Question 1

Which of the following is a lipophilic primary message that crosses the plasma membrane and interacts with a cytosolic receptor?

Accepted Answer

A) estrogen 
B) EGF 
C) pertussis toxin 
D) TGFβ 
E) PDGF 
A) estrogen 
B) EGF 
C) pertussis toxin 
D) TGFβ 
E) PDGF

Question 2

In smooth muscle cells,acetylcholine stimulates activation of the enzyme ________,which cleaves ________ to form the second messengers ________ and ________.

Accepted Answer

phospholip

Question 3

Inhibitors of which of the following would interfere with nitric oxide stimulation of cardiac artery dilation through relaxation of smooth muscle cells?

Accepted Answer

A) protein kinase G. 
B) nitric oxide synthase 
C) guanylyl cyclase 
D) calmodulin 
E) Inhibitors of all of the above would interfere with nitric oxide stimulation. 
A) protein kinase G. 
B) nitric oxide synthase 
C) guanylyl cyclase 
D) calmodulin 
E) Inhibitors of all of the above would interfere with nitric oxide stimulation.

Question 4

In a hormone-stimulated signaling system,the concentration of hormone exposed to the receptor is

Accepted Answer

A) always equal to the receptor Kd for binding the hormone. 
B) never equal to the receptor Kd for binding the hormone. 
C) below the receptor Kd for binding the hormone before stimulation of hormone secretion. 
D) above the receptor Kd for binding the hormone before stimulation of hormone secretion. 
E) always constant. 
A) always equal to the receptor Kd for binding the hormone. 
B) never equal to the receptor Kd for binding the hormone. 
C) below the receptor Kd for binding the hormone before stimulation of hormone secretion. 
D) above the receptor Kd for binding the hormone before stimulation of hormone secretion. 
E) always constant.

Question 5

Following fertilization of animal eggs,________ are the second messengers that trigger egg activation.

Accepted Answer

The answer of Following fertilization of animal eggs,________ are the...

Question 6

________ nucleotides are common second messengers in animal cells.

Accepted Answer

The answer of ________ nucleotides are common second messengers in...

Question 7

Each of the following is correct about cholera and its effect on G-protein-adenylyl cyclase activity except

Accepted Answer

A) Vibrio cholera bacteria colonize the gut. 
B) Cholera toxin is secreted by Vibrio cholera bacteria. 
C) Intestinal cells infected with cholera toxin import abnormally high levels of salts and fluids into the bloodstream. 
D) Cholera toxin alters Gsα so that it no longer hydrolyzes GTP. 
E) Intestinal cells infected with cholera toxin maintain abnormally high cAMP levels. 
A) Vibrio cholera bacteria colonize the gut. 
B) Cholera toxin is secreted by Vibrio cholera bacteria. 
C) Intestinal cells infected with cholera toxin import abnormally high levels of salts and fluids into the bloodstream. 
D) Cholera toxin alters Gsα so that it no longer hydrolyzes GTP. 
E) Intestinal cells infected with cholera toxin maintain abnormally high cAMP levels.

Question 8

Each of the following ligands binds to an intracellular receptor except

Accepted Answer

A) cortisol. 
B) retinoic acid. 
C) thyroid hormone. 
D) epinephrine. 
E) estrogen. 
A) cortisol. 
B) retinoic acid. 
C) thyroid hormone. 
D) epinephrine. 
E) estrogen.

Question 9

Each of the following is a correct cell-specific response of Epinephrine-cAMP signaling except

Accepted Answer

A) liver cell glycogen breakdown to glucose. 
B) stronger heart muscle contraction. 
C) stronger smooth muscle contraction. 
D) inhibition of platelet activation during blood clotting. 
E) increase in intestinal epithelial cell fluid secretion. 
A) liver cell glycogen breakdown to glucose. 
B) stronger heart muscle contraction. 
C) stronger smooth muscle contraction. 
D) inhibition of platelet activation during blood clotting. 
E) increase in intestinal epithelial cell fluid secretion.

