Question 1

Which gives the correct order from lowest to highest number of molecules activated by a single molecule of epinephrine in liver cells?

Accepted Answer

A)  cAMP, protein kinase A, phosphorylase kinase, glycogen phosphorylase 
B)  Glycogen phosphorylase, phosphorylase kinase, protein kinase A, cAMP 
C)  cAMP, phosphorylase kinase, glycogen phosphorylase, protein kinase A 
D)  Glycogen phosphorylase, cAMP, protein kinase A, phosphorylase kinase 
E)  Phosphorylase kinase, glycogen phosphorylase, cAMP, protein kinase A 
A)  cAMP, protein kinase A, phosphorylase kinase, glycogen phosphorylase 
B)  Glycogen phosphorylase, phosphorylase kinase, protein kinase A, cAMP 
C)  cAMP, phosphorylase kinase, glycogen phosphorylase, protein kinase A 
D)  Glycogen phosphorylase, cAMP, protein kinase A, phosphorylase kinase 
E)  Phosphorylase kinase, glycogen phosphorylase, cAMP, protein kinase A

Question 2

In the signal cascade triggered by epinephrine in liver cells, glycogen phosphorylase is

Accepted Answer

A)  inactivated and binds to glucose. 
B)  activated and releases glucose. 
C)  inactivated and produces glycogen. 
D)  inactivated by protein kinase A. 
E)  activated by cyclic AMP. 
A)  inactivated and binds to glucose. 
B)  activated and releases glucose. 
C)  inactivated and produces glycogen. 
D)  inactivated by protein kinase A. 
E)  activated by cyclic AMP.

Question 3

Which sequence lists signaling types in order of increasing distance between signal cells and target cells?

Accepted Answer

A)  Autocrine, paracrine, juxtacrine, hormone 
B)  Juxtacrine, autocrine, paracrine, hormone 
C)  Paracrine, juxtacrine, hormone, autocrine 
D)  Autocrine, juxtacrine, paracrine, hormone 
E)  Juxtacrine, autocrine, hormone, paracrine 
A)  Autocrine, paracrine, juxtacrine, hormone 
B)  Juxtacrine, autocrine, paracrine, hormone 
C)  Paracrine, juxtacrine, hormone, autocrine 
D)  Autocrine, juxtacrine, paracrine, hormone 
E)  Juxtacrine, autocrine, hormone, paracrine

Question 4

A researcher finds that mouse kidney cells and mouse muscle cells both use cAMP as a second messenger in two different signal transduction pathways that result in different cellular responses.Which other condition related to these two pathways would be expected in these cells?

Accepted Answer

A)  Both cells have the same cell surface receptor for the two pathways. 
B)  One cell has a cell surface receptor and the other has an intracellular receptor for these pathways. 
C)  Both pathways in the two cells have the same target protein whose activity changes when it binds cAMP. 
D)  Both cell types express the adenylate cyclase gene. 
E)  One pathway involves cAMP inhibition of a target protein, while the other pathway involves cAMP activation of a target protein. 
A)  Both cells have the same cell surface receptor for the two pathways. 
B)  One cell has a cell surface receptor and the other has an intracellular receptor for these pathways. 
C)  Both pathways in the two cells have the same target protein whose activity changes when it binds cAMP. 
D)  Both cell types express the adenylate cyclase gene. 
E)  One pathway involves cAMP inhibition of a target protein, while the other pathway involves cAMP activation of a target protein.

Question 5

Cells can regulate the cellular response to a transducer by all of the following except

Accepted Answer

A)  decreasing the extracellular concentration of calcium. 
B)  inhibiting phosphodiesterase. 
C)  increasing the rate of nitric oxide synthesis. 
D)  synthesizing adenylyl cyclase. 
E)  increasing the concentration of cAMP. 
A)  decreasing the extracellular concentration of calcium. 
B)  inhibiting phosphodiesterase. 
C)  increasing the rate of nitric oxide synthesis. 
D)  synthesizing adenylyl cyclase. 
E)  increasing the concentration of cAMP.

Question 6

Cells use different mechanisms to respond to external signals.One mechanism uses ion channels that respond by opening or closing.Another mechanism uses transcription factors that respond by turning on or turning off the expression of genes.A third mechanism uses _______ that respond by altering the rate of chemical reactions in the cell.

Accepted Answer

The answer of Cells use different mechanisms to respond to...

