Ch. 5

Question 1

1. The process of _______ arises from the molecular agitation that exists in all systems above absolute zero and the tendency for such agitation to carry more molecules out of regions of relatively high concentration than into these regions.
   a. solute affinity
   b. facilitated diffusion
   c. active transport
   d. diffusion
   e. osmosis

Answer 1

D

Question 2

2. Outward diffusion of a substance from an animal cell increases the concentration of that substance around the outer surface of the cell. This surface is called the
   a. boundary layer.
   b. bulk solution of the cell.
   c. stagnant diffusion membrane.
   d. region of backup diffusion.
   e. low-concentration region.

Answer 2

A

Question 3

3. In the Fick diffusion equation, if the units of D are cm2 ∙ s‒1, which of the following best represents the units for J?
   a. Moles ∙ cm‒2 ∙ s‒1
   b. M ∙ cm ∙ s
   c. Moles ∙ sec‒1
   d. M ∙ g‒1 ∙ cm‒2
   e. M ∙ cm2 ∙ s

Answer 3

A

Question 4

4. When X increases in the Fick diffusion equation, J
   a. also increases.
   b. decreases.
   c. remains the same.
   d. can increase or decrease.
   e. None of the above; J and X are not related.

Answer 4

B

Question 5

5. According to the Fick diffusion equation, which letter represents permeability?
   a. J
   b. Permeability is integrated into D
   c. Permeability is integrated into C1 – C2
   d. C1 ‒ C2
   e. X

Answer 5

B

Question 6

7. Outward diffusion of a substance from an animal cell increases the concentration of that substance around the outer surface of the cell. If this process continues,
   a. the rate of diffusion will increase.
   b. the rate of diffusion will decrease.
   c. the rate of diffusion will remain the same.
   d. active transport will be initiated.
   e. the rate of diffusion will increase or decrease, depending on the substance.

Answer 6

B

Question 7

10. If a change in the voltage of a cell membrane causes all the voltage-gated Na+ channels to open, the permeability of the cell membrane to Na+ has been
    a. inhibited.
    b. decreased.
    c. unaffected.
    d. destroyed.
    e. increased.

Answer 7

E

Question 8

11. A solution that has a concentration effect on diffusion that is equal, but opposite, to the electrical effect is said to be
    a. in a steady state.
    b. part of the Nernst equation.
    c. in isoelectric balance.
    d. in electrochemical equilibrium.
    e. permeable.

Answer 8

D

Question 9

12. In the animal cell, the overall concentration effects on Na+ diffusion cause Na+ to _______ the cell.
    a. move into
    b. move out of
    c. remain equal on both sides of
    d. remain inside of
    e. remain outside of

Answer 9

A

Question 10

13. In the animal cell, the overall electrical effects on Cl‒ diffusion cause Cl‒ to _______ the cell.
    a. move into
    b. move out of
    c. remain equal on both sides of
    d. remain inside of
    e. remain outside of

Answer 10

E

Question 11

14. In the animal cell, the combined concentration and electrical effects on K+ cause K+ to _______ the cell.
    a. move into
    b. leak out of
    c. remain equal on both sides of
    d. remain inside of
    e. remain outside of

Answer 11

B

Question 12

15. Among the ions outside and inside a typical living cell, which ion is furthest from electrochemical equilibrium?
    a. Cl‒
    b. Na+
    c. K+
    d. Mg2+
    e. Ca2+

Answer 12

B

Question 13

19. Which of the following statements about facilitated diffusion is false?
    a. Diffusion occurs in the direction of electrochemical equilibrium.
    b. Solutes move faster with the protein facilitators than they would without them.
    c. Solutes bind reversibly to the protein facilitators.
    d. Protein facilitators change conformation with the help of ATP.
    e. Facilitated diffusion can occur across a cell membrane.

Answer 13

D

Question 14

20. In the intestine, glucose is brought into the cell membrane by
    a. simple diffusion.
    b. active transport.
    c. facilitated diffusion.
    d. chemiosmosis.
    e. osmosis.

