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Name: __________________________________________________
Unit 4 Homeostasis and Cell Transport
Period: ________
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I. Passive Transport
- homeostasis = maintenance of a __________________________________________ even though
environmental conditions are constantly changing
- cell membranes __________________________________________ by controlling what enters and
leaves the cell
- passive transport = process by which some substances ________________________________________
__________________________
A. Diffusion – the net __________________________________________________________________
_________________________________________________________________________________
- Occurs because of the _______________________________ in molecules (random movement)
B. Diffusion in Water
Why does the food dye diffuse? Food dye slowly diffuses b/c ____________________________
______________________________________________________________________________
C. Diffusion in air
Why does the smell diffuse? The odor molecules ______________________________________
and the gas molecules in the air and slowly diffuse into the classroom.
D. Concentration Gradient –
__________________________________________________________
E. Dynamic Equilibrium –
the condition in which there is _____________________________________________________
- This means there ___________________________________________________________
i. there is no ___________________________________________ – everything is equal
ii. Draw dynamic equilibrium in a glass with a solute…
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F. Osmosis –
a. Diffusion of water goes from ________________________________
b. http://www.youtube.com/watch?v=sdiJtDRJQEc&feature=related
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MB: p. 95-100
BDOL: p. 195-198
1. Look at the U-shaped tube in the figure. Why did the number of water molecules on each side of the
membrane change after osmosis, whereas the number of sugar molecules stayed the
same?____________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
2. How does the plasma membrane of a cell compare with the membrane in the U-shaped tube?
___________________________________________________
________________________________________________________________
_______________________________________________________________________________________
_________________________________________
3. Explain the behavior of molecules in an isotonic solution. _________________
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________
_______________________________________________________________________________________
_________________________________________
4. Does osmosis occur if a cell is placed in an isotonic solution? Explain. ______
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________________________________________________________________________
5. Why does water enter a cell that is placed in a hypotonic solution?__________
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________________________________________________________________________
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6. What happens to the turgor pressure inside a plant cell that is placed in a hypertonic solution?
________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________________________________________________________________________
7. What can happen to animal cells exposed to hypotonic solutions? What mechanism have some protests
evolved for living in a hypotonic environment?
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________
8. What causes a plant to wilt? _______________________________________
________________________________________________________________
2. Solution –
a. Example:
3. Solute 4. Solvent –
a. What is the most common solvent? ___________________________
5. Isotonic Solution –
a. Would osmosis occur in this situation?
6. Hypotonic Solution –
a. Which way will the water move?
7. Hypertonic Solution –
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a. Which direction will the water move?
8. Turgor Pressure –
a. High turgor pressure can cause
animal cells to burst. Why?
b. What would happen if there is
low turgor pressure in plants?
9. Contractile Vacuoles –
a. Uses ____________
b. Usually found in unicellular _________________________
c. This prevents them from bursting in a _________________________.
10. Plasmolysis –
a. What happens to a plant during plasmolysis?
i.
ii. The plants plasma membrane and cytoplasm _________________________________
_________________________________________
11. HYPOTONIC / HYPERTONIC – REVIEW
a. What will happen to an Elodea Leaf in a hypertonic solution?
i. Water will _____________________________________
ii. Which is called _____________________, which will cause the plant leaves to
______________
b. If we put Elodea leaves in a hypotonic solution, what happens?
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i. Water will ________________________________
ii. …which will cause the cell to ___________________. If it’s an animal cell it
will….______________________, UNLESS the cell has a
________________________to pump the water out.
1. Define the following terms:
A. Osmosis-________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________
B. Hypotonic Solution- _______________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________
C. Hypertonic Solution- ______________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________
D. Isotonic Solution- _________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________
2. In a hypotonic solution, how will water molecules move? _________________
_______________________________________________________________________________________
_________________________________________
3. In a hypertonic solution, how will water molecules move? _________________
_______________________________________________________________________________________
_________________________________________
4. In an isotonic solution, how will water molecules move? __________________
_______________________________________________________________________________________
_________________________________________
5. Explain how hypotonic conditions can make a plant become rigid. __________
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________
6. Explain how hypertonic conditions can make a plant wilt. _________________
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_______________________________________________________________________________________
_______________________________________________________________________________________
__________________
7. Osmosis is the diffusion of water molecules. What is the name for the diffusion of dissolved particles?
What special structures are involved in this process? ____
_______________________________________________________________________________________
_______________________________________________________________________________________
__________________________________________________________________________________
12. Selective Permeability –
a. Why is selective permeability important?
i. So the cell can allow important substance
_____________________________________and keep harmful substances out, like
________________________.
13. Passive Transport –
a. This process uses ___________________
b. Molecules moving from _________________________________________
14. Facilitated Diffusion –
a.
b. Example:
i. Glucose going from ______________________
outside the cell to ________________________
inside the cell
This is a ____________________
c. Why doesn’t this need energy?
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i. Because it’s still along the _______________________
15. Comparison of Diffusion and Facilitated Diffusion
16. Transport proteins –
17. Ion channels –
a. Ions like _____________________ are not _________________________, so they must
travel through __________________________
b. Ion channels are ion specific
c. Some channels are always open, some have gate
d. Gates open from stimuli: stretching of cell membrane, electrical or chemical signals
18. Active Transport –
19. ATP (adenosine tri-phosphate) –
a. Breaks down from ATP to_______________________
b. Hydrolysis of the phosphate ____________________________________
20. Sodium-potassium Pump –
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a. Creates an _______________________electrical gradient which is important for
_________________________________
.
21. Endocytosis –
22. Pinocytosis –
23. Phagocytosis –
a. Phagocytes –
i. Cells that ______________________________and _____________________ fuse w/
vesicle to destroy them before harm done
ii. http://www.youtube.com/watch?v=1w10R9lv7eQ
24. Exocytosis –
a. Cell exports _______________________________________________________ this way
b. This process uses __________
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Extra Stuff:
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