Florida International UniversityBIO PCB 4023

Chapter 4

1)What is responsible for the unequal distribution of ions across a membrane, thereby causing a charge?

1. 1. the ability of permeable ions to pass through a membrane
   2. the concentration of impermeable charged molecules
   3. the concentration of carrier proteins in the membrane
   4. the semipermeable membrane
   5. the concentration of ions seeking equilibrium with respect to their charge
2. The chemical force for which of the following ions is directed into the cell?
   1. calcium only
   2. potassium only
   3. sodium only
   4. both potassium and sodium
   5. both sodium and calcium
3. Which of the following is found in greater concentration inside the cell than outside?
   1. water B) sodium C) potassium D) chloride E) calcium
4. When molecules are passively transported across a membrane, the direction of their movement is dictated by the molecule's tendency to move
   1. into a cell.
   2. out of a cell.
   3. from lower to higher energy.
   4. from higher to lower energy.
   5. in both directions; there is no preference.
5. Of the gradients listed below, which is the MOST accurate description of the force that ultimately determines the movement of ions across the membrane?
   1. electrochemical gradient
   2. electrical gradient
   3. chemical gradient
   4. potential gradient
   5. concentration gradient
6. Molecules tend to move spontaneously    their chemical gradient.
   1. through B) down C) over D) around E) up

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7. When more than one ion species (i.e., Na+ and K+) is present on both sides of the membrane, the chemical driving force acting on Na+ will include
   1. all ions present.
   2. all negatively charged ions.
   3. all positively charged ions.
   4. sodium only.
   5. the most concentrated ion only.
8. Which of the following is a reflection of the unequal distribution of positive and negative ions across the plasma membrane?
   1. extracellular potential
   2. membrane potential
   3. chemical driving force
   4. electrochemical driving force
   5. chemical gradient
9. Comparing intracellular to extracellular fluid, the intracellular fluid has a        charge relative to the

outside of a cell due to the presence of more in that solution.

9. 1. positive : cations
   2. neutral : cations
   3. negative : anions
   4. negative : cations
   5. positive : anions
10. The unequal distribution of charge in solutions on either side of a membrane will lead to a  of charge across the membrane and a   of counter ions in a region close to the membrane.
    1. collection : restriction
    2. collection : clustering
    3. separation : clustering
    4. buildup : restriction
    5. separation : restriction
11. If the solutions on either side of the membrane have an unequal distribution of charged ions, with the inside having an excess of anions, then the inside of the cell would have to be
    1. less negative, relative to the outside of the cell.
    2. more highly charged than the outside of the cell.
    3. less highly charged than the outside of the cell.
    4. more negative, relative to the outside of the cell.
    5. more positive, relative to the outside of the cell.

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12. As an ion moves passively across a membrane into the cell, the progressive increase in concentration within the cell will
    1. accelerate the rate of diffusion.
    2. decrease the net flux across the membrane.
    3. increase the net flux across the membrane.
    4. decrease the need for active transport to continue transporting.
    5. cause a switch to facilitated diffusion.
13. Based solely upon its electrical charge, the inside of a typical cell will tend to attract extracellular  to move inward.
    1. ions whose concentration gradient allows them
    2. cations
    3. proteins
    4. anions
    5. uncharged ions
14. Which of the following is NOT a determinant of the magnitude and direction of the equilibrium potential for an ion?
    1. charge of the ion
    2. valence of the ion
    3. chemical driving force
    4. concentration gradient
    5. lipid solubility of the ion
15. If a positively charged ion is more concentrated outside the cell, the electrical forces required to balance the chemical gradient would be directed   . Thus, the equilibrium potential for this ion would be

              charged.

1. 1. outward : negatively
   2. inward : negatively
   3. outward : positively
   4. inward : positively
   5. outward : neutrally

16. Which of the following cells would have a greater electrical attraction for sodium ions to enter the cell?
    1. cell with membrane potential = -50 mV
    2. cell with membrane potential = 0 mV
    3. cell with membrane potential = -70 mV
    4. cell with membrane potential = -90 mV
    5. cell with membrane potential = +20 mV

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17. If a positively charged ion is more concentrated inside the cell, the electrical forces required to balance the chemical gradient would be directed   . Thus, the equilibrium potential for this ion would be

              charged.

