Question 1

Which of the following would you expect to happen if you added EGF to a cell extract from which only the plasma membrane fraction has been removed?

Accepted Answer

A)  cAMP will be produced.
B)  Gsα will be activated.
C)  Adenylyl cyclase will be activated.
D)  Calcium ions will be released.
E)  None of the above will happen.F) B) and C)
G) A) and B)

Question 2

Cells can regulate precisely where signaling occurs within the cell (e.g.,in the yeast mating pathway)by association of the signal pathway proteins with a ________.

Accepted Answer

scaffold protein or scaffold complex

Question 3

Each of the following is a step in the epinephrine-cAMP pathway in which the signal is amplified except

Accepted Answer

A)  receptor activation of G-protein.
B)  G-protein activation of adenylyl cyclase.
C)  adenylyl cyclase production of cAMP.
D)  protein kinase A phosphorylation of target proteins.E) A) and D)
F) All of the above

Question 4

Which of the following would best be used to demonstrate XFF is most like EGF?

Accepted Answer

A)  exposure of cells to radioactive XFF
B)  receptor binding assays
C)  microinjection into cells of nonhydrolyzable GTP analogues
D)  exposure of cells to ryanodine
E)  exposure of cells to tyrosine kinase inhibitorsF) A) and D)
G) A) and C)

Question 5

Compare and contrast GPCR and RTK receptors with respect to (a)structure-especially the transmembrane region,(b)activation mechanism,(c)initial signal transduction across the membrane.

Accepted Answer

a)GPCRs have seven transmembrane helices...

Question 6

________ is the messenger that regulates blood pressure by causing arterial smooth muscle relaxation.

Accepted Answer

The answer of ________ is the messenger that regulates blood...

Question 7

Gsα activates ________.

Accepted Answer

Question 8

Each of the following is a plant hormone except

Accepted Answer

A)  brassinosteroids
B)  abscisic acid.
C)  ethylene.
D)  All the above are plant hormones.
E)  None of the above are plant hormones.F) A) and B)
G) A) and C)

Question 9

The concentration of the primary messenger (ligand) in the bloodstream changes from −9 M when the signal is not being secreted to 10−7 M when it is being secreted.Which of the following Kds for binding that ligand would be optimal for a receptor involved in a responsive signaling system?

Accepted Answer

A)  10−10
B)  10−9
C)  10−8
D)  10−7
E)  10−6F) A) and B)
G) A) and C)

Question 10

The α-subunit of a heterotrimeric G-protein is active when bound to ________.

Accepted Answer

The answer of The α-subunit of a heterotrimeric G-protein is...

Question 11

A strain of Drosophila known as dunce produces one-half the amount of cAMP phosphodiesterase found in wild-type flies,which causes a learning defect.Another strain of Drosophila known as rutabaga produces a defective adenylyl cyclase protein (one of the AC types expressed in most cells)and also causes a learning defect.A dunce-rutabaga double mutant fly has relatively normal learning.Explain these curious observations.

Accepted Answer

cAMP accumulates to higher levels and pe...

Question 12

Protein kinase C (PKC) activity is involved in each of the following except

Accepted Answer

A)  ion channel regulation.
B)  cytoskeleton changes.
C)  increase in cellular pH.
D)  secretion of proteins and other substances.
E)  PKC is involved in all of the above.F) C) and E)
G) A) and E)

Question 13

You are seeking a new anti-inflammatory drug to inhibit local responses to stress and injury.Which of the following activities would you look for in a potential anti-inflammatory agent?

Accepted Answer

A)  stimulates release of prostaglandins
B)  blocks adenylate cyclase activity
C)  blocks an enzyme associated with arachidonic acid production
D)  stimulates the activation of platelets
E)  increases estrogen secretionF) A) and D)
G) None of the above

Question 14

Reception of a signal released by the same cell is which of the following types of signaling?

