Question 1

Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal?

Accepted Answer

A)  Voltage-gated calcium channels in the membrane open. 
B)  Synaptic vesicles fuse with the membrane. 
C)  Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft. 
D)  An EPSP or IPSP is generated in the postsynaptic cell. 
A)  Voltage-gated calcium channels in the membrane open. 
B)  Synaptic vesicles fuse with the membrane. 
C)  Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft. 
D)  An EPSP or IPSP is generated in the postsynaptic cell. A

Question 2

The selectivity of a particular ion channel refers to its

Accepted Answer

A)  permitting passage by positive but not negative ions. 
B)  permitting passage by negative but not positive ions. 
C)  ability to change its size depending on the ion needing transport. 
D)  binding with only one type of neurotransmitter. 
E)  permitting passage only to a specific ion. 
A)  permitting passage by positive but not negative ions. 
B)  permitting passage by negative but not positive ions. 
C)  ability to change its size depending on the ion needing transport. 
D)  binding with only one type of neurotransmitter. 
E)  permitting passage only to a specific ion. E

Question 3

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. B

Question 4

The nervous system can alter the activities of skeletal muscle fibers because

Accepted Answer

A)  it is electrically coupled by gap junctions to the muscles. 
B)  its signals bind to receptor proteins on the muscles. 
C)  its signals reach the muscles via the blood. 
D)  its light pulses activate contraction in the muscles. 
E)  it is connected to the internal neural network of the muscles. 
A)  it is electrically coupled by gap junctions to the muscles. 
B)  its signals bind to receptor proteins on the muscles. 
C)  its signals reach the muscles via the blood. 
D)  its light pulses activate contraction in the muscles. 
E)  it is connected to the internal neural network of the muscles.

Question 5

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 6

Assume that a single IPSP has a negative magnitude of -0.5 mV at the axon hillock and that a single EPSP has a positive magnitude of +0.5 mV. For a neuron with an initial membrane potential of -70 mV, the net effect of the simultaneous arrival of six IPSPs and two EPSPs would be to move the membrane potential to

Accepted Answer

A)  -72 mV. 
B)  -71 mV. 
C)  -70 mV. 
D)  -69 mV. 
E)  -68 mV. 
A)  -72 mV. 
B)  -71 mV. 
C)  -70 mV. 
D)  -69 mV. 
E)  -68 mV.

Question 7

Researchers created a genetic strain of mice that were lacking both genes for MyRF, a transcription factor that is required for oligodendrocytes to function normally. What is the most likely effect that this would have on the mice?

Accepted Answer

A)  loss of salutatory conduction 
B)  thicker myelin sheaths 
C)  impaired ability for potassium ions to cross neuronal membranes 
D)  growth of dendrites 
A)  loss of salutatory conduction 
B)  thicker myelin sheaths 
C)  impaired ability for potassium ions to cross neuronal membranes 
D)  growth of dendrites

Question 8

After the depolarization phase of an action potential, the resting potential is restored by

Accepted Answer

A)  the opening of voltage-gated sodium channels. 
B)  the opening of voltage-gated potassium channels and the closing of sodium channels. 
C)  a decrease in the membrane's permeability to potassium and chloride ions. 
D)  a brief inhibition of the sodium-potassium pump. 
E)  the opening of more voltage-gated sodium channels. 
A)  the opening of voltage-gated sodium channels. 
B)  the opening of voltage-gated potassium channels and the closing of sodium channels. 
C)  a decrease in the membrane's permeability to potassium and chloride ions. 
D)  a brief inhibition of the sodium-potassium pump. 
E)  the opening of more voltage-gated sodium channels.

Question 9

In Figure 37.1, 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

Most of the synapses in vertebrates conduct information in only one direction

Accepted Answer

A)  as a result of the nodes of Ranvier. 
B)  as a result of voltage-gated sodium channels found only in the vertebrate system. 
C)  because vertebrate nerve cells have dendrites. 
D)  because only the postsynaptic cells can bind and respond to neurotransmitters. 
E)  because the sodium-potassium pump moves ions in one direction. 
A)  as a result of the nodes of Ranvier. 
B)  as a result of voltage-gated sodium channels found only in the vertebrate system. 
C)  because vertebrate nerve cells have dendrites. 
D)  because only the postsynaptic cells can bind and respond to neurotransmitters. 
E)  because the sodium-potassium pump moves ions in one direction.

Question 11

Researchers injected bark scorpion venom in mouse neurons (both a common house mouse and the southern grasshopper mouse) and measured the flow of sodium ions across the cell membrane. Their data is shown below.   Based on these data, what effect do you think the venom is having on the grasshopper mouse?

Accepted Answer

A)  The venom is blocking voltage-gated sodium channels. 
B)  The venom is blocking voltage-gated potassium channels. 
C)  The venom is opening voltage-gated sodium channels. 
D)  The venom is opening voltage-gated potassium channels. 
A)  The venom is blocking voltage-gated sodium channels. 
B)  The venom is blocking voltage-gated potassium channels. 
C)  The venom is opening voltage-gated sodium channels. 
D)  The venom is opening voltage-gated potassium channels.

