Question 1

Kinases and phosphatases are essential in the cell because they

Accepted Answer

A) sense short poly A tails in mRNA as a signal to degrade the mRNA. 
B) are enzymes that destroy damaged proteins. 
C) help turn proteins "on and off" through changes in phosphorylation status. 
D) destroy second messengers, thereby turning off a signal transduction pathway. 
E) all of the above 
A) sense short poly A tails in mRNA as a signal to degrade the mRNA. 
B) are enzymes that destroy damaged proteins. 
C) help turn proteins "on and off" through changes in phosphorylation status. 
D) destroy second messengers, thereby turning off a signal transduction pathway. 
E) all of the above C

Question 2

MAPKs are activated by

Accepted Answer

A) microtubules. 
B) methylation. 
C) membranes. 
D) mitogens. 
E) methionine. 
A) microtubules. 
B) methylation. 
C) membranes. 
D) mitogens. 
E) methionine. D

Question 3

Which of the following is NOT a receptor tyrosine kinase?

Accepted Answer

A) EGF 
B) TGF 
C) FGF 
D) TGF. 
E) PDGF. 
A) EGF 
B) TGF 
C) FGF 
D) TGF. 
E) PDGF. B

Question 4

The Ga- subunit is responsible for activation of .

Accepted Answer

The answer of The Ga- subunit is responsible for activation...

Question 5

In ulcerative colitis, gas within the lumen of the large intestine can have as much as 100 times more nitric oxide than non- ulcerative colitis controls. In light of your understanding of the nitric oxide signal transduction pathway, interpret these findings.

Accepted Answer

Answer should be similar to pathway laid

Question 6

Which of the following statements regarding Fas- mediated programmed cell death is false?

Accepted Answer

A) Fas ligand and receptor interaction results in the recruitment of adaptor proteins in the target cell. 
B) The capase cascade results in the cleavage of the proteins within the target cell. 
C) Capases are activated in the process. 
D) It ultimately results in death of the cell. 
E) Fas ligand binding with Fas receptor stimulates a specific G protein. 
A) Fas ligand and receptor interaction results in the recruitment of adaptor proteins in the target cell. 
B) The capase cascade results in the cleavage of the proteins within the target cell. 
C) Capases are activated in the process. 
D) It ultimately results in death of the cell. 
E) Fas ligand binding with Fas receptor stimulates a specific G protein.

Question 7

G protein- adenyl cyclase activity has been shown, in some cases, to be associated with certain diseases. In the case of cholera, which of the following is NOT correct?

Accepted Answer

A) Vibrio cholera bacteria colonize the gut. 
B) Cholera toxin is secreted by Vibrio cholera bacteria. 
C) The cholera toxin causes the cells of the gut to take in salts and fluids. 
D) The toxin, by altering Gs, keeps intracellular cAMP levels high and doesn't allow them to decrease. 
E) Cholera toxin alters Gs so that it no longer hydrolyzes GTP. 
A) Vibrio cholera bacteria colonize the gut. 
B) Cholera toxin is secreted by Vibrio cholera bacteria. 
C) The cholera toxin causes the cells of the gut to take in salts and fluids. 
D) The toxin, by altering Gs, keeps intracellular cAMP levels high and doesn't allow them to decrease. 
E) Cholera toxin alters Gs so that it no longer hydrolyzes GTP.

Question 8

When nitric oxide is used in the dilation of smooth muscle cells, which of the following would interfere with the relaxation of the smooth muscle cells? Inhibitors of

Accepted Answer

A) nitric oxide. 
B) calmodulin. 
C) calcium release by the ER. 
D) guanylyl cyclase. 
E) all of the above 
A) nitric oxide. 
B) calmodulin. 
C) calcium release by the ER. 
D) guanylyl cyclase. 
E) all of the above

Question 9

IL- 2 is a growth factor that acts on

Accepted Answer

A) T lymphocytes. 
B) embryonic cells. 
C) muscle cells. 
D) macrophages. 
E) epithelial cells. 
A) T lymphocytes. 
B) embryonic cells. 
C) muscle cells. 
D) macrophages. 
E) epithelial cells.

