Question 1

The G proteins that coupled to metabotropic receptors are

Accepted Answer

A)   small homomeric GTP binding proteins made up of only α-subunits.
B)   heterotrimeric GTP binding proteins made up of α-, β-, and γ-subunits.
C)   heterotrimeric cGMP binding proteins made up of α-, β-, and γ-subunits.
D)   small homomeric GTP binding proteins made up of only β-subunits.
E)   small homomeric GTP binding proteins made up of only γ-subunits.F) All of the above
G) B) and D)

Question 2

You are recording calcium channel currents using whole cell patch clamp methods from frog sympathetic ganglia neurons with GTP-γ-s included in the patch pipet. What would happen when you added norepinephrine to the solution bathing this neuron.

Accepted Answer

A)   Norepinephrine would activate calcium currents for a shorter amount of time than normal.
B)   Norepinephrine would switch its target and couple to potassium currents.
C)   Norepinephrine would not affect calcium currents.
D)   Norepinephrine would persistently activate calcium currents.
E)   Norepinephrine would persistently inhibit calcium currents.F) A) and D)
G) B) and E)

Question 3

Endocannabinoids are formed by

Accepted Answer

A)   adenylate cyclase cleavage of membrane phospholipids.
B)   phospholipase A2 cleavage of cAMP.
C)   phospholipase C or D cleavage of cAMP.
D)   adenylate cyclase cleavage of cAMP.
E)   phospholipase C or D cleavage of membrane phospholipids.F) C) and D)
G) A) and C)

Question 4

When comparing direct and indirect synaptic transmission, indirect synaptic transmission

Accepted Answer

A)   mediates reflex arcs in the spinal cord.
B)   is mediated by ligand-gated ion channels.
C)   is required for high speed, integrated motor performance.
D)   is mediated by metabotropic receptors that activate intracellular second-messenger pathways.
E)   mediates skeletal muscle contraction.F) A) and E)
G) C) and E)

Question 5

Metabotropic receptors that couple to second messenger signaling

Accepted Answer

A)   all trigger the generation of cAMP in cells.
B)   can activate one of many enzymes in cells.
C)   have faster action than direct metabotropic signaling.
D)   all inhibit ion channels within cells.
E)   all trigger the cleavage of PIP2 to generate IP3 and DAG.F) A) and B)
G) C) and D)

Question 6

What is the difference between direct and indirect actions of receptor activated G proteins on ion channels?

Accepted Answer

The direct action occurs when a subunit ...

Question 7

When we are excited or frightened, our heart rate increases. Explain how nervous system uses either direct or indirect transmission to mediate this type of response?

Accepted Answer

Our sympathetic nervous system is stimul...

Question 8

In a cell with β-adrenergic receptors coupled to the cAMP second messenger system, what would happen to that signaling pathway if you blocked adenylate cyclase?

Accepted Answer

A)   This would make β-adrenergic receptor activation using the cAMP pathway irreversible.
B)   This would have no effects on β-adrenergic receptor signaling using the cAMP pathway.
C)   This would make β-adrenergic receptor activation using the cAMP pathway last longer.
D)   This would prevent β-adrenergic receptor activation from causing any effects through the cAMP pathway.
E)   This would mimic the signaling pathway, causing the same effect as activation of the β-adrenergic receptor.F) A) and B)
G) A) and E)

Question 9

What would happen to metabotropic signaling in a cell if you added cholera toxin?

Accepted Answer

A)   This would irreversibly activate metabotropic signaling mediated by Gs.
B)   This would irreversibly activate metabotropic signaling mediated by Gi and Go.
C)   This would irreversibly inhibit metabotropic signaling mediated by Gs.
D)   This would irreversibly inhibit metabotropic signaling mediated by Gi and Go.
E)   This would have no effect on metabotropic signaling.F) None of the above
G) All of the above

Question 10

What would happen to metabotropic signaling in a cell if you added GTP-γ-s to the cell cytoplasm?

