Question 1

Which of the following signaling methods is absent in plants but present in other eukaryotes?

Accepted Answer

A) MAP kinase pathway 
B) Ca2+ signaling 
C) phosphoinositide signaling 
D) cyclic nucleotides 
E) extracellular receptors 
A) MAP kinase pathway 
B) Ca2+ signaling 
C) phosphoinositide signaling 
D) cyclic nucleotides 
E) extracellular receptors

Question 2

Which heterotrimeric G proteins function by inhibiting adenylyl cyclase?

Accepted Answer

A) Gs family 
B) Gq family 
C) Gi family 
D) G12/13family 
E) Gr family 
A) Gs family 
B) Gq family 
C) Gi family 
D) G12/13family 
E) Gr family

Question 3

Which of the following processes is NOT reported to be regulated by eicosanoids?

Accepted Answer

A) pain 
B) inflammation 
C) blood pressure 
D) blood clotting 
E) neurotransmission 
A) pain 
B) inflammation 
C) blood pressure 
D) blood clotting 
E) neurotransmission

Question 4

Which inorganic gas has been shown to act as a second messenger that relaxes the smooth muscles of blood vessels?

Accepted Answer

A) NO 
B) N2O 
C) nitrous oxide 
D) CO 
E) N2 
A) NO 
B) N2O 
C) nitrous oxide 
D) CO 
E) N2

Question 5

How is signaling by an activated Gα subunit terminated?

Accepted Answer

A) The bound GTP is hydrolyzed to GMP. 
B) The bound GDP is hydrolyzed to GTP. 
C) The bound GTP is hydrolyzed to GDP. 
D) The bound GDP is phosphorylated to GTP. 
E) The Gα subunit releases GDP and binds GTP. 
A) The bound GTP is hydrolyzed to GMP. 
B) The bound GDP is hydrolyzed to GTP. 
C) The bound GTP is hydrolyzed to GDP. 
D) The bound GDP is phosphorylated to GTP. 
E) The Gα subunit releases GDP and binds GTP.

Question 6

Why does calcium not bind to calmodulin in a non-stimulated cell?

Accepted Answer

A) Calmodulin's affinity for calcium ions is too low to allow binding in a nonstimulated cell. 
B) Calmodulin's affinity for calcium ions is too high to allow binding in a nonstimulated cell. 
C) In a nonstimulated cell, calcium ions are destroyed. 
D) In a nonstimulated cell, calcium ions are produced. 
E) In a nonstimulated cell, calcium ions preferentially bind to another protein in the cytosol. 
A) Calmodulin's affinity for calcium ions is too low to allow binding in a nonstimulated cell. 
B) Calmodulin's affinity for calcium ions is too high to allow binding in a nonstimulated cell. 
C) In a nonstimulated cell, calcium ions are destroyed. 
D) In a nonstimulated cell, calcium ions are produced. 
E) In a nonstimulated cell, calcium ions preferentially bind to another protein in the cytosol.

Question 7

Orai1 is a tetrameric _______ that has been identified as being involved in a particular type of inherited human immune deficiency that results from a lack of Ca2+ stores in ________.

Accepted Answer

A) Ca2+ ion channel, B lymphocytes 
B) Ca2+ ion pump, B lymphocytes 
C) Ca2+ ion channel, T lymphocytes 
D) Ca2+ ion pump, T lymphocytes 
E) Ca2+ ion channel, macrophages 
A) Ca2+ ion channel, B lymphocytes 
B) Ca2+ ion pump, B lymphocytes 
C) Ca2+ ion channel, T lymphocytes 
D) Ca2+ ion pump, T lymphocytes 
E) Ca2+ ion channel, macrophages

Question 8

How does the immune system manage to avoid recognizing and attacking normal cells within the body?

