Deck 4: Cell Membrane Transport

Question 1

Which of the following solutions bathing a red blood cell would be considered hypotonic?

A)a solution containing 200 mOsm NaCl
B)a solution containing 300 mM NaCl
C)a solution containing 100 mM MgCl2
D)a solution containing 300 mM NaHCO3
E)a solution containing 400 mOsm non- permeating solute

Answer 1

A

Question 2

Based solely upon its electrical charge, the inside of a typical cell will tend to attract extracellular to move inward.

A)proteins
B)cations
C)anions
D)ions whose concentration gradient allows them
E)uncharged ions

Answer 2

B

Question 3

The osmotic pressure of a solution is a(n)

A)indirect measure of its solute concentration.
B)direct measure of its solvent concentration.
C)indirect measure of its solvent concentration.
D)indication of its glucose concentration.
E)direct measure of its solute concentration.

Answer 3

A

Question 4

The diffusion rate is

A)the speed at which diffusion takes place.
B)the thickness of the membrane through which a material has to diffuse.
C)the amount of time necessary for diffusion to take place.
D)the amount of material to diffuse through a membrane.
E)fastest at body temperature.

Question 5

When solute is actively transported across epithelium, what usually follows?

A)active transport of the solute in the opposite direction
B)passive transport of solute in the same direction
C)water movement in the same direction
D)passive transport of the solute in the opposite direction
E)water movement in the opposite direction

Question 6

Which of the following transport mechanisms requires energy?

A)primary active transport only
B)secondary active transport only
C)facilitated diffusion only
D)both primary and secondary active transport
E)both primary active transport and facilitated diffusion

Question 7

Which of the following statements about glucose cotransport with sodium is TRUE?

A)Glucose moves into the cell while sodium moves out of the cell.
B)Glucose moves out of the cell while sodium moves into the cell.
C)Glucose and sodium both move into the cell.
D)Glucose and sodium both move out of the cell.
E)Sodium moves out of the cell, but the movement of glucose will vary based on the type of cell.

Question 8

Which the following descriptions would be an example of receptor- mediated endocytosis?

A)a low- density lipoprotein that becomes internalized by a hepatic cell
B)the elimination of a phagolysosome's contents from a neutrophil
C)bacteria that is engulfed by a white blood cell
D)acetylcholine released from a neuron
E)a macrophage imbibing its surrounding tissue fluid and nutrients

Question 9

The potassium equilibrium potential is - 94 mV. What does this mean?

A)At the resting membrane potential of neurons, potassium is at equilibrium.
B)At - 94 mV, potassium movement is opposed exactly by sodium movement.
C)At - 94 mV, the chemical force for potassium movement is zero.
D)At - 94 mV, the chemical force for potassium movement is opposed exactly by the electrical force.
E)At - 94 mV, the electrical force for potassium movement is zero.

Question 10

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

A)desmosomes
B)aquaporins
C)hemidesmosomes
D)tight junctions
E)gap junctions

Question 11

Which of the following solutions bathing a red blood cell would be considered isotonic?

A)a solution containing 300 mM NaCl
B)a solution containing 100 mM MgCl2
C)a solution containing 400 mOsm non- permeating solute
D)a solution containing 150 mM glucose
E)a solution containing 200 mOsm NaCl

Question 12

As the molecular weight of a molecule increases, its

A)membrane permeability decreases.
B)ability to form a charge decreases.
C)ability to dissolve in lipid will also increase.
D)concentration in a solution decreases.
E)rate of diffusion will also increase.

Question 13

Secretory vesicles are a part of what transport mechanism?

A)pinocytosis
B)phagocytosis
C)osmosis
D)exocytosis
E)receptor- mediated endocytosis

Question 14

Which of the following transport mechanisms requires energy?

A)phagocytosis
B)osmosis
C)diffusion
D)facilitated diffusion
E)movement of ion through ion channels

Question 15

All of the following statements concerning severe hyperglycemia's effect on serum Na+ levels are true, EXCEPT

A)the amount of Na+ is really unchanged since the water has only changed location and not left the body.
B)administering a hypertonic saline would help compensate for the decreased Na+ levels.
C)as insulin is administered, serum Na+ levels will return to normal.
D)levels are measured as a concentration, so as water decreases, levels increase.
E)the Na+ levels would appear decreased as the ICF water leaves for the hyperosmotic ECF.