Answer 14

C

Question 15

23. Which of the following best represents an electrogenic process?
    a. Glucose transport into the small intestine epithelium
    b. Acid production in the stomach
    c. Sodium uptake in the freshwater fish gill
    d. The sodium‒potassium pump on a typical cell membrane
    e. None of the above

Answer 15

D

Question 16

27. On the cell membrane, the Na+‒ K+ pump transports _______ in for every _______ that it transports out.
    a. 3 Na+; 2 K+
    b. 2 Na+; 3 K+
    c. 3 K+; 2 Na+
    d. 2 K+; 3 Na+
    e. 3 K+; 3 Na+

Answer 16

D

Question 17

28. The molecular species that binds and unbinds to the Na+‒K+-ATPase, causing sodium and potassium to shuttle through it, is
    a. PO42‒.
    b. ATP.
    c. Na+‒K+-ATPase.
    d. ADP.
    e. None of the above

Answer 17

B

Question 18

29. Which of the following statements about the transport of glucose into the gut epithelial cell through the apical membrane is true?
    a. The glucose transporter on the apical membrane uses ATP-bond energy.
    b. The Na+ transporter on the apical membrane uses ATP-bond energy.
    c. Glucose diffuses through the apical membrane using its own concentration gradient; therefore, it does not use any energy.
    d. Na+ uses ATP-bond energy as it brings in glucose at the apical membrane.
    e. ATP-bond energy is used at the Na+‒K+ pump in setting up the Na+ gradient.

Answer 18

E

Question 19

35. Which of the following statements about ion transport in the typical freshwater fish gill is true?
    a. Na+ and HCO3‒ are transported into the blood plasma.
    b. Na+ and Cl‒ are transported into the water.
    c. Na+ and H+ are transported into the blood plasma.
    d. H+ and K+ are transported into the water.
    e. Na+ and Cl‒ are transported into the blood plasma

Answer 19

E

Question 20

36. Which of the following statements regarding channels and transporters is false?
    a. Multiple molecular forms of channel and transporter proteins are common.
    b. The forms and amounts of channel and transporter proteins in a particular cell are under the control of gene expression.
    c. Channel and transporter proteins have rapid turnover on the plasma membrane.
    d. Channel and transporter proteins are subject to covalent and noncovalent modulation.
    e. Channel and transporter proteins can be inserted into or retrieved from the plasma membrane.

Answer 20

C

Question 21

37. Which of the following depends simply on the number of dissolved entities per unit of volume rather than the chemical nature of the dissolved entities?
    a. Colligative properties
    b. Osmotic pressure
    c. Freezing point
    d. Osmolarity
    e. Ultrafiltration

Answer 21

A

Question 22

38. The osmotic pressure of a solution _______ the concentration of dissolved entities.
    a. is double
    b. is approximately proportional to
    c. is specific to
    d. is exponentially related to
    e. has no relationship to

Answer 22

B

Question 23

39. Which of the following measures is not affected by the colligative properties of an aqueous solution?
    a. Freezing point
    b. Boiling point
    c. Temperature
    d. Osmotic pressure
    e. water-vapor pressure

Answer 23

C

Question 24

40. A 1-M solution of Na2SO4 has _______ a-1M solution of glucose.
    a. one-third the osmolarity of
    b. twice the osmolarity of
    c. half the osmolarity of
    d. three times the osmolarity of
    e. the same osmolarity as

Answer 24

D

Question 25

41. A 1-osmolar solution a. has 1 kg of dissolved entities per liter. b. has 1 dalton of dissolved entities per liter. c. is a 1-M solution d. has 1.0 × 1023 independent dissolved entities per liter. e. has 6.022 × 1023 independent dissolved entities per liter.