Question 12

The major inhibitory neurotransmitter of the human brain is

Accepted Answer

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

Question 13

An inhibitory postsynaptic potential (IPSP) occurs in a membrane made more permeable to

Accepted Answer

A)  potassium ions. 
B)  sodium ions. 
C)  calcium ions. 
D)  ATP. 
A)  potassium ions. 
B)  sodium ions. 
C)  calcium ions. 
D)  ATP.

Question 14

Figure 37.2
Figure 37.2 shows many channels in a cell membrane. The channel third from the left is a voltage-gated sodium channel. What would happen if this channel became blocked and thus unable to function?

Accepted Answer

A)  The cell's membrane potential would not change. 
B)  The cell would hyperpolarize. 
C)  The cell would depolarize. 
D)  There is not enough information to make a conclusion. 
A)  The cell's membrane potential would not change. 
B)  The cell would hyperpolarize. 
C)  The cell would depolarize. 
D)  There is not enough information to make a conclusion.

Question 15

Please use the following information to answer the question(s) below.
The Arizona bark scorpion is the most venomous scorpion in North America, and its bite will cause extensive pain to a human that lasts up to three days. However, the southern grasshopper mouse is essentially immune to the sting of this scorpion and actually eats the scorpions as prey. Researchers have recently elucidated the neuronal reason for why the southern grasshopper mouse does not feel pain from bark scorpion venom.
-When mice feel pain on their bodies, they lick that part of their body. Researchers injected bark scorpion venom into the hind paws of the common house mouse and the southern grasshopper mouse; they also injected 0.9% saline (essentially salt water) as a control. The researchers then observed how long the mice licked their paws. What data do you think the researchers collected?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 16

Motor neurons alter skeletal muscle activities by releasing neurotransmitters because

Accepted Answer

A)  they are electrically coupled by gap junctions to the muscles. 
B)  their signals bind to receptor proteins on the muscles. 
C)  their signals reach the muscles via the blood. 
D)  their light pulses activate contraction in the muscles. 
E)  they are connected to the internal neural network of the muscles. 
A)  they are electrically coupled by gap junctions to the muscles. 
B)  their signals bind to receptor proteins on the muscles. 
C)  their signals reach the muscles via the blood. 
D)  their light pulses activate contraction in the muscles. 
E)  they are connected to the internal neural network of the muscles.

Question 17

In Figure 37.1, the membrane's permeability to sodium ions is at its maximum 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 18

The period in which voltage-gated potassium channels are open and hyperpolarization has yet to occur is 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 19

The "threshold" potential of a membrane is the

Accepted Answer

A)  maximum depolarization needed to operate sodium-potassium pumps. 
B)  lowest frequency of action potentials a neuron can produce. 
C)  minimum hyperpolarization needed to prevent the occurrence of action potentials. 
D)  minimum depolarization needed to operate the voltage-gated sodium and potassium channels. 
E)  peak amount of depolarization seen in an action potential. 
A)  maximum depolarization needed to operate sodium-potassium pumps. 
B)  lowest frequency of action potentials a neuron can produce. 
C)  minimum hyperpolarization needed to prevent the occurrence of action potentials. 
D)  minimum depolarization needed to operate the voltage-gated sodium and potassium channels. 
E)  peak amount of depolarization seen in an action potential.

Question 20

Neurotransmitters categorized as inhibitory are expected to

Accepted Answer

A)  act independently of their receptor proteins. 
B)  close potassium channels. 
C)  open sodium channels. 
D)  close chloride channels. 
E)  hyperpolarize the membrane. 
A)  act independently of their receptor proteins. 
B)  close potassium channels. 
C)  open sodium channels. 
D)  close chloride channels. 
E)  hyperpolarize the membrane.

Exam 37: Neurons, Synapses, and Signaling

Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal?

The selectivity of a particular ion channel refers to its

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

The nervous system can alter the activities of skeletal muscle fibers because

A neuropeptide that might function as a natural analgesic is

Researchers created a genetic strain of mice that were lacking both genes for MyRF, a transcription factor that is required for oligodendrocytes to function normally. What is the most likely effect that this would have on the mice?

After the depolarization phase of an action potential, the resting potential is restored by

In Figure 37.1, the neuronal membrane is at its resting potential at label

Most of the synapses in vertebrates conduct information in only one direction

The major inhibitory neurotransmitter of the human brain is

An inhibitory postsynaptic potential (IPSP) occurs in a membrane made more permeable to

Figure 37.2 Figure 37.2 shows many channels in a cell membrane. The channel third from the left is a voltage-gated sodium channel. What would happen if this channel became blocked and thus unable to function?

Motor neurons alter skeletal muscle activities by releasing neurotransmitters because

In Figure 37.1, the membrane's permeability to sodium ions is at its maximum at label

The period in which voltage-gated potassium channels are open and hyperpolarization has yet to occur is at label

The "threshold" potential of a membrane is the

Neurotransmitters categorized as inhibitory are expected to

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Development, Stem Cells, and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition, Nutrition, and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Species Interactions

Ecosystems and Energy

Global Ecology and Conservation Biology

Filters