Question 1

Adjacent cells can signal others by direct contact,while nearby cells that are not touching can communicate by the release of __________ signals.

Accepted Answer

A)  autocrine
B)  neurosecretory
C)  peptide
D)  paracrineE) B) and C)
F) C) and D)

Question 2

The space into which neurotransmitters are released is called a chemical

Accepted Answer

A)  synapse.
B)  junction.
C)  channel.
D)  desmosome.
E)  vesiclE.F) B) and D)
G) A) and E)

Question 3

A team of researchers at a pesticide company are working produce a new rodent poison to address a growing problem of rat infestations at an old waterfront warehouse.The researchers are developing a poison that will cause the junctions between intestinal cells to break down.The poison will be incorporated into grain and left where the rodents will feed on it.Which of the following describes the most likely effect of this poison?

Accepted Answer

A)  The gap junctions will break down resulting in leaks in the digestive tract.
B)  The tight junctions will break down resulting in leaks in the digestive tract.
C)  The gap junctions will break down and interfere with absorption of nutrients.
D)  The tight junctions will break down and interfere with absorption of nutrients.E) A) and C)
F) C) and D)

Question 4

Protein kinases,enzymes which add phosphate groups to proteins,are an example of ______________ receptors.

Accepted Answer

A)  enzymatic
B)  extracellular
C)  phosphogenic
D)  ATPE) A) and B)
F) B) and C)

Question 5

You are studying the effect of a secreted signal molecule on the activity of a cytoplasmic enzyme.Prior studies have shown the signal molecule is required for enzyme activity.You add the signal molecule to a test tube solution containing both the enzyme and its substrate.After incubating the solution,you assay for the reaction product as a measure of enzyme activity,however,no product was detected.By comparison,when you add the signal molecule to a vial containing intact cells,you are able to detect the reaction product.Which of the following statements is inconsistent with these experimental results?

Accepted Answer

A)  The cells express a receptor for the signal molecule.
B)  There is no direct interaction