Question 1

The   subunit of trimeric G proteins can function to

Accepted Answer

A)  regulate ion channels. 
B)  activate adenylate cyclase. 
C)  inhibit phospholipase A. 
D)  inhibit phosphodiesterase. 
A)  regulate ion channels. 
B)  activate adenylate cyclase. 
C)  inhibit phospholipase A. 
D)  inhibit phosphodiesterase.

Question 2

Which scenario would allow   -arrestin to bind to the GPCR?

Accepted Answer

A)    ARK is internalized into the endosome. 
B)  The receptor is phosphorylated. 
C)    is bound to GDP. 
D)  The regulatory subunit of  
-arrestin is removed. 
A)    ARK is internalized into the endosome. 
B)  The receptor is phosphorylated. 
C)    is bound to GDP. 
D)  The regulatory subunit of  
-arrestin is removed.

Question 3

The PI-3K signaling pathway is activated by the binding of __________ to its receptor.This leads to an increase in glucose uptake and in __________ synthesis.

Accepted Answer

The answer of The PI-3K signaling pathway is activated by...

Question 4

A Western blot analysis of the expression of estrogen receptors in ovarian tissues at different times of the estrous cycle showed approximately four times greater protein levels at day 2 compared with day 10 of the cycle.Which of the following may be true given these data?

Accepted Answer

A)  Estrogen is acting as an endocrine signal in the ovaries. 
B)  Estrogen is acting as an autocrine signal in the ovaries. 
C)  Ovaries only secrete estrogen early in the estrous cycle. 
D)  Ovarian tissue is responsive to estrogen only early in the estrous cycle. 
A)  Estrogen is acting as an endocrine signal in the ovaries. 
B)  Estrogen is acting as an autocrine signal in the ovaries. 
C)  Ovaries only secrete estrogen early in the estrous cycle. 
D)  Ovarian tissue is responsive to estrogen only early in the estrous cycle.

Question 5

On binding of an insulin molecule to the insulin receptor,a conformational change occurs that

Accepted Answer

A)  increases the affinity of a second insulin binding site. 
B)  causes the dimerization of the receptor. 
C)  brings the L1 region of the  
subunit closer to the membrane. 
D)  stimulates tyrosine autophosphorylation in the  
Subunits. 
A)  increases the affinity of a second insulin binding site. 
B)  causes the dimerization of the receptor. 
C)  brings the L1 region of the  
subunit closer to the membrane. 
D)  stimulates tyrosine autophosphorylation in the  
Subunits.

Question 6

Which of the following is a GTPase?

Accepted Answer

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

Question 7

Which of the following is true of procaspase 8?

Accepted Answer

A)  It is proteolytically active. 
B)  It can cleave caspase 3. 
C)  It can be activated by proteolysis. 
D)  It is a kinase. 
A)  It is proteolytically active. 
B)  It can cleave caspase 3. 
C)  It can be activated by proteolysis. 
D)  It is a kinase.

Question 8

Contrast the structures and nucleotide binding properties of   when interacting with adenylate cyclase versus   protein.

Accepted Answer

When interacting with adenylate cyclase,

Question 9

Glycogen synthesis was monitored in a liver cell in the presence of glucagon binding to the   
2-adrenergic receptor and after its removal.How would the activity of enzymes involved in glycogen synthesis and glycogen degradation be altered if the experiment were carried out after the cells were treated with caffeine,an inhibitor of cAMP phosphodiesterase? Explain your reasoning.

Accepted Answer

If cAMP phosphodiesterase is inhibited,t

Question 10

Hsp90 is a type of

Accepted Answer

A)  chaperonin. 
B)  kinase. 
C)  response element. 
D)  heat sensing protease. 
A)  chaperonin. 
B)  kinase. 
C)  response element. 
D)  heat sensing protease.

Question 11

A ligand binds to a transmembrane protein.This causes a conformational change in the protein that is detected by an intracellular protein.The intracellular protein is an enzyme that adds phosphate groups to target proteins.The phosphorylated proteins cause a physiological change within the cell.This is an example of

Accepted Answer

A)  a metabolic pathway. 
B)  homeostasis. 
C)  a signal transduction pathway. 
D)  an allosteric inhibition pathway. 
A)  a metabolic pathway. 
B)  homeostasis. 
C)  a signal transduction pathway. 
D)  an allosteric inhibition pathway.

Question 12

Levels of diacylglycerol increase in a cell on binding of a ligand to a taste receptor.Which trimeric G protein subunit is most likely to be bound to GTP?

Accepted Answer

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

Question 13

If GRB2 were truncated so that the N-terminal domain was missing,the truncated protein would be unable to bind the

Accepted Answer

A)  phosphorylated Tyr of the SOS protein. 
B)  phosphorylated Tyr of the RTK substrate. 
C)  proline-rich sequence of the SOS protein. 
D)  protein-rich sequence of the RTK substrate. 
A)  phosphorylated Tyr of the SOS protein. 
B)  phosphorylated Tyr of the RTK substrate. 
C)  proline-rich sequence of the SOS protein. 
D)  protein-rich sequence of the RTK substrate.

