Question 1

The surface on a neuron that discharges the contents of synaptic vesicles is the

Accepted Answer

A)  dendrite. 
B)  axon hillock. 
C)  node of Ranvier. 
D)  postsynaptic membrane. 
E)  presynaptic membrane. 
A)  dendrite. 
B)  axon hillock. 
C)  node of Ranvier. 
D)  postsynaptic membrane. 
E)  presynaptic membrane.

Question 2

The operation of the sodium-potassium "pump" moves

Accepted Answer

A)  sodium and potassium ions into the cell. 
B)  sodium and potassium ions out of the cell. 
C)  sodium ions into the cell and potassium ions out of the cell. 
D)  sodium ions out of the cell and potassium ions into the cell. 
E)  sodium and potassium ions into the mitochondria. 
A)  sodium and potassium ions into the cell. 
B)  sodium and potassium ions out of the cell. 
C)  sodium ions into the cell and potassium ions out of the cell. 
D)  sodium ions out of the cell and potassium ions into the cell. 
E)  sodium and potassium ions into the mitochondria.

Question 3

For the following questions, refer to the graph of an action potential.
  
-Action potentials are normally carried in only one direction: from the axon hillock toward the axon terminals. If you experimentally depolarize the middle of the axon to threshold, using an electronic probe, then

Accepted Answer

A)  no action potential will be initiated. 
B)  an action potential will be initiated and proceed only in the normal direction toward the axon terminal. 
C)  an action potential will be initiated and proceed only back toward the axon hillock. 
D)  two action potentials will be initiated, one going toward the axon terminal and one going back toward the hillock. 
E)  an action potential will be initiated, but it will die out before it reaches the axon terminal. 
A)  no action potential will be initiated. 
B)  an action potential will be initiated and proceed only in the normal direction toward the axon terminal. 
C)  an action potential will be initiated and proceed only back toward the axon hillock. 
D)  two action potentials will be initiated, one going toward the axon terminal and one going back toward the hillock. 
E)  an action potential will be initiated, but it will die out before it reaches the axon terminal.

Question 4

Although the membrane of a "resting" neuron is highly permeable to potassium ions, its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is also

Accepted Answer

A)  fully permeable to sodium ions. 
B)  slightly permeable to sodium ions. 
C)  fully permeable to calcium ions. 
D)  impermeable to sodium ions. 
E)  highly permeable to chloride ions. 
A)  fully permeable to sodium ions. 
B)  slightly permeable to sodium ions. 
C)  fully permeable to calcium ions. 
D)  impermeable to sodium ions. 
E)  highly permeable to chloride ions.

Question 5

An example of the action of metabotropic receptors is when

Accepted Answer

A)  voltage-gated ion channels open. 
B)  voltage-gated ion channels close. 
C)  acetylcholine-gated sodium channels open. 
D)  cAMP-linked ion channels open. 
E)  the undershoot/after-hyperpolarization occurs. 
A)  voltage-gated ion channels open. 
B)  voltage-gated ion channels close. 
C)  acetylcholine-gated sodium channels open. 
D)  cAMP-linked ion channels open. 
E)  the undershoot/after-hyperpolarization occurs.

Question 6

A toxin that binds specifically to voltage-gated sodium channels in axons would be expected to

Accepted Answer

A)  prevent the hyperpolarization phase of the action potential. 
B)  prevent the depolarization phase of the action potential. 
C)  prevent graded potentials. 
D)  increase the release of neurotransmitter molecules. 
E)  have most of its effects on the dendritic region of a neuron. 
A)  prevent the hyperpolarization phase of the action potential. 
B)  prevent the depolarization phase of the action potential. 
C)  prevent graded potentials. 
D)  increase the release of neurotransmitter molecules. 
E)  have most of its effects on the dendritic region of a neuron.

Question 7

The primary means by which a neuron can communicate to a second neuron is by

Accepted Answer

A)  the frequency of its action potentials. 
B)  the peak of the depolarization phase of an action potential. 
C)  the peak of the undershoot/hyperpolarization of an action potential. 
D)  varying how much neurotransmitter it releases for a given action potential. 
E)  remaining in the depolarization phase of the action potential for an extended interval. 
A)  the frequency of its action potentials. 
B)  the peak of the depolarization phase of an action potential. 
C)  the peak of the undershoot/hyperpolarization of an action potential. 
D)  varying how much neurotransmitter it releases for a given action potential. 
E)  remaining in the depolarization phase of the action potential for an extended interval.