17. 1. outward : neutrally
    2. inward : positively
    3. outward : positively
    4. outward : negatively
    5. inward : negatively
18. Which of the following can be used to determine an ion's equilibrium potential?
    1. Nernst equation
    2. concentration of an ion only
    3. Navier-Stokes equation
    4. oscilloscope
    5. intracellular voltmeter
19. The potassium equilibrium potential is -94 mV. What does this mean?
    1. At -94 mV, potassium movement is opposed exactly by sodium movement.
    2. At -94 mV, the chemical force for potassium movement is opposed exactly by the electrical force.
    3. At -94 mV, the electrical force for potassium movement is zero.
    4. At the resting membrane potential of neurons, potassium is at equilibrium.
    5. At -94 mV, the chemical force for potassium movement is zero.
20. Chloride has an equilibrium potential of -90 mV. What direction are the chemical and electrical forces acting on the anion at the resting membrane potential (-70 mV)?
    1. The chemical force is directed into the cell and the electrical force is directed out of the cell.
    2. Both the chemical and electrical forces are directed out of the cell.
    3. The chemical force is directed out of the cell and the electrical force is directed into the cell.
    4. Both the chemical and electrical forces are directed into the cell.
    5. There is insufficient information to answer this question.
21. What effect would increasing the extracellular concentration of K+ have on the resting membrane potential (RMP)?
    1. The effects are really seen on the generating potential.
    2. Increasing extracellular K+ will have no effect on the RMP because of the Na+/ K+ pump.
    3. Increasing extracellular K+ will have no effect on the RMP because it displaces Na+.
    4. The RMP would become more negative.
    5. The RMP would become more positive (less negative).

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22. An anion is found in greater concentration inside the cell than outside. Which of the following statements BEST describes forces acting on the anion at the resting membrane potential (-70 mV)?
    1. The chemical force is directed into the cell and the electrical force is directed out of the cell.
    2. Both the chemical and electrical forces are directed out of the cell.
    3. The chemical force is directed out of the cell and the electrical force is directed into the cell.
    4. Both the chemical and electrical forces are directed into the cell.
    5. There is insufficient information to answer this question.

23. The equilibrium potential for a cation is +120 mV. Which of the following statements is TRUE when a cell is at the resting membrane potential (-70 mV)?
    1. The chemical force is directed into the cell and the electrical force is directed out of the cell.
    2. Both the chemical and electrical forces are directed out of the cell.
    3. The chemical force is directed out of the cell and the electrical force is directed into the cell.
    4. Both the chemical and electrical forces are directed into the cell.
    5. There is insufficient information to answer this question.
24. The equilibrium potential describes the membrane potential where what two forces are balanced?
    1. density and magnetic
    2. electrical and permeability
    3. temperature and density
    4. chemical and electrical
    5. chemical and temperature
25. Which of the following is NOT required to determine equilibrium potential of a particular ion?
    1. charge or valence of the ion
    2. size of the ion
    3. temperature
    4. the log of the concentration ratio
    5. concentration gradient for ion across the membrane
26. Which of the following would NOT increase the rate of simple diffusion across the phospholipid bilayer of the plasma membrane?
    1. greater concentration gradient
    2. greater lipid solubility
    3. greater available surface area
    4. greater number of protein carriers
    5. smaller size

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27. Which of the following pairs of characteristics is more likely to make a substance diffuse through the cell membrane?
    1. large, amphipathic molecule
    2. small, non-polar molecule
    3. large, polar molecule
    4. small, polar molecule
    5. large, non-polar molecule
28. Oxygen diffuses from blood into cells down its concentration gradient. As cells become more active and oxidative phosphorylation increases in the cell, which of the following occurs?
    1. The concentration gradient for oxygen and its rate of movement into the cell do not change.
    2. The concentration gradient for oxygen increases and oxygen movement into the cell decreases.
    3. The concentration gradient for oxygen decreases and oxygen movement into the cell increases.
    4. The concentration gradient for oxygen decreases and oxygen movement into the cell decreases.
    5. The concentration gradient for oxygen increases and oxygen movement into the cell increases.
29. As a cell's metabolism increases, so does its O2 consumption, giving rise to what product at a ratio of 2:1?
    1. H2O
    2. ATP
    3. CO2
    4. lactic acid
    5. pyruvic acid
30. If a molecule crosses a membrane and is quickly removed from the area by the blood stream or some

biological pathway, what effect does this have on its rate of diffusion?

30. 1. Diffusion rate will progressively decrease until zero.
    2. Diffusion rate will decrease.
    3. Diffusion rate will increase.
    4. Diffusion rate will not be affected.
    5. Diffusion rate will remain constant.
31. The diffusion rate is
    1. the amount of material to diffuse through a membrane.
    2. the thickness of the membrane through which a material has to diffuse.
    3. fastest at body temperature.
    4. the amount of time necessary for diffusion to take place.
    5. the speed at which diffusion takes place.

