Question 1

Which of the following would be correctly described as a juxtacrine signaling?

Accepted Answer

A) a signal that requires physical contact between cell 
B) a signal that acts on the cell that produces it 
C) a signal that diffuses over long distances from the producing cell 
D) a signal that diffuses over short distances from the producing cell 
E) a hormonal signal 
A) a signal that requires physical contact between cell 
B) a signal that acts on the cell that produces it 
C) a signal that diffuses over long distances from the producing cell 
D) a signal that diffuses over short distances from the producing cell 
E) a hormonal signal

Question 2

Compounds that inhibit receptors by preventing the natural messenger from binding are known as

Accepted Answer

A) agonists. 
B) arrestins. 
C) sildenafils. 
D) syndecans. 
E) antagonists. 
A) agonists. 
B) arrestins. 
C) sildenafils. 
D) syndecans. 
E) antagonists.

Question 3

Kinase 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 4

Gsα nucleotide exchange is stimulated by a ________,whereas Ras nucleotide exchange is stimulated by ________.

Accepted Answer

GPCR/EGF r

Question 5

IP3 receptors are associated with

Accepted Answer

A) plasma membranes. 
B) Golgi apparatus membranes. 
C) mitochondrial membranes. 
D) ER membranes. 
E) endosome membranes. 
A) plasma membranes. 
B) Golgi apparatus membranes. 
C) mitochondrial membranes. 
D) ER membranes. 
E) endosome membranes.

Question 6

Each of the following is a second messenger except

Accepted Answer

A) cyclic adenosine monophosphate. 
B) inositol trisphosphate. 
C) diacylglycerol. 
D) epinephrine. 
E) calcium ions. 
A) cyclic adenosine monophosphate. 
B) inositol trisphosphate. 
C) diacylglycerol. 
D) epinephrine. 
E) calcium ions.

Question 7

In heterotrimeric G-proteins,the ________ subunit stimulates adenylyl kinase.

Accepted Answer

The answer of In heterotrimeric G-proteins,the ________ subunit stimulates adenylyl...

Question 8

cAMP affects cell activities by interacting directly with

Accepted Answer

A) adenylyl cyclase. 
B) protein kinase A regulatory subunits. 
C) protein kinase A catalytic subunits. 
D) cAMP phosphodiesterase. 
E) calmodulin. 
A) adenylyl cyclase. 
B) protein kinase A regulatory subunits. 
C) protein kinase A catalytic subunits. 
D) cAMP phosphodiesterase. 
E) calmodulin.

Question 9

A mutation in RTK receptor that allows the receptor to bind the ligand and pair with a wild-type receptor but blocks signal transduction is classified as a ________ mutation,whereas a mutation that activates RTK pairing signal transduction even in the absence of ligand is classified as a ________ mutation.

Accepted Answer

dominant n

Question 10

Compare and contrast receptor tyrosine kinase (RTK)signaling pathways such as the EGF-Ras-MAPK pathway with serine/threonine kinase (S/TK)signaling pathways such as the TGF? pathway with respect to (a)receptors,(b)phosphorylation targets,(c)signal transduction from the plasma membrane through the cytoplasm to the nucleus,and (d)effects on gene regulation.

Accepted Answer

a)A single RTK contains a cytoplasmic ki

Question 11

Each of the following activates a receptor tyrosine kinase except

Accepted Answer

A) EGF. 
B) PDGF. 
C) TGFβ 
D) FGF. 
E) Insulin. 
A) EGF. 
B) PDGF. 
C) TGFβ 
D) FGF. 
E) Insulin.

Question 12

cAMP activates

Accepted Answer

A) protein kinase A. 
B) protein kinase B. 
C) protein kinase C. 
D) protein kinase G. 
E) MAPK. 
A) protein kinase A. 
B) protein kinase B. 
C) protein kinase C. 
D) protein kinase G. 
E) MAPK.

Question 13

________ are genetically engineered proteins that respond directly to cytosolic calcium fluxes by changing their fluorescence intensity.

Accepted Answer

The answer of ________ are genetically engineered proteins that respond...

Question 14

Each of the following is a G-protein coupled receptor (GPCR)or type of GPCR except

Accepted Answer

A) steroid hormone receptors. 
B) opioid receptors. 
C) thyroid-stimulating hormone receptors. 
D) olfactory receptors. 
E) β-adrenergic receptors. 
A) steroid hormone receptors. 
B) opioid receptors. 
C) thyroid-stimulating hormone receptors. 
D) olfactory receptors. 
E) β-adrenergic receptors.

