1. Activating Prior Knowledge
Egg Osmosis
Soak a chicken egg in vinegar to
Remove the cell, and
Denature the outer protein
Then you have a big cell to experiment with!
View and Interpret
Egg Osmosis Video
What is an egg?
A chicken egg to be more precise…

2. After this lesson, you should be able to
explain the impact of water on life processes (i.e., osmosis, diffusion, SB1d).
explain the role of the cell membrane, in maintaining homeostasis (transporting materials in/out of cell).
Use vocabulary:
hypertonic, hypotonic, isotonic
Passive Transport: diffusion, osmosis, facilitated diffusion
Active Transport: sodium/potassium pump and endo/exocytosis

3. Solution Review
Solvent – the larger material {liquid} that dissolves the solute
Water is considered the “universal” solvent
Solute – smaller substance that is dissolved by the solvent. Ex. tea & sugar
Solution – Complete mixture of solute and solvent
Ex. Sweet tea

4. Quick Check!
I mixed Kool-Aid powder in water. Describe the mixture using the terms:
solute, solvent, and solution.

5. Words to know: Hypertonic Isotonic More solute Solution has
Hyper means higher
{more concentrated}
Isotonic
Solution has
achieved
equilibrium
Hypotonic
Less solute
Hypo means lower
less concentrated
Equilibrium
achieving balance or equal

7. Diffusion Demonstration
Equal volume of cold and warm water, each in separate clear cups
What will happen if we drop equal amounts of food coloring in each?
Let’s try it and observe.
youtube
Explain what you see.
Lead discussion to develop diffusion definition including
Movement of a substance
Random molecular motion
Kinetic energy
Concentration gradient
equilibrium

8. Diffusion
Movement of substances from high concentration to low concentration
Movement “down a concentration gradient”
Due in part to random, rapid motion of molecules.
Net Movement
Equilibrium State
Simple Diffusion.
Roles in the Body
Factors that Affect Rate:
permeability of membrane
Size of gradient
temperature

10. Passive Transport
Movement of materials in & out of the cell without {NO} Energy
Hypertonic
High Low
Hypertonic hypotonic
Hypotonic

11. Diffusion Passive O2, CO2, H2O across cell membrane Smells spreading
Movement of any molecules from a high concentration to a low concentration.

13. Osmosis
Diffusion of water across a semi- permeable membrane

14. Osmosis Diffusion of water through a selectively permeable membrane.
Movement of water
from “less salty” to “more salty” side of membrane
from low solute concentration to high solute concentration.
from high water concentration to low water concentration.
Hypertonic
Hypotonic
Isotonic
In everyday life:
Preservation of food
Eating of salty or sugary foods
Salt on a slug
contractile vacuoles
turgur pressure in plants

15. Diffusion and Osmosis Experiment
Initial Contents
Initial Solution Color
Final Solution Color
Initial Presence of Glucose
Final Presence of Glucose
Dialysis Tubing or Plastic Bag
Beaker or Clear Cup

16. OSMOSIS DEMONSTRATION (DIALYSIS BAGS)

17. Interpret this experiment!

18. OSMOSIS IN PLANT CELLS What’s happening to the water in the cell?
HYPOTONIC SOLUTION= NORMAL TURGOR PRESSURE
HYPERTONIC SOLUTION= PLASMOLYSIS

19. OSMOSIS IN PLANT CELLS (Elodea)
Plasmolyzed cells

20. Solution Concentrations
Isotonic Solution
When a cell is in a solution that has the same concentration of water and solutes
Hypotonic Solution
A cell is in a solution that has a lower concentration of solute
Hypertonic Solution
A cell is in a solution that has a higher concentration of solute outside of the cell

21. Quick Check
Knowing what we know about osmosis, what would happen to the water in a cell in:
1. an isotonic solution?
2. a hypotonic solution?
3. a hypertonic solution?

22. Osmosis Passive Hyper to Hypo
Diffusion of water molecules across a membrane.
Net movement of water toward high solute (hypertonic) side of membrane

23. Osmosis and Animal Cells
NO CHANGE
CRENATION
WILL LYSE

24. Facilitated Diffusion
Passive
Diffusion that uses channel proteins
Hyper to Hypo
Large molecules like glucose

25. Facilitated Diffusion
Movement from high concentration to low concentration through carrier proteins.
Used to move ionic or large substances into or out of cells
Passive process
Carrier proteins are specific (will only move one substance)
Important for moving sugars and amino acids into cells

26. Active Transport Low to High
Movement of materials in & out cell WITH energy
High
Low

27. Quick Check!
What is the main difference between active and passive transport?

28. Ion or Solute pump Active Protein channel hypotonic to hypertonic
Ex. Na+ K + pump
To “pump” means it uses energy (ATP)

29. Active Transport
Sodium-Potassium Pump
Pumps sodium out of cells and potassium into cells.
Important for the functioning of nerves and muscles.
Pump is a membrane protein and an enzyme--ATPase.
Movement of substances against a concentration gradient.
From low concentration to high concentration.
requires energy
pumping a substance
ATP must be hydrolyzed to fuel this process

31. Sodium-Potassium Pump (this allows for nerve function!)
3 Na+ pumped in for every 2 K+ pumped out; creates a membrane potential

32. Exocytosis- moving things out.
Moving the “Big Stuff”
Exocytosis- moving things out.
Molecules are moved out of the cell by vesicles that fuse with the plasma membrane.
This is how many hormones are secreted and how nerve cells communicate with one another.

33. Pinocytosis Cell forms an invagination
Materials dissolve in water to be brought into cell
Called “Cell Drinking”

34. Endocytosis – Phagocytosis
Used to engulf large particles such as food, bacteria, etc. into vesicles
Called “Cell Eating”

35. Three Forms of Transport Across the Membrane

36. Cellular Transport On-Line Tutorial (11 slides with animated molecules moving across cell membrane; includes quiz questions along the way)
ANOTHER ONLINE TUTORIAL

37. Passive Transport Osmosis O2, CO2, H2O glucose Na+ & K+ ions
Closing Challenge – Create a “Cell Transport Concept Map” with these words:
Active Transport ATP
Cell Transport Concentration Gradient Diffusion Endocytosis Exocytosis Facilitated Diffusion
Passive Transport Osmosis O2, CO2, H2O glucose Na+ & K+ ions