1. Why is this traffic across the membrane so important?
Cellular Transport
How do cells move nutrients, products and wastes in and out of the cell?
Why is this traffic across the membrane so important?

2. Cells are filled and surrounded by watery fluid.
This fluid helps solids move around inside, outside the cell and cross the cell membrane.

3. Cell Membrane
The cell membrane controls what moves in and out of the cell.

4. Semi-permeable membrane
Cell membranes only allow some solutes (solids) to move across it. Movement across the membrane depends on size and type of the solute (solid).

5. Membranes are just so beautiful!!!!!

6. Types of Transport Down the concentration gradient Low concentration
High concentration
Up the concentration gradient
High concentration
Low concentration

7. Summary: Types of Transport
Passive Transport
Molecules move from area of high concentration to area of low concentration
Movement is down the concentration gradient
No energy needed
Small molecules such as H2O, O2 and CO2
Active Transport
Molecules move from area of low concentration to area of high concentration
Movement is up the concentration gradient
Energy is required (ATP)
Large molecules, ions

8. Diffusion – molecules move from area of high concentration to area of low concentration.

9. Osmosis – water moves across membranes (diffuses) to where there is less water.

10. Concentrations affect Osmosis
Water moves out of the cell
Water moves across membrane (in/out) at equal rates.
Water moves into the cell

11. Red Blood Cells in Hypertonic solution (video)

12. Plants and Osmosis Hypertonic solution (video)

13. Concentrations affect osmosis
equal amount of solute in and out of cells
higher amount of solute outside cells
lower amount of solute outside cells

14. Let’s Review Solution is made of solutes dissolved in a liquid or gas.
Hypertonic Solution = high amount of solutes
Hypotonic Solution = low amount of solutes
Isotonic Solution = equal amount of solutes
Dynamic Equilibrium is reached when solutes and water move across a membrane at equal rates because concentrations are equal (isotonic).
Homeostasis = all living systems need to maintain perfect concentrations inside each cell
Let’s Review

16. Test your knowledge On your left side, number 1-14 (short answer)
15 and 16 Extended answers required

17. 1. Which side is hypertonic? 2. Why? A B A B
1. Which side is hypertonic?
2. Why?
3. Can the solutes fit across the membrane?
4. How can you describe the membrane since it is very selective about what can move across?
5. How can both sides reach equilibrium?
Lower
concentration
of solute (sugar)
Higher
of sugar
Same concentration
Selectively
permeable mem-
brane: sugar mole-
cules cannot pass
through pores, but
water molecules can
More free water
molecules (higher
concentration)
Water molecules
cluster around
sugar molecules
Fewer free water
molecules (lower
Water moves from an area of higher
free water concentration to an area
of lower free water concentration 
Osmosis

18. ENVIRONMENT
NaCL (salt is ionic, cannot pass through membrane without energy)
10% NaCL 90% H2O ?
CELL
10% NaCL
90% H2O
What is the direction of water movement?_________
Describe the solution outside the cell. ________
Describe the solution inside the cell. __________

19. ? CELL 10% NaCL 90% H2O 20% NaCL 80% H2O
9. What is the direction of water movement?________
10. Describe the solution outside the cell. ________
11.Describe the solution inside the cell. __________

20. ? CELL 15% NaCl 85% H2O 5% NaCl 95% H2O
12. What is the direction of water movement?_______
13. Describe the solution outside the cell. ________
14. Describe the solution inside the cell. __________

21. How do cell move nutrients, products and wastes in and out of the cell?
Why is this traffic across the membrane so important?

22. Demo Lab Materials Celery sticks in different salt solutions???
Iodine solution / starch solution???
Potato cores in different salt solutions???
Procedure

23. Selectively permeable Hypotonic Hypertonic Isotonic Passive transport
Cell membrane
Selectively permeable
Hypotonic
Hypertonic
Isotonic
Passive transport
Diffusion
Concentration gradient
Solution
Solute
Equilibrium/Homeostasis
Active transport
Membrane proteins
Osmosis
Osmoregulation
Facilitated Diffusion
ATP
tendency of any molecule to spread out into available space
diffusion of a substance across a biological membrane
These help transport things across the membrane
lower concentration of solutes
passage of molecules and ions with transport proteins across a membrane down the concentration gradient
movement of a substance against its concentration gradient with the help of cellular energy
Membrane only allows certain things across
Barrier made up of phospholipids and proteins that controls what enters and exits the cell
When there are two different concentrations across a membrane. Molecules always move from high to low concentration without energy (ATP)
equal concentrations of solutes
the diffusion of water across a selectively permeable membrane
control of water balance
Combination of a solvent and a solute equally mixed
Molecule used in living systems for energy
State where molecules move across the membrane at equal rates
A substance being dissolved in another
higher concentration of solutes