Question 16

When a substance crossing the membrane is driven by diffusion, the net flux of that molecule can be described mathematically by

A)the Navier- Stokes equation.
B)the Goldman- Hodgkin- Katz equation.
C)Einstein's equation.
D)the Nernst equation.
E)Fick's law.

Question 17

When the Na+/ K+ pump moves its bound molecules of Na+ to the outside of the membrane, it

A)immediately returns to the inside of the cell, ready to transport more Na+ back outside.
B)pumps more K+ back into the cell than the amount of Na+ that just came out.
C)binds to ATP to release the energy required to power the return trip.
D)cannot return to the inside empty- handed, so it must bind two K+ first.
E)releases the bound ATP to return to its normal confirmation.

Question 18

The Na+/ K+ pump transports in which directions and what amounts per molecule of ATP hydrolyzed?

A)3 sodium ions in and 3 potassium ions out per molecule of ATP hydrolyzed
B)3 sodium ions out and 2 potassium ions in per molecule of ATP hydrolyzed
C)They are transported in a 3:2:1 ratio in opposite directions.
D)They are transported in a 1:1 ratio in opposite directions per molecule of ATP hydrolyzed.
E)They are transported in a 3:2:2 ratio.

Question 19

Which the following descriptions would be an example of pinocytosis?

A)a low- density lipoprotein that becomes internalized by a hepatic cell
B)choline's reabsorption by a neuron
C)the elimination of a phagolysosome's contents from a neutrophil
D)bacteria that is engulfed by a white blood cell
E)a macrophage drinking its surrounding tissue fluid and nutrients

Question 20

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.

A)basement
B)basolateral
C)apical
D)transport
E)abluminal

Question 21

All of the following solutes are found in higher concentration inside of the cell EXCEPT

A)ATP.
B)glucose.
C)phosphate.
D)calcium.
E)potassium.

Question 22

In facilitated diffusion, a molecule is moved

A)against its concentration gradient while Na is moved with its concentration gradient.
B)against its concentration gradient with the assistance of a protein carrier molecule, but no energy is required.
C)down its concentration gradient with the assistance of a protein carrier molecule, and no energy is required.
D)against its concentration gradient with the assistance of a protein carrier molecule and requires energy.
E)with its concentration gradient while Na is moved against its concentration gradient.

Question 23

As a cell's metabolism increases, so does its O2 consumption, giving rise to what product at a ratio of 2:1?

A)pyruvic acid
B)lactic acid
C)ATP
D)CO2
E)H2O

Question 24

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.

A)positive : anions
B)positive : cations
C)negative : anions
D)neutral : cations
E)negative : cations

Question 25

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?

A)Diffusion rate will remain constant.
B)Diffusion rate will not be affected.
C)Diffusion rate will decrease.
D)Diffusion rate will increase.
E)Diffusion rate will progressively decrease until zero.

Question 26

What is the meaning of carrier proteins and pumps becoming saturated?

A)These transporters have reached a maximal net flux, beyond which further increases in concentration no longer affect their rate.
B)These transporters have become entirely depleted and can no longer transport without further ATP production.
C)They have a hydrogen molecule at every possible carbon bond and are, therefore, a solid at room temperature.
D)These transporters have reached the point where only an increase in the transported molecule will change the net flux.
E)Saturation kinetics (demonstrated graphically as a line curving upward as a function of concentration)indicates that transport will increase as concentrations increase.

Question 27

Which of the following is a reflection of the unequal distribution of positive and negative ions across the plasma membrane?

A)extracellular potential
B)electrochemical driving force
C)chemical driving force
D)chemical gradient
E)membrane potential

Question 28

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)?

A)The chemical force is directed into the cell and the electrical force is directed out of the cell.
B)Both the chemical and electrical forces are directed out of the cell.
C)The chemical force is directed out of the cell and the electrical force is directed into the cell.
D)Both the chemical and electrical forces are directed into the cell.
E)There is insufficient information to answer this question.

Question 29

The electrochemical gradient is to diffusion as is to active transport.

A)ATP
B)entropy
C)an ion channel
D)thermal energy
E)glucose

Question 30

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

A)hypotonic.
B)hypertonic.
C)isotonic.
D)hyperosmotic.
E)iso- osmotic.

Question 31

Which of the following would NOT increase the rate of simple diffusion across the phospholipid bilayer of the plasma membrane?

A)smaller size
B)greater available surface area
C)greater concentration gradient
D)greater number of protein carriers
E)greater lipid solubility

Question 32

Which of the following cells would have a greater electrical attraction for sodium ions to enter the cell?