Question 10

EGF (epidermal growth factor)activates cell division by binding to ________.

Accepted Answer

receptor t

Question 11

Dilation of blood vessels is regulated by the second messenger

Accepted Answer

A) cAMP. 
B) Ca2+. 
C) IP3. 
D) CO2. 
E) NO. 
A) cAMP. 
B) Ca2+. 
C) IP3. 
D) CO2. 
E) NO.

Question 12

What compounds or probes could you use to investigate (a)G-protein-mediated signal transduction,(b)nitric oxide signal transduction,and (c)calcium ion-dependent fluxes and effects.

Accepted Answer

a)Nonhydrolyzable GTP analogues prolong

Question 13

You are investigating a cell activity that you suspect is activated by a rise in intracellular calcium ions.Which of the following agents could you use to cause an increase in intracellular calcium in the cells you are studying?

Accepted Answer

A) cameleon 
B) A23187 
C) phorbol ester 
D) sildenafil 
E) NO 
A) cameleon 
B) A23187 
C) phorbol ester 
D) sildenafil 
E) NO

Question 14

Types of regulators of G-protein signaling (RGS)proteins known as ________ accelerate termination of signaling by stimulating a G-protein to ________ GTP.

Accepted Answer

The answer of Types of regulators of G-protein signaling (RGS)proteins...

Question 15

Each of the following is a characteristic of calmodulin except

Accepted Answer

A) It binds two calcium ions at each end of the protein. 
B) When activated by calcium ion binding,it wraps around proteins that have calmodulin binding sites. 
C) It can activate specific kinases and phosphatases. 
D) It has a very high affinity for calcium ions,and binds calcium ions irreversibly. 
E) All are characteristics of calmodulin. 
A) It binds two calcium ions at each end of the protein. 
B) When activated by calcium ion binding,it wraps around proteins that have calmodulin binding sites. 
C) It can activate specific kinases and phosphatases. 
D) It has a very high affinity for calcium ions,and binds calcium ions irreversibly. 
E) All are characteristics of calmodulin.

Question 16

Phosphatase enzymes

Accepted Answer

A) add phosphate groups. 
B) always inhibit target molecule activity. 
C) bind tightly by wrapping around a target molecule to regulate its activity. 
D) remove phosphate groups. 
E) metabolize glucose. 
A) add phosphate groups. 
B) always inhibit target molecule activity. 
C) bind tightly by wrapping around a target molecule to regulate its activity. 
D) remove phosphate groups. 
E) metabolize glucose.

Question 17

Theophylline,a methylxanthine like caffeine,is used to treat asthma.Explain the mechanism by which a methylxanthine can alleviate asthma symptoms resulting from bronchial constriction.

Accepted Answer

Methylxanthines are cAMP phosphodiestera

Question 18

Kinases and phosphatases are essential in the cell because they directly

Accepted Answer

A) turn proteins "on and off" through changes in phosphorylation status. 
B) bind hydrophobic hormones in the cytoplasm. 
C) bind and release calcium ions. 
D) destroy IP3,turning off that signaling pathway. 
E) activate and repress genes. 
A) turn proteins "on and off" through changes in phosphorylation status. 
B) bind hydrophobic hormones in the cytoplasm. 
C) bind and release calcium ions. 
D) destroy IP3,turning off that signaling pathway. 
E) activate and repress genes.

Question 19

You add a large amount of XFF to cultured alien liver cells.Which of the following would confirm that XFF is the alien equivalent of human epinephrine?

Accepted Answer

A) increased cell division 
B) decreased cell division 
C) glycogen breakdown 
D) increased glucose uptake 
E) insensitivity to insulin 
A) increased cell division 
B) decreased cell division 
C) glycogen breakdown 
D) increased glucose uptake 
E) insensitivity to insulin

Question 20

Previous experiments have not conclusively demonstrated XFF is the alien epinephrine,so you decide to investigate other XFF properties using radioactive XFF.Which of the following XFF behaviors confirm that XFF is similar to estrogen?

