Question 1

Explain how mutations in the following proteins might result in either loss of responsiveness to a given hormone or production of a continuous signal even in the absence of the hormone: 
(a)a mutation in the regulatory (R)subunit of cAMP-dependent protein kinase,making R incapable of binding to the catalytic (C)subunit; 
(b)a mutation in a growth factor receptor with protein kinase activity; 
(c)a defect in a G protein that renders the GTPase activity inactive.

Accepted Answer

(a)When a mutation in the R subunit of c...

Question 2

Most transduction systems for hormones and sensory stimuli that involve trimeric G proteins have in common all of the following except:

Accepted Answer

A)  cyclic nucleotides.
B)  nuclear receptors.
C)  receptors that interact with a G protein.
D)  receptors with multiple transmembrane segments.
E)  self-inactivation.F) B) and D)
G) A) and D)

Question 3

Match the signal input with the result:
-

Accepted Answer

(a)-(2);
...

Question 4

Briefly compare the two types of guanylyl cyclases that participate in signal transduction.

Accepted Answer

One type is a membrane-bound homodimer w...

Question 5

Compare and contrast the modes of action of epinephrine,acting through the $\beta$-adrenergic receptor,and of insulin,acting through the insulin receptor.

Accepted Answer

[The mechanisms of epinephrine and insul...

Question 6

Explain how the cytokine erythropoetin activates transcription of specific genes essential in blood maturation.

Accepted Answer

Binding of erythropoetin to its plasma m...

Question 7

Describe three factors that contribute to the high degree of sensitivity of signal transduction systems.

Accepted Answer

The sensitivity of signal transduction r...

Question 8

Compare and contrast ligand-gated and voltage-gated ion channels;give an example of each.

Accepted Answer

Ion channels are protein-based passages ...

Question 9

Protein kinase A (PKA) is:

Accepted Answer

A)  activated by covalent binding of cyclic AMP.
B)  affected by cyclic AMP only under unusual circumstances.
C)  allosterically activated by cyclic AMP.
D)  competitively inhibited by cyclic AMP.
E)  noncompetitively inhibited by cyclic AMP.F) B) and C)
G) A) and C)

Question 10

Which of the following statements concerning signal transduction by the insulin receptor is not correct?

Accepted Answer

A)  Activation of the receptor protein kinase activity results in the activation of additional protein kinases.
B)  Binding of insulin to the receptor activates a protein kinase.
C)  Binding of insulin to the receptor results in a change in its quaternary structure.
D)  The receptor protein kinase activity is specific for tyrosine residues on the substrate proteins.
E)  The substrates of the receptor protein kinase activity are mainly proteins that regulate transcription.F) C) and D)
G) A) and B)

Question 11

Explain two different approaches to targeting the activity of aberrant protein kinases for treating cancer.Give examples of each.

Accepted Answer

One approach is to design small molecule...

Question 12

Calmodulin is a(n) :

Accepted Answer

A)  allosteric activator of calcium-dependent enzymes.
B)  allosteric inhibitor of calcium-dependent enzymes.
C)  calcium-dependent enzyme.
D)  cell surface calcium receptor.
E)  regulatory subunit of calcium-dependent enzymes.F) C) and D)
G) A) and B)

Question 13

What is meant by multivalent adaptor proteins in signaling pathways?

Accepted Answer

The reversible phosphorylation (at Ser,T...

Question 14

Which of the following is not a step in the response to photon absorption by rhodopsin?

Accepted Answer

A)  Rhodopsin catalyzes GDP/GTP exchange on transducin.
B)  Rhodopsin is phosphorylated by rhodopsin kinase.
C)  Arrestin binds to the phosphorylated end of rhodopsin.
D)  Light absorption converts all-trans?-retinal to 11-cis-retinal.
E)  All-trans?-retinal is replaced with 11-cis-retinal.F) A) and E)
G) B) and E)

Question 15

What is the mechanism of action of the drug tamoxifen in the treatment of breast cancer?