Question 10

Base your answers to the questions below on the following information:
You have isolated a factor from the blood of a space alien and named it XFF (for X- files factor). Based on preliminary data, you think that XFF could be one of three compounds normally found in human blood: epidermal growth factor (EGF), epinephrine, or estrogen.
-You add a large amount of XFF to cultured liver cells. Which of the following might you observe if XFF can bind to human epinephrine receptors?

Accepted Answer

A) glycogen breakdown 
B) increased cell division 
C) decreased protein synthesis 
D) glucose 6- phosphate polymerization 
E) all of the above 
A) glycogen breakdown 
B) increased cell division 
C) decreased protein synthesis 
D) glucose 6- phosphate polymerization 
E) all of the above

Question 11

Desensitization of a cell to a ligand may involve all BUT

Accepted Answer

A) a lessened response to the ligand. 
B) receptor down- regulation. 
C) lowered affinity of a receptor for the ligand. 
D) destruction of the ligand. 
E) receptor- mediated endocytosis. 
A) a lessened response to the ligand. 
B) receptor down- regulation. 
C) lowered affinity of a receptor for the ligand. 
D) destruction of the ligand. 
E) receptor- mediated endocytosis.

Question 12

You wish to determine if cytosolic calcium fluxes are associated with signal transduction in a particular cell type. One means of observing the calcium fluxes would be to utilize

Accepted Answer

A) cameleons. 
B) caspases. 
C) nitric oxide. 
D) radioactive cAMP. 
E) cytochrome c. 
A) cameleons. 
B) caspases. 
C) nitric oxide. 
D) radioactive cAMP. 
E) cytochrome c.

Question 13

Base your answers to the questions below on the following information:
You have isolated a factor from the blood of a space alien and named it XFF (for X- files factor). Based on preliminary data, you think that XFF could be one of three compounds normally found in human blood: epidermal growth factor (EGF), epinephrine, or estrogen.
-You argue with one of your fellow students that other features of the protein suggest that the protein is much like EGF. To discredit this, you would show the data obtained with

Accepted Answer

A) amino acid phosphorylation. 
B) tyrosine kinase inhibition studies. 
C) radioactive XFF. 
D) binding assay. 
E) use of nonhydrolyzable GTP analogs. 
A) amino acid phosphorylation. 
B) tyrosine kinase inhibition studies. 
C) radioactive XFF. 
D) binding assay. 
E) use of nonhydrolyzable GTP analogs.

Question 14

Mice lacking the ability to make caspase- 9 die as the result of numerous defects. During the necropsy (animal autopsy)of the animal you note that the brains of these mice are dramatically enlarged. This is most likely a result of

Accepted Answer

A) overstimulation of G- protein mediated transduction. 
B) overproduction of the Etr1 receptor protein. 
C) lack of apoptosis of some cells. 
D) unregulated growth of the nerve cells. 
E) all of the above 
A) overstimulation of G- protein mediated transduction. 
B) overproduction of the Etr1 receptor protein. 
C) lack of apoptosis of some cells. 
D) unregulated growth of the nerve cells. 
E) all of the above

Question 15

nucleotides are common signals in animal cells, but not in plant cells.

Accepted Answer

The answer of nucleotides are common signals in animal cells,...

Question 16

All of the following participate in apoptosis EXCEPT

Accepted Answer

A) death promoting proteins. 
B) calcium ions. 
C) Bcl- 2. 
D) caspases. 
E) mitochondria. 
A) death promoting proteins. 
B) calcium ions. 
C) Bcl- 2. 
D) caspases. 
E) mitochondria.

Question 17

are genetically engineered proteins that allow cytosolic calcium fluxes to be observed by an increase in fluorescence.

Accepted Answer

The answer of are genetically engineered proteins that allow cytosolic...

