Hour) Unit 2-Plasma Membrane Transport Review

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Name: _______________________________________________ Class: APBIO / Rozema (3rd Hour)

Unit 2-Plasma Membrane Transport Review

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--Terminology--

Vocabulary Term Definition

1. Hydrophilic:

2. Hydrophobic:

3. Ion:

4. Integral Protein:

5. Peripheral Protein:

6. Glycoprotein:

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7. Glycolipid:

8. Cholesterol:

9. Homeostasis:

10. Surface Area “Equation”:

11. Volume “Equation”:

12. SemiPermeable:

13. Concentration:

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14. Hypertonic Cell:

15. Hypotonic Cell:

16. Isotonic Cell:

17. Hypertonic Solution:

18. Hypotonic Solution:

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19. Isotonic Solution:

20. Passive Transport:

21. Active Transport:

22. Diffusion:

23. Osmosis:

24. Facilitated Diffusion:

25. Channel Proteins:

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26. Carrier Proteins:

27. Aquaporins:

28. Water Potential:

29. Water Potential Equation:

30. Solute Potential Equation:

31. (i) Ionization Constant:

32. (R) Pressure Constant:

33. (T) Temperature:

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34. Phagocytosis:

35. Endocytosis:

36. Exocytosis:

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--Practice Free Response--

1. Cells are small because they are more efficient at supplying needed materials and removing waste than a large

cell. Here are two cubes representing cells. The formula for calculating the surface area of a cube is 6 x s2. The

formula for calculating the volume of a cube is s3. *Which cube would make for a better cell? Why? How does

this relate to Cell Biology?

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2. You prepare a slide of living elodea leaf and look at the cells under 40x magnification. You see many rectangular

shaped cells filled with green chloroplasts. While you are observing the tissue, you carefully place three drops of

4% salt solution next to the right side of the cover slip and draw the solution across the slide by holding a piece

of paper towel on the left edge of the cover slip. You notice that suddenly the chloroplasts have clustered into

the middle of every cell and are surrounded by a membrane. The cell walls remain unchanged. Explain what

has occurred and the mechanism behind it.

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3. The plasma membrane allows the selective passage of materials into and out of the cell.

a. Several macromolecules are involved in the formation of the plasma membrane. Identify three

structures within a typical animal plasma membrane that are involved in the transport of materials

across the plasma membrane, and explain the role of each of these components plays in regulating

the cell’s internal environment.

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b. Using what you know about the chemical properties of structures within the plasma membrane,

describe how each of the following might enter an animal cell:

i. Viral RNA:

ii. Steroid hormones:

iii. Water molecules:

iv. Oxygen gas

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4. Which figure depicts an animal cell placed into a solution hypotonic to the cell? Why? (Answer to the Right.)

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5. For each of the following labs, discuss the main Biology Concepts that were learned, and evidence/proof that

those principles exist:

Lab Biology Concepts Learned Proof/Evidence of Concepts

#1 (Surface Area

& Volume)

#2 (Dialysis Tubing)

#3 (Water

Potential & Potatoes)

*Students should be familiar with how to interpret, use, and calculate any data from these 3 labs, for the

Unit 2-Exam!

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--Practice Multiple Choice--

6. Which of the following is NOT true about water potential?

a. The water potential inside a cell is positive.

b. The water potential of pure water is zero.

c. Two factors that affect water potential are solute concentration and solute pressure.

d. Water will naturally move across a membrane from higher water potential to lower water potential.