Accepted Answer

A) XFF binds only to the cell surface. 
B) XFF diffuses into the cell cytoplasm. 
C) XFF is internalized by receptor-mediated endocytosis. 
D) Ryanodine blocks the interaction of XFF with cells. 
E) Opioids block the interaction of XFF with cells. 
A) XFF binds only to the cell surface. 
B) XFF diffuses into the cell cytoplasm. 
C) XFF is internalized by receptor-mediated endocytosis. 
D) Ryanodine blocks the interaction of XFF with cells. 
E) Opioids block the interaction of XFF with cells.

Exam 23: Signal Transduction Mechanisms: Iimessengers and Receptors

Which of the following is a lipophilic primary message that crosses the plasma membrane and interacts with a cytosolic receptor?

In smooth muscle cells,acetylcholine stimulates activation of the enzyme ________,which cleaves ________ to form the second messengers ________ and ________.

Inhibitors of which of the following would interfere with nitric oxide stimulation of cardiac artery dilation through relaxation of smooth muscle cells?

In a hormone-stimulated signaling system,the concentration of hormone exposed to the receptor is

Following fertilization of animal eggs,________ are the second messengers that trigger egg activation.

________ nucleotides are common second messengers in animal cells.

Each of the following is correct about cholera and its effect on G-protein-adenylyl cyclase activity except

Each of the following ligands binds to an intracellular receptor except

Each of the following is a correct cell-specific response of Epinephrine-cAMP signaling except

EGF (epidermal growth factor)activates cell division by binding to ________.

Dilation of blood vessels is regulated by the second messenger

What compounds or probes could you use to investigate (a)G-protein-mediated signal transduction,(b)nitric oxide signal transduction,and (c)calcium ion-dependent fluxes and effects.

You are investigating a cell activity that you suspect is activated by a rise in intracellular calcium ions.Which of the following agents could you use to cause an increase in intracellular calcium in the cells you are studying?

Types of regulators of G-protein signaling (RGS)proteins known as ________ accelerate termination of signaling by stimulating a G-protein to ________ GTP.

Each of the following is a characteristic of calmodulin except

Phosphatase enzymes

Theophylline,a methylxanthine like caffeine,is used to treat asthma.Explain the mechanism by which a methylxanthine can alleviate asthma symptoms resulting from bronchial constriction.

Kinases and phosphatases are essential in the cell because they directly

You add a large amount of XFF to cultured alien liver cells.Which of the following would confirm that XFF is the alien equivalent of human epinephrine?

Previous experiments have not conclusively demonstrated XFF is the alien epinephrine,so you decide to investigate other XFF properties using radioactive XFF.Which of the following XFF behaviors confirm that XFF is similar to estrogen?

A Preview of Cell Biology

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

Cytoskeletal Systems

Cellular Movement: Motility and Contractility

Beyond the Cell: Cell Adhesions, cell Junctions, and Extracellular Structures

The Structural Basis of Cellular Information: Dna, chromosomes, and the Nucleus

DNA Replication, repair, and Recombination

Gene Expression: Ithe Genetic Code and Transcription

Gene Expression: Iiprotein Synthesis and Sorting

The Regulation of Gene Expression

Molecular Biology Techniques for Cell Biology

Signal Transduction Mechanisms: Ielectrical and Synaptic Signaling in Neurons

The Cell Cycle and Mitosis

Sexual Reproduction,meiosis,and Genetic Recombination

Filters

In smooth muscle cells,acetylcholine stimulates activation of the enzyme ,which cleaves to form the second messengers and .

Types of regulators of G-protein signaling (RGS)proteins known as accelerate termination of signaling by stimulating a G-protein to GTP.