Question 7

A protein kinase cascade can amplify an intracellular signal by

Accepted Answer

A)  opening gap junctions to allow diffusion of signals from neighboring cells. 
B)  activating a G protein, which then binds and activates a second protein, amplifying the signal. 
C)  using nitric oxide to quickly diffuse into cells, amplifying the response. 
D)  using transcription factors to increase gene expression. 
E)  activating one kinase molecule that can then trigger the activation of many proteins. 
A)  opening gap junctions to allow diffusion of signals from neighboring cells. 
B)  activating a G protein, which then binds and activates a second protein, amplifying the signal. 
C)  using nitric oxide to quickly diffuse into cells, amplifying the response. 
D)  using transcription factors to increase gene expression. 
E)  activating one kinase molecule that can then trigger the activation of many proteins.

Question 8

Refer to the figure below, which illustrates a signal transduction pathway involving a G protein-coupled receptor and the two second messengers IP3 and DAG.   Lithium inhibits this pathway in two places.As a result, calcium ion levels within the cytoplasm stay low and there are lower levels of active phospholipase C.Based on this information and the figure shown, what are the two most likely places that lithium will block the pathway?

Accepted Answer

A)  G protein activation and protein kinase C activation 
B)  Receptor activation and protein kinase C activation 
C)  Hormone binding and PIP2 hydrolysis 
D)  G protein activation and IP3 formation 
E)  Phospholipase C activation and protein kinase C activation 
A)  G protein activation and protein kinase C activation 
B)  Receptor activation and protein kinase C activation 
C)  Hormone binding and PIP2 hydrolysis 
D)  G protein activation and IP3 formation 
E)  Phospholipase C activation and protein kinase C activation

Question 9

Which statement about the abnormal form of the ras protein found in some cancer cells is true?

Accepted Answer

A)  Because it is inactive, it is unable to inhibit growth factors. 
B)  It is always active because it is continuously bound to GTP. 
C)  If it were inhibited, cells would continue to divide. 
D)  It acts as an ion channel receptor. 
E)  It directly stimulates epinephrine production. 
A)  Because it is inactive, it is unable to inhibit growth factors. 
B)  It is always active because it is continuously bound to GTP. 
C)  If it were inhibited, cells would continue to divide. 
D)  It acts as an ion channel receptor. 
E)  It directly stimulates epinephrine production.

Question 10

Which statement about intracellular receptors is false?

Accepted Answer

A)  They may respond to light. 
B)  Some are transcription factors. 
C)  Their ligands are usually hydrophilic. 
D)  They may be bound to chaperone proteins. 
E)  They may move into the nucleus. 
A)  They may respond to light. 
B)  Some are transcription factors. 
C)  Their ligands are usually hydrophilic. 
D)  They may be bound to chaperone proteins. 
E)  They may move into the nucleus.

Question 11

The specific term for a signal that is made by a cell and that diffuses to and affects a nearby cell is a(n)

Accepted Answer

A)  peptide signal. 
B)  hormone. 
C)  autocrine signal. 
D)  paracrine signal. 
E)  juxtacrine signal. 
A)  peptide signal. 
B)  hormone. 
C)  autocrine signal. 
D)  paracrine signal. 
E)  juxtacrine signal.

Question 12

A researcher has isolated a protein produced by a snail and thought to be an intercellular chemical signaling agent.The researcher will incubate this agent with snail cells to test whether a specific cellular response occurs.What control should be run at the same time?

Accepted Answer

A)  Incubate normal snail cells with a solution that does not contain the signal protein. 
B)  Incubate normal snail cells with a solution containing signal protein that has been chemically altered. 
C)  Incubate normal snail cells with a solution that contains a signal protein other than the one being investigated. 
D)  Incubate mutant snail cells known to be incapable of the cellular response with the signal protein. 
E)  Incubate mutant snail cells that constantly carry out the cellular response with the signal protein. 
A)  Incubate normal snail cells with a solution that does not contain the signal protein. 
B)  Incubate normal snail cells with a solution containing signal protein that has been chemically altered. 
C)  Incubate normal snail cells with a solution that contains a signal protein other than the one being investigated. 
D)  Incubate mutant snail cells known to be incapable of the cellular response with the signal protein. 
E)  Incubate mutant snail cells that constantly carry out the cellular response with the signal protein.

Question 13

A protein that changes the expression of a gene is called a(n) _______ factor.

Accepted Answer

The answer of A protein that changes the expression of...

Question 14

Refer to the figure below.   The figure illustrates how a(n) _______ responds to an external chemical signal.

Accepted Answer

The answer of Refer to the figure below.  ...

Question 15

Which molecule acts as a second messenger in the cascade by which epinephrine stimulates the activation of the enzyme glycogen phosphorylase?

Accepted Answer

A)  Adenosine 
B)  Caffeine 
C)  Citric acid 
D)  Cyclic AMP 
E)  Adenylyl cyclase 
A)  Adenosine 
B)  Caffeine 
C)  Citric acid 
D)  Cyclic AMP 
E)  Adenylyl cyclase

Question 16

Refer to the figure below.   The figure shows a signal transduction pathway that is stimulated by the binding of a growth factor to a cell membrane receptor.The structure labeled A and then B in the figure is a _______ that stimulates gene expression during the cellular response.