Accepted Answer

Tamoxifen is an antagonist of estrogen,a...

Question 16

What is meant by the two-component system of bacterial cell signaling?

Accepted Answer

The two-component system drives bacteria...

Question 17

Steroid hormones are carried on specific carrier proteins because the hormones:

Accepted Answer

A)  are too unstable to survive in the blood on their own.
B)  cannot dissolve readily in the blood because they are too hydrophobic.
C)  cannot find their target cells without them.
D)  need them in order to pass through the plasma membrane.
E)  require subsequent binding to specific receptor proteins in the nucleus.F) B) and D)
G) A) and B)

Question 18

Which of the following is not a shared feature of signaling by mammalian vision and gustatory receptor pathways?

Accepted Answer

A)  Changes in cAMP levels
B)  GDP/GTP exchange
C)  Heterotrimeric G proteins
D)  Open/closing of ion channels
E)  Transmembrane receptorsF) A) and E)
G) B) and D)

Question 19

The ion channel that opens in response to acetylcholine is an example of a ____________ signal transduction system.

Accepted Answer

A)  G-protein
B)  ligand-gated
C)  receptor-enzyme
D)  serpentine receptor
E)  voltage-gatedF) None of the above
G) B) and C)

Question 20

Describe two examples of steroid hormone action that occur too rapidly to be the consequence of altered levels of

Accepted Answer

Progesterone can cause a rapid decrease ...

Exam 12: Biosignaling

The ion channel that opens in response to acetylcholine is an example of a ____________ signal transduction system.

Correct Answer
verified

Which of the following is not a shared feature of signaling by mammalian vision and gustatory receptor pathways?

Correct Answer
verified

Explain how the cytokine erythropoetin activates transcription of specific genes essential in blood maturation.

Correct Answer
verified
Binding of erythropoetin to its plasma m...
View Answer

Match the signal input with the result: -

Correct Answer
verified
(a)-(2);
...
View Answer

Correct Answer
verified
(a)When a mutation in the R subunit of c...
View Answer

Which of the following statements concerning signal transduction by the insulin receptor is not correct?

Correct Answer
verified

What is the mechanism of action of the drug tamoxifen in the treatment of breast cancer?

Correct Answer
verified
Tamoxifen is an antagonist of estrogen,a...
View Answer

Compare and contrast ligand-gated and voltage-gated ion channels;give an example of each.

Correct Answer
verified
Ion channels are protein-based passages ...
View Answer

Briefly compare the two types of guanylyl cyclases that participate in signal transduction.

Correct Answer
verified
One type is a membrane-bound homodimer w...
View Answer

Explain two different approaches to targeting the activity of aberrant protein kinases for treating cancer.Give examples of each.

Correct Answer
verified
One approach is to design small molecule...
View Answer

What is meant by multivalent adaptor proteins in signaling pathways?

Correct Answer
verified
The reversible phosphorylation (at Ser,T...
View Answer

Steroid hormones are carried on specific carrier proteins because the hormones:

Correct Answer
verified

Compare and contrast the modes of action of epinephrine,acting through the $\beta$ -adrenergic receptor,and of insulin,acting through the insulin receptor.

Correct Answer
verified
[The mechanisms of epinephrine and insul...
View Answer

What is meant by the two-component system of bacterial cell signaling?

Correct Answer
verified
The two-component system drives bacteria...
View Answer

Describe two examples of steroid hormone action that occur too rapidly to be the consequence of altered levels of

Correct Answer
verified
Progesterone can cause a rapid decrease ...
View Answer

Which of the following is not a step in the response to photon absorption by rhodopsin?

Correct Answer
verified

Calmodulin is a(n) :

Correct Answer
verified

Most transduction systems for hormones and sensory stimuli that involve trimeric G proteins have in common all of the following except:

Correct Answer
verified

Describe three factors that contribute to the high degree of sensitivity of signal transduction systems.

Correct Answer
verified
The sensitivity of signal transduction r...
View Answer

Protein kinase A (PKA) is:

Correct Answer
verified

Exam 12: Biosignaling

The ion channel that opens in response to acetylcholine is an example of a ____________ signal transduction system.