Question 8

Immediately after an action potential passes along an axon, it is not possible to generate a second action potential; thus, we state that the membrane is briefly

Accepted Answer

A)  hyperexcitable. 
B)  refractory. 
C)  fully depolarized. 
D)  above threshold. 
E)  at the equilibrium potential. 
A)  hyperexcitable. 
B)  refractory. 
C)  fully depolarized. 
D)  above threshold. 
E)  at the equilibrium potential.

Question 9

For the following questions, refer to the graph of an action potential.
  
-The neuronal membrane is at its resting potential at label

Accepted Answer

A)  A. 
B)  B. 
C)  C. 
D)  D. 
E)  E. 
A)  A. 
B)  B. 
C)  C. 
D)  D. 
E)  E.

Question 10

In a simple synapse, neurotransmitter chemicals are received by

Accepted Answer

A)  the dendritic membrane. 
B)  the presynaptic membrane. 
C)  axon hillocks. 
D)  cell bodies. 
E)  ducts on the smooth endoplasmic reticulum. 
A)  the dendritic membrane. 
B)  the presynaptic membrane. 
C)  axon hillocks. 
D)  cell bodies. 
E)  ducts on the smooth endoplasmic reticulum.

Question 11

When several EPSPs arrive at the axon hillock from different dendritic locations, depolarizing the postsynaptic cell to threshold for an action potential, this is an example of

Accepted Answer

A)  temporal summation. 
B)  spatial summation. 
C)  tetanus. 
D)  the refractory state. 
E)  an action potential with an abnormally high peak of depolarization. 
A)  temporal summation. 
B)  spatial summation. 
C)  tetanus. 
D)  the refractory state. 
E)  an action potential with an abnormally high peak of depolarization.

Question 12

The observation that the acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it is an example of

Accepted Answer

A)  a voltage-gated sodium channel. 
B)  a voltage-gated potassium channel. 
C)  a ligand-gated sodium channel. 
D)  a second-messenger-gated sodium channel. 
E)  a chemical that inhibits action potentials. 
A)  a voltage-gated sodium channel. 
B)  a voltage-gated potassium channel. 
C)  a ligand-gated sodium channel. 
D)  a second-messenger-gated sodium channel. 
E)  a chemical that inhibits action potentials.

Question 13

A neuropeptide that might function as a natural analgesic is

Accepted Answer

A)  acetylcholine. 
B)  epinephrine. 
C)  endorphin. 
D)  nitric oxide. 
E)  GABA. 
A)  acetylcholine. 
B)  epinephrine. 
C)  endorphin. 
D)  nitric oxide. 
E)  GABA.

Question 14

In certain large animals, this type of neuron can extend beyond 1 meter in length.

Accepted Answer

A)  glial cell in the brain 
B)  a sensory neuron 
C)  an interneuron 
D)  a glial cell at a ganglion 
E)  a neuron that controls eye movements 
A)  glial cell in the brain 
B)  a sensory neuron 
C)  an interneuron 
D)  a glial cell at a ganglion 
E)  a neuron that controls eye movements

Question 15

In the sequence of permeability changes for a complete action potential, the first of these events that occurs is

Accepted Answer

A)  the activation of the sodium-potassium "pump." 
B)  the inhibition of the sodium-potassium "pump." 
C)  the opening of voltage-gated sodium channels. 
D)  the closing of voltage-gated potassium channels. 
E)  the opening of voltage-gated potassium channels. 
A)  the activation of the sodium-potassium "pump." 
B)  the inhibition of the sodium-potassium "pump." 
C)  the opening of voltage-gated sodium channels. 
D)  the closing of voltage-gated potassium channels. 
E)  the opening of voltage-gated potassium channels.

Question 16

The activity of acetylcholine in a synapse is terminated by

Accepted Answer

A)  its active transport across the presynaptic membrane. 
B)  its diffusion across the presynaptic membrane. 
C)  its active transport across the postsynaptic membrane. 
D)  its diffusion across the postsynaptic membrane. 
E)  its degradation by a hydrolytic enzyme on the postsynaptic membrane. 
A)  its active transport across the presynaptic membrane. 
B)  its diffusion across the presynaptic membrane. 
C)  its active transport across the postsynaptic membrane. 
D)  its diffusion across the postsynaptic membrane. 
E)  its degradation by a hydrolytic enzyme on the postsynaptic membrane.