Answer 25

E

Question 26

42. Most marine invertebrates typically have internal fluids of a. 500 Osm. b. 1 mOsm. c. 1 Osm. d. 10 Osm. e. 300 mOsm.

Answer 26

C

Question 27

43. A 1-M solution of serum albumin (66,000 daltons) has _______ a 1-M solution of urea (66 daltons). a. one-thousandth the osmolarity of b. twice the osmolarity of c. half the osmolarity of d. one thousand times the osmolarity of e. the same osmolarity as

Answer 27

E

Question 28

47. Which of the following statements regarding osmosis is true? a. Water cannot be described in terms of concentration. b. Osmotic pressure is inversely proportional to temperature. c. Large concentration gradients across cell membranes can generate osmotic pressure. d. Osmosis applies only to the movement of salts. e. None of the above

Answer 28

C

Question 29

48. The passive transport of water across a membrane is called a. facilitated diffusion. b. diffusion. c. osmotic pressure. d. osmosis. e. aquaporins.

Answer 29

D

Question 30

49. When two solutions exchange water by osmosis, water always moves a. from the solution with the lower osmotic pressure to the one with the higher osmotic pressure. b. from the solution with the higher osmotic pressure to the one with the lower osmotic pressure. c. in the direction of gravity. d. via facilitated diffusion. e. from the lowest water concentration to the highest water concentration.

Answer 30

A

Question 31

50. If you were to drop a mammalian red blood cell into a 10 mOsm solution, the red cell would _______ in this _______ solution. a. maintain a constant volume; isosmotic b. shrivel; hyposmotic c. swell and burst; hyposmotic d. swell and burst; hyperosmotic e. shrivel; hyperosmotic

Answer 31

C

Question 32

1. In the Fick equation, J measures a. the total diffusion. b. the rate of diffusion. c. the net rate of diffusion. d. concentration. e. concentration differences.

Answer 32

C

Question 33

2. Which of the following is not a variable in the Fick equation? a. The concentration in the relatively concentrated solution b. Distance separating regions of high and low concentration c. Concentration difference d. Diffusion coefficient e. Charge

Answer 33

E

Question 34

3. According to the Fick equation, what happens to J when X (the distance between the two concentrations) is increased? a. The net rate of diffusion decreases b. Diffusion changes direction c. The concentration increases d. The net rate of diffusion increases e. The diffusion coefficient increases

Answer 34

A

Question 35

4. Boundary layers tend to a. increase the net rate of diffusion. b. decrease the net rate of diffusion. c. increase the rate of evaporation. d. affect permeability only. e. increase the local rate of diffusion but not the net rate of diffusion.

Answer 35

B

Question 36

5. Electrical charges on molecules _______ diffusion across a membrane. a. play a large role in b. play an insignificant role in c. accelerate d. inhibit e. are required for

Answer 36

A

Question 37

6. Which of the following is not a type of gated channel? a. Voltage-gated b. Stretch-gated c. Phosphorylation-gated d. Ion-gated e. Ligand-gated

Answer 37

D

Question 38

7. In a typical animal cell, K+ tends to leak a. into the cell due to its electrical gradient. b. into the cell due to its concentration gradient. c. out of the cell due to its electrical gradient. d. out of the cell due to its concentration gradient. e. into or out of the cell depending on where Na+ is moving.

Answer 38

D

Question 39

8. A membrane that is permeable to only Na+ separates two solutions. The initial solutions are a 1M solution of K+ on the left side of the membrane and a 1M solution of Na+ on the right side. What will occur? a. Na+ will diffuse to the left side of the membrane, causing a net positive charge on the right side. b. Na+ will diffuse to the left side of the membrane, causing a net negative charge on the right side. c. Na+ will diffuse to the left side of the membrane, but there will be no separation of charges. d. There will be no net movement of ions. e. The movement of Na+ will be balanced out by the movement of K+; therefore, there will be no net charge difference.

