Question 1

Which of the following is responsible for the amplification of an intracellular signal?

Accepted Answer

A)  protein phosphatase activity
B)  protein kinase activity
C)  adenylyl cyclase activity
D)  phosphodiesterase activity

Question 2

A bacterium releases a toxin that binds to and activates a G protein-coupled receptor in the mammalian gut. The result is high levels of cAMP in these cells. This toxin might work by:

Accepted Answer

A)  binding to and activating the G protein-coupled receptor in these cells.
B)  binding to and inhibiting the G protein-coupled receptor in these cells.
C)  causing the  subunit of the G protein to stay associated with the  and  subunits.
D)  causing the  subunit of the G protein to bind GDP constantly.
E)  causing adenylyl cyclase to dissociate from the membrane.

Question 3

Communication between neurons is an example of which type of cell signaling?

Accepted Answer

A)  contact-dependent
B)  paracrine
C)  autocrine
D)  endocrine
E)  All of these choices are correct.

Question 4

The extent and duration of a cellular response to a signal depend on the:

Accepted Answer

A)  binding affinity of the receptor to the signaling molecule.
B)  concentration of the signaling molecule in the vicinity of the receptor.
C)  level of expression of the signal transduction proteins.
D)  level of expression of proteins that terminate the response.
E)  All of these choices are correct.

Question 5

Which of the following signaling molecules would you expect to travel the LONGEST distance in the human body?

Accepted Answer

A)  testosterone
B)  Delta
C)  PDGF
D)  neurotransmitters
E)  Notch

Question 6

You are a medical student working in a cancer research laboratory. Your boss has given you samples of cancer cells and blood from a patient. She has told you that the cells have no mutations in any of their signaling molecule proteins (that is, all the proteins are normal) , but that the cells' signaling transduction properties are not normal, causing them to be cancerous. Which of the following could account for the increased cell proliferation in the patient?

Accepted Answer

A)  The cells taken from the patient have more growth factor receptors than normal.
B)  The concentration of a signaling molecule in the patient is higher than usual.
C)  The cells taken from the patient exhibit a reduced level of signal amplification.
D)  None of the other answer options is correct.

Question 7

How does an "activated" receptor transfer information into the cell?

Accepted Answer

A)  by altering the ligand-binding site of the receptor
B)  through a conformational change of the receptor
C)  by decreased phosphorylation of the receptor
D)  by increased translation of the receptor

Question 8

Imagine that a researcher is studying the embryonic development of mice that do not express the signal molecule Delta. What will likely be TRUE of these mice?

Accepted Answer

A)  These mice will have more neurons compared with their normal counterparts.
B)  These mice will have fewer neurons compared with their normal counterparts.
C)  These mice will have more glia compared with their normal counterparts.
D)  The mice will have fewer glia compared with their normal counterparts.
E)  The mice will have fewer neurons and more glia compared with their normal counterparts.

Question 9

Vascular endothelial growth factor (abbreviated VEGF and pronounced "Veg-F")  is a peptide signaling molecule related to platelet-derived growth factor. VEGF is important in the formation of the circulatory system because its signaling pathway causes the formation of blood vessels in developing embryos during normal development. Tumors also produce and secrete VEGF, causing the formation of new blood vessels that supply these tumors. Given what you know about the different kinds of cell signaling and VEGF, which one of the following statements is TRUE?

Accepted Answer

A)  VEGF is an endocrine-signaling molecule because it circulates through the bloodstream inside of platelets.
B)  VEGF is an endocrine-signaling molecule because it is released from platelets into the bloodstream and is carried throughout the body, causing widespread activation of platelet-derived growth factor receptors on cells in a variety of tissues.
C)  VEGF is a paracrine signaling molecule because it binds to receptors on cells at the site where new blood vessels are needed.

Question 10

A researcher is using a small molecule as an inhibitor to manipulate a signaling pathway. This inhibitor prevents phosphorylation and MOST likely targets a:

Accepted Answer

A)  G protein-coupled receptor.
B)  G protein.
C)  receptor kinase.
D)  ligand-gated ion channel.
E)  phosphatase.

Question 11

Ras is most similar to:

Accepted Answer

A)  the alpha subunit of three-subunit G proteins.
B)  the beta subunit of three-subunit G proteins.
C)  the gamma subunit of three-subunit G proteins.
D)  receptor kinases.
E)  ion channels.

Question 12

What determines the specificity of a receptor protein?

Accepted Answer

A)  the cytoplasmic domain
B)  the transmembrane domain
C)  the ligand-binding site
D)  the extracellular domain

Question 13

Many mutations in receptor kinases that lead to cancer allow the receptor to dimerize and become activated, even in the absence of signaling molecules. An example is a mutant form of the EGF receptor kinase called Her2/neu. An antibody that prevents dimerization of Her2/neu receptor kinases is being tested for its effectiveness in preventing cancer. At which stage does this drug work?

Accepted Answer

A)  It prevents the signaling cell from producing the signal.
B)  It prevents the receptor from binding to the signal.
C)  It prevents the receptor from becoming activated.
D)  It prevents the termination of the signal.

Question 14

How are steroid hormone receptors and cell-surface receptors similar?

Accepted Answer

Both types undergo a...

Question 15

Which of the following CORRECTLY lists the types of cellular communication from shortest to longest distance traveled by the signaling molecule to reach its responding cell?