Accepted Answer

transcript

Question 17

When a G protein is activated in a signal transduction pathway,

Accepted Answer

A)  GDP is released from the G protein, and GTP occupies the nucleotide-binding site. 
B)  GTP is released from the G protein, and GDP occupies the nucleotide-binding site. 
C)  cGMP occupies the otherwise empty nucleotide-binding site on the G protein. 
D)  cGMP leaves the otherwise occupied nucleotide-binding site on the G protein. 
E)  GDP causes a conformational change in the G protein. 
A)  GDP is released from the G protein, and GTP occupies the nucleotide-binding site. 
B)  GTP is released from the G protein, and GDP occupies the nucleotide-binding site. 
C)  cGMP occupies the otherwise empty nucleotide-binding site on the G protein. 
D)  cGMP leaves the otherwise occupied nucleotide-binding site on the G protein. 
E)  GDP causes a conformational change in the G protein.

Question 18

The dissociation constant, KD, is

Accepted Answer

A)  the rate at which a ligand binds its receptors. 
B)  the rate at which a ligand unbinds from its receptors. 
C)  a measure of the affinity of the receptor for its ligand. 
D)  lower when receptor-ligand binding requires high ligand concentrations. 
E)  a measure of the ligand concentration. 
A)  the rate at which a ligand binds its receptors. 
B)  the rate at which a ligand unbinds from its receptors. 
C)  a measure of the affinity of the receptor for its ligand. 
D)  lower when receptor-ligand binding requires high ligand concentrations. 
E)  a measure of the ligand concentration.

Question 19

Signals that diffuse to and affect nearby cells are known as _______ signals.

Accepted Answer

The answer of Signals that diffuse to and affect nearby...

Question 20

The three ways that a cell might respond to an external chemical signal include F1F1F1S1F1F1F10F1F1F1S1F1F1F10Changes in gene expression
F1F1F1S1F1F1F10F1F1F1S1F1F1F10Ion channel opening/closing
F1F1F1S1F1F1F10F1F1F1S1F1F1F10Enzyme activation/deactivation
Which general features of these three response mechanisms is most varied?

Accepted Answer

A)  Specificity of response 
B)  Sensitivity of response 
C)  Speed of response 
D)  Ability to be regulated 
E)  Ability to change via genetic mutation 
A)  Specificity of response 
B)  Sensitivity of response 
C)  Speed of response 
D)  Ability to be regulated 
E)  Ability to change via genetic mutation

Exam 7: Cell Communication and Multicellularity

Which gives the correct order from lowest to highest number of molecules activated by a single molecule of epinephrine in liver cells?

In the signal cascade triggered by epinephrine in liver cells, glycogen phosphorylase is

Which sequence lists signaling types in order of increasing distance between signal cells and target cells?

A researcher finds that mouse kidney cells and mouse muscle cells both use cAMP as a second messenger in two different signal transduction pathways that result in different cellular responses.Which other condition related to these two pathways would be expected in these cells?

Cells can regulate the cellular response to a transducer by all of the following except

A protein kinase cascade can amplify an intracellular signal by

Which statement about the abnormal form of the ras protein found in some cancer cells is true?

Which statement about intracellular receptors is false?

The specific term for a signal that is made by a cell and that diffuses to and affects a nearby cell is a(n)

A researcher has isolated a protein produced by a snail and thought to be an intercellular chemical signaling agent.The researcher will incubate this agent with snail cells to test whether a specific cellular response occurs.What control should be run at the same time?

A protein that changes the expression of a gene is called a(n) _______ factor.

Refer to the figure below. The figure illustrates how a(n) _______ responds to an external chemical signal.

Which molecule acts as a second messenger in the cascade by which epinephrine stimulates the activation of the enzyme glycogen phosphorylase?

Refer to the figure below. The figure shows a signal transduction pathway that is stimulated by the binding of a growth factor to a cell membrane receptor.The structure labeled A and then B in the figure is a _______ that stimulates gene expression during the cellular response.

When a G protein is activated in a signal transduction pathway,

The dissociation constant, KD, is

Signals that diffuse to and affect nearby cells are known as _______ signals.

The three ways that a cell might respond to an external chemical signal include Changes in gene expression Ion channel opening/closing Enzyme activation/deactivation Which general features of these three response mechanisms is most varied?

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Animal Development

Neurons, Glia, and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Functions

Musculoskeletal Systems

Gas Exchange

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen Excretion

Animal Behavior

The Physical Environment and Biogeography of Life

Populations

Species Interactions

Communities

Ecosystems

A Changing Biosphere

Filters

The dissociation constant, K_D, is