Question 18

It would then be useful to determine if the mechanism of action for the XFF - XFF receptor is similar to that of estrogen or epinephrine. To test this, you use a nonhydrolyzable analog of GTP in the reaction mixture. If the mechanism is still similar to that of epinephrine, you would expect the cellular responses would be

Accepted Answer

A) delayed. 
B) blocked. 
C) prolonged. 
D) both B and C 
E) You cannot determine this from the given information. 
A) delayed. 
B) blocked. 
C) prolonged. 
D) both B and C 
E) You cannot determine this from the given information.

Question 19

To have a hormone receptor system that is responsive to changes in hormone concentration, it is useful if the concentration of the hormone is

Accepted Answer

A) never more than 10 times the Kd. 
B) far below the Kd before the stimulation of hormone secretion. 
C) always more than 10 times the Kd. 
D) far above the Kd before the stimulation of hormone secretion. 
E) always constant. 
A) never more than 10 times the Kd. 
B) far below the Kd before the stimulation of hormone secretion. 
C) always more than 10 times the Kd. 
D) far above the Kd before the stimulation of hormone secretion. 
E) always constant.

Question 20

Blood pressure is regulated by the second messenger

Accepted Answer

A) Ca2+. 
B) CO. 
C) IP3. 
D) NO. 
E) cAMP. 
A) Ca2+. 
B) CO. 
C) IP3. 
D) NO. 
E) cAMP.

Exam 14: Signal Transduction Mechanisms: Ii Messengers and Receptors

Kinases and phosphatases are essential in the cell because they

MAPKs are activated by

Which of the following is NOT a receptor tyrosine kinase?

The Ga- subunit is responsible for activation of .

In ulcerative colitis, gas within the lumen of the large intestine can have as much as 100 times more nitric oxide than non- ulcerative colitis controls. In light of your understanding of the nitric oxide signal transduction pathway, interpret these findings.

Which of the following statements regarding Fas- mediated programmed cell death is false?

G protein- adenyl cyclase activity has been shown, in some cases, to be associated with certain diseases. In the case of cholera, which of the following is NOT correct?

When nitric oxide is used in the dilation of smooth muscle cells, which of the following would interfere with the relaxation of the smooth muscle cells? Inhibitors of

IL- 2 is a growth factor that acts on

Desensitization of a cell to a ligand may involve all BUT

You wish to determine if cytosolic calcium fluxes are associated with signal transduction in a particular cell type. One means of observing the calcium fluxes would be to utilize

Mice lacking the ability to make caspase- 9 die as the result of numerous defects. During the necropsy (animal autopsy)of the animal you note that the brains of these mice are dramatically enlarged. This is most likely a result of

nucleotides are common signals in animal cells, but not in plant cells.

All of the following participate in apoptosis EXCEPT

are genetically engineered proteins that allow cytosolic calcium fluxes to be observed by an increase in fluorescence.

To have a hormone receptor system that is responsive to changes in hormone concentration, it is useful if the concentration of the hormone is

Blood pressure is regulated by the second messenger

A Preview of the Cell

The Chemistry of the Cell

The Macromolecules of the Cell

Cells and Organelles

Bioenergetics: The Flow of Energy in the Cell

Enzymes: The Catalysts of Life

Membranes: Their Structure, Function, and Chemistry

Transport Across Membranes: Overcoming the Permeability Barrier

Chemotrophic Energy Metabolism: Glycolysis and Fermentation

Chemotrophic Energy Metabolism: Aerobic Respiration

Phototrophic Energy Metabolism: Photosynthesis

The Endomembrane System and Peroxisomes

Signal Transduction Mechanisms: I Electrical and Synaptic Signaling in Neurons

Cytoskeletal Systems

Cellular Movement: Motility and Contractility

Beyond the Cell: Cell Adhesion, Cell Junctions, and Extracellular Structures

The Structural Basis of Cellular Information: DNA, Chromosomes, and the Nucleus

The Cell Cycle, Dna Replication, and Mitosis

Sexual Reproduction, Meiosis, and Genetic Recombination

Gene Expression: I the Genetic Code and Transcription

Gene Expression: II Protein Synthesis and Sorting

The Regulation of Gene Expression

Cancer Cells

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