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32. The concentration of sodium is greater in the extracellular fluid compared to the intracellular fluid. If the membrane potential was equal to the equilibrium potential for sodium, then what would be the direction of the electrochemical force acting on sodium?
    1. inward
    2. outward
    3. equal in both directions
    4. varies by cell
    5. varies based on concentration of potassium in the intracellular and extracellular fluids
33. If a cell's Na+/ K+ pump worked in reverse and had more leak channels for Na+ than for K+, what would the ion concentrations of the cell look like?
    1. The cell would swell since water follows Na+.
    2. Intracellular Cl- would be increased, following Na+.
    3. Although the body tries to maintain an extracellular concentration of Na+ at 145mM, the intracellular concentration of Na+ would still be higher.
    4. Intracellular concentration of K+ would still be higher than Na+ because the body tries to maintain an extracellular concentration of Na+ at 145 mM.
    5. Intracellular anions would decrease in number.
34. One way that membrane surface area is increased in absorptive cells is through increasing the     of the apical membrane.
    1. number of protein carriers
    2. number of protein channels
    3. receptor number
    4. thickness
    5. folding
35. When a substance crossing the membrane is driven by diffusion, the net flux of that molecule can be described mathematically by
    1. the Nernst equation.
    2. Fick's law.
    3. the Goldman-Hodgkin-Katz equation.
    4. the Navier-Stokes equation.
    5. Einstein's equation.
36. Which of the following will NOT increase the net flux of an ion across a membrane?
    1. elevated permeability of the membrane
    2. more channels for that ion in the membrane
    3. enhanced surface area
    4. increased concentration gradient across the membrane
    5. reduced surface area

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37. Molecules with a relatively high lipid solubility are capable of crossing the membrane
    1. directly through the lipid bilayer.
    2. only with the addition of energy.
    3. indirectly by moving across a carrier protein.
    4. only through specific protein channels.
    5. through specific lipid channels.
38. With pulmonary hypertension, the lung's capillary walls become thicker to compensate for the higher pressure. What does Fick's law suggest will happen to CO2 concentrations?
    1. CO2 levels in the tissues will decrease.
    2. CO2 levels in the blood will remain the same.
    3. CO2 levels in the cells will decrease.
    4. CO2 in the alveoli will increase.
    5. CO2 levels in the blood will increase.
39. Which of the following molecules is LEAST likely to diffuse through the phospholipid bilayer of the plasma membrane?
    1. water
    2. fatty acid
    3. disaccharide
    4. oxygen
    5. steroids
40. Which of the following is NOT true for all three of these transport mechanisms: facilitated diffusion, primary active transport, and secondary active transport?
    1. Transport can be increased by increasing the number of transport molecules in the plasma membrane.
    2. The transport mechanism has a limit to the total number of molecules that can be transported per unit of time.
    3. The transport mechanism requires energy.
    4. The transport mechanism is specific for (a) particular solute(s).
    5. The transport mechanism requires a protein.
41. Which of the following transport mechanisms is passive?
    1. movement of sodium through ion channels
    2. countertransport of hydrogen ions with sodium
    3. transport of sodium and potassium across the membrane by the Na+/ K+ pump
    4. movement of calcium out of the cytosol
    5. cotransport of glucose with sodium

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42. A carrier is a transmembrane protein that moves molecules across the membrane through
    1. conformational changes in its protein shape.
    2. opening its gate and allowing molecules through.
    3. small gaps in the fluid portion of the membrane.
    4. a lipid-filled pore.
    5. a water-filled pore.
43. In general, the molecules that move through specific carrier proteins are determined by which of the following?
    1. a water-filled pore
    2. the size of a molecule
    3. the unique fit to binding sites on the channel or carrier protein
    4. the molecule's lipid solubility
    5. conformational changes in the pore

44. In facilitated diffusion, a molecule is moved
    1. against its concentration gradient with the assistance of a protein carrier molecule and requires energy.
    2. against its concentration gradient while Na is moved with its concentration gradient.
    3. against its concentration gradient with the assistance of a protein carrier molecule, but no energy is required.
    4. down its concentration gradient with the assistance of a protein carrier molecule, and no energy is required.
    5. with its concentration gradient while Na is moved against its concentration gradient.
45. Which of the following transport mechanisms requires energy?
    1. primary active transport only
    2. secondary active transport only
    3. facilitated diffusion only
    4. both primary and secondary active transport
    5. both primary active transport and facilitated diffusion
46. Transporting a substance against its concentration gradient requires
    1. a transporter that is facilitated in its diffusion.
    2. cotransport with another molecule against its concentration gradient.
    3. a channel that is specific for that substance.
    4. countertransport with another molecule against its concentration gradient.
    5. a transporter that uses energy.