Accepted Answer

A)   This would irreversibly activate all G protein-coupled metabotropic signaling.
B)   This would irreversibly inhibit all G protein-coupled metabotropic signaling.
C)   This would have no effect on G protein-coupled metabotropic signaling.
D)   This would irreversibly activate G protein-coupled metabotropic signaling mediated by only Gi and Go.
E)   This would irreversibly inhibit G protein-coupled metabotropic signaling mediated by only Gi and Go.F) A) and B)
G) A) and C)

Question 11

Anterograde signaling is defined as

Accepted Answer

A)   diffusion around sites of release to affect neighboring cells.
B)   the use of a chemical signal that communicates from the presynaptic cell to the postsynaptic cell.
C)   the use of a second messenger signal within the postsynaptic cell.
D)   the use of a chemical signal that communicates from the postsynaptic cell to the presynaptic cell.
E)   the use of a chemical signal that communicates from the presynaptic cell back onto the same presynaptic cell.F) C) and D)
G) A) and B)

Question 12

Which of the following tests would be effective at determining if a transmitter action was mediated by a G protein-coupled receptor?

Accepted Answer

A)   Adding extra GTP to the cell cytoplasm to activate G protein-coupled receptors.
B)   The addition of cholera toxin to inhibit G protein-coupled receptors.
C)   The addition of GDP-β-s enhances and greatly prolongs agonist-induced activation of G protein-mediated responses.
D)   The addition of GTP-γ-s enhances and greatly prolongs agonist-induced activation of G protein-mediated responses.
E)   The addition of pertussis toxin to activate G protein-coupled receptors.F) All of the above
G) B) and C)

Question 13

The particular neurotransmitter present at a synapse

Accepted Answer

A)   indicates the subtype of G protein that will be coupled the receptor.
B)   does not indicate the subtype of G protein or second messenger that will be coupled to the receptor.
C)   indicates the second messenger that will be coupled to the receptor.
D)   indicates the ion channels that will be targeted by second messengers.
E)   indicates if the effect on the synapse will be excitatory or inhibitory.F) A) and C)
G) B) and C)

Question 14

How is cAMP used as a second messenger in indirect actions of metabotropic receptors?

Accepted Answer

Metabotropic receptors activate the α-su...

Question 15

Nitric oxide

Accepted Answer

A)   is packaged into synaptic vesicles for release.
B)   is moved across cell membranes by a transporter that uses ATP as the energy for transport.
C)   is moved across cell membranes by a transporter that exchanges sodium ions for nitric oxide.
D)   is moved across cell membranes by facilitated diffusion.
E)   diffuses directly across cell membranes.F) B) and E)
G) B) and C)

Question 16

What happens when PIP2 is cleaved by phospholipase A2?

Accepted Answer

A)   This cleavage generates cAMP that acts as a second messenger.
B)   This cleavage generates active protein kinase A that phosphorylates proteins.
C)   This cleavage generates arachidonic acid that acts as a second messenger.
D)   This cleavage generates 12-HPETE that acts as a second messenger.
E)   This cleavage generates inositol-1,4,5-trisphosphate (IP3)  and diacylglycerol (DAG)  that act as second messengers.F) All of the above
G) A) and B)

Question 17

Which of the following neurotransmitters is not stored in synaptic vesicles?

Accepted Answer

A)   Glutamate
B)   Acetylcholine
C)   Endocannabinoids
D)   Norepinephrine
E)   DopamineF) C) and E)
G) B) and E)

Question 18

Describe 4 mechanisms that cells use to regulating the cytoplasmic calcium concentration.

Accepted Answer

Calcium enters cell through ligand-gated...

Question 19

Compare and contrast convergence vs. divergence of signals generated by indirectly coupled receptors?

Accepted Answer

Convergence occurs when a large number o...

