Question 1

Receptors can be divided into two general classes according to their cellular location: _______ receptors and _______ receptors.

Accepted Answer

A)  intracellular; membrane 
B)  membrane; protein kinase 
C)  ion channel; intracellular 
D)  G protein-coupled; intracellular 
E)  membrane; ion channel 
A)  intracellular; membrane 
B)  membrane; protein kinase 
C)  ion channel; intracellular 
D)  G protein-coupled; intracellular 
E)  membrane; ion channel

Question 2

How does a protein kinase cascade amplify an intracellular signal?

Accepted Answer

A)  It opens gap junctions, allowing the signal to spread to other cells. 
B)  The activated G protein in the cascade binds and activates a second protein, amplifying the signal. 
C)  Nitric oxide in the cascade opens gap junctions, allowing protein kinase molecules to move quickly from cell to cell. 
D)  Second messengers in the cascade create shortcuts that create multiple cascades. 
E)  Activation of the protein kinase receptors can trigger the activation of many other proteins. 
A)  It opens gap junctions, allowing the signal to spread to other cells. 
B)  The activated G protein in the cascade binds and activates a second protein, amplifying the signal. 
C)  Nitric oxide in the cascade opens gap junctions, allowing protein kinase molecules to move quickly from cell to cell. 
D)  Second messengers in the cascade create shortcuts that create multiple cascades. 
E)  Activation of the protein kinase receptors can trigger the activation of many other proteins.

Question 3

Refer to the figure below.   The figure illustrates how an external chemical signal can alter _______ in a cell.

Accepted Answer

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

Question 4

The reversibility of ligand‒receptor binding

Accepted Answer

A)  ensures that the ligands are not metabolized. 
B)  maintains the specificity of the receptor. 
C)  prevents the receptor from being continuously stimulated. 
D)  initiates a cellular response. 
E)  controls the number of ligand‒receptor interactions. 
A)  ensures that the ligands are not metabolized. 
B)  maintains the specificity of the receptor. 
C)  prevents the receptor from being continuously stimulated. 
D)  initiates a cellular response. 
E)  controls the number of ligand‒receptor interactions.

Question 5

The concentration of cAMP in a cell is usually increased by activity of

Accepted Answer

A)  phosphodiesterase. 
B)  cGMP. 
C)  a protein kinase. 
D)  a second messenger. 
E)  adenylyl cyclase. 
A)  phosphodiesterase. 
B)  cGMP. 
C)  a protein kinase. 
D)  a second messenger. 
E)  adenylyl cyclase.

Question 6

Refer to the figure showing an insulin receptor.   The insulin receptor in the figure shown is considered to be which receptor type?

Accepted Answer

A)  Ion channel 
B)  Protein kinase receptor 
C)  G protein-coupled receptor 
D)  Cytoplasmic receptor 
E)  Nonpolar signal receptor 
A)  Ion channel 
B)  Protein kinase receptor 
C)  G protein-coupled receptor 
D)  Cytoplasmic receptor 
E)  Nonpolar signal receptor

Question 7

After a signal arrives at a target cell, the next step in a signal transduction pathway involves

Accepted Answer

A)  receptor binding. 
B)  hormone activation. 
C)  signal transcription. 
D)  signal regulation. 
E)  enzyme activation. 
A)  receptor binding. 
B)  hormone activation. 
C)  signal transcription. 
D)  signal regulation. 
E)  enzyme activation.

Question 8

Which statement about cyclic AMP is false?

Accepted Answer

A)  It has targets in multiple transduction pathways. 
B)  The enzyme adenylyl cyclase catalyzes its formation. 
C)  It is produced from ATP. 
D)  It is a second messenger. 
E)  It possesses enzymatic activity. 
A)  It has targets in multiple transduction pathways. 
B)  The enzyme adenylyl cyclase catalyzes its formation. 
C)  It is produced from ATP. 
D)  It is a second messenger. 
E)  It possesses enzymatic activity.