Question 14

Place the following steps in proper order: 
A.phosphorylation of RTK cytoplasmic tails
B.activation of downstream signaling pathways
C.ligand binding,receptor dimerization,and kinase activation
D.protein binding to RTK phosphotyrosines and phosphorylation of target proteins

Accepted Answer

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

Question 15

The PPAR   -RXR  
Heterodimer interacts with DNA via

Accepted Answer

A)  the LXXLL sequences. 
B)  leucine zipper motifs. 
C)  zinc finger motifs. 
D)  basic leucine zipper motifs. 
A)  the LXXLL sequences. 
B)  leucine zipper motifs. 
C)  zinc finger motifs. 
D)  basic leucine zipper motifs.

Question 16

Ligand binding causes which of the following to form trimers?

Accepted Answer

A)  tumor necrosis factor receptors 
B)  receptor tyrosine kinases 
C)  G protein-coupled receptors 
D)  nicotinic acetylcholine receptors 
A)  tumor necrosis factor receptors 
B)  receptor tyrosine kinases 
C)  G protein-coupled receptors 
D)  nicotinic acetylcholine receptors

Question 17

Which of the following compounds is a pharmaceutical adrenergic receptor agonist?

Accepted Answer

A)  dopamine 
B)  metoprolol 
C)  norepinephrine 
D)  clonidine 
A)  dopamine 
B)  metoprolol 
C)  norepinephrine 
D)  clonidine

Question 18

Below shows the cell survival pathway promoted by TNF-   .A complex is indicated with a question mark.What is this complex?

Accepted Answer

A)  inactive NF$\kappa$B 
B)  active NF$\kappa$B 
C)  active CASP3 
D)  NIK 
A)  inactive NF$\kappa$B 
B)  active NF$\kappa$B 
C)  active CASP3 
D)  NIK

Question 19

Which of the following prevents GPCR from reassociating with the   complex?

Accepted Answer

A)    -arrestin 
B)  GTPase activating protein 
C)  cAMP phosphodiesterase 
D)  RGS 
A)    -arrestin 
B)  GTPase activating protein 
C)  cAMP phosphodiesterase 
D)  RGS

Question 20

The levels of the second messenger involved in vasodilation are increased by __________ and decreased by __________.

Accepted Answer

A)  cGMP cyclase; guanylate phosphodiesterase 
B)  guanylate phosphodiesterase; cGMP cyclase 
C)  guanylate cyclase; cGMP phosphodiesterase 
D)  cGMP phosphodiesterase; guanylate cyclase 
A)  cGMP cyclase; guanylate phosphodiesterase 
B)  guanylate phosphodiesterase; cGMP cyclase 
C)  guanylate cyclase; cGMP phosphodiesterase 
D)  cGMP phosphodiesterase; guanylate cyclase

Exam 8: Cell Signaling Systems

The subunit of trimeric G proteins can function to

Which scenario would allow -arrestin to bind to the GPCR?

The PI-3K signaling pathway is activated by the binding of __________ to its receptor.This leads to an increase in glucose uptake and in __________ synthesis.

A Western blot analysis of the expression of estrogen receptors in ovarian tissues at different times of the estrous cycle showed approximately four times greater protein levels at day 2 compared with day 10 of the cycle.Which of the following may be true given these data?

On binding of an insulin molecule to the insulin receptor,a conformational change occurs that

Which of the following is a GTPase?

Which of the following is true of procaspase 8?

Contrast the structures and nucleotide binding properties of when interacting with adenylate cyclase versus protein.

Hsp90 is a type of

Levels of diacylglycerol increase in a cell on binding of a ligand to a taste receptor.Which trimeric G protein subunit is most likely to be bound to GTP?

If GRB2 were truncated so that the N-terminal domain was missing,the truncated protein would be unable to bind the

Place the following steps in proper order: A.phosphorylation of RTK cytoplasmic tails B.activation of downstream signaling pathways C.ligand binding,receptor dimerization,and kinase activation D.protein binding to RTK phosphotyrosines and phosphorylation of target proteins

The PPAR -RXR Heterodimer interacts with DNA via

Ligand binding causes which of the following to form trimers?

Which of the following compounds is a pharmaceutical adrenergic receptor agonist?

Below shows the cell survival pathway promoted by TNF- .A complex is indicated with a question mark.What is this complex?

Which of the following prevents GPCR from reassociating with the complex?

The levels of the second messenger involved in vasodilation are increased by __________ and decreased by __________.

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

Filters

The PI-3K signaling pathway is activated by the binding of to its receptor.This leads to an increase in glucose uptake and in synthesis.

The levels of the second messenger involved in vasodilation are increased by and decreased by .