7. Which one of the following would not normally diffuse through the lipid bilayer of a plasma membrane and

gives the reason for your answer?

a. CO2; because it is small and polar

b. Amino acid; because it is acidic and charged

c. Starch; because it is too large

d. Water; because it is strongly polar

8. Which of the following requires ATP?

a. The uptake of cholesterol by a cell

b. The facilitated diffusion of glucose into a cell

c. Countercurrent exchange

d. The diffusion of oxygen into a fish’s gills

9. Which of the following best characterizes the structure of the plasma membrane?

a. Rigid and unchanging

b. Rigid but varying from cell to cell

c. Fluid but unorganized

d. Very active

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10. Identify the hydrophilic portion of a lipid molecule. Answer: ________________

11. Identify the proteins involved in transport. Answer: ________________

12. Identify the structure involved in cell-to-cell communication. Answer: ______________

13. If a piece of potato is allowed to sit out on the counter and dry out, the water potential of the potato cells

would

a. Increase

b. Decrease

c. Remain the same

d. Increase, then decrease

14. Which of the following correctly indicates the gradient of water potential, knowing water must travel up a

plant?

a. Root, soil, stem, leaf, air

b. Soil, root, stem, leaf, air

c. Air, leaf, stem, root, soil

d. Root, leaf, stem, soil, air

15. In a diffusion lab with 6 bags of dialysis tubing, why do you use the percent change in mass rather than simply

the change in mass?

a. Doing so was arbitrary and applies to these instructions only; it really does not matter.

b. Doing so is the convention.

c. The percent change in mass is not as accurate.

d. The bags did not all weight exactly the same mass at the start, and percent provides consistency.

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16. The plasma membrane is selectively permeable and regulates what enters and leaves a cell. It consists of a

phospholipid bilayer embedded with proteins. Which of the following statements about the membrane is

correct?

a. Carbon dioxide is a polar molecule and readily diffuses through the hydrophilic layers of the membrane.

b. Starch readily diffuses across the membrane into the liver, where it is stored as glycogen.

c. Aquaporins are special water channels in the plasma membrane that facilitate the uptake of large

amounts of water without the expenditure of energy.

d. Oxygen passes through the cristae membrane of the mitochrondria mainly through ATP synthase

channels.

17. Active Transport involves the movement of a substance across a membrane against its concentration or

electrochemical gradient. Active transport is mediated by specific transport proteins and requires the

expenditure of energy. Which of the following statements describes an example of active transport?

a. Glucose is transported across some membranes by carrier proteins down a concentration gradient.

b. Freshwater protists such as amoeba and paramecia have contractile vacuoles that pump out excess

water.

c. Countercurrent exchange in the capillaries of fish gills enables fish to absorb large amounts of oxygen

from the surrounding water, where oxygen levels are low, even if already containing sufficient

concentrations of oxygen.

d. A red blood cell will lyse (burst) if placed into a hypotonic solution because large amounts of water flood

into the cell.

18. Which of the following works against concentration gradients that can then be used to help with dynamic

homeostasis in cells?

a. Active Transport

b. Diffusion

c. Facilitated Diffusion

d. Osmosis

19. A red blood cell is approximately 1% sodium by concentration. How would you describe a red blood cell in a

beaker of pure water?

a. The red blood cell is hypotonic to the surrounding water.

b. The red blood cell is hypertonic to the surrounding water.

c. The red blood cell is isotonic to the surrounding water.

d. The red blood cell does not have any tonicity compared to the surrounding water.

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20. The sodium-potassium pump is an enzyme located in the plasma membrane of all animal cells. The sodium

potassium pump is illustrated above in four different stages of its mechanism. The pump uses energy derived

from ATP hydrolysis to move three sodium ions out of the cell and two potassium ions into the cell. The

movement of sodium and potassium ions across the plasma membrane in this fashion is an example of which

of the following?

a. Passive transport

b. Active transport

c. Facilitated diffusion

d. Endocytosis

21. Which of the following types of transport involves the movement of a substance from an area of higher

concentration to an area of lower concentration? (Choose ALL correct.)

a. Osmosis

b. Active transport

c. Facilitated transport

d. Sodium-potassium pumps

22. Suppose a toxin has been applied which forms pores in the cell membrane of neuron cells. Which of the

following accurately describes the movement and change in charge associated with the flow of sodium ions?

a. The sodium ions would rush out of the cell causing a depolarization of the membrane.

b. The sodium ions would rush out of the cell causing a repolarization of the membrane.

c. The sodium ions would rush into the cell causing a depolarization of the membrane.

d. The sodium ions would rush into the cell causing a repolarization of the membrane.