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47. In active transport, the affinity of the carrier protein for the molecule being transported is greater on which side of the membrane?
    1. always the side facing the intracellular fluid
    2. always the side facing the extracellular fluid
    3. on the side where the molecule is in lower concentration
    4. on the side where the molecule is in greater concentration
    5. Neither; it is equal on both sides of the membrane.
48. During cotransport of glucose with sodium, sodium increases the affinity of the carrier molecule for glucose when the binding site is facing which side?
    1. Sodium decreases the affinity of the carrier for glucose; it does not increase affinity.
    2. Both sides are affected equally.
    3. the extracellular fluid
    4. the intracellular fluid
    5. Cotransport does not involve changes in affinity of the carrier molecule.
49. When the Na+/ K+ pump moves its bound molecules of Na+ to the outside of the membrane, it
    1. pumps more K+ back into the cell than the amount of Na+ that just came out.
    2. binds to ATP to release the energy required to power the return trip.
    3. cannot return to the inside empty-handed, so it must bind two K+ first.
    4. immediately returns to the inside of the cell, ready to transport more Na+ back outside.
    5. releases the bound ATP to return to its normal confirmation.
50. Most water molecules that cross the plasma membrane do so by
    1. active transport by aquaporins.
    2. diffusion through aquaporins.
    3. active transport by ion channels.
    4. diffusion through the plasma membrane.
    5. diffusion through ion channels.
51. What transport process couples the movement of an ion against its electrochemical gradient to another ion

that is moving down its electrochemical gradient that was established using cellular energy (ATP)?

1. 1. primary active transport
   2. secondary active transport
   3. tertiary passive transport
   4. primary passive transport
   5. secondary passive transport

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52. The first step of the Na+/ K+ pump's activity involves the binding of which of the following?
    1. 3 Na+ to their binding site on the inside of the cell
    2. 2 K+ to their binding site on the outside of the cell
    3. 3 Na+ to their binding site on the outside of the cell
    4. 3 Na+ and 2 K+ to their respective binding sites
    5. 2 K+ to their binding site on the inside of the cell
53. The hydrolysis of ATP on the Na+/ K+ pump results in
    1. a conformational change that exposes the K+ binding site to the outside of the cell.
    2. a conformational change that exposes the Na+ binding site to the inside of the cell.
    3. a conformational change that exposes the K+ binding site to the inside of the cell.
    4. Na+ adhering to its binding site.
    5. a conformational change that exposes the Na+ binding site to the outside of the cell.
54. Na+ is released from its binding site on the Na+/ K+ pump as a result of the
    1. binding of K+ to its binding site.
    2. interaction of the Na+ and K+ binding sites.
    3. exposure of the Na+ binding site to the inside of the cell.
    4. conformational change decreasing the affinity of the Na+ binding site.
    5. enzyme on the inside of the cell which cleaves the Na+ from its binding site.
55. If a cell becomes damaged and is temporarily unable to produce ATP, what is the likely outcome with respect to H2O?
    1. dehydration, as water diffusion is a passive process
    2. cellular swelling, as water follows Na+ into the cell
    3. no change in water movement, as K+ is exchanged equally for Na+
    4. dehydration, as water must be pumped in through aquaporins
    5. no change in water movement, as the anionic proteins lose their charge and can no longer create a membrane potential

56. Which of the following statements about Ca2+ pumps is FALSE?
    1. The pump is also an ATPase.
    2. Calcium is actively transported from an organelle into the cytosol.
    3. Calcium is actively transported from the cytosol into the extracellular fluid.
    4. It maintains low cytosolic calcium levels.
    5. It is a form of primary active transport.

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57. In secondary active transport with sodium, which of the following is FALSE?
    1. The molecule being transported moves down its electrochemical gradient.
    2. ATP is necessary to produce an electrochemical gradient for sodium ions across the cell membrane.
    3. Sodium binds to a carrier molecule, changing its binding properties for another molecule to be transported across the cell membrane.
    4. Sodium always moves into the cell.
    5. The molecule being transported into the cell may move in or out, depending on the carrier molecule.
58. Which of the following statements about glucose cotransport with sodium is TRUE?
    1. Glucose moves into the cell while sodium moves out of the cell.

