Question 1

A transport system that moves one solute into the cell and another one out of the cell during a single cycle accompanied by the expenditure of energy through ATP hydrolysis could be called a(n)_______
A)active antiport
B)active uniport
C)passive antiport
D)active symport
E)passive symport

Accepted Answer

This transport system is an active antiport because it moves two different solutes in opposite directions across the membrane and requires energy from ATP hydrolysis.

Question 2

Where is the neuron cell nucleus located?
A)axon hillock
B)cell body
C)dendrites
D)axon
E)terminal knob

Accepted Answer

The cell body, also called the soma, is the largest part of the neuron and contains the nucleus, as well as other organelles. The axon hillock, dendrites, axon, and terminal knob are all other parts of the neuron that are involved in transmitting signals, but they do not contain the nucleus.

Question 3

What is caused by the inability of Na+ ion channels to open for several milliseconds after their inactivation?
A)hyperpolarization
B)depolarization
C)termination
D)a refractory period
E)an action potential

Accepted Answer

The inability of Na+ ion channels to open for several milliseconds after their inactivation causes a refractory period. During this period, it is impossible to generate another action potential, no matter how strong the stimulus. This ensures that each action potential is separate and prevents them from overlapping.

Question 4

Where in a myelinated axon are nearly all of the ion channels concentrated?
A)the cell body
B)nodes of Ranvier
C)dendrites
D)axon terminals
E)neuron nucleus

Accepted Answer

Nearly all of the ion channels in myelinated axons are concentrated in the nodes of Ranvier, which are the small gaps between adjacent myelin sheaths where the axon membrane is exposed. This allows for efficient propagation of action potentials along the axon.

Question 5

What is thought to cause the sodium channels that initiate an action potential to be inactivated for a brief time after being open for about 1 msec?
A)a higher positive charge
B)a higher negative charge
C)the random diffusion of an inactivation peptide into the opening of the channel pore
D)removal of a peptide from the channel protein
E)covalent addition of a peptide to the cytoplasmic end of the channel protein

Accepted Answer

The inactivation of sodium channels is caused by the random diffusion of an inactivation peptide into the opening of the channel pore, which blocks the passage of sodium ions through the channel. This inactivation peptide is rapidly removed from the pore, allowing the channel to recover its ability to conduct sodium ions.

Question 6

Long-term potentiation is associated with NMDA receptors,one of several types of receptors that bind to the excitatory neurotransmitter _______.Its binding opens an internal cation channel within the receptor that allows _____ influx into the postsynaptic neuron,triggering a cascade of biochemical changes that lead to synaptic strengthening.
A)GABA,Ca2+ ion
B)glutamate,Ca2+ ion
C)glutamate,K+ ion
D)GABA,K+ ion
E)acetylcholine,Ca2+ ion

Accepted Answer

Glutamate is the excitatory neurotransmitter associated with NMDA receptors. When glutamate binds to NMDA receptors, it opens an internal cation channel that allows Ca2+ ion influx into the postsynaptic neuron, leading to long-term potentiation.

Question 7

The ability,possessed by all organisms,to respond to external stimulation is known as _______.
A)excitation
B)irritability
C)irritation
D)irrigation
E)irrigatability

Accepted Answer

Irritability is the correct term used to describe the ability of organisms to respond to external stimulation. Excitation refers to the process of activating or stimulating a cell, tissue, or organ. Irritation is a response to noxious or unpleasant stimuli, whereas irrigation refers to the supply of water to land or crops. Irrigatability is not a valid term.

Question 8

How is a nerve impulse usually transmitted across a synapse from a presynaptic to a postsynaptic cell?
A)via a direct connection
B)via a spark
C)via a neurotransmitter
D)via Na+ ions
E)via plasmodesmata

Accepted Answer

A nerve impulse is typically transmitted across a synapse via a neurotransmitter which is released from the presynaptic cell and picked up by receptors on the postsynaptic cell. This allows for the transfer of information between neurons.

Question 9

As an action potential is initiated,the membrane is ______.This is caused by the ____ of ____ ions.
A)hyperpolarized,efflux,Na+
B)depolarized,influx,Na+
C)depolarized,influx,K+
D)hyperpolarized,influx,Na+
E)depolarized,efflux,Na+

Accepted Answer

As an action potential is initiated, the membrane is depolarized. This is caused by the influx of sodium ions.

Question 10

___________ is a process that strengthens certain synapses by repeated neuron stimulation over a short time period.
A)Denturation
B)Long term potentiation
C)Short term memory
D)Temporality
E)Long term deviation

Accepted Answer

Long term potentiation is the process by which certain synapses are strengthened by repeated neuron stimulation over a short time period. This is thought to be a mechanism underlying learning and memory.

Question 11

How do Na+ ions enter a neuron when an action potential is initiated?
A)the Na+/K+-ATPase
B)a gated Na+ pump
C)a voltage-gated Na+ channel
D)the ligand-gated Na+ channel
E)a voltage-gated Na+ facilitated transporter

Accepted Answer

During an action potential, voltage-gated Na+ channels open on the neuron's membrane, allowing Na+ ions to diffuse into the cell.

Question 12

Which site in a neuron receives incoming information from external sources?
A)Dendrites
B)Axon
C)Axon hillock
D)Terminal knob
E)Cell body

Accepted Answer

Dendrites are the branch-like structures that extend from the cell body of a neuron and serve as the main site for receiving incoming information from external sources.