Correct AnswerverifiedShow Answer

Which of the following is not a shared feature of signaling by mammalian vision and gustatory receptor pathways?

Correct AnswerverifiedShow Answer

Explain how the cytokine erythropoetin activates transcription of specific genes essential in blood maturation.

Correct AnswerverifiedBinding of erythropoetin to its plasma m...View AnswerShow Answer

Match the signal input with the result: -

Correct Answerverified(a)-(2); ...View AnswerShow Answer

Correct Answerverified(a)When a mutation in the R subunit of c...View AnswerShow Answer

Which of the following statements concerning signal transduction by the insulin receptor is not correct?

Correct AnswerverifiedShow Answer

What is the mechanism of action of the drug tamoxifen in the treatment of breast cancer?

Correct AnswerverifiedTamoxifen is an antagonist of estrogen,a...View AnswerShow Answer

Compare and contrast ligand-gated and voltage-gated ion channels;give an example of each.

Correct AnswerverifiedIon channels are protein-based passages ...View AnswerShow Answer

Briefly compare the two types of guanylyl cyclases that participate in signal transduction.

Correct AnswerverifiedOne type is a membrane-bound homodimer w...View AnswerShow Answer

Explain two different approaches to targeting the activity of aberrant protein kinases for treating cancer.Give examples of each.

Correct AnswerverifiedOne approach is to design small molecule...View AnswerShow Answer

What is meant by multivalent adaptor proteins in signaling pathways?

Correct AnswerverifiedThe reversible phosphorylation (at Ser,T...View AnswerShow Answer

Steroid hormones are carried on specific carrier proteins because the hormones:

Correct AnswerverifiedShow Answer

Compare and contrast the modes of action of epinephrine,acting through the β\betaβ -adrenergic receptor,and of insulin,acting through the insulin receptor.

Correct Answerverified[The mechanisms of epinephrine and insul...View AnswerShow Answer

What is meant by the two-component system of bacterial cell signaling?

Correct AnswerverifiedThe two-component system drives bacteria...View AnswerShow Answer

Describe two examples of steroid hormone action that occur too rapidly to be the consequence of altered levels of

Correct AnswerverifiedProgesterone can cause a rapid decrease ...View AnswerShow Answer

Which of the following is not a step in the response to photon absorption by rhodopsin?

Correct AnswerverifiedShow Answer

Calmodulin is a(n) :

Correct AnswerverifiedShow Answer

Most transduction systems for hormones and sensory stimuli that involve trimeric G proteins have in common all of the following except:

Correct AnswerverifiedShow Answer

Describe three factors that contribute to the high degree of sensitivity of signal transduction systems.

Correct AnswerverifiedThe sensitivity of signal transduction r...View AnswerShow Answer

Protein kinase A (PKA) is:

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Binding of erythropoetin to its plasma m...
View Answer

Correct Answer
verified
(a)-(2);
...
View Answer

Correct Answer
verified
(a)When a mutation in the R subunit of c...
View Answer

Correct Answer
verified

Correct Answer
verified
Tamoxifen is an antagonist of estrogen,a...
View Answer

Correct Answer
verified
Ion channels are protein-based passages ...
View Answer

Correct Answer
verified
One type is a membrane-bound homodimer w...
View Answer

Correct Answer
verified
One approach is to design small molecule...
View Answer

Correct Answer
verified
The reversible phosphorylation (at Ser,T...
View Answer

Correct Answer
verified

Compare and contrast the modes of action of epinephrine,acting through the $\beta$ -adrenergic receptor,and of insulin,acting through the insulin receptor.

Correct Answer
verified
[The mechanisms of epinephrine and insul...
View Answer

Correct Answer
verified
The two-component system drives bacteria...
View Answer

Correct Answer
verified
Progesterone can cause a rapid decrease ...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The sensitivity of signal transduction r...
View Answer

Correct Answer
verified