A)cell with membrane potential = - 70 mV
B)cell with membrane potential = 0 mV
C)cell with membrane potential = - 90 mV
D)cell with membrane potential = +20 mV
E)cell with membrane potential = - 50 mV

Question 33

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?

A)Water will move from side B to A, but solute will not move.
B)Both water and solute will move from side B to A.
C)Solute will move from side A to B, and water will move from side B to A.
D)Water will move from side A to B, but solute will not move.
E)Solute will move from side B to A, and water will move from side A to B.

Question 34

Transporting a substance against its concentration gradient requires

A)a transporter that is facilitated in its diffusion.
B)a channel that is specific for that substance.
C)cotransport with another molecule against its concentration gradient.
D)a transporter that uses energy.
E)countertransport with another molecule against its concentration gradient.

Question 35

Molecules with a relatively high lipid solubility are capable of crossing the membrane

A)only through specific protein channels.
B)only with the addition of energy.
C)through specific lipid channels.
D)directly through the lipid bilayer.
E)indirectly by moving across a carrier protein.

Question 36

The first step of the Na+/ K+ pump's activity involves the binding of which of the following?

A)2 K+ to their binding site on the outside of the cell
B)3 Na+ and 2 K+ to their respective binding sites
C)2 K+ to their binding site on the inside of the cell
D)3 Na+ to their binding site on the inside of the cell
E)3 Na+ to their binding site on the outside of the cell

Question 37

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?

A)The concentration gradient for oxygen increases and oxygen movement into the cell decreases.
B)The concentration gradient for oxygen and its rate of movement into the cell do not change.
C)The concentration gradient for oxygen increases and oxygen movement into the cell increases.
D)The concentration gradient for oxygen decreases and oxygen movement into the cell decreases.
E)The concentration gradient for oxygen decreases and oxygen movement into the cell increases.

Question 38

Which of the following transport mechanisms has no energy requirement?

A)exocytosis
B)active transport
C)osmosis through aquaporins
D)secondary active transport
E)endocytosis

Question 39

In active transport, the affinity of the carrier protein for the molecule being transported is greater on which side of the membrane?

A)always the side facing the intracellular fluid
B)always the side facing the extracellular fluid
C)on the side where the molecule is in lower concentration
D)on the side where the molecule is in greater concentration
E)Neither; it is equal on both sides of the membrane.

Question 40

Which of the following pairs of characteristics is more likely to make a substance diffuse through the cell membrane?

A)large, non- polar molecule
B)small, non- polar molecule
C)small, polar molecule
D)large, amphipathic molecule
E)large, polar molecule

Question 41

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.

A)hyperosmotic
B)hypertonic
C)hypo- osmotic
D)hypotonic
E)iso- osmotic

Question 42

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

A)more negative, relative to the outside of the cell.
B)more positive, relative to the outside of the cell.
C)more highly charged than the outside of the cell.
D)less highly charged than the outside of the cell.
E)less negative, relative to the outside of the cell.

Question 43

If a cell becomes damaged and is temporarily unable to produce ATP, what is the likely outcome with respect to H2O?

A)no change in water movement, as K+ is exchanged equally for Na+
B)cellular swelling, as water follows Na+ into the cell
C)no change in water movement, as the anionic proteins lose their charge and can no longer create a membrane potential
D)dehydration, as water must be pumped in through aquaporins
E)dehydration, as water diffusion is a passive process

Question 44

Molecules tend to move spontaneously their chemical gradient.

A)through
B)over
C)around
D)down
E)up

Question 45

The chemical force for which of the following ions is directed into the cell?

A)calcium only
B)sodium only
C)potassium only
D)both potassium and sodium
E)both sodium and calcium

Question 46

Which the following descriptions would be an example of phagocytosis?

A)a macrophage imbibing its surrounding tissue fluid and nutrients
B)choline's reabsorption by a neuron
C)the elimination of a phagolysosome's contents from a neutrophil
D)bacteria that is engulfed by a white blood cell
E)a low- density lipoprotein that becomes internalized by a hepatic cell

Question 47

Which ion(s)would have a positive equilibrium potential? (Assume a resting membrane potential (Vm)of - 70mV.)

