1. D.N.A Objective: Compare isotonic, hypertonic, and hypotonic solutions, and predict the path of water and solutes in given examples through a lab
Root Word: Hypo-Below
1. Which of the following correctly matches an organelle with its function?
A. Mitochondria – photosynthesis
B. Nucleus – cellular respiration
C. Ribosome – manufacture of lipids
D. Lysosome-movement
E. Central vacuole – storage
2. A cell possesses ribosomes, a plasma membrane, a cell wall, and other parts. If could not be
A. Bacterium
B. A cell from a fungus
C. A cell from a mouse
D. An oak tree cell
E. A bacterium or a cell from a pine tree

2. D.N.A Objective: SWBAT compare isotonic, hypertonic, and hypotonic solutions, and predict the path of water and solutes in given examples through a laboratory simulation
Using your knowledge of osmosis/diffusion, what makes a french fry so crispy?

3. Exploration Question
In your same lab group as yesterday, discuss a basic experimental design/procedure to test how to make crispy fries using your knowledge on osmosis/diffusion
Materials: Potatoes, Salt, Water

4. Osmosis Through A Membrane
Things to consider:
What is your experimental hypothesis?
What results to expect to occur to the dialysis bags under different environments (water/sucrose)?

5. Osmosis in A Plant Cell Things to consider:
When using your microscope, first focus on the specimen on the lowest power, then switch to the highest power

6. 3. If the nucleus is a cell’s “control center”, and chloroplasts its “solar collectors,” which of the following might be called the cell’s garbage disposer?
A. Lysosome
B. Golgi apparatus
C. Flagellum
D. Ribosome
E. Nucleolus

7. Movement across the Cell Membrane

8. How do things move across the membrane?
All living cells exist in a liquid environment
Even the cells inside of plants in the desert!

9. Concentration gradient
The liquid inside of cell (cytoplasm) and the liquid outside of the cell is not pure water, it has different particles dissolved into it
A solution

10. Concentration Gradient
Concentration is the measure of how many particles are dissolved in the liquid
High concentration = more particles
Low concentration = less particles

11. Concentration Gradient
HIGH CONCENTRATION
LOW CONCENTRATION
Dissolved Particle
Dissolved Particle

12. 1st type of transport: Diffusion
movement of particles from HIGH  LOW concentration
Movement from high concentration of that substance to low concentration of that substance.

13. Simple Diffusion Move from HIGH to LOW concentration movement of water
“passive transport”
no energy needed
movement of water
diffusion
osmosis

14. Facilitated Diffusion
Diffusion through protein channels
channels move specific molecules across cell membrane
no energy needed
facilitated = with help
open channel = fast transport
HIGH
LOW
Donuts!
Each transport protein is specific as to the substances that it will translocate (move).
For example, the glucose transport protein in the liver will carry glucose from the blood to the cytoplasm, but not fructose, its structural isomer.
Some transport proteins have a hydrophilic channel that certain molecules or ions can use as a tunnel through the membrane -- simply provide corridors allowing a specific molecule or ion to cross the membrane.
These channel proteins allow fast transport.
For example, water channel proteins, aquaporins, facilitate massive amounts of diffusion.
“The Bouncer”

15. 2nd type of transport: Active Transport
Cells may need to move molecules AGAINST concentration gradient
conformational shape change transports solute from one side of membrane to other
protein “pump”
“costs” energy = ATP
conformational change
LOW
HIGH
Some transport proteins do not provide channels but appear to actually translocate the solute-binding site and solute across the membrane as the protein changes shape. These shape changes could be triggered by the binding and release of the transported molecule. This is model for active transport.
ATP
“The Doorman”

17. Getting through cell membrane
Passive Transport
Simple diffusion
HIGH  LOW concentration gradient
Facilitated transport
through a protein channel
Active transport
diffusion against concentration gradient
LOW  HIGH
uses a protein pump
requires ATP (energy)
ATP

18. Transport summary simple diffusion facilitated diffusion
ATP
active transport

19. How about large molecules?
Moving large molecules into & out of cell
through vesicles & vacuoles
endocytosis
phagocytosis = “cellular eating”
pinocytosis = “cellular drinking”
exocytosis
exocytosis

20. The movement of big particles INTO the cell
Endocytosis
The movement of big particles INTO the cell
The cell actually engulfs the particles and brings them into the cell

21. ENDOCYTOSIS Protist eating another
Animation from:
Protist eating
another

22. The movement of big particles INTO the cell
Endocytosis
The movement of big particles INTO the cell
The cell actually engulfs the particles and brings them into the cell

23. The movement of big particles OUT of the cell
EXOCYTOSIS
The movement of big particles OUT of the cell

24. The Special Case of Water Movement of water across the cell membrane

25. Osmosis is just diffusion of water
Water is very important to life, so we talk about water separately
Diffusion of water from HIGH concentration of water to LOW concentration of water
across a semi-permeable membrane

26. Osmosis Water likes to move to the area where there are MORE particles
Water will move until the number of water particles is equal to the dissolved particles
Direction of water movement

27. Concentration of water
Direction of osmosis is determined by comparing total solute concentrations
Hypertonic - more solute, less water
Hypotonic - less solute, more water
Isotonic - equal solute, equal water
hypotonic
hypertonic
water
net movement of water

28. Water entering = water leaving
ISOTONIC (“Same strength”): EQUAL OUTSIDE AND INSIDE
Cells try to “maintain stable internal conditions =
____________________
HOMEOSTASIS
Water entering = water leaving

29. swell and possibly burst
Animation from:
OSMOSIS
HYPOTONIC (“Below strength”): Concentration outside cell is ________________ inside the cell More water enters than leaves cell so cell will ___________________
LESS THAN
swell and possibly burst

30. OSMOSIS shrinks GREATER THAN
Animation from:
OSMOSIS
HYPERTONIC (“Above Strength): Concentration outside cell is ____________________ inside cell
More water leaves cell than enters so cell ____________
GREATER THAN
shrinks
Choose Blood
Hypertonic link

31. Managing water balance
Cell survival depends on balancing water uptake & loss
freshwater
balanced
saltwater

32. Osmotic Pressure

33. CFUs!
WATER
Is the solution that the cell is it hypertonic or hypotonic?
Where does the water want to go?
IN OR OUT OF THE CELL
What will eventually happen to the cell?
BURST!

34. CFUs! Is the solution that the cell is is hypertonic or hypotonic?
Where does the water want to go?
IN OR OUT OF THE CELL
What will eventually happen to the cell?
SHRINK!

35. Do you understand Osmosis…
Cell (compared to beaker)  hypertonic or hypotonic
Beaker (compared to cell)  hypertonic or hypotonic
Which way does the water flow?  in or out of cell

36. Any Questions??