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The cell membrane organization is referred to as the fluid mosaic model due to the fluid-like flexibility and structure of

the membrane. The structure above displays the plasma membrane of a cell including different types of membrane

associated proteins. Depending upon the function of the proteins, they may be present on one side of the membrane,

or may span the membrane. Some proteins are glycosylated, which have exposed sugar chains.

23. Which of the labeled structures in the figure above represents an integral protein?

a. Structure A

b. Structure B

c. Structure C

d. Structure D

24. Which of the labeled structures in the figure may allow for the movement of small ions such as Calcium into

the cell?

a. Structure A

b. Structure B

c. Structure C

d. Structure D

25. A glycoprotein is depicted in the model above. Which of the following accurately describes the role of these

proteins?

a. To facilitate the transmembrane movement of small ions such as sodium or potassium down their

respective concentration gradients.

b. To facilitate adhesion and cell recognition to other cells.

c. To increase fluidity of the cell membrane.

d. To serve as a receptor for cell signaling.

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26. A key characteristic of the plasma membrane is its semi-permeability to substances. Which of the following

may pass through the membrane by simple diffusion?

a. Large polar molecules

b. Proteins

c. Small ions

d. Small Hydrophobic molecules

27. The cell pictured was placed in a hypertonic solution. Which of the following describes the movement of

water, if any, across the cell membrane?

a. Into the cell

b. Out of the cell

c. Equal movement into and out of the cell

d. Into the space between the two layers of the phospholipid bilayer

28. An animal cell is bathed in a hypertonic solution. Which of the following is expected to occur?

a. The cell will remain the same size due to equivalent movement of water into and out of the cell.

b. The cell will shrink due to movement of water out of the cell.

c. The cell will expand due to movement of water into the cell.

d. The cell will stay the same size due to its cell wall, but its membranes will shrink.

29. The value for water potential in root tissue was found to be -0.15MPa. If you take the root tissue and place it

in a 0.1M solution of sucrose (with a water potential of -0.23MPa), which of these would describe the

movement of water?

a. The net flow of water would be from the tissue into the sucrose solution.

b. The net flow of water would be from the sucrose solution into the soil.

c. Water would flow in both directions with no net change.

d. Water would flow from the soil into the root tissue where water potential is higher.

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30. In the left hand panel, potassium and water are both moving into the guard cells, and the use of ATP is high.

Why?

a. Energy is required to move water molecules into the guard cells.

b. Water is being lost through the stoma by transpiration.

c. Energy is required to move oxygen into the leaf through the stoma.

d. Energy is required to move potassium into the guard cells against the gradient.

31. What is true of the guard cells shown in the right hand panel of this figure?

a. Their turgor pressure is increasing.

b. Their water potential is lower than the surrounding cells.

c. Their water potential is higher than the surrounding cells.

d. These cells are hypotonic.

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Below refers to an experiment in which there is an initial setup of a U-tube with its two sides separated by a

membrane that permits the passage of water and NaCl but not molecules of glucose. The U-tube is filled on one side

with a solution of 0.4Mglucose and 0.5MNaCl, and on the other, 0.8Mglucose and 0.4MNaCl.

32. When this U-tube was set up, at time zero in the experiment, which of the following was true?

a. The solution on side A was hypertonic to the solution on side B.

b. The solution on side B was hypertonic to the solution on side A.

c. The two solutions were isotonic.

d. Active transport moved glucose from side A to side B.

33. After the experiment ran for 1 hour, the expected fluid levels in the U-tube would be

a. Higher on side A than side B

b. Higher on side B than side A

c. Even

d. Equal, but the solutes would be reverse

34. At the conclusion of the experiment, the NaCl would

a. Show no movement

b. Show some movement from side A to side B

c. Show some movement from side B to side A

d. Make side A hypertonic

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Hour) Unit 2-Plasma Membrane Transport Review