Question 9

The entire cell signaling process is known as a signal _______ pathway.

Accepted Answer

The answer of The entire cell signaling process is known...

Question 10

Oxytocin stimulates a G protein-coupled signal transduction pathway.During signal transduction in this pathway, a G protein becomes activated.Which three molecules does G protein interact with in this pathway?

Accepted Answer

A)  Ligand, GDP, and GTP 
B)  G protein-coupled receptor, ATP, and enzyme 
C)  Hormone, G protein-linked receptor, and GTP 
D)  G protein-linked receptor, GTP, and effector protein 
E)  GTP, cytoplasmic receptor, and transcription factor 
A)  Ligand, GDP, and GTP 
B)  G protein-coupled receptor, ATP, and enzyme 
C)  Hormone, G protein-linked receptor, and GTP 
D)  G protein-linked receptor, GTP, and effector protein 
E)  GTP, cytoplasmic receptor, and transcription factor

Question 11

Intracellular receptors

Accepted Answer

A)  bind large proteins that diffuse through the cell membrane. 
B)  are located in the cytoplasm or the nucleus. 
C)  can be chaperone proteins. 
D)  cause their ligands to change shape. 
E)  bind to G proteins. 
A)  bind large proteins that diffuse through the cell membrane. 
B)  are located in the cytoplasm or the nucleus. 
C)  can be chaperone proteins. 
D)  cause their ligands to change shape. 
E)  bind to G proteins.

Question 12

Refer to the table below.   A pharmaceutical company is developing five new drugs to act as antagonists with respect to five different receptor proteins.Listed in the table are dissociation constants for ligand and drug in each case.In which case will the dosage of drug necessary to achieve a biological effect be the smallest?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E

Question 13

Which statement about protein kinase cascades is true?

Accepted Answer

A)  Signal amplification occurs only at the initial step in the pathway. 
B)  Information received as a signal at the cell membrane can be communicated to the nucleus. 
C)  Only the first step allows for the specificity of the process. 
D)  The proteins involved in these pathways are generally not subject to regulation. 
E)  These pathways function without second-messenger intermediates. 
A)  Signal amplification occurs only at the initial step in the pathway. 
B)  Information received as a signal at the cell membrane can be communicated to the nucleus. 
C)  Only the first step allows for the specificity of the process. 
D)  The proteins involved in these pathways are generally not subject to regulation. 
E)  These pathways function without second-messenger intermediates.

Question 14

Refer to the table below.   The table shows dissociation constants for the binding of glycine to its membrane receptor in three cell lines.The cell lines differ only in the gene for the receptor protein.Normal cells contain no mutation in this gene, while mutants 1 and 2 contain mutations at different sites in this gene.The cell lines placed in increasing order of affinity for glycine are mutant 1 first, then normal, and _______ last.

Accepted Answer

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

Question 15

During an investigation, researchers worked with mouse cells cultured in artificial media in dishes.The researchers found that mutant cells could not survive in a particular type of growth medium because they lacked the ability to synthesize a molecule critical for survival.Which investigation could be done to test whether intercellular transport could provide this molecule to cells?

Accepted Answer

A)  Use electron microscopy to look for gap junctions between cells. 
B)  Measure the rate of radiolabeled molecule uptake by normal cells. 
C)  Test the survival rate of mutant cells when incubated with normal cells. 
D)  Test the ability of mutant cells to synthesize the molecule when incubated with normal cells. 
E)  Measure the size of the needed molecule to determine whether it could be transported between cells through gap junctions. 
A)  Use electron microscopy to look for gap junctions between cells. 
B)  Measure the rate of radiolabeled molecule uptake by normal cells. 
C)  Test the survival rate of mutant cells when incubated with normal cells. 
D)  Test the ability of mutant cells to synthesize the molecule when incubated with normal cells. 
E)  Measure the size of the needed molecule to determine whether it could be transported between cells through gap junctions.