Question 15

Desensitization of a cell to a ligand may involve each of the following except

Accepted Answer

A) destruction of the ligand. 
B) decrease in receptor ability to activate intracellular signaling pathway. 
C) receptor destruction. 
D) receptor endocytosis. 
E) decrease in receptor affinity for the ligand. 
A) destruction of the ligand. 
B) decrease in receptor ability to activate intracellular signaling pathway. 
C) receptor destruction. 
D) receptor endocytosis. 
E) decrease in receptor affinity for the ligand.

Question 16

Which of the following is the correct order of steps in the EGF-cAMP signaling pathway?

Accepted Answer

A) ligand binding-G-protein activation- adenylyl cyclase activation-cAMP production-protein kinase A activation 
B) ligand binding-protein kinase A activation-G-protein activation-adenylyl cyclase activation-cAMP production 
C) G-protein activation-ligand binding-adenylyl cyclase activation-cAMP production-protein kinase A activation. 
D) ligand binding-G-protein activation-adenylyl cyclase activation-cAMP production-protein kinase A activation 
E) ligand binding-adenylyl cyclase activation-G-protein activation-cAMP production-protein kinase A activation 
A) ligand binding-G-protein activation- adenylyl cyclase activation-cAMP production-protein kinase A activation 
B) ligand binding-protein kinase A activation-G-protein activation-adenylyl cyclase activation-cAMP production 
C) G-protein activation-ligand binding-adenylyl cyclase activation-cAMP production-protein kinase A activation. 
D) ligand binding-G-protein activation-adenylyl cyclase activation-cAMP production-protein kinase A activation 
E) ligand binding-adenylyl cyclase activation-G-protein activation-cAMP production-protein kinase A activation

Question 17

Insulin-stimulated increase in glucose uptake and storage in cells is promoted by activation of each of the following except

Accepted Answer

A) Ras. 
B) PI 3-kinase. 
C) PTEN. 
D) Akt kinase. 
E) Glut4. 
A) Ras. 
B) PI 3-kinase. 
C) PTEN. 
D) Akt kinase. 
E) Glut4.

Question 18

The low level of cytosolic calcium ions in unactivated cells is established by which of the following?

Accepted Answer

A) calmodulin 
B) calcium ATPases 
C) kinases 
D) phosphatases 
E) phospholipase C 
A) calmodulin 
B) calcium ATPases 
C) kinases 
D) phosphatases 
E) phospholipase C

Question 19

To test whether the XFF signal system is similar to that of epinephrine,you microinject a nonhydrolyzable analogue of GTP into an XFF-responsive cell.If the XFF mechanism is similar to that of epinephrine,you would expect the cellular response to be

Accepted Answer

A) blocked completely. 
B) prolonged. 
C) delayed. 
D) 50 percent of normal. 
E) It is not possible to predict without knowing how many receptors are present on the cell. 
A) blocked completely. 
B) prolonged. 
C) delayed. 
D) 50 percent of normal. 
E) It is not possible to predict without knowing how many receptors are present on the cell.

Question 20

Which of the following is a synthetic protein produced from engineered DNA that is used to determine whether cytosolic calcium fluxes are associated with signal transduction in a particular cell type?

Accepted Answer

A) sildenafil 
B) ionomycin 
C) A23187 
D) fura-2 
E) a cameleons 
A) sildenafil 
B) ionomycin 
C) A23187 
D) fura-2 
E) a cameleons

Exam 23: Signal Transduction Mechanisms: Iimessengers and Receptors

Which of the following would be correctly described as a juxtacrine signaling?

Compounds that inhibit receptors by preventing the natural messenger from binding are known as

Kinase enzymes

Gsα nucleotide exchange is stimulated by a ________,whereas Ras nucleotide exchange is stimulated by ________.

IP3 receptors are associated with

Each of the following is a second messenger except

In heterotrimeric G-proteins,the ________ subunit stimulates adenylyl kinase.

cAMP affects cell activities by interacting directly with

Each of the following activates a receptor tyrosine kinase except

cAMP activates

________ are genetically engineered proteins that respond directly to cytosolic calcium fluxes by changing their fluorescence intensity.

Each of the following is a G-protein coupled receptor (GPCR)or type of GPCR except

Desensitization of a cell to a ligand may involve each of the following except

Which of the following is the correct order of steps in the EGF-cAMP signaling pathway?

Insulin-stimulated increase in glucose uptake and storage in cells is promoted by activation of each of the following except

The low level of cytosolic calcium ions in unactivated cells is established by which of the following?

To test whether the XFF signal system is similar to that of epinephrine,you microinject a nonhydrolyzable analogue of GTP into an XFF-responsive cell.If the XFF mechanism is similar to that of epinephrine,you would expect the cellular response to be

Which of the following is a synthetic protein produced from engineered DNA that is used to determine whether cytosolic calcium fluxes are associated with signal transduction in a particular cell type?

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

G_sα nucleotide exchange is stimulated by a ,whereas Ras nucleotide exchange is stimulated by .

IP₃ receptors are associated with