Accepted Answer

A)  paracrine
B)  endocrine
C)  autocrine
D)  juxtacrine
E)  exocrineF) B) and E)
G) A) and B)

Question 15

The coordinated response of cells to an array of different signals from the environment is known as ________.

Accepted Answer

The answer of The coordinated response of cells to an...

Question 16

Initial attempts to culture cells demonstrated that blood serum but not blood plasma provided factors that increased the viability and proliferation of the cultured cells.Explain.

Accepted Answer

The difference between blood plasma and serum is that serum is what remains when a clot forms and is removed from the plasma.During the clotting process,platelets are activated to secrete growth factors such as PDGF,which activates fibroblast RTK receptors to stimulate cell growth and division.

Question 17

Each of the following is a characteristic of hormones except

Accepted Answer

A)  synthesis by endocrine tissue cells.
B)  secretion directly into the bloodstream.
C)  having a hormone-specific lifespan in the blood ranging from seconds to hours.
D)  interacting with specific receptors on cells in target tissues throughout the body.
E)  All are characteristics of endocrine hormones.F) None of the above
G) All of the above

Question 18

Each of the following is true about Ras except

Accepted Answer

A)  Ras is monomeric.
B)  Ras activity is inhibited by GTPase activating proteins (GAPs) .
C)  Ras binds steroid hormones.
D)  Ras is activated by Sos,a guanine nucleotide exchange factor.
E)  Ras activates a cascade of phosphorylation events within the cell.F) B) and E)
G) A) and D) C

Question 19

Each of the following hormones is an amino acid derivative except

Accepted Answer

A)  histamine.
B)  norepinephrine.
C)  prostaglandins.
D)  epinephrine.
E)  thyroxine.F) A) and E)
G) None of the above

Question 20

You recently identified a molecule that you believe is a primary messenger for a signal transduction mechanism.All you know about this ligand is that it is hydrophilic.Where would you expect to find initial interaction of the molecule with its receptor?

Accepted Answer

A)  on the outer surface of the plasma membrane
B)  within the cytoplasm of the cell
C)  within the nucleus of the cell
D)  on the cytoplasmic side of the plasma membrane
E)  in endosome vesiclesF) B) and E)
G) C) and E)

Exam 23: Signal Transduction Mechanisms: Iimessengers and Receptors

Which of the following would you expect to happen if you added EGF to a cell extract from which only the plasma membrane fraction has been removed?

Correct Answer
verified

Cells can regulate precisely where signaling occurs within the cell (e.g.,in the yeast mating pathway)by association of the signal pathway proteins with a ________.

Correct Answer
verified
scaffold protein or scaffold complex

Each of the following is a step in the epinephrine-cAMP pathway in which the signal is amplified except

Correct Answer
verified

Which of the following would best be used to demonstrate XFF is most like EGF?

Correct Answer
verified

Compare and contrast GPCR and RTK receptors with respect to (a)structure-especially the transmembrane region,(b)activation mechanism,(c)initial signal transduction across the membrane.

Correct Answer
verified
a)GPCRs have seven transmembrane helices...
View Answer

________ is the messenger that regulates blood pressure by causing arterial smooth muscle relaxation.

Correct Answer
verified

G_sα activates ________.

Correct Answer
verified

Each of the following is a plant hormone except

Correct Answer
verified

The concentration of the primary messenger (ligand) in the bloodstream changes from <10⁻⁹ M when the signal is not being secreted to 10⁻⁷ M when it is being secreted.Which of the following K_ds for binding that ligand would be optimal for a receptor involved in a responsive signaling system?

Correct Answer
verified

The α-subunit of a heterotrimeric G-protein is active when bound to ________.

Correct Answer
verified

Correct Answer
verified
cAMP accumulates to higher levels and pe...
View Answer

Protein kinase C (PKC) activity is involved in each of the following except

Correct Answer
verified

You are seeking a new anti-inflammatory drug to inhibit local responses to stress and injury.Which of the following activities would you look for in a potential anti-inflammatory agent?