Question 16

Refer to the figure below.   The figure shows a signal transduction pathway in a cell.How does adenylyl cyclase become activated so that it can relay the signal during a signal transduction event in this particular pathway?

Accepted Answer

A)  It becomes phosphorylated. 
B)  It becomes dephosphorylated. 
C)  It binds ATP. 
D)  It changes conformation. 
E)  It is hydrolyzed. 
A)  It becomes phosphorylated. 
B)  It becomes dephosphorylated. 
C)  It binds ATP. 
D)  It changes conformation. 
E)  It is hydrolyzed.

Question 17

In the signal cascade triggered by epinephrine within liver cells, glycogen synthase is

Accepted Answer

A)  inactivated and does not produce glycogen. 
B)  activated and binds to glucose. 
C)  inactivated and produces glycogen. 
D)  activated by protein kinase A. 
E)  activated by cyclic AMP. 
A)  inactivated and does not produce glycogen. 
B)  activated and binds to glucose. 
C)  inactivated and produces glycogen. 
D)  activated by protein kinase A. 
E)  activated by cyclic AMP.

Question 18

A mutation in the thyroid-stimulating hormone receptor (TSH receptor) results in a change in the behavior of the receptor toward its ligand, thyroid-stimulating hormone (TSH).Explain what measuring the TSH dissociation constant, KD, will reveal about this behavior, and explain how a change in this value will affect cells that have this receptor embedded in their cell membranes.

Accepted Answer

Measuring the K_D will reveal any changes

Question 19

Refer to the table below.   The table lists three ways that a cell might respond to an external chemical signal.What are the cell components labeled A, B, and C?

Accepted Answer

A)  A = ion channels, B = transcription factors, C = cellular enzymes 
B)  A = cellular enzymes, B = transcription factors, C = ion channels 
C)  A = transcription factors, B = cellular enzymes, C = ion channels 
D)  A = ion channels, B = cellular enzymes, C = transcription factors 
E)  A = transcription factors, B = ion channels, C = cellular enzymes 
A)  A = ion channels, B = transcription factors, C = cellular enzymes 
B)  A = cellular enzymes, B = transcription factors, C = ion channels 
C)  A = transcription factors, B = cellular enzymes, C = ion channels 
D)  A = ion channels, B = cellular enzymes, C = transcription factors 
E)  A = transcription factors, B = ion channels, C = cellular enzymes

Question 20

A(n) _______ binds to a receptor in place of a ligand and prevents stimulation of the signal transduction pathway.

Accepted Answer

The answer of A(n) _______ binds to a receptor in...

Exam 7: Cell Communication and Multicellularity

Receptors can be divided into two general classes according to their cellular location: _______ receptors and _______ receptors.

How does a protein kinase cascade amplify an intracellular signal?

Refer to the figure below. The figure illustrates how an external chemical signal can alter _______ in a cell.

The reversibility of ligand‒receptor binding

The concentration of cAMP in a cell is usually increased by activity of

Refer to the figure showing an insulin receptor. The insulin receptor in the figure shown is considered to be which receptor type?

After a signal arrives at a target cell, the next step in a signal transduction pathway involves

Which statement about cyclic AMP is false?

The entire cell signaling process is known as a signal _______ pathway.

Oxytocin stimulates a G protein-coupled signal transduction pathway.During signal transduction in this pathway, a G protein becomes activated.Which three molecules does G protein interact with in this pathway?

Intracellular receptors

Which statement about protein kinase cascades is true?

Refer to the figure below. The figure shows a signal transduction pathway in a cell.How does adenylyl cyclase become activated so that it can relay the signal during a signal transduction event in this particular pathway?

In the signal cascade triggered by epinephrine within liver cells, glycogen synthase is

Refer to the table below. The table lists three ways that a cell might respond to an external chemical signal.What are the cell components labeled A, B, and C?

A(n) _______ binds to a receptor in place of a ligand and prevents stimulation of the signal transduction pathway.

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

Receptors can be divided into two general classes according to their cellular location: _ receptors and _ receptors.