Question 13

Tetrahydrocannabinol,the active ingredient in marijuana,binds to receptors located in the ________ terminals of certain brain neurons.It lowers the likelihood that these neurons will release ________.
A)postsynaptic,neurotransmitters
B)presynaptic,neurotransmitters
C)presynaptic,Ca2+ ions
D)postsynaptic,Ca2+ ions
E)dendritic,neurotransmitters

Accepted Answer

THC binds to presynaptic receptors and decreases the release of neurotransmitters. Therefore, option B is the correct choice as it specifies presynaptic receptors and neurotransmitters.

Question 14

What happens after a subthreshold depolarization?
A)a full action potential
B)a partial action potential
C)no action potential
D)a proportional action potential
E)a reversal of the direction of the neural impulse

Accepted Answer

A subthreshold depolarization is not strong enough to reach the threshold for an action potential to occur. Therefore, no action potential would be generated.

Question 15

______ trigger fusion of synaptic vesicles with the synaptic membranes of the presynaptic cell.This same stimulus also triggers ________.
A)Ca2+ ions,exocytosis
B)Ca2+ ions,endocytosis
C)acetylcholine,exocytosis
D)acetylcholine,endocytosis
E)Na+ ions,exocytosis

Accepted Answer

Calcium ions are responsible for triggering the fusion of synaptic vesicles with the synaptic membranes of the presynaptic cell, leading to exocytosis of neurotransmitters into the synaptic cleft. Calcium ions are also involved in various other cellular processes, but in the context of synaptic transmission, their role is primarily associated with triggering exocytosis.

Question 16

What causes the membrane potential to return to the normal negative value after an action potential has occurred?
A)opening of a voltage-gated K+ channel
B)opening of a voltage-gated Na+ channel
C)closing of a voltage-gated K+ channel
D)opening of a ligand-gated Na+ channel
E)opening of a voltage-gated K+ facilitated transporter

Accepted Answer

The opening of voltage-gated K+ channels allows K+ ions to flow out of the cell, repolarizing the membrane back to its resting negative potential after an action potential.

Question 17

Which part of a neuron conducts impulses away from the cell body toward the target cell(s)?
A)axon hillock
B)cell body
C)dendrites
D)axon
E)terminal knob

Accepted Answer

The axon is the part of the neuron that conducts impulses away from the cell body toward the target cell(s).

Question 18

Impulse propagation by a myelinated axon is called ________ conduction.
A)saltatory
B)myelinated
C)rapid fire
D)jump stop
E)leap frog

Accepted Answer

Saltatory conduction occurs when an action potential travels down a myelinated axon by jumping from one node of Ranvier to the next, which speeds up the propagation of the signal.

Question 19

Cocaine acts by _________.
A)enhancing the degradation of acetylcholine.
B)depressing the degradation of acetylcholine
C)interfering with dopamine reuptake from the synaptic cleft
D)enhancing dopamine reuptake from the synaptic cleft
E)destroying dopamine in the synapse

Accepted Answer

Cocaine interferes with dopamine reuptake from the synaptic cleft. It does not affect acetylcholine, and does not enhance or destroy dopamine in the synapse.

Question 20

Which disease below is caused by the deterioration of the myelin sheath?
A)myasthenia gravis
B)multiple sclerosis
C)muscular dystrophy
D)diabetes mellitus
E)lupus erythematosus

Accepted Answer

Multiple sclerosis is caused by the deterioration of the myelin sheath, which leads to a disruption in the communication between the nerves, resulting in various symptoms such as muscle weakness, vision loss, and difficulty with coordination. Myasthenia gravis and muscular dystrophy affect the muscles directly, while diabetes mellitus and lupus erythematosus impact different organs and systems in the body.

Quiz 4: The Structure and Function of the Plasma Membrane

A transport system that moves one solute into the cell and another one out of the cell during a single cycle accompanied by the expenditure of energy through ATP hydrolysis could be called a(n) _______

Where is the neuron cell nucleus located?

What is caused by the inability of Na+ ion channels to open for several milliseconds after their inactivation?

Where in a myelinated axon are nearly all of the ion channels concentrated?

What is thought to cause the sodium channels that initiate an action potential to be inactivated for a brief time after being open for about 1 msec?

The ability,possessed by all organisms,to respond to external stimulation is known as _______.

How is a nerve impulse usually transmitted across a synapse from a presynaptic to a postsynaptic cell?

As an action potential is initiated,the membrane is __.This is caused by the of ions.

___________ is a process that strengthens certain synapses by repeated neuron stimulation over a short time period.

How do Na+ ions enter a neuron when an action potential is initiated?

Which site in a neuron receives incoming information from external sources?

Tetrahydrocannabinol,the active ingredient in marijuana,binds to receptors located in the terminals of certain brain neurons.It lowers the likelihood that these neurons will release .

What happens after a subthreshold depolarization?

trigger fusion of synaptic vesicles with the synaptic membranes of the presynaptic cell.This same stimulus also triggers __.

What causes the membrane potential to return to the normal negative value after an action potential has occurred?

Which part of a neuron conducts impulses away from the cell body toward the target cell(s) ?

Impulse propagation by a myelinated axon is called ________ conduction.

Cocaine acts by _________.

Which disease below is caused by the deterioration of the myelin sheath?