Correct Answer
verified

Reception of a signal released by the same cell is which of the following types of signaling?

Correct Answer
verified

The coordinated response of cells to an array of different signals from the environment is known as ________.

Correct Answer
verified

Initial attempts to culture cells demonstrated that blood serum but not blood plasma provided factors that increased the viability and proliferation of the cultured cells.Explain.

Each of the following is a characteristic of hormones except

Correct Answer
verified

Each of the following is true about Ras except

Correct Answer
verified
C

Each of the following hormones is an amino acid derivative except

Correct Answer
verified

You recently identified a molecule that you believe is a primary messenger for a signal transduction mechanism.All you know about this ligand is that it is hydrophilic.Where would you expect to find initial interaction of the molecule with its receptor?

Correct Answer
verified

Exam 23: Signal Transduction Mechanisms: Iimessengers and Receptors

Which of the following would you expect to happen if you added EGF to a cell extract from which only the plasma membrane fraction has been removed?

Correct AnswerverifiedShow Answer

Cells can regulate precisely where signaling occurs within the cell (e.g.,in the yeast mating pathway)by association of the signal pathway proteins with a ________.

Correct Answerverifiedscaffold protein or scaffold complex

Each of the following is a step in the epinephrine-cAMP pathway in which the signal is amplified except

Correct AnswerverifiedShow Answer

Which of the following would best be used to demonstrate XFF is most like EGF?

Correct AnswerverifiedShow Answer

Compare and contrast GPCR and RTK receptors with respect to (a)structure-especially the transmembrane region,(b)activation mechanism,(c)initial signal transduction across the membrane.

Correct Answerverifieda)GPCRs have seven transmembrane helices...View AnswerShow Answer

________ is the messenger that regulates blood pressure by causing arterial smooth muscle relaxation.

Correct AnswerverifiedShow Answer

Gsα activates ________.

Correct AnswerverifiedShow Answer

Each of the following is a plant hormone except

Correct AnswerverifiedShow Answer

The concentration of the primary messenger (ligand) in the bloodstream changes from <10−9 M when the signal is not being secreted to 10−7 M when it is being secreted.Which of the following Kds for binding that ligand would be optimal for a receptor involved in a responsive signaling system?

Correct AnswerverifiedShow Answer

The α-subunit of a heterotrimeric G-protein is active when bound to ________.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedcAMP accumulates to higher levels and pe...View AnswerShow Answer

Protein kinase C (PKC) activity is involved in each of the following except

Correct AnswerverifiedShow Answer

You are seeking a new anti-inflammatory drug to inhibit local responses to stress and injury.Which of the following activities would you look for in a potential anti-inflammatory agent?

Correct AnswerverifiedShow Answer

Reception of a signal released by the same cell is which of the following types of signaling?

Correct AnswerverifiedShow Answer

The coordinated response of cells to an array of different signals from the environment is known as ________.

Correct AnswerverifiedShow Answer

Initial attempts to culture cells demonstrated that blood serum but not blood plasma provided factors that increased the viability and proliferation of the cultured cells.Explain.

Each of the following is a characteristic of hormones except

Correct AnswerverifiedShow Answer

Each of the following is true about Ras except

Correct AnswerverifiedC

Each of the following hormones is an amino acid derivative except

Correct AnswerverifiedShow Answer

You recently identified a molecule that you believe is a primary messenger for a signal transduction mechanism.All you know about this ligand is that it is hydrophilic.Where would you expect to find initial interaction of the molecule with its receptor?

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified
scaffold protein or scaffold complex

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
a)GPCRs have seven transmembrane helices...
View Answer

Correct Answer
verified

G_sα activates ________.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
cAMP accumulates to higher levels and pe...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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Correct Answer
verified

Correct Answer
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C

Correct Answer
verified

Correct Answer
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