Answer 39

B

Question 40

9. A membrane that is permeable to Na+ and K+ separates two solutions. The initial solutions are a 1-M solution of K+ on the left side of the membrane and a 1 M solution of Na+ on the right side. What will occur? a. Na+ will diffuse to the left side of the membrane, causing a net positive charge on the right side. b. Na+ will diffuse to the left side of the membrane, causing a net negative charge on the right side. c. Na+ will diffuse to the left side of the membrane and K+ will not diffuse; however, there will be no separation of charges. d. There will be no net movement of ions. e. The movement of Na+ will be balanced out by the movement of K+; therefore, there will be no net charge difference.

Answer 40

E

Question 41

10. Which of the following statements about facilitated diffusion is false? a. It always occurs in the direction of electrochemical equilibrium. b. It is a form of passive transport. c. Energy is used by the proteins in the transport process. d. Solutes transported by this mechanism move across membranes much more quickly than they would if they did not associate with transporter proteins. e. Solutes bind reversibly with the binding sites on transporter proteins.

Answer 41

C

Question 42

11. The proton pump in the stomach is an example of a(n) _______ pump. a. electroneutral b. electrogenic c. passive d. glucose-mediated e. facilitated

Answer 42

A

Question 43

12. Na+‒K+-ATPase pumps _______ the cell while _______ the cell. a. 2 Na+ out of; pumping 3 K+ into b. 3 Na+ into; pumping 2 K+ out of c. 3 Na+ out of; pumping 2 K+ into d. 2 Na+ into; pumping 3 K+ out of e. 3 Na+ out of; K+ passively moves into

Answer 43

C

Question 44

13. Which of the following is the best description of the immediate process by which glucose is transported across the epithelial membrane of the small intestine? a. Active transport using Na+ b. Cotransport with K+ c. Active transport using ATP d. Cotransport with Na+ e. Secondary passive transport

Answer 44

D

Question 45

14. According to the whole-epithelium view of the gill, how does Cl‒ enter the gill membrane of a freshwater teleost fish? a. Passive countertransport with HCO3‒ b. Passive cotransport with Na+ c. Active countertransport with HCO3‒ d. Active cotransport with HCO3‒ e. Active cotransport with Na+

Answer 45

C

Question 46

15. Energy is used by _______ when bringing glucose into the intestinal epithelial cell. a. Na+‒K+-ATPase b. the Na+-glucose cotransporter c. Na+‒H+-ATPase d. the K+-glucose cotransporter e. None of the above; the process of glucose transport does not use energy.

Answer 46

A

Question 47

16. Which of the following is not a probable method of modulating channel or transporter function? a. The existence of multiple molecular forms of the same channel or transporter b. Control of the tissue-level expression of channels or transporters by gene expression c. Modification of channels or transporters by ligands d. Blocking or permanent disabling of channels or transporters by ligands e. Insertion or removal of channels or transporters from the plasma membrane

Answer 47

D

Question 48

17. The colligative properties of an aqueous solution are the properties that depend on the a. concentration of non-ionic particles dissolved in solution. b. number of dissolved entities per unit volume. c. number of dissolved entities per unit volume as well as their chemical nature. d. concentration of ions dissolved in solution. e. number of dissolved entities per unit volume, their chemical nature, and the number of suspended particles in the solution.

Answer 48

B

Question 49

18. A 5 mOsm solution behaves as if it has a. 5 Avogadro’s number of independent dissolved entities per liter. b. 1 Avogadro’s number of independent dissolved entities per liter. c. 5 M of dissolved nonionic entities. d. 5 mM dissolved nonionic entities. e. 0.005 Avogadro’s number of independent dissolved entities per liter.

Answer 49

E

Question 50

19. The passive transport of water across a membrane is called a. osmotic pressure. b. osmosis. c. diffusion. d. ultrafiltration. e. oncotic transport.

Answer 50

B

Question 51

20. The blood plasma of a freshwater teleost fish is _______ relative to the pond water in which it lives. a. diluted b. isotonic c. isosmotic d. hyposmotic e. hyperosmotic

Answer 51

E