A)X+, whose [ECF] is 120 mM and [ICF] is 30 mM
B)A- , whose [ECF] is 100 mM and [ICF] is 100 mM
C)B- , whose [ECF] is 140 mM and [ICF] is 30 mM
D)both X+ and B- ions
E)X+, A- , and B- ions

Question 48

Which of the following is NOT true for all three of these transport mechanisms: facilitated diffusion, primary active transport, and secondary active transport?

A)The transport mechanism is specific for (a)particular solute(s).
B)The transport mechanism requires energy.
C)Transport can be increased by increasing the number of transport molecules in the plasma membrane.
D)The transport mechanism has a limit to the total number of molecules that can be transported per unit of time.
E)The transport mechanism requires a protein.

Question 49

If a solution contains 0.1 M glucose along with 0.15 M NaCl, what is the osmolarity of this solution?

A)0)4 M
B)400 mOsm
C)350 mOsm
D)250 mOsm
E)0)25 M

Question 50

During phagocytosis, the phagosome binds with a(n)to form a(n).

A)bacteria : null cell
B)ribosome : hybrid phagosome
C)lysosome : phagolysosome
D)Golgi apparatus : vacuole
E)ingested particle : digested particle

Question 51

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.)

A)X+, whose [ECF] is 120 mM and [ICF] is 30 mM
B)A- , whose [ECF] is 100 mM and [ICF] is 100 mM
C)B- , whose [ECF] is 140 mM and [ICF] is 30 mM
D)both X+ and B- ions
E)X+, A- , and B- ions

Question 52

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.

A)luminal : interstitial
B)apical : basement
C)apical : basolateral
D)secretory : attachment
E)epithelial : basement

Question 53

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.

A)inward : negatively
B)inward : positively
C)outward : positively
D)outward : neutrally
E)outward : negatively

Question 54

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

A)the most concentrated ion only.
B)all ions present.
C)all positively charged ions.
D)all negatively charged ions.
E)sodium only.

Question 55

When molecules are passively transported across a membrane, the direction of their movement is dictated by the molecule's tendency to move

A)into a cell.
B)out of a cell.
C)from lower to higher energy.
D)from higher to lower energy.
E)in both directions; there is no preference.

Question 56

The hydrolysis of ATP on the Na+/ K+ pump results in

A)a conformational change that exposes the K+ binding site to the outside of the cell.
B)a conformational change that exposes the Na+ binding site to the inside of the cell.
C)a conformational change that exposes the K+ binding site to the inside of the cell.
D)a conformational change that exposes the Na+ binding site to the outside of the cell.
E)Na+ adhering to its binding site.

Question 57

Which of the following is NOT a determinant of the magnitude and direction of the equilibrium potential for an ion?

A)lipid solubility of the ion
B)concentration gradient
C)charge of the ion
D)chemical driving force
E)valence of the ion

Question 58

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?

A)burst
B)swell
C)no change
D)shrink (shrivel)
E)increased turgor

Question 59

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

A)2)15 Osm
B)300 mOsm
C)2)30 Osm
D)350 mOsm
E)500 mOsm

Question 60

Vesicles formed during phagocytosis or endocytosis often fuse with the membrane of which of the following organelles?

A)rough endoplasmic reticulum
B)peroxisome
C)mitochondria
D)smooth endoplasmic reticulum
E)lysosome

Question 61

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?

A)It creates a hypertonic environment, drawing water from the surrounding cells and plasma.
B)These particles have no effect on tonicity, since their precursors were already in the body.
C)It dehydrates the area due to the increase in lysosomal waste products.
D)Swelling of the nearby cells and plasma ensues due to the hypotonic nature of the area.
E)Plasma water moves to the interstitium by osmosis and then into the adjacent cells.

Question 62

Which of the following is found in greater concentration inside the cell than outside?

A)chloride
B)water
C)sodium
D)calcium
E)potassium

Question 63

An erythrocyte is placed in a hypotonic solution of 100 mOsm. What will happen to the cell?

A)The cell swells to three times its original volume, Vf = 3Vo.
B)The cell shrinks to one half its original volume, Vf = 1/2 Vo.
C)The cell swells to twice its original volume, Vf = 2Vo.
D)The cell volume increases by one third, Vf = 4/3 Vo.
E)The cell volume remains unchanged.

Question 64

The extent of ion movement through the space between epithelial cells is determined by the extent of coupling between neighboring epithelial cells.

A)paracellular : tight junctional
B)transcellular : tight junctional
C)paracellular : gap junctional
D)transcellular : desmosomal
E)transcellular : gap junctional

Question 65

What is the primary role for the Na+/ K+ pump?