Question 20

Which of the following experiments provided experimental evidence that potassium channels in cardiac muscle cells were opened by the direct action of βγ-subunits of activated G proteins?

Accepted Answer

A)   Cardiac potassium channels were opened in inside-out patch clamp recordings when pure recombinant α-subunit was applied to the intracellular side of the patch.
B)   Cardiac potassium channels were opened in inside-out patch clamp recordings when pure recombinant βγ-subunit was applied to the intracellular side of the patch.
C)   Removal of intracellular GTP prevents the activation of cardiac muscarinic receptors from opening of potassium channels.
D)   The addition of intracellular Gpp(NH) p prolongs the opening of potassium channels after activation of cardiac muscarinic receptors.
E)   Muscarinic receptor-mediated activation of potassium channels is blocked by pertussis toxin.F) A) and E)
G) A) and B)

Exam 12: Indirect Mechanisms of Synaptic Transmission

When we are excited or frightened, our heart rate increases. Explain how nervous system uses either direct or indirect transmission to mediate this type of response?

Correct AnswerverifiedOur sympathetic nervous system is stimul...View AnswerShow Answer

Anterograde signaling is defined as

Correct AnswerverifiedShow Answer

What happens when PIP2 is cleaved by phospholipase A2?

Correct AnswerverifiedShow Answer

In a cell with β-adrenergic receptors coupled to the cAMP second messenger system, what would happen to that signaling pathway if you blocked adenylate cyclase?

Correct AnswerverifiedShow Answer

What would happen to metabotropic signaling in a cell if you added cholera toxin?

Correct AnswerverifiedShow Answer

You are recording calcium channel currents using whole cell patch clamp methods from frog sympathetic ganglia neurons with GTP-γ-s included in the patch pipet. What would happen when you added norepinephrine to the solution bathing this neuron.

Correct AnswerverifiedShow Answer

Metabotropic receptors that couple to second messenger signaling

Correct AnswerverifiedShow Answer

Describe 4 mechanisms that cells use to regulating the cytoplasmic calcium concentration.

Correct AnswerverifiedCalcium enters cell through ligand-gated...View AnswerShow Answer

Compare and contrast convergence vs. divergence of signals generated by indirectly coupled receptors?

Correct AnswerverifiedConvergence occurs when a large number o...View AnswerShow Answer

The particular neurotransmitter present at a synapse

Correct AnswerverifiedShow Answer

How is cAMP used as a second messenger in indirect actions of metabotropic receptors?

Correct AnswerverifiedMetabotropic receptors activate the α-su...View AnswerShow Answer

Which of the following neurotransmitters is not stored in synaptic vesicles?

Correct AnswerverifiedShow Answer

Which of the following experiments provided experimental evidence that potassium channels in cardiac muscle cells were opened by the direct action of βγ-subunits of activated G proteins?

Correct AnswerverifiedShow Answer

What is the difference between direct and indirect actions of receptor activated G proteins on ion channels?

Correct AnswerverifiedThe direct action occurs when a subunit ...View AnswerShow Answer

Endocannabinoids are formed by

Correct AnswerverifiedShow Answer

The G proteins that coupled to metabotropic receptors are

Correct AnswerverifiedShow Answer

What would happen to metabotropic signaling in a cell if you added GTP-γ-s to the cell cytoplasm?

Correct AnswerverifiedShow Answer

When comparing direct and indirect synaptic transmission, indirect synaptic transmission

Correct AnswerverifiedShow Answer

Nitric oxide

Correct AnswerverifiedShow Answer

Which of the following tests would be effective at determining if a transmitter action was mediated by a G protein-coupled receptor?

Correct AnswerverifiedShow Answer

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Our sympathetic nervous system is stimul...
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Calcium enters cell through ligand-gated...
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Convergence occurs when a large number o...
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Correct Answer
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Metabotropic receptors activate the α-su...
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The direct action occurs when a subunit ...
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