Human Physiology 5e (Silverthorn), Chapter 5, Membrane Dynamics

The Na+-K+-ATPase pumps __________ Na+ ions into/out of the cell and __________ K+ into/out of the cell.

3 Na+, out of; 2 K+, into

At rest, nerve cells have a voltage of __________ mV

: -70 [Note to instructor: All nerve cells are different, so you may wish to accept a range of similar values instead of insisting on precisely this value.]

A living body is electrically A) neutral. B) positive. C) negative.

A

Cations will __________ anions. A) attract B) repel C) not react with

A

Match the terms to changes presented, assuming a resting membrane potential of -70 mV. Answers may be used once, more than once, or not at all. any value other than 0 mV, regardless of relationship to resting potential A. electrical polarization B. hyperpolarization C. depolarization D. repolarization E. more than one of the above

A

Pinocytosis and potocytosis are types of A) endocytosis. B) exocytosis. C) phagocytosis. D) A and B E) B and C

A

The cell membrane acts as a good A) electrical insulator. B) electrical conductor. C) electrical gradient. D) source of ions.

A

Caveolae and clathrin-coated pits are both used in A) endocytosis. B) exocytosis. C) phagocytosis. D) all of the above E) none of the above

A) endocytosis

Which of the following is a way for solutes in an aqueous solution to move from an area of high solute concentration to an area of low solute concentration? A) facilitated diffusion B) osmosis C) active transport D) A and B E) none of the above

A) facilitated diffusion

Permeability is a property of A) membranes. B) ions. C) solutes. D) solvents. E) proteins.

A) membranes

Match the type of transport with its description. movement from the extracellular fluid into the lumen of an organ A. secretion B. paracellular transport C. transcellular transport D. absorption

A. secretion

A cell membrane that is selectively permeable A) randomly chooses which substances will pass through. B) can change which substances pass through by changing its lipid and protein content. C) is impermeable to all substances but water. D) will only allow substances in or out if their concentration in the cell is above or below a certain point

B

A cell that is permeable to Solute X is placed into solution containing a higher concentration of X. Diffusion occurs until equilibrium is attained. At this time A) there is no further movement of Solute X across the membrane. B) there is no further change in concentration of Solute X. C) both A and B D) neither A nor B

B

Anions will __________ each other. A) attract B) repel C) not react with

B

Cations will __________ each other. A) attract B) repel C) not react with

B

Fick's law of diffusion states that the rate of diffusion across a membrane is A) proportional to surface area and membrane thickness, but inversely proportional to concentration gradient. B) proportional to concentration gradient, surface area, and membrane permeability. C) proportional to membrane permeability, but inversely proportional to concentration gradient and surface area. D) proportional to membrane thickness and surface area.

B

Match the potential or potential change with the causative circumstances. Assume ion movements are net movements. Answers may be used more than once or not at all. Cl- enters the cell A. resting membrane potential B. hyperpolarization C. depolarization D. repolarization E. more than one of the above

B

Match the terms to changes presented, assuming a resting membrane potential of -70 mV. Answers may be used once, more than once, or not at all. to -90 mV from resting potential A. electrical polarization B. hyperpolarization C. depolarization D. repolarization E. more than one of the above

B

Substances that readily dissolve in water and do not readily dissolve in lipids are A) hydrophobic and lipophobic. B) hydrophilic and lipophobic. C) hydrophobic and lipophilic. D) hydrophilic and lipophilic.

B

Using CO2 as an example, which of the following summarizes the Law of Mass Balance? A) total load of CO2 in body = intake + metabolism + production - excretion B) total load of CO2 in body = intake + production - excretion - metabolism C) total load of CO2 in body = intake - production - excretion - metabolism D) total load of CO2 in body = intake + production - excretion + metabolism E) total load of CO2 in body = intake - production - excretion + metabolism

B

Water will always move from __________ areas to __________ areas, if there are no impermeable barriers. A) hyperosmotic, hyposmotic B) hyposmotic, hyperosmotic C) hyposmotic, isosmotic D) hyperosmotic, isosmotic

B

Which of the following does NOT influence membrane permeability? A) the size of the diffusing molecule B) the thickness of the lipid bilayer C) the lipid solubility of the diffusing molecule D) the composition of the lipid bilayer

B

The resting membrane potential in a typical nerve cell is approximately A) +70 mV. B) -70 mV. C) +35 mV. D) -35 mV. E) 0 mV.

B) -70 mV.

The term cellular (metabolic) energy indicates any biological process requiring A) energy in any form. B) ATP. C) thermal energy. D) chemical energy. E) C and D

B) ATP.

The ion that plays a key role in initiating electrical signals in neurons is A) K+. B) Na+. C) Cl-. D) Ca2+.

B) Na+.

In an epithelium, the apical membrane is also known as the __________ membrane. A) basolateral B) mucosal C) serosal D) basement E) nictitating

B) mucosal

Compared to the outside surface, the inside of a resting cell membrane is A) positively charged. B) negatively charged. C) electrically neutral. D) continuously reversing its electrical charge. E) positively charged whenever the sodium-potassium pump is active.

