Unit 4 Review Sheet
Name ___________________________________
1. Diffusion is the movement of molecules from the area of _____High______concentration to the area of
______Low______concentration.
2. Osmosis is the movement of _____Water_______across a selectively permeable membrane.
3. A cell is isotonic to a solution of 0.01% sugar.
A. What concentration would by hypertonic? ________anything > 0.01 %___________
B. What concentration would be hypotonic? _________anything < 0.01 %___________
4. a) What happens to an animal cell in a hypotonic solution? _Water Enters the cell, cell expands and bursts__
b) What happens to an animal cell in a hypertonic solution? _Water leaves the cell and cell shrinks____
5. List 3 ways in which active transport differs from the process of diffusion across a cell membrane.
I.
II.
III.
Active uses energy, diffusion does not
Active goes against concentration gradient (low to high), diffusion goes down (high to low)
Active uses carrier proteins, diffusion uses channel proteins
6. List 2 ways in which facilitated transport differs from active transport.
I. Facilitated does not use energy (its passive transport), active uses energy
II. Facilitated goes down the concentration gradient (High to low), active goes against (low to high)
7. Within each of the three pairs, choose the more concentrated solution:
1st Pair: a. 80% water, 20% starch
b. 90% water, 10% starch
Most Concentrated _______A________
2nd Pair: a. 5 g salt, 50 g water
b. 5 g salt, 25 g water
Most Concentrated ______B_________
3rd Pair: a. 85% solvent, 15% solute
b. 75% solvent, 25% solute
Most Concentrated ______B_________
True or False:
8.
9.
10.
11.
If a plant cell is placed in salt solution, the central vacuole will shrink TRUE
If a red blood cell is placed in distilled water (no solutes), it will shrink FALSE
If a plant cell is placed in distilled water (no solutes), the cell membrane will lose internal pressure FALSE
If a red blood cell is placed in a salt solution, salt will enter the cells, giving them a strange appearance
FALSE
12. A small lipid molecule passes easily through the cell membrane. Which of these statements is the most likely
explanation?
A.
B.
C.
D.
A protein carrier must be at work
The cell membrane is partly composed of lipid molecules and simple diffusion is occurring
The cell is expending (using) energy to do this
Phagocytosis has enclosed this molecule in a vacuole
13. Which of these does not require an expenditure (usage) of energy?



Diffusion
Osmosis
Phagocytosis



Facilitated Diffusion
Endocytosis
Exocytosis
14. The thyroid gland contains a high concentration of iodine. Adding iodine to an area that already has a high
concentration would be an example of:
A.
B.
C.
D.
passive transport
active transport
facilitated diffusion
exocytosis
15. Cell drinking is synonymous with a) cell eating b) endocytosis c) phagocytosis d) pinocytosis
16. Which of the following substances would be taken into a cell by phagocytosis?
A.
B.
C.
D.
water
proteins
simple sugars
small lipids
17. An animal cell will always take in water when placed in a (n):
A.
B.
C.
D.
hypertonic solution
hypotonic solution
isotonic solution
active solution
Consider the diagram to the right.
Note: This is not a cell.
18. Will the concentration of water on
side A stay the same, increase, or
decrease over time? _____Increase___
Side A
Side B
20% Protein
2% Glucose
4% Glucose
75% w ater
98% Water
E.
membrane
19. Will the concentration of protein on side A stay the same, increase, or decrease over time? __Decrease___
20. Glucose will cross the membrane in which direction? ___Right to Left_____
21. What type of transport is being represented by the diagram below? ______Passive (Diffusion)____________
22. On the same diagram as 21, label the phosphate groups (polar heads) and the fatty
acid tails.
22. What molecule helps stabilize the plasma membrane’s fatty acids and keeps it flexible?
_______Cholesterol_________
23. What is a tell-tale sign that the kidneys are failing? _______Protein is found in urine_________________