Accepted Answer

A) The body never makes T lymphocytes that can react against normal cells within the body. 
B) T lymphocytes that have the ability to recognize normal cells within the body are eliminated by apoptosis early in the development of the immune system. 
C) Normal body cells are coated with a special secreted protective proteoglycan that prevents the immune system from attacking them. 
D) Normal body cells are coated with a special secreted protective glycoprotein that prevents the immune system from attacking them. 
E) Normal body cells are coated with a mixture of special secreted protective proteoglycans and glycoproteins that prevents the immune system from attacking them. 
A) The body never makes T lymphocytes that can react against normal cells within the body. 
B) T lymphocytes that have the ability to recognize normal cells within the body are eliminated by apoptosis early in the development of the immune system. 
C) Normal body cells are coated with a special secreted protective proteoglycan that prevents the immune system from attacking them. 
D) Normal body cells are coated with a special secreted protective glycoprotein that prevents the immune system from attacking them. 
E) Normal body cells are coated with a mixture of special secreted protective proteoglycans and glycoproteins that prevents the immune system from attacking them.

Question 9

Why did the smooth muscle in cultured strips of aorta not respond to acetylcholine by relaxing, while the smooth muscle of aortic rings did?

Accepted Answer

A) Smooth muscle cells in aortic strips are physically incapable of relaxing under any circumstances. 
B) Acetylcholine in the strips could not penetrate to the muscle cells while in the rings it could. 
C) Smooth muscle cells in aortic rings express acetylcholine receptors, while those in strips do not. 
D) The delicate endothelial layer in aortal strips had been rubbed away during dissection, while in aortal rings it remained intact. 
E) The endothelial layer in aortal strips was abnormally thickened, while in aortal rings it was not. 
A) Smooth muscle cells in aortic strips are physically incapable of relaxing under any circumstances. 
B) Acetylcholine in the strips could not penetrate to the muscle cells while in the rings it could. 
C) Smooth muscle cells in aortic rings express acetylcholine receptors, while those in strips do not. 
D) The delicate endothelial layer in aortal strips had been rubbed away during dissection, while in aortal rings it remained intact. 
E) The endothelial layer in aortal strips was abnormally thickened, while in aortal rings it was not.

Question 10

________ are asmall group of proteins that bind to GPCRs and compete for binding to those GPCRs with heterotrimeric G proteins.

Accepted Answer

A) Stablins 
B) Arrestins 
C) Monomeric G proteins 
D) G protein-coupled receptor kinases 
E) Desensitizers 
A) Stablins 
B) Arrestins 
C) Monomeric G proteins 
D) G protein-coupled receptor kinases 
E) Desensitizers

Question 11

What kinds of responses have NOT been observed when signals traveling down signaling pathways reach their target proteins?

Accepted Answer

A) a change in gene expression 
B) a change in ion permeability 
C) cessation of DNA synthesis and degradation of DNA 
D) the death of the cell 
E) an alteration of the activity of metabolic enzymes 
A) a change in gene expression 
B) a change in ion permeability 
C) cessation of DNA synthesis and degradation of DNA 
D) the death of the cell 
E) an alteration of the activity of metabolic enzymes

Question 12

Two αβ heterodimers of the insulin receptor are held together by ____ between the _______.

Accepted Answer

A) ionic bonds, α chains 
B) ionic bonds, β chains 
C) disulfide bonds, α chains 
D) disulfide bonds, β chains 
E) disulfide bonds, α chain of one heterodimer and the β chain of the other 
A) ionic bonds, α chains 
B) ionic bonds, β chains 
C) disulfide bonds, α chains 
D) disulfide bonds, β chains 
E) disulfide bonds, α chain of one heterodimer and the β chain of the other

Question 13

What molecule is responsible for activating Rsk-2?

Accepted Answer

A) PKA 
B) CREB 
C) MAPKK 
D) MAPK 
E) cAMP 
A) PKA 
B) CREB 
C) MAPKK 
D) MAPK 
E) cAMP

Question 14

What holds Ras at the inner surface of the plasma membrane?