Question 17

An amino acid that operates at inhibitory synapses in the brain is

Accepted Answer

A)  acetylcholine. 
B)  epinephrine. 
C)  endorphin. 
D)  nitric oxide. 
E)  GABA. 
A)  acetylcholine. 
B)  epinephrine. 
C)  endorphin. 
D)  nitric oxide. 
E)  GABA.

Question 18

Two fundamental concepts about the ion channels of a "resting" neuron are that the channels

Accepted Answer

A)  are always open, but the concentration gradients of ions frequently change. 
B)  are always closed, but ions move closer to the channels during excitation. 
C)  open and close depending on stimuli, and are specific as to which ion can traverse them. 
D)  open and close depending on chemical messengers, and are nonspecific as to which ion can traverse them. 
E)  open in response to stimuli, and then close simultaneously, in unison. 
A)  are always open, but the concentration gradients of ions frequently change. 
B)  are always closed, but ions move closer to the channels during excitation. 
C)  open and close depending on stimuli, and are specific as to which ion can traverse them. 
D)  open and close depending on chemical messengers, and are nonspecific as to which ion can traverse them. 
E)  open in response to stimuli, and then close simultaneously, in unison.

Question 19

An action potential can start in the middle of an axon and proceed in both opposite directions when

Accepted Answer

A)  the neuron is an inhibitory neuron and operating normally. 
B)  only the middle section of the axon has been artificially stimulated by an electrode. 
C)  the dendritic region fires an action potential. 
D)  it is in its typical refractory state. 
E)  its membrane potential is above the threshold. 
A)  the neuron is an inhibitory neuron and operating normally. 
B)  only the middle section of the axon has been artificially stimulated by an electrode. 
C)  the dendritic region fires an action potential. 
D)  it is in its typical refractory state. 
E)  its membrane potential is above the threshold.

Question 20

A cation that is more abundant as a solute in the cytosol of a neuron than it is in the interstitial fluid outside the neuron is

Accepted Answer

A)  HCO₃⁻. 
B)  Cl⁻. 
C)  Ca⁺⁺. 
D)  Na⁺. 
E)  K⁺. 
A)  HCO₃⁻. 
B)  Cl⁻. 
C)  Ca⁺⁺. 
D)  Na⁺. 
E)  K⁺.

Exam 48: Neurons, Synapses, and Signaling

The surface on a neuron that discharges the contents of synaptic vesicles is the

The operation of the sodium-potassium "pump" moves

For the following questions, refer to the graph of an action potential. -Action potentials are normally carried in only one direction: from the axon hillock toward the axon terminals. If you experimentally depolarize the middle of the axon to threshold, using an electronic probe, then

Although the membrane of a "resting" neuron is highly permeable to potassium ions, its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is also

An example of the action of metabotropic receptors is when

A toxin that binds specifically to voltage-gated sodium channels in axons would be expected to

The primary means by which a neuron can communicate to a second neuron is by

Immediately after an action potential passes along an axon, it is not possible to generate a second action potential; thus, we state that the membrane is briefly

For the following questions, refer to the graph of an action potential. -The neuronal membrane is at its resting potential at label

In a simple synapse, neurotransmitter chemicals are received by

When several EPSPs arrive at the axon hillock from different dendritic locations, depolarizing the postsynaptic cell to threshold for an action potential, this is an example of

The observation that the acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it is an example of

A neuropeptide that might function as a natural analgesic is

In certain large animals, this type of neuron can extend beyond 1 meter in length.

In the sequence of permeability changes for a complete action potential, the first of these events that occurs is

The activity of acetylcholine in a synapse is terminated by

An amino acid that operates at inhibitory synapses in the brain is

Two fundamental concepts about the ion channels of a "resting" neuron are that the channels

An action potential can start in the middle of an axon and proceed in both opposite directions when

A cation that is more abundant as a solute in the cytosol of a neuron than it is in the interstitial fluid outside the neuron is

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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