58. 2. Glucose moves out of the cell while sodium moves into the cell.
    3. Glucose and sodium both move into the cell.
    4. Glucose and sodium both move out of the cell.
    5. Sodium moves out of the cell, but the movement of glucose will vary based on the type of cell.
59. The concentration of an anion inside a cell is 0.3%. The concentration of this anion outside the cell is 0.1%. How could the cell obtain more of this ion inside the cell?
    1. pinocytosis
    2. passive transport
    3. active transport
    4. exocytosis
    5. osmosis
60. What effect does uncontrolled diabetes mellitus have on blood osmolarity?
    1. It decreases it, causing a hyperosmotic state compared to normal.
    2. It increases it, causing a hypo-osmotic state compared to normal.
    3. It increases it, causing a hyperosmotic state compared to normal.
    4. It decreases it, causing a hypo-osmotic state compared to normal.
    5. none
61. All of the following statements concerning severe hyperglycemia's effect on serum Na+ levels are true, EXCEPT
    1. the Na+ levels would appear decreased as the ICF water leaves for the hyperosmotic ECF.
    2. levels are measured as a concentration, so as water decreases, levels increase.
    3. the amount of Na+ is really unchanged since the water has only changed location and not left the body.
    4. administering a hypertonic saline would help compensate for the decreased Na+ levels.
    5. as insulin is administered, serum Na+ levels will return to normal.

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62. The sodium-proton exchanger is an example of a(n)
    1. symporter.
    2. cotransporter.
    3. antiporter.
    4. passive transporter.
    5. primary active transporter.
63. The flow of water across a membrane down its concentration gradient is called
    1. osmosis.
    2. antiporting.
    3. facilitated diffusion.
    4. symporting.
    5. leaking.

64. A membrane permeable to water separates a chamber into two compartments: A and B. Compartment A contains a 10 mM solution of non-permeating solute, whereas compartment B contains a 40 mM solution of non-permeating solute. Which of the following statements is TRUE?
    1. Water will move from side B to A, but solute will not move.
    2. Solute will move from side B to A, and water will move from side A to B.
    3. Solute will move from side A to B, and water will move from side B to A.
    4. Water will move from side A to B, but solute will not move.
    5. Both water and solute will move from side B to A.
65. A cell with normal tonicity is placed in a 200 mM NaCl solution. This solution is          and the cell will

             .

1. 1. hypotonic : shrink
   2. hypertonic : swell

65. 3. hypertonic : shrink
    4. isotonic : not change size
    5. hypotonic : swell
66. If a solution contains 0.1 M glucose along with 0.15 M NaCl, what is the osmolarity of this solution?
    1. 400 mOsm B) 350 mOsm C) 0.4 M D) 0.25 M E) 250 mOsm
67. If solution 1 (0.1 M glucose and 0.15 M NaCl) and solution 2 (0.4 M glucose) are separated by a membrane, then solution 1 is            relative to solution 2.
    1. iso-osmotic
    2. hyperosmotic
    3. hypotonic
    4. hypo-osmotic
    5. hypertonic  13
68. If there is a difference in osmolarity between a cell and its environment, water will move    its osmotic pressure gradient.
    1. between B) through C) down D) across E) up
69. The osmotic pressure of a solution is a(n)
    1. indirect measure of its solvent concentration.
    2. indication of its glucose concentration.
    3. indirect measure of its solute concentration.
    4. direct measure of its solvent concentration.
    5. direct measure of its solute concentration.
70. A cell is placed into a solution that has the same osmolarity. However, one of the solutes in the solution is able to move across the membrane (the cell does not contain this solute). After a period of time, the solution into which the cell was placed would become
    1. iso-osmotic.
    2. hypertonic.
    3. hypotonic.
    4. isotonic.
    5. hyperosmotic.
71. An erythrocyte is placed in a hypotonic solution of 100 mOsm. What will happen to the cell?
    1. The cell swells to three times its original volume, Vf = 3Vo.
    2. The cell shrinks to one half its original volume, Vf = 1/2 Vo.
    3. The cell swells to twice its original volume, Vf = 2Vo.
    4. The cell volume increases by one third, Vf = 4/3 Vo.
    5. The cell volume remains unchanged.
72. White blood cells are an important component of our immune system. One thing they do is consume and destroy bacteria by extending their plasma membrane around the bacterium and bringing it inside the cell in a vesicle. By what process do they engulf the bacterium?
    1. exocytosis
    2. transcytosis
    3. receptor-mediated endocytosis
    4. pinocytosis
    5. phagocytosis
73. When white blood cells are called to an area of infection, not only is there phagocytosis taking place, but also exocytosis of undigested particles from the white blood cells into the interstitial space. What effect does this have on water in the surrounding cells and capillary plasma?
    1. It dehydrates the area due to the increase in lysosomal waste products.