B) negatively charged

Passive transport refers to a process that requires A) no energy at all. B) no cellular energy. C) no pressure gradient. D) no concentration gradient. E) no electrical gradient.

B) no cellular energy

What are the two extracellular fluid compartments in the body? A) intracellular and plasma B) plasma and interstitial C) interstitial and intracellular D) plasma and the fluid portion of the blood E) none of the above

B) plasma and interstitial

Water is a polar molecule, yet it easily moves through the nonpolar portions of cell membranes. Which transport process is responsible? A) facilitated diffusion B) simple diffusion C) uniport D) symport E) antiport

B) simple diffusion

a form of mediated transport is... A.simple diffusion B.facilitated diffusion C. both D.neither

B. facilitated diffusion

conform(s) to the properties of specificity, competition, and saturation is... A.simple diffusion B.facilitated diffusion C. both D.neither

B. facilitated diffusion

Match the type of transport with its description. between adjacent cells A. secretion B. paracellular transport C. transcellular transport D. absorption

B. paracellular transport

Facilitated diffusion and active transport differ in that A) facilitated diffusion uses cell membrane proteins to move substances, whereas active transport does not. B) facilitated diffusion uses a substrate to bind to a protein carrier, whereas active transport does not. C) ATP is necessary for active transport, but not for facilitated diffusion. D) facilitated diffusion moves water across the cell membrane, whereas active transport does not. E) energy is required for active transport but not for facilitated diffusion

C

Match the potential or potential change with the causative circumstances. Assume ion movements are net movements. Answers may be used more than once or not at all. Na+ enters the cell A. resting membrane potential B. hyperpolarization C. depolarization D. repolarization E. more than one of the above

C

Match the potential or potential change with the causative circumstances. Assume ion movements are net movements. Answers may be used more than once or not at all. membrane potential is 0 mV A. resting membrane potential B. hyperpolarization C. depolarization D. repolarization E. more than one of the above

C

Match the terms to changes presented, assuming a resting membrane potential of -70 mV. Answers may be used once, more than once, or not at all. to +30 mV from resting potential A. electrical polarization B. hyperpolarization C. depolarization D. repolarization E. more than one of the above

C

Match the terms to changes presented, assuming a resting membrane potential of -70 mV. Answers may be used once, more than once, or not at all. to -50 mV from resting potential A. electrical polarization B. hyperpolarization C. depolarization D. repolarization E. more than one of the above

C

Sodium ions are more concentrated in the extracellular fluid than in the intracellular fluid. This is an example of A) electrical disequilibrium. B) osmotic equilibrium. C) chemical disequilibrium. D) failed homeostasis.

C

The inside of a resting cell is slightly negative relative to the outside. This is an example of A) electrical disequilibrium. B) osmotic equilibrium. C) chemical disequilibrium. D) failed homeostasis.

C

Which body fluid compartment contains high levels of K+, large anions, and proteins? A) plasma B) interstitial fluid C) intracellular fluid D) A and C E) A and B

C

Which property of diffusion best helps explain the necessity of the circulatory system in multicellular organisms? A) Molecules move from an area of higher concentration to an area of lower concentration. B) Diffusion can take place in an open system or across a partition that separates two systems. C) Diffusion is rapid over short distances but much slower over long distances. D) Diffusion rate is inversely related to molecule size.

C

Which of the following statements about the resting membrane potential is TRUE? A) It is normally equal to zero volts. B) The inside of the membrane is positively charged compared to the outside. C) It results, in part, from the concentration gradients for Na+ and K+. D) It is due in part to the presence of extracellular proteins.

C) It results, in part, from the concentration gradients for Na+ and K+.

Saturation occurs when A) molecules are moved by the use of vesicles. B) the energy required to move molecules results from a high-energy bond. C) a group of carrier proteins is operating at its maximum rate. D) a preference of a carrier protein for a substance is demonstrated based on the differing affinities of the carrier for the substrates. E) a carrier molecule has the ability to transport only one molecule or a group of closely related molecules.

C) a group of carrier proteins is operating at its maximum rate.

As the charge on the membrane of a typical neuron approaches 0 from -70 mV, the cell is A) repolarizing. B) hyperpolarizing. C) depolarizing. D) becoming more difficult to stimulate. E) B and D

C) depolarizing

The means by which a cell transports large molecules out of the cell is called A) phagocytosis. B) endocytosis. C) exocytosis. D) diffusion. E) active transport.

C) exocytosis

Bulk flow is fluid flow as a result of a __________ gradient. A) concentration B) electrical C) pressure D) two of the above E) none of the above

C) pressure

Which of the following is NOT involved in creating the resting potential of a neuron? A) diffusion of potassium ions out of the cell B) diffusion of sodium ions into the cell C) resting membrane permeability for sodium ions greater than potassium ions D) resting membrane permeability for potassium ions greater than sodium ions E) The interior of the cell membrane has an excess of negatively charged protein molecules

C) resting membrane permeability for sodium ions greater than potassium ions

All of the following are types of mediated transport except one. Identify the exception. A) facilitated diffusion B) primary active transport C) simple diffusion D) secondary active transport

C) simple diffusion

Voltage-gated (voltage-dependent) channels and antiport carriers are both types of A) structural proteins. B) enzymes. C) transporters. D) receptors.

