Question 1

Briefly explain the principle of "noise analysis."

Accepted Answer

Noise analysis uses the properties of the noise in a whole cell current recording while channels are opening and closing to estimate the single channel current size and mean open time. If the single-channel currents are relatively large, then the size of the noise fluctuations will be large as well, while if single channel currents are small, the size of the noise fluctuations will be small. If channels open for a relatively long time they will produce low-frequency noise, while if they open only briefly they will produce higher frequency noise.

Question 2

Permeability can be defined as

Accepted Answer

A)  the ease with which ions can move across the membrane. 
B)  the voltage-dependence of activation of an ion channel. 
C)  the mean open time of a channel. 
D)  the equilibrium potential of an ion. 
E)  simple diffusion of ions down their concentration gradient. 
A)  the ease with which ions can move across the membrane. 
B)  the voltage-dependence of activation of an ion channel. 
C)  the mean open time of a channel. 
D)  the equilibrium potential of an ion. 
E)  simple diffusion of ions down their concentration gradient. A

Question 3

If the potassium ion concentration is 3 mM outside and 88 mM in the cytoplasm, and potassium selective channels open with the membrane potential at -30 mV, which will occur?

Accepted Answer

A)  The net flux of potassium ions will be inward. 
B)  The net flux of potassium ions will be outward. 
C)  There will be no net flux of potassium ions-it will be equal in and out. 
D)  There will be no movement of potassium ions across the membrane. 
E)  Potassium channels will inactivate 
A)  The net flux of potassium ions will be inward. 
B)  The net flux of potassium ions will be outward. 
C)  There will be no net flux of potassium ions-it will be equal in and out. 
D)  There will be no movement of potassium ions across the membrane. 
E)  Potassium channels will inactivate B

Question 4

In the continued presence of the stimulus to open, after opening initially, some ligand-gated channels will close and remain closed for the remainder of the stimulus. This is called

Accepted Answer

A)  activation. 
B)  inactivation. 
C)  deactivation. 
D)  contraction. 
E)  desensitization. 
A)  activation. 
B)  inactivation. 
C)  deactivation. 
D)  contraction. 
E)  desensitization.

Question 5

The "whole cell" patch clamp technique

Accepted Answer

A)  allows the experimenter to easily change the solution bathing the inside surface of the cell during the recording and study the activity of single voltage-gated channel currents. 
B)  allows the experimenter to easily change the solution bathing the outside surface of the cell during the recording and study the activity of single voltage-gated channel currents. 
C)  does not allow the experimenter to change the solution on either side of the cell, but you can study the summed activity of all voltage-gated channels in the cell (macroscopic current). 
D)  allows the experimenter to easily change the solution bathing the inside surface of the cell during the recording and study the summed activity of all voltage-gated channels in the cell (macroscopic current). 
E)  allows the experimenter to easily change the solution bathing the outside surface of the cell during the recording and study the summed activity of all voltage-gated channels in the cell (macroscopic current). 
A)  allows the experimenter to easily change the solution bathing the inside surface of the cell during the recording and study the activity of single voltage-gated channel currents. 
B)  allows the experimenter to easily change the solution bathing the outside surface of the cell during the recording and study the activity of single voltage-gated channel currents. 
C)  does not allow the experimenter to change the solution on either side of the cell, but you can study the summed activity of all voltage-gated channels in the cell (macroscopic current). 
D)  allows the experimenter to easily change the solution bathing the inside surface of the cell during the recording and study the summed activity of all voltage-gated channels in the cell (macroscopic current). 
E)  allows the experimenter to easily change the solution bathing the outside surface of the cell during the recording and study the summed activity of all voltage-gated channels in the cell (macroscopic current).

Question 6

When a large molecule binds to and physically obstructs the pore of a channel, it is called

Accepted Answer

A)  mechanoreception. 
B)  ligand gating. 
C)  an open channel block. 
D)  channel deactivation. 
E)  a sensitivity filter. 
A)  mechanoreception. 
B)  ligand gating. 
C)  an open channel block. 
D)  channel deactivation. 
E)  a sensitivity filter.

Question 7

The equilibrium potential for a channel can be described as proportional to the

Accepted Answer

A)  difference between the concentration inside the cell and outside the cell. 
B)  between the logarithms of the concentration inside the cell and outside the cell. 
C)  addition of the logarithms of the concentration inside the cell and outside the cell. 
D)  addition of the concentration inside the cell and outside the cell. 
E)  multiplication of the logarithms of the concentration inside the cell and outside the cell. 
A)  difference between the concentration inside the cell and outside the cell. 
B)  between the logarithms of the concentration inside the cell and outside the cell. 
C)  addition of the logarithms of the concentration inside the cell and outside the cell. 
D)  addition of the concentration inside the cell and outside the cell. 
E)  multiplication of the logarithms of the concentration inside the cell and outside the cell.