Accepted Answer

A)  paracrine, autocrine, endocrine
B)  autocrine, endocrine, paracrine
C)  autocrine, paracrine, endocrine
D)  endocrine, paracrine, autocrine

Question 16

Second messengers:

Accepted Answer

A)  are small intracellular molecules that participate in signal transduction.
B)  play a role in activation of intracellular signal transduction.
C)  are removed in order to terminate a cellular signaling response.
D)  amplify the effects of the signal.
E)  All of these choices are correct.

Question 17

What does a ligand-gated channel do?

Accepted Answer

A)  It binds small, nonpolar signaling molecules.
B)  It activates a G protein.
C)  It allows ions to move across the plasma membrane.
D)  It triggers the activity of a phosphatase.

Question 18

Cancer is a disease of cell division.

Accepted Answer

A) True 
 B)False

Question 19

Based on the data provided in the two graphs shown in Figure 9.5, which method of culturing resulted in the greatest number of fibroblast cells on day 6?

Accepted Answer

A)  fibroblasts cultured with serum
B)  fibroblasts cultured with platelet proteins
C)  fibroblasts cultured with plasma
D)  The same results are obtained whether the fibroblasts are cultured with serum or with platelet proteins.

Question 20

Many diseases are the result of a problem with cell signaling. Which of the following diseases BEST exemplifies this fact?

Accepted Answer

A)  cystic fibrosis, which is caused by a mutation in a channel protein, resulting in a buildup of mucus
B)  congestive heart failure, which is caused by chronic high blood pressure due to excessive sodium intake
C)  a specific type of cancer, which is caused by a truncated receptor that becomes stuck in the activated for.
D)  familial hypercholesterolemia (high cholesterol in the blood) , which is caused by a decrease in the number of receptors for cholesterol.

Exam 9: Cell Signaling

A bacterium releases a toxin that binds to and activates a G protein-coupled receptor in the mammalian gut. The result is high levels of cAMP in these cells. This toxin might work by:

Correct Answer
verified

The extent and duration of a cellular response to a signal depend on the:

Correct Answer
verified

Imagine that a researcher is studying the embryonic development of mice that do not express the signal molecule Delta. What will likely be TRUE of these mice?

Correct Answer
verified

How does an "activated" receptor transfer information into the cell?

Correct Answer
verified

Correct Answer
verified

Cancer is a disease of cell division.

Correct Answer
verified

What determines the specificity of a receptor protein?

Correct Answer
verified

Many diseases are the result of a problem with cell signaling. Which of the following diseases BEST exemplifies this fact?

Correct Answer
verified

How are steroid hormone receptors and cell-surface receptors similar?

Correct Answer
verified
Both types undergo a...
View Answer

Which of the following is responsible for the amplification of an intracellular signal?

Correct Answer
verified

Based on the data provided in the two graphs shown in Figure 9.5, which method of culturing resulted in the greatest number of fibroblast cells on day 6?

Correct Answer
verified

Ras is most similar to:

Correct Answer
verified

Which of the following CORRECTLY lists the types of cellular communication from shortest to longest distance traveled by the signaling molecule to reach its responding cell?

Correct Answer
verified

What does a ligand-gated channel do?

Correct Answer
verified

Which of the following signaling molecules would you expect to travel the LONGEST distance in the human body?

Correct Answer
verified

Second messengers:

Correct Answer
verified

Correct Answer
verified

Communication between neurons is an example of which type of cell signaling?

Correct Answer
verified

A researcher is using a small molecule as an inhibitor to manipulate a signaling pathway. This inhibitor prevents phosphorylation and MOST likely targets a:

Correct Answer
verified

Correct Answer
verified

Exam 9: Cell Signaling

A bacterium releases a toxin that binds to and activates a G protein-coupled receptor in the mammalian gut. The result is high levels of cAMP in these cells. This toxin might work by:

Correct AnswerverifiedShow Answer

The extent and duration of a cellular response to a signal depend on the:

Correct AnswerverifiedShow Answer

Imagine that a researcher is studying the embryonic development of mice that do not express the signal molecule Delta. What will likely be TRUE of these mice?

Correct AnswerverifiedShow Answer

How does an "activated" receptor transfer information into the cell?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Cancer is a disease of cell division.

Correct AnswerverifiedShow Answer

What determines the specificity of a receptor protein?

Correct AnswerverifiedShow Answer

Many diseases are the result of a problem with cell signaling. Which of the following diseases BEST exemplifies this fact?

Correct AnswerverifiedShow Answer

How are steroid hormone receptors and cell-surface receptors similar?

Correct AnswerverifiedBoth types undergo a...View AnswerShow Answer

Which of the following is responsible for the amplification of an intracellular signal?

Correct AnswerverifiedShow Answer

Based on the data provided in the two graphs shown in Figure 9.5, which method of culturing resulted in the greatest number of fibroblast cells on day 6?

Correct AnswerverifiedShow Answer

Ras is most similar to:

Correct AnswerverifiedShow Answer

Which of the following CORRECTLY lists the types of cellular communication from shortest to longest distance traveled by the signaling molecule to reach its responding cell?

Correct AnswerverifiedShow Answer

What does a ligand-gated channel do?

Correct AnswerverifiedShow Answer

Which of the following signaling molecules would you expect to travel the LONGEST distance in the human body?

Correct AnswerverifiedShow Answer

Second messengers:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Communication between neurons is an example of which type of cell signaling?

Correct AnswerverifiedShow Answer

A researcher is using a small molecule as an inhibitor to manipulate a signaling pathway. This inhibitor prevents phosphorylation and MOST likely targets a:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
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Correct Answer
verified

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
verified

Correct Answer
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Correct Answer
verified
Both types undergo a...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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