C) transporters.

the movement of molecules from an area of high concentration to an area of low concentration is... A.simple diffusion B.facilitated diffusion C. both D.neither

C. both

Match the type of transport with its description. in one side of a cell and out the other A. secretion B. paracellular transport C. transcellular transport D. absorption

C. transcellular transport

Match the terms to changes presented, assuming a resting membrane potential of -70 mV. Answers may be used once, more than once, or not at all. to -70 mV from -50 mV A. electrical polarization B. hyperpolarization C. depolarization D. repolarization E. more than one of the above

D

Match the terms to changes presented, assuming a resting membrane potential of -70 mV. Answers may be used once, more than once, or not at all. to -70 mV from -90 mV A. electrical polarization B. hyperpolarization C. depolarization D. repolarization E. more than one of the above

D

When a neuron changes its ion permeability from the resting state, A) a variety of gated ion channels may open or close. B) Na+ channels may open, allowing Na+ to enter the cell. C) K+ channels must open, allowing K+ to enter the cell. D) A and B E) A, B, and C

D) A and B

Which of the following statements about the Na+/K+ pump is FALSE? A) It transports Na+ out of the cell and K+ into the cell. B) It is present in neurons. C) Its activity requires the expenditure of metabolic (cellular) energy. D) It transports Na+ and K+ in a 1:1 ratio.

D) It transports Na+ and K+ in a 1:1 ratio

Gated channels for sodium ions may include A) mechanical gates, which respond to pressure. B) chemical gates, which respond to ligands. C) voltage gates, which respond to electrical signals. D) all of the above E) none of the above

D) all of the above

Hyposmotic solutions A) have higher concentrations of solutes than hyperosmotic solutions. B) have lower concentrations of solutes than other hyposmotic solutions. C) have the same concentration of solutes as hyperosmotic solutions. D) have lower concentrations of solutes than hyperosmotic solutions. E) none of the above

D) have lower concentrations of solutes than hyperosmotic solutions.

Match the type of transport with its description. from an organ's lumen to the extracellular fluid A. secretion B. paracellular transport C. transcellular transport D. absorption

D. absorption

the use of ATP to move molecules is... A.simple diffusion B.facilitated diffusion C. both D.neither

D. neither

Match the potential or potential change with the causative circumstances. Assume ion movements are net movements. Answers may be used more than once or not at all. K+ leaves the cell A. resting membrane potential B. hyperpolarization C. depolarization D. repolarization E. more than one of the above

E

Which body fluid compartment contains higher levels of Na+, Cl-, and HCO3-? A) plasma B) interstitial fluid C) intracellular fluid D) A and C E) A and B

E

Which of the following molecules can move across the phospholipid bilayer by simple diffusion? A) lipids B) steroids C) water D) A and C E) all of the above

E

"the movement of molecules against the concentration gradient" is what term?

active transport

"the movement of molecules via proteins embedded in the cell membrane; requires ATP " is what term?

active transport

Channel proteins that allow water to pass are called __________.

aquaporins

The function of transporters is

bind to molecules to facilitate entry to or exit from the cell

The membrane proteins that change shape and bind with specific molecules to transport them across the cell membrane are __________.

carrier proteins

The three types of gated channels are __________, __________, and __________.

chemically gated channels, voltage-gated channels, mechanically gated channels

The walls of the __________ separate the two extracellular fluid compartments.

circulatory system

A pump that helps maintain an electrical gradient, such as the Na+-K+-ATPase is a(n) __________ pump.

electrogenic

The membrane proteins that catalyze reactions that take place on the external or internal surface of the cell are __________.

enzymes

The function of structural proteins is

form cell-to-cell connections

Membrane protein pores that can be opened and closed are called __________ channels.

gated (regulated)

The function of enzymes is

ligands bind to these proteins and are changed by the protein

This type of membrane protein extends all the way through the cell membrane into both the extra- and intracellular fluids:

membrane-spanning

Membrane protein pores that are essentially always open are called __________ or __________ channels

open, leak (either order)

"tends to create an equilibrium state"

passive transport

"the movement of molecules from an area of high concentration to an area of low concentration" is what term?

passive transport

The two extracellular compartments in the body are __________ and __________.

plasma, interstitial fluid

The membrane proteins that bind to a ligand and act in the body's chemical signaling system are __________.

receptors

At rest, nerve cells have an unequal distribution of ions on either side of the cell membrane, producing the __________.

resting membrane potential

Carrier proteins operating at their maximum rate are said to be __________.

saturated

The ability of a carrier molecule to transport only one specific molecule or a group of closely related molecules is called __________.

specificity

The membrane proteins that provide for support of the cell membrane and allow for cells to connect to each other are __________.

structural proteins

The function of receptors is

transfer signals from the extracellular environment to the cytoplasm of the cell