Question 8

Based on the Nernst equation, if the concentration of potassium outside was 3 mM and the concentration of sodium in the cytoplasm was 88 mM, what is the potassium equilibrium potential?

Accepted Answer

A)  -85 mV 
B)  -30 mV 
C)  0 mV 
D)  +30 mV 
E)  +60 mV 
A)  -85 mV 
B)  -30 mV 
C)  0 mV 
D)  +30 mV 
E)  +60 mV

Question 9

If the potassium ion concentration is 3 mM outside and 88 mM in the cytoplasm, and potassium selective channels open with the membrane potential at -85 mV, which will occur?

Accepted Answer

A)  The net flux of potassium ions will be inward. 
B)  The net flux of potassium ions will be outward. 
C)  There will be no net flux of potassium ions-it will be equal in and out. 
D)  There will be no movement of potassium ions across the membrane. 
E)  Potassium channels will inactivate. 
A)  The net flux of potassium ions will be inward. 
B)  The net flux of potassium ions will be outward. 
C)  There will be no net flux of potassium ions-it will be equal in and out. 
D)  There will be no movement of potassium ions across the membrane. 
E)  Potassium channels will inactivate.

Question 10

What governs the movement of ions through channels in the plasma membrane?

Accepted Answer

A)  Ions move through such channels passively, driven by concentration gradients and by the electrical potential across the membrane. 
B)  Ions move through channels actively, driven by the energy provided by ATP. 
C)  Ions move through channels passively, driven only by the concentration gradient. 
D)  Ions move through channels passively, driven only by the electrical potential across the membrane. 
E)  Ions move through channels actively, driven by the energy provided by GTP. 
A)  Ions move through such channels passively, driven by concentration gradients and by the electrical potential across the membrane. 
B)  Ions move through channels actively, driven by the energy provided by ATP. 
C)  Ions move through channels passively, driven only by the concentration gradient. 
D)  Ions move through channels passively, driven only by the electrical potential across the membrane. 
E)  Ions move through channels actively, driven by the energy provided by GTP.

Question 11

Ion permeation can be described as

Accepted Answer

A)  simple diffusion of ions down their concentration gradient. 
B)  active transport of ions against their concentration gradient. 
C)  facilitated transport of ions against their concentration gradient. 
D)  hopping or jumping of ions along electrostatic binding sites in the pore driven by the concentration gradient and the charge across the membrane. 
E)  hopping or jumping of ions along electrostatic binding sites in the pore driven by the concentration gradient. 
A)  simple diffusion of ions down their concentration gradient. 
B)  active transport of ions against their concentration gradient. 
C)  facilitated transport of ions against their concentration gradient. 
D)  hopping or jumping of ions along electrostatic binding sites in the pore driven by the concentration gradient and the charge across the membrane. 
E)  hopping or jumping of ions along electrostatic binding sites in the pore driven by the concentration gradient.

Question 12

Under which of the following conditions would the current-voltage relation for a channel be nonlinear?

Accepted Answer

A)  When the voltage across the plasma membrane is very negative 
B)  When the ion concentrations on either side of the channel are symmetrical, or because the channel itself is nonrectifying 
C)  When the ion concentrations on either side of the channel are not symmetrical, or because the channel itself is rectifying 
D)  When the equilibrium potential for the channel is at zero millivolts 
E)  When the mean open time of the channel randomly varies 
A)  When the voltage across the plasma membrane is very negative 
B)  When the ion concentrations on either side of the channel are symmetrical, or because the channel itself is nonrectifying 
C)  When the ion concentrations on either side of the channel are not symmetrical, or because the channel itself is rectifying 
D)  When the equilibrium potential for the channel is at zero millivolts 
E)  When the mean open time of the channel randomly varies

Question 13

What does the "gate" on an ion channel do?

Accepted Answer

A gate is the part of the ion channel pr

Question 14

Can voltage-gated ion channels ever move an ion against its concentration gradient? If so, when does this occur?

Accepted Answer

The direction of movement of the ions th

Question 15

In the continued presence of the stimulus to open, after opening initially, some voltage-gated channels will close and remain closed for the remainder of the stimulus. This is called

Accepted Answer

A)  activation. 
B)  inactivation. 
C)  deactivation. 
D)  contraction. 
E)  desensitization. 
A)  activation. 
B)  inactivation. 
C)  deactivation. 
D)  contraction. 
E)  desensitization.

Question 16

If the potassium ion concentration is 3 mM outside and 88 mM in the cytoplasm, and potassium selective channels open with the membrane potential at -95 mV, which will occur?

