Test Bank
to accompany
Neuroscience, Sixth Edition
Purves • Augustine • Fitzpatrick • Hall • LaMantia • Mooney • Platt • White
Chapter 4: Ion Channels and Transporters
Multiple Choice
1. Ion channels that are involved in generation of action potentials open or close in
response to
a. voltage.
b. neurotransmitters.
c. second messengers.
d. mechanical stimulation.
e. temperature.
Answer: a
Textbook Reference: Overview
Bloom’s Level: 2. Understanding
2. In what way are ion channels similar to active transporters?
a. Both are proteins.
b. Both actively move ions from one side of the membrane to the other.
c. Both create ion concentration gradients.
d. Both maintain ion concentration gradients.
e. Both enable selective ion permeability.
Answer: a
Textbook Reference: Overview
Bloom’s Level: 2. Understanding
3. Based on the observations made by Hodgkin and Huxley, one can expect ion channels
to
a. allow ions to move across the membrane quickly.
b. work with the electrochemical gradients to pass ions.
c. exist in distinct variants, allowing different types of ions to pass.
d. respond to changes in the membrane potential.
e. All of the above
Answer: e
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 1. Remembering
4. Which technique would you use to study the effects of the extracellular environment
on ion channel activity?
a. Conventional voltage clamp
b. Whole-cell patch clamp
,c. Inside-out patch clamp
d. Outside-out patch clamp
e. Cell-attached patch clamp
Answer: d
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 3. Applying
5. Refer to the figure.
Which technique is illustrated in the figure, and what can it be used to measure?
a. Whole-cell patch clamp; measures potentials from the entire cell
b. Whole-cell patch clamp; measures the current that flows through a single ion channel
c. Cell-attached patch clamp; measures potentials from the entire cell
d. Cell-attached patch clamp; measures the current that flows through a single ion
channel
e. Outside-out patch clamp; measures the current that flows through a single ion channel
Answer: d
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 2. Understanding
6. What do microscopic and macroscopic Na+ currents have in common?
a. They flow through a single ion channel
b. They flow through multiple ion channels
c. They flow through a large area of neuronal membrane
d. They represent a flow of many ions
e. They have a magnitude of 1–10 pA
Answer: d
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 4. Analyzing
7. Which evidence supports the assertion that the macroscopic Na+ current is the sum of
many microscopic Na+ currents?
a. The probability of a Na+ channel opening increases as the membrane is hyperpolarized.
b. The averaged collective response of single channels resembles the time course of the
macroscopic current.
c. Opening and closing of Na+ channels is concentration-dependent.
, d. Tetrodotoxin blocks macroscopic, but not microscopic, currents.
e. All of the above
Answer: b
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 2. Understanding
8. Refer to the graph.
Which statement does the graph illustrate?
a. Microscopic current is directed inward when the membrane potential is more negative
than the Na+ equilibrium potential.
b. The averaged collective response of single Na+ channels resembles the time course of
the macroscopic current.
c. The behavior of Na+ channels is voltage dependent.
d. Tetrodotoxin blocks both microscopic and macroscopic currents.
e. Channels activate in response to depolarization and subsequently deactivate.
Answer: c
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 4. Analyzing
9. Which property is characteristic of Na+ channels but not K+ channels?
a. Ion permeability
b. Ion selectivity
c. Voltage sensitivity
d. Ability to inactivate
e. Ability to bind neurotoxins
Answer: d
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 2. Understanding
10. The K+ channel is made up of _______, each of which contains helical membrane-
spanning domains with a _______ between them.
a. two subunits; pore loop
b. four domains; pore loop
to accompany
Neuroscience, Sixth Edition
Purves • Augustine • Fitzpatrick • Hall • LaMantia • Mooney • Platt • White
Chapter 4: Ion Channels and Transporters
Multiple Choice
1. Ion channels that are involved in generation of action potentials open or close in
response to
a. voltage.
b. neurotransmitters.
c. second messengers.
d. mechanical stimulation.
e. temperature.
Answer: a
Textbook Reference: Overview
Bloom’s Level: 2. Understanding
2. In what way are ion channels similar to active transporters?
a. Both are proteins.
b. Both actively move ions from one side of the membrane to the other.
c. Both create ion concentration gradients.
d. Both maintain ion concentration gradients.
e. Both enable selective ion permeability.
Answer: a
Textbook Reference: Overview
Bloom’s Level: 2. Understanding
3. Based on the observations made by Hodgkin and Huxley, one can expect ion channels
to
a. allow ions to move across the membrane quickly.
b. work with the electrochemical gradients to pass ions.
c. exist in distinct variants, allowing different types of ions to pass.
d. respond to changes in the membrane potential.
e. All of the above
Answer: e
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 1. Remembering
4. Which technique would you use to study the effects of the extracellular environment
on ion channel activity?
a. Conventional voltage clamp
b. Whole-cell patch clamp
,c. Inside-out patch clamp
d. Outside-out patch clamp
e. Cell-attached patch clamp
Answer: d
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 3. Applying
5. Refer to the figure.
Which technique is illustrated in the figure, and what can it be used to measure?
a. Whole-cell patch clamp; measures potentials from the entire cell
b. Whole-cell patch clamp; measures the current that flows through a single ion channel
c. Cell-attached patch clamp; measures potentials from the entire cell
d. Cell-attached patch clamp; measures the current that flows through a single ion
channel
e. Outside-out patch clamp; measures the current that flows through a single ion channel
Answer: d
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 2. Understanding
6. What do microscopic and macroscopic Na+ currents have in common?
a. They flow through a single ion channel
b. They flow through multiple ion channels
c. They flow through a large area of neuronal membrane
d. They represent a flow of many ions
e. They have a magnitude of 1–10 pA
Answer: d
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 4. Analyzing
7. Which evidence supports the assertion that the macroscopic Na+ current is the sum of
many microscopic Na+ currents?
a. The probability of a Na+ channel opening increases as the membrane is hyperpolarized.
b. The averaged collective response of single channels resembles the time course of the
macroscopic current.
c. Opening and closing of Na+ channels is concentration-dependent.
, d. Tetrodotoxin blocks macroscopic, but not microscopic, currents.
e. All of the above
Answer: b
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 2. Understanding
8. Refer to the graph.
Which statement does the graph illustrate?
a. Microscopic current is directed inward when the membrane potential is more negative
than the Na+ equilibrium potential.
b. The averaged collective response of single Na+ channels resembles the time course of
the macroscopic current.
c. The behavior of Na+ channels is voltage dependent.
d. Tetrodotoxin blocks both microscopic and macroscopic currents.
e. Channels activate in response to depolarization and subsequently deactivate.
Answer: c
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 4. Analyzing
9. Which property is characteristic of Na+ channels but not K+ channels?
a. Ion permeability
b. Ion selectivity
c. Voltage sensitivity
d. Ability to inactivate
e. Ability to bind neurotoxins
Answer: d
Textbook Reference: Ion Channels Underlying Action Potentials
Bloom’s Level: 2. Understanding
10. The K+ channel is made up of _______, each of which contains helical membrane-
spanning domains with a _______ between them.
a. two subunits; pore loop
b. four domains; pore loop
