS
Hypotonic
Water rushes in; cell GROWS

16. Examples (don’t write!)

17. Which side is yellow hypertonic to?
QUICK CHECK
Which side is yellow hypertonic to?
RIGHT
Which side is yellow hypotonic to ?
LEFT

18. WHERE WILL THE WATER GO? 80% H2O 90% H2O 20% Sugar 10% Sugar
Water movement
90% H2O
10% Sugar
Water movement

19. Once H2O finished moving, both sides are isotonic to each other
WHERE WILL THE WATER GO?
85% H2O
15% Sugar
Once H2O finished moving, both sides are isotonic to each other

20. EXAMPLE Where will the water go? 90% H2O 10% Sugar 80% H2O 20% Sugar
Water movement
Water movement

21. EXAMPLE
What will the cell look like ?
AFTER
BEFORE
Cell & beaker are isotonic

22. EXAMPLE Where will the water go? 70% H2O 30% Sugar 80% H2O 20% Sugar
Water movement
Water movement

23. EXAMPLE
What will the cell look like ?
AFTER
BEFORE
Cell & beaker are isotonic

24. MAXIMUM TO CELL SIZE?
Can a cell get too small or too big?
Absolutely!

25. To Do’s Provincial Q’s Sheet  right side page Dictionary:
Isotonic, hypertonic, hypotonic, solute, solvent, diffusion