1. 2. Plasma water moves to the interstitium by osmosis and then into the adjacent cells.
   3. It creates a hypertonic environment, drawing water from the surrounding cells and plasma.
   4. These particles have no effect on tonicity, since their precursors were already in the body.
   5. Swelling of the nearby cells and plasma ensues due to the hypotonic nature of the area.

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74. Vesicles formed during phagocytosis or endocytosis often fuse with the membrane of which of the following organelles?
    1. mitochondria
    2. rough endoplasmic reticulum
    3. smooth endoplasmic reticulum
    4. lysosome
    5. peroxisome
75. Endocytosis is a form of active transport (requiring energy) to move vesicles
    1. containing particles into and out of the cell, also known as phagocytosis.
    2. filled with particles and/or fluids into the cell.
    3. filled with particles and/or fluids out of the cell.
    4. containing fluids into and out of the cell, also known as pinocytosis.
    5. containing proteins out of the cell, also known as secretion.
76. Secretory vesicles are a part of what transport mechanism?
    1. receptor-mediated endocytosis
    2. osmosis
    3. exocytosis
    4. phagocytosis
    5. pinocytosis
77. Epithelial cells are polarized with different structures at either end of the cell. The portion of the membrane that faces the lumen is called the          membrane.
    1. basolateral B) basement C) abluminal D) apical E) transport
78. The extent of ion movement through the   space between epithelial cells is determined by the extent of  coupling between neighboring epithelial cells.
    1. transcellular : desmosomal
    2. paracellular : tight junctional
    3. transcellular : gap junctional
    4. transcellular : tight junctional
    5. paracellular : gap junctional
79. The movement of a number of molecules across the apical surface of the epithelial cell by secondary transporters is coupled to the                                                gradient that is maintained by the                                           on the basolateral surface of the epithelial cell.
    1. K+ : K+ pump
    2. Na+ : Na+ channel
    3. Na+ : Na+/ K+ pump
    4. Ca2+ : Na+/ K+ pump
    5. K+ : K+ channel

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80. The electrochemical gradient is to diffusion as is to active transport.
    1. thermal energy
    2. an ion channel
    3. ATP
    4. entropy
    5. glucose

81. When solute is actively transported across epithelium, what usually follows?
    1. active transport of the solute in the opposite direction
    2. water movement in the same direction
    3. passive transport of the solute in the opposite direction
    4. water movement in the opposite direction
    5. passive transport of solute in the same direction
82. All of the following solutes are found in higher concentration outside of the cell EXCEPT
    1. sodium.
    2. magnesium.
    3. chloride.
    4. HCO3-.
    5. proteins.
83. All of the following solutes are found in higher concentration inside of the cell EXCEPT
    1. glucose. B) calcium. C) potassium. D) ATP. E) phosphate.
84. Which of the following transport mechanisms requires energy?
    1. facilitated diffusion
    2. osmosis
    3. diffusion
    4. movement of ion through ion channels
    5. phagocytosis
85. Which of the following transport mechanisms has no energy requirement?
    1. endocytosis
    2. secondary active transport
    3. exocytosis
    4. osmosis through aquaporins
    5. active transport

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86. Which of the following solutions bathing a red blood cell would be considered isotonic?
    1. a solution containing 200 mOsm NaCl
    2. a solution containing 300 mM NaCl
    3. a solution containing 400 mOsm non-permeating solute
    4. a solution containing 100 mM MgCl2
    5. a solution containing 150 mM glucose
87. Which of the following solutions bathing a red blood cell would be considered hypotonic?
    1. a solution containing 100 mM MgCl2
    2. a solution containing 200 mOsm NaCl
    3. a solution containing 300 mM NaHCO3
    4. a solution containing 400 mOsm non-permeating solute
    5. a solution containing 300 mM NaCl
88. Which the following descriptions would be an example of receptor-mediated endocytosis?
    1. a macrophage imbibing its surrounding tissue fluid and nutrients
    2. the elimination of a phagolysosome's contents from a neutrophil
    3. acetylcholine released from a neuron
    4. bacteria that is engulfed by a white blood cell
    5. a low-density lipoprotein that becomes internalized by a hepatic cell
89. Which the following descriptions would be an example of phagocytosis?
    1. a low-density lipoprotein that becomes internalized by a hepatic cell