Accepted Answer

A) weak interactions with the phospholipid head groups 
B) weak interactions with integral membrane proteins 
C) hydrophilic interactions of the Ras protein with the interior of the phospholipid bilayer 
D) attachment to a lipid group that is embedded in the inner leaflet of the bilayer 
E) attachment to a carbohydrate group that is embedded in the inner leaflet of the bilayer 
A) weak interactions with the phospholipid head groups 
B) weak interactions with integral membrane proteins 
C) hydrophilic interactions of the Ras protein with the interior of the phospholipid bilayer 
D) attachment to a lipid group that is embedded in the inner leaflet of the bilayer 
E) attachment to a carbohydrate group that is embedded in the inner leaflet of the bilayer

Question 15

Specificity in MAP kinase pathways is sometimes achieved by spatial localization of the pathway's component proteins. Spatial localization of these components is done by structural (i.e., nonenzymatic)proteins called _____________.

Accepted Answer

A) sequestration proteins 
B) partitioning proteins 
C) scaffolding proteins 
D) framework proteins 
E) spatial organization proteins 
A) sequestration proteins 
B) partitioning proteins 
C) scaffolding proteins 
D) framework proteins 
E) spatial organization proteins

Question 16

Which of the following is NOT generally characteristic of pathways activated by second messengers?

Accepted Answer

A) Each signaling pathway consists of a series of distinct proteins that operate in sequence. 
B) Each protein in the pathway typically acts by altering the conformation of the previous (upstream)protein in the series, an event that activates or inhibits the protein. 
C) Alterations in the conformations of signaling proteins are often accomplished by protein kinases and protein phosphatases that, respectively, add or remove phosphate groups from other proteins. 
D) Some phosphatases and protein kinases in the pathway have numerous proteins as their substrates; others act on only a single protein substrate or a single amino acid of a protein substrate. 
E) Many of the protein substrates of the pathway enzymes are enzymes themselves, like other kinases and phosphatases, but they include ion channels, transcription factors and various regulatory molecules. 
A) Each signaling pathway consists of a series of distinct proteins that operate in sequence. 
B) Each protein in the pathway typically acts by altering the conformation of the previous (upstream)protein in the series, an event that activates or inhibits the protein. 
C) Alterations in the conformations of signaling proteins are often accomplished by protein kinases and protein phosphatases that, respectively, add or remove phosphate groups from other proteins. 
D) Some phosphatases and protein kinases in the pathway have numerous proteins as their substrates; others act on only a single protein substrate or a single amino acid of a protein substrate. 
E) Many of the protein substrates of the pathway enzymes are enzymes themselves, like other kinases and phosphatases, but they include ion channels, transcription factors and various regulatory molecules.

Question 17

The _________ pathway of apoptosis is one in which internal stimuli activate apoptosis.

Accepted Answer

A) extrinsic 
B) external 
C) intrinsic 
D) peripheral 
E) integral 
A) extrinsic 
B) external 
C) intrinsic 
D) peripheral 
E) integral

Question 18

What recruits cytoplasmic GRKs (G protein-coupled receptor kinases)to the plasma membrane?

Accepted Answer

A) inhibition of certain G proteins 
B) destruction of the GPCRs 
C) activation of GPCRs 
D) inhibition of the GPCRs 
E) destruction of the hormone 
A) inhibition of certain G proteins 
B) destruction of the GPCRs 
C) activation of GPCRs 
D) inhibition of the GPCRs 
E) destruction of the hormone

Question 19

Sometimes an enzyme is activated by a receptor and brings about the cellular response by generating a second messenger. Such an enzyme is called __________.

Accepted Answer

A) an activator 
B) an effector 
C) an affector 
D) a refractor 
E) a generator 
A) an activator 
B) an effector 
C) an affector 
D) a refractor 
E) a generator

Question 20

What generally triggers the release of calcium ions by ryanodine receptors?

Accepted Answer

A) potassium efflux 
B) sodium influx 
C) an action potential 
D) IP3 release 
E) IP3 uptake 
A) potassium efflux 
B) sodium influx 
C) an action potential 
D) IP3 release 
E) IP3 uptake

Which of the following signaling methods is absent in plants but present in other eukaryotes?

Which heterotrimeric G proteins function by inhibiting adenylyl cyclase?

Which of the following processes is NOT reported to be regulated by eicosanoids?

Which inorganic gas has been shown to act as a second messenger that relaxes the smooth muscles of blood vessels?

How is signaling by an activated G_α subunit terminated?

