Question 1

Cyclic GMP is the __________ during vasodilation.

Accepted Answer

A)  first messenger 
B)  second messenger 
C)  paracrine signal 
D)  activator of nitric oxide synthetase 
A)  first messenger 
B)  second messenger 
C)  paracrine signal 
D)  activator of nitric oxide synthetase

Question 2

Activation of caspases ultimately leads to the programmed death of the cell.What is this process known as? Explain why this may be a beneficial outcome to the organism.

Accepted Answer

Apoptosis.Apoptosis is advanta

Question 3

A liver cell is exposed to glucagon and epinephrine and glucose export is monitored.On addition of an adenylate cyclase inhibitor,the level of glucose export is reduced but not eliminated.Propose a reason for this partial reduction.

Accepted Answer

Epinephrine can bind to two different re

Question 4

Explain why the retinoblastoma gene is considered a tumor suppressor.

Accepted Answer

The retinoblastoma gene is con

Question 5

What characteristic is true for both RTKs and GPCRs?

Accepted Answer

A)  The receptor binds to intracellular proteins only when activated. 
B)  When activated, the receptor has enzymatic activity. 
C)  The receptor transmits ions. 
D)  The receptor undergoes a conformational change on activation. 
A)  The receptor binds to intracellular proteins only when activated. 
B)  When activated, the receptor has enzymatic activity. 
C)  The receptor transmits ions. 
D)  The receptor undergoes a conformational change on activation.

Question 6

A new protein is discovered that contains a pleckstrin homology domain.Which of the following is likely to bind to the protein?

Accepted Answer

A)  PIP3 
B)  PI-3K 
C)  phosphorylated tyrosines 
D)  Ca2+ 
A)  PIP3 
B)  PI-3K 
C)  phosphorylated tyrosines 
D)  Ca2+

Question 7

Cell-specific responses to signaling molecules are possible because

Accepted Answer

A)  nuclear receptor expression is cell specific. 
B)  target palindromic DNA sequences are ubiquitous. 
C)  signaling molecules are hydrophobic and can pass through the plasma membrane. 
D)  only some cells express gated channels for the signaling molecules. 
A)  nuclear receptor expression is cell specific. 
B)  target palindromic DNA sequences are ubiquitous. 
C)  signaling molecules are hydrophobic and can pass through the plasma membrane. 
D)  only some cells express gated channels for the signaling molecules.

Question 8

A response element is

Accepted Answer

A)  any protein whose expression is changed in response to a signal. 
B)  a sequence of regulatory DNA. 
C)  a domain of the glucocorticoid receptor that binds DNA. 
D)  a sequence of DNA coding for a steroid or metabolite receptor. 
A)  any protein whose expression is changed in response to a signal. 
B)  a sequence of regulatory DNA. 
C)  a domain of the glucocorticoid receptor that binds DNA. 
D)  a sequence of DNA coding for a steroid or metabolite receptor.

Question 9

Which of the following does NOT participate in a signal transduction pathway?

Accepted Answer

A)  second messenger 
B)  first messenger 
C)  receptor protein 
D)  lipid transporter 
A)  second messenger 
B)  first messenger 
C)  receptor protein 
D)  lipid transporter

Question 10

Predict which bond of a target protein would be cleaved by caspase 3 executioner enzyme.

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
A)  1 
B)  2 
C)  3 
D)  4

Question 11

When the regulatory subunit of PKA is bound to cAMP,

Accepted Answer

A)  it dissociates into monomers. 
B)  the pseudosubstrate is phosphorylated. 
C)  it cannot bind to catalytic subunit of PKA. 
D)  it is part of a tetramer. 
A)  it dissociates into monomers. 
B)  the pseudosubstrate is phosphorylated. 
C)  it cannot bind to catalytic subunit of PKA. 
D)  it is part of a tetramer.

Question 12

Construct a functional signal transduction pathway by placing the following actors in the correct order: 
A.upstream signaling protein
B.second messenger
C.receptor protein
D.first messenger
E.target proteins
F.downstream signaling protein

Accepted Answer

A)  D, E, C, A, B, F 
B)  C, D, A, B, F, E 
C)  D, C, A, B, F, E 
D)  D, C, B, A, F, E 
A)  D, E, C, A, B, F 
B)  C, D, A, B, F, E 
C)  D, C, A, B, F, E 
D)  D, C, B, A, F, E

Question 13

If a mutation occurred in SODD that prohibited its interaction with the DD of TNF receptor,the TNF receptor would

Accepted Answer

A)  no longer form a trimer. 
B)  no longer be able to release TNF-   
C)  bind TRADD, even in the absence of TNF-   
D)  bind NF$\kappa$B, even in the absence of TNF-   
A)  no longer form a trimer. 
B)  no longer be able to release TNF-   
C)  bind TRADD, even in the absence of TNF-   
D)  bind NF$\kappa$B, even in the absence of TNF-

Question 14

Some breast cancers express estrogen receptors and are estrogen dependent.Tamoxifen is a chemotherapy agent used in the treatment of estrogen-responsive breast cancers.What is tamoxifen in relation to the estrogen receptor and why does it have this effect?