89. 2. the elimination of a phagolysosome's contents from a neutrophil
    3. a macrophage imbibing its surrounding tissue fluid and nutrients
    4. choline's reabsorption by a neuron
    5. bacteria that is engulfed by a white blood cell
90. Which the following descriptions would be an example of exocytosis?
    1. bacteria that is engulfed by a white blood cell
    2. a macrophage imbibing its surrounding tissue fluid and nutrients
    3. acetylcholine released from a neuron
    4. choline's reabsorption by a neuron
    5. a low-density lipoprotein that becomes internalized by a hepatic cell
91. Which the following descriptions would be an example of pinocytosis?
    1. a macrophage drinking its surrounding tissue fluid and nutrients
    2. choline's reabsorption by a neuron
    3. a low-density lipoprotein that becomes internalized by a hepatic cell
    4. the elimination of a phagolysosome's contents from a neutrophil
    5. bacteria that is engulfed by a white blood cell

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92. The process of diffusion involves the random movement of
    1. molecules that is inversely proportional to its concentration.
    2. individual molecules based on their size and weight.
    3. charged particles across a membrane.
    4. ions against their concentration gradient.
    5. individual molecules due to thermal motion.
93. As the molecular weight of a molecule increases, its
    1. rate of diffusion will also increase.
    2. ability to dissolve in lipid will also increase.
    3. membrane permeability decreases.
    4. ability to form a charge decreases.
    5. concentration in a solution decreases.
94. What effect does a cell's overall thickness have on its permeability?
    1. As the cell's thickness increases, its permeability decreases.
    2. The larger a cell becomes, the greater its proportional surface area, which increases the cell's permeability.
    3. The cell's permeability is directly proportional to the thickness traversed.
    4. Only the cell's membrane thickness, not that of its cytoplasm, have an effect on its permeability.
    5. As the cell's thickness increases, its permeability increases.
95. The Na+/ K+ pump transports in which directions and what amounts per molecule of ATP hydrolyzed?
    1. 3 sodium ions in and 3 potassium ions out per molecule of ATP hydrolyzed
    2. 3 sodium ions out and 2 potassium ions in per molecule of ATP hydrolyzed
    3. They are transported in a 3:2:1 ratio in opposite directions.
    4. They are transported in a 1:1 ratio in opposite directions per molecule of ATP hydrolyzed.
    5. They are transported in a 3:2:2 ratio.
96. What is the meaning of carrier proteins and pumps becoming saturated?
    1. These transporters have reached a maximal net flux, beyond which further increases in concentration no longer affect their rate.
    2. These transporters have reached the point where only an increase in the transported molecule will change the net flux.
    3. These transporters have become entirely depleted and can no longer transport without further ATP production.

1. 4. Saturation kinetics (demonstrated graphically as a line curving upward as a function of concentration) indicates that transport will increase as concentrations increase.
   5. They have a hydrogen molecule at every possible carbon bond and are, therefore, a solid at room temperature.

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97. Why are primary active transporters many times called ATPases?
    1. They often breakdown ATP to AMP and pyrophosphate (an ATPase activity).
    2. They must first bind to an ATP molecule before binding any transported molecule.
    3. ATP is synthesized during the reverse reaction and is named for that ability.
    4. They act as enzymes to release energy from ATP.
    5. ATP is the universal currency to get work done in the cell.
98. What is the primary role for the Na+/ K+ pump?
    1. the maintenance of Na+ and K+ concentrations once inside the membrane
    2. to produce ATP while pumping Na+ and K+ against their concentration gradients
    3. to create a polarized membrane in an excitable cell
    4. to pump Na+ and K+ down their concentration gradients out of the cell
    5. the maintenance of Na+ and K+ concentrations on either side of the membrane
99. Which condition exists when there are more solutes present in a solution?
    1. There is a greater need for an active transporter.
    2. There is a lower thermal energy affecting diffusion.
    3. There is a greater pressure for water to leave.
    4. There is a lower concentration of water in that solution.
    5. There is a greater concentration of water to leave that solution.
100. During phagocytosis, the phagosome binds with a(n) to form a(n)           .

1. ribosome : hybrid phagosome
2. Golgi apparatus : vacuole
3. ingested particle : digested particle
4. bacteria : null cell
5. lysosome : phagolysosome

101. In epithelial tissue, the cells are linked together by     , which prevent paracellular movement from lumen to extracellular fluid.

1. tight junctions
2. desmosomes
3. aquaporins
4. gap junctions
5. hemidesmosomes

102. In epithelial tissue, the portion of the plasma membrane facing the lumen is called the       membrane. The portion of the plasma membrane facing the connective tissue/interstitial fluid is called the                                                                                                                             membrane.