Why does calcium not bind to calmodulin in a non-stimulated cell?

Orai1 is a tetrameric _ that has been identified as being involved in a particular type of inherited human immune deficiency that results from a lack of Ca²⁺ stores in __.

How does the immune system manage to avoid recognizing and attacking normal cells within the body?

Why did the smooth muscle in cultured strips of aorta not respond to acetylcholine by relaxing, while the smooth muscle of aortic rings did?

________ are asmall group of proteins that bind to GPCRs and compete for binding to those GPCRs with heterotrimeric G proteins.

What kinds of responses have NOT been observed when signals traveling down signaling pathways reach their target proteins?

Two αβ heterodimers of the insulin receptor are held together by between the ___.

What molecule is responsible for activating Rsk-2?

What holds Ras at the inner surface of the plasma membrane?

Specificity in MAP kinase pathways is sometimes achieved by spatial localization of the pathway's component proteins. Spatial localization of these components is done by structural (i.e., nonenzymatic)proteins called _____________.

Which of the following is NOT generally characteristic of pathways activated by second messengers?

The _________ pathway of apoptosis is one in which internal stimuli activate apoptosis.

What recruits cytoplasmic GRKs (G protein-coupled receptor kinases)to the plasma membrane?

Sometimes an enzyme is activated by a receptor and brings about the cellular response by generating a second messenger. Such an enzyme is called __________.

What generally triggers the release of calcium ions by ryanodine receptors?

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

Bioenergetics, Enzymes and Metabolism

The Structure and Function of the Plasma Membrane

Aerobic Respiration and the Mitochondrion

Photosynthesis and the Chloroplast

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, Function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Gene Expression: From Transcription to Translation

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

Exam 15: Cell Signaling and Signal Transduction: Communication Between Cells

Which of the following signaling methods is absent in plants but present in other eukaryotes?

Which heterotrimeric G proteins function by inhibiting adenylyl cyclase?

Which of the following processes is NOT reported to be regulated by eicosanoids?

Which inorganic gas has been shown to act as a second messenger that relaxes the smooth muscles of blood vessels?

How is signaling by an activated Gα subunit terminated?

Why does calcium not bind to calmodulin in a non-stimulated cell?

Orai1 is a tetrameric _______ that has been identified as being involved in a particular type of inherited human immune deficiency that results from a lack of Ca2+ stores in ________.

How does the immune system manage to avoid recognizing and attacking normal cells within the body?

Why did the smooth muscle in cultured strips of aorta not respond to acetylcholine by relaxing, while the smooth muscle of aortic rings did?

________ are asmall group of proteins that bind to GPCRs and compete for binding to those GPCRs with heterotrimeric G proteins.

What kinds of responses have NOT been observed when signals traveling down signaling pathways reach their target proteins?

Two αβ heterodimers of the insulin receptor are held together by ____ between the _______.

What molecule is responsible for activating Rsk-2?

What holds Ras at the inner surface of the plasma membrane?

Specificity in MAP kinase pathways is sometimes achieved by spatial localization of the pathway's component proteins. Spatial localization of these components is done by structural (i.e., nonenzymatic)proteins called _____________.

Which of the following is NOT generally characteristic of pathways activated by second messengers?

The _________ pathway of apoptosis is one in which internal stimuli activate apoptosis.

What recruits cytoplasmic GRKs (G protein-coupled receptor kinases)to the plasma membrane?

Sometimes an enzyme is activated by a receptor and brings about the cellular response by generating a second messenger. Such an enzyme is called __________.

What generally triggers the release of calcium ions by ryanodine receptors?

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

Bioenergetics, Enzymes and Metabolism

The Structure and Function of the Plasma Membrane

Aerobic Respiration and the Mitochondrion

Photosynthesis and the Chloroplast

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, Function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Gene Expression: From Transcription to Translation

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

How is signaling by an activated G_α subunit terminated?

Orai1 is a tetrameric _ that has been identified as being involved in a particular type of inherited human immune deficiency that results from a lack of Ca²⁺ stores in __.

Two αβ heterodimers of the insulin receptor are held together by between the ___.