Accepted Answer

Tamoxifen is an antagonist of

Question 15

Estradiol is secreted by the ovaries,travels through the bloodstream,and interacts with estrogen receptors on breast epithelial cells.In this scenario estradiol is acting through which type of mechanism?

Accepted Answer

A)  synacrine 
B)  paracrine 
C)  endocrine 
D)  autocrine 
A)  synacrine 
B)  paracrine 
C)  endocrine 
D)  autocrine

Question 16

Place the following steps of the apoptotic pathway in their proper order. 
A.CASP3 cleavage of cellular proteins
B.Cleavage of procaspase 8
C.Cleavage of procaspase 3
D.Assembly of DD and DED protein complexes

Accepted Answer

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

Question 17

Construct the order of signaling termination through the   -adrenergic receptor that includes the following steps:
A)Internalization of the receptor into endosomes
B)Dissociation of heterotrimeric G protein complex from the receptor
C)Phosphorylation of the receptor
D)Recruitment of  
ARK to the receptor
E)  
-arrestin association with GPCR

Accepted Answer

The answer of Construct the order of signaling termination through...

Question 18

What is the TNF receptor-TRADD-FADD-procaspase 8 adaptor complex also known as?

Accepted Answer

The death-

Question 19

Both the silence of death domain and TNF receptor-associated death domain proteins

Accepted Answer

A)  inhibit downstream signaling. 
B)  activate downstream signaling. 
C)  are phosphorylated when TNF-  
Is bound to its receptor. 
D)  bind TNF receptor death domains. 
A)  inhibit downstream signaling. 
B)  activate downstream signaling. 
C)  are phosphorylated when TNF-  
Is bound to its receptor. 
D)  bind TNF receptor death domains.

Question 20

A culture of insulin-responsive cells are analyzed after stimulation with insulin.The insulin receptors are then isolated (assume that during the isolation protocol the insulin is removed from the receptor).Half of the sample is analyzed by SDS-PAGE followed by Coomassie blue staining.The other half of the sample is analyzed via SDS-PAGE followed by a Western blot.The primary antibody used in the blot recognizes phosphorylated tyrosine residues.Predict how many bands will be seen on the SDS-PAGE compared with the Western blot and explain your answer.

Accepted Answer

There will be two bands on the SDS-PAGE,

Exam 8: Cell Signaling Systems

Cyclic GMP is the __________ during vasodilation.

Activation of caspases ultimately leads to the programmed death of the cell.What is this process known as? Explain why this may be a beneficial outcome to the organism.

A liver cell is exposed to glucagon and epinephrine and glucose export is monitored.On addition of an adenylate cyclase inhibitor,the level of glucose export is reduced but not eliminated.Propose a reason for this partial reduction.

Explain why the retinoblastoma gene is considered a tumor suppressor.

What characteristic is true for both RTKs and GPCRs?

A new protein is discovered that contains a pleckstrin homology domain.Which of the following is likely to bind to the protein?

Cell-specific responses to signaling molecules are possible because

A response element is

Which of the following does NOT participate in a signal transduction pathway?

Predict which bond of a target protein would be cleaved by caspase 3 executioner enzyme.

When the regulatory subunit of PKA is bound to cAMP,

Construct a functional signal transduction pathway by placing the following actors in the correct order: A.upstream signaling protein B.second messenger C.receptor protein D.first messenger E.target proteins F.downstream signaling protein

If a mutation occurred in SODD that prohibited its interaction with the DD of TNF receptor,the TNF receptor would

Some breast cancers express estrogen receptors and are estrogen dependent.Tamoxifen is a chemotherapy agent used in the treatment of estrogen-responsive breast cancers.What is tamoxifen in relation to the estrogen receptor and why does it have this effect?

Estradiol is secreted by the ovaries,travels through the bloodstream,and interacts with estrogen receptors on breast epithelial cells.In this scenario estradiol is acting through which type of mechanism?

Place the following steps of the apoptotic pathway in their proper order. A.CASP3 cleavage of cellular proteins B.Cleavage of procaspase 8 C.Cleavage of procaspase 3 D.Assembly of DD and DED protein complexes

What is the TNF receptor-TRADD-FADD-procaspase 8 adaptor complex also known as?

Both the silence of death domain and TNF receptor-associated death domain proteins

Principles of Biochemistry

Physical Biochemistry: Energy Conversion,water,and Membranes

Nucleic Acid Structure and Function

Protein Structure

Methods in Protein Biochemistry

Protein Function

Enzyme Mechanisms

Glycolysis: a Paradigm of Metabolic Regulation

The Citrate Cycle

Oxidative Phosphorylation

Photosynthesis

Carbohydrate Structure and Function

Carbohydrate Metabolism

Lipid Structure and Function

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Metabolic Integration

Dna Replication, repair, and Recombination

Rna Synthesis, processing, and Gene Silencing

Protein Synthesis, posttranslational Modification, and Transport

Gene Regulation

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