1. luminal : interstitial
2. secretory : attachment
3. apical : basolateral
4. epithelial : basement
5. apical : basement

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103. In epithelial transport, movement from the internal environment to the external environment is called

             , whereas movement from the external environment to the internal environment is called       .

1. pinocytosis : exocytosis
2. secretion : absorption

3. excretion : ingestion
4. catch : release
5. absorption : excretion

104. Which ion(s) have a net chemical force acting to move the ion(s) into the cell? (Assume a resting membrane potential (Vm) of -70mV.)

1. X+, whose [ECF] is 120 mM and [ICF] is 30 mM
2. A-, whose [ECF] is 100 mM and [ICF] is 100 mM
3. B-, whose [ECF] is 140 mM and [ICF] is 30 mM
4. both X+ and B- ions
5. X+, A-, and B- ions

105. Which ion(s) have a net electrical force acting to move the ion(s) into the cell? (Assume a resting membrane potential (Vm) of -70mV.)

1. X+, whose [ECF] is 120 mM and [ICF] is 30 mM
2. A-, whose [ECF] is 100 mM and [ICF] is 100 mM
3. B-, whose [ECF] is 140 mM and [ICF] is 30 mM
4. both X+ and B- ions
5. X+, A-, and B- ions

106. Which ion(s) would have a positive equilibrium potential? (Assume a resting membrane potential (Vm) of

-70mV.)

1. X+, A-, and B- ions
2. both X+ and B- ions
3. X+, whose [ECF] is 120 mM and [ICF] is 30 mM
4. B-, whose [ECF] is 140 mM and [ICF] is 30 mM
5. A-, whose [ECF] is 100 mM and [ICF] is 100 mM

107. Insulin triggers the insert of what protein into the cell membrane of its target cell?

1. hexose-6-kinase
2. glucagon
3. insulin-like growth factor receptor
4. GLUT4
5. insulin-like growth factor 1

108. If there is 0.2 M glucose along with 0.15 M NaCl in solution, what is the osmolarity of this solution?

A) 350 mOsm B) 2.15 Osm C) 500 mOsm D) 2.30 Osm E) 300 mOsm

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109. If a 300 mOsm cell (10 mOsm of which are from the membrane permeable molecule urea) is placed into 300 mOsm solution containing no urea, what will happen to the cell?

1. burst
2. swell
3. shrink (shrivel)
4. no change
5. increased turgor

110. A beaker with a membrane is separating two solutions, initially of equal volumes. The solution on side A is 100 mM KCl while the solution on side B is 150 mM sucrose. The membrane is not permeable to ions or carbohydrates. In what way will the water move?

1. down its concentration gradient from side B to side A
2. down its concentration gradient from side A to side B
3. In osmosis, water moves against its concentration gradient.
4. As sucrose dissociates, it creates more individual molecules in solution and is therefore the higher concentration gradient.
5. There is no movement of water.

111. Describe the chemical and electrical driving forces that move ions across a membrane.

112. Since it is the electrochemical gradient that determines the direction and magnitude of an ion's movement across a membrane, describe how one can determine the direction of ion movement based on the electrical

and chemical gradients.

113. Describe the factors that affect the rate of passive transport of molecules across a membrane.

114. Since diffusion is defined as the random movement of molecules, how can this random movement result in the net movement of ions across a membrane?

115. Describe the process of facilitated diffusion and the proteins involved in that process.

116. Describe the processes of primary and secondary active transport, including the factors that can affect active transport.

117. Describe the process whereby the Na+/K+ pump is involved in moving those ions across a membrane.

118. Describe the process whereby water moves passively across a membrane.

119. Discuss the differences between the osmolarity and tonicity of a solution.

120. When comparing the molecular energies of two different concentrations of the same molecule, the one with the (higher concentration/lower concentration) would have the higher energy.

121. If glucose molecules outside a cell have higher energy than those inside the cell, then those molecules would move (into/out of) the cells.

122. With a concentration of 10 mM glucose and 5 mM K+ on the outside of the membrane and 1 mM glucose and 140 mM K+ on the inside, the glucose would move (into/out of) the cells if the membrane is permeable to

glucose.

123. If the solutions on either side of the membrane have an unequal distribution of charged ions with the inside having an excess of anions, then the inside of the cell would be (negative/positive) relative to the outside.

124. As the magnitude of charge difference across the membrane increases, the magnitude of the electrical driving force would (increase/decrease) across that membrane.

125. If one ion carried a greater quantity of charge than another, then the electrical driving force for the ion with the greater quantity of charge would (increase/decrease).

126. If the concentration of sodium in the extracellular fluid increased, then the equilibrium potential would (become more positive/become less positive/remain the same).