Accepted Answer

A)  The net flux of potassium ions will be inward. 
B)  The net flux of potassium ions will be outward. 
C)  There will be no net flux of potassium ions-it will be equal in and out. 
D)  There will be no movement of potassium ions across the membrane. 
E)  Potassium channels will inactivate. 
A)  The net flux of potassium ions will be inward. 
B)  The net flux of potassium ions will be outward. 
C)  There will be no net flux of potassium ions-it will be equal in and out. 
D)  There will be no movement of potassium ions across the membrane. 
E)  Potassium channels will inactivate.

Question 17

What is the diameter of the tip of a pipette used for patch clamp recording?

Accepted Answer

A)  Less than 0.5 micrometers 
B)  1 micrometer 
C)  1 millimeter 
D)  100 micrometers 
E)  10 millimeters 
A)  Less than 0.5 micrometers 
B)  1 micrometer 
C)  1 millimeter 
D)  100 micrometers 
E)  10 millimeters

Question 18

Define and explain the equilibrium potential for an ion.

Accepted Answer

The equilibrium potential for an ion is

Question 19

When using patch clamp recording, what is the difference between an "inside-out patch" and an outside-out patch"?

Accepted Answer

An inside-out patch is formed when the e

Question 20

Driving force on a specific ion is

Accepted Answer

A)  the voltage-dependence of activation for that ion channel. 
B)  equal to the voltage across the membrane minus the equilibrium potential for the ion. 
C)  equal to the equilibrium potential for the ion. 
D)  equal to the concentration gradient across the membrane for the ion. 
E)  equal to the conductance through channels for the ion. 
A)  the voltage-dependence of activation for that ion channel. 
B)  equal to the voltage across the membrane minus the equilibrium potential for the ion. 
C)  equal to the equilibrium potential for the ion. 
D)  equal to the concentration gradient across the membrane for the ion. 
E)  equal to the conductance through channels for the ion.

Exam 4: Ion Channels and Signaling

Briefly explain the principle of "noise analysis."

Permeability can be defined as

If the potassium ion concentration is 3 mM outside and 88 mM in the cytoplasm, and potassium selective channels open with the membrane potential at -30 mV, which will occur?

In the continued presence of the stimulus to open, after opening initially, some ligand-gated channels will close and remain closed for the remainder of the stimulus. This is called

The "whole cell" patch clamp technique

When a large molecule binds to and physically obstructs the pore of a channel, it is called

The equilibrium potential for a channel can be described as proportional to the

Based on the Nernst equation, if the concentration of potassium outside was 3 mM and the concentration of sodium in the cytoplasm was 88 mM, what is the potassium equilibrium potential?

If the potassium ion concentration is 3 mM outside and 88 mM in the cytoplasm, and potassium selective channels open with the membrane potential at -85 mV, which will occur?

What governs the movement of ions through channels in the plasma membrane?

Ion permeation can be described as

Under which of the following conditions would the current-voltage relation for a channel be nonlinear?

What does the "gate" on an ion channel do?

Can voltage-gated ion channels ever move an ion against its concentration gradient? If so, when does this occur?

In the continued presence of the stimulus to open, after opening initially, some voltage-gated channels will close and remain closed for the remainder of the stimulus. This is called

If the potassium ion concentration is 3 mM outside and 88 mM in the cytoplasm, and potassium selective channels open with the membrane potential at -95 mV, which will occur?

What is the diameter of the tip of a pipette used for patch clamp recording?

Define and explain the equilibrium potential for an ion.

When using patch clamp recording, what is the difference between an "inside-out patch" and an outside-out patch"?

Driving force on a specific ion is

Principles of Signaling and Organization

Signaling in the Visual System

Functional Architecture of the Visual Cortex

Structure of Ion Channels

Ionic Basis of the Resting Potential

Ionic Basis of the Action Potential

Electrical Signaling in Neurons

Ion Transport Across Cell Membranes

Properties and Functions of Neuroglial Cells

Mechanisms of Direct Synaptic Transmission

Indirect Mechanisms of Synaptic Transmission

Release of Neurotransmitters

Neurotransmitters in the Central Nervous System

Transmitter Synthesis, Storage, Transport, and Inactivation

Synaptic Plasticity

The Molecular and Cellular Biology of Synaptic Plasticity

Mechanisms of Extrasynaptic Communication

Autonomic Nervous System

Walking, Flying, and Swimming: Cellular Mechanisms of Sensorimotor Behavior in Invertebrates

Sensory Transduction

Transduction and Transmission in the Retina

Touch, Pain, and Texture Sensation

Auditory and Vestibular Sensation

Constructing Perception

Initiation and Control of Coordinated Muscular Movements

Development of the Nervous System

Critical Periods in Sensory Systems

Regeneration and Repair of Synaptic Connections After Injury

Appendix

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