A)to create a polarized membrane in an excitable cell
B)to produce ATP while pumping Na+ and K+ against their concentration gradients
C)to pump Na+ and K+ down their concentration gradients out of the cell
D)the maintenance of Na+ and K+ concentrations once inside the membrane
E)the maintenance of Na+ and K+ concentrations on either side of the membrane

Question 66

In secondary active transport with sodium, which of the following is FALSE?

A)The molecule being transported moves down its electrochemical gradient.
B)ATP is necessary to produce an electrochemical gradient for sodium ions across the cell membrane.
C)Sodium always moves into the cell.
D)The molecule being transported into the cell may move in or out, depending on the carrier molecule.
E)Sodium binds to a carrier molecule, changing its binding properties for another molecule to be transported across the cell membrane.

Question 67

The process of diffusion involves the random movement of

A)molecules that is inversely proportional to its concentration.
B)ions against their concentration gradient.
C)individual molecules due to thermal motion.
D)individual molecules based on their size and weight.
E)charged particles across a membrane.

Question 68

What effect does a cell's overall thickness have on its permeability?

A)As the cell's thickness increases, its permeability increases.
B)The larger a cell becomes, the greater its proportional surface area, which increases the cell's permeability.
C)As the cell's thickness increases, its permeability decreases.
D)Only the cell's membrane thickness, not that of its cytoplasm, have an effect on its permeability.
E)The cell's permeability is directly proportional to the thickness traversed.

Question 69

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.

A)inward : positively
B)outward : neutrally
C)outward : positively
D)outward : negatively
E)inward : negatively

Question 70

As an ion moves passively across a membrane into the cell, the progressive increase in concentration within the cell will

A)decrease the net flux across the membrane.
B)accelerate the rate of diffusion.
C)decrease the need for active transport to continue transporting.
D)cause a switch to facilitated diffusion.
E)increase the net flux across the membrane.

Question 71

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?

A)The cell would swell since water follows Na+.
B)Intracellular Cl- would be increased, following Na+.
C)Intracellular concentration of K+ would still be higher than Na+ because the body tries to maintain an extracellular concentration of Na+ at 145 mM.
D)Although the body tries to maintain an extracellular concentration of Na+ at 145mM, the intracellular concentration of Na+ would still be higher.
E)Intracellular anions would decrease in number.

Question 72

Which of the following statements about Ca2+ pumps is FALSE?

A)Calcium is actively transported from the cytosol into the extracellular fluid.
B)It is a form of primary active transport.
C)It maintains low cytosolic calcium levels.
D)Calcium is actively transported from an organelle into the cytosol.
E)The pump is also an ATPase.

Question 73

A cell with normal tonicity is placed in a 200 mM NaCl solution. This solution is _ and the cell will _.

A)hypertonic : swell
B)hypotonic : shrink
C)hypertonic : shrink
D)hypotonic : swell
E)isotonic : not change size

Question 74

Which of the following can be used to determine an ion's equilibrium potential?

A)intracellular voltmeter
B)oscilloscope
C)Nernst equation
D)concentration of an ion only
E)Navier- Stokes equation

Question 75

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.

A)separation : restriction
B)buildup : restriction
C)collection : restriction
D)collection : clustering
E)separation : clustering

Question 76

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?

A)transcytosis
B)phagocytosis
C)exocytosis
D)receptor- mediated endocytosis
E)pinocytosis

Question 77

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)?

A)The chemical force is directed into the cell and the electrical force is directed out of the cell.
B)Both the chemical and electrical forces are directed out of the cell.
C)The chemical force is directed out of the cell and the electrical force is directed into the cell.
D)Both the chemical and electrical forces are directed into the cell.
E)There is insufficient information to answer this question.

Question 78

The equilibrium potential describes the membrane potential where what two forces are balanced?

A)density and magnetic
B)chemical and temperature
C)chemical and electrical
D)temperature and density
E)electrical and permeability

Question 79

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.)

A)X+, whose [ECF] is 120 mM and [ICF] is 30 mM
B)A- , whose [ECF] is 100 mM and [ICF] is 100 mM
C)B- , whose [ECF] is 140 mM and [ICF] is 30 mM
D)both X+ and B- ions
E)X+, A- , and B- ions

Question 80

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?

A)osmosis
B)exocytosis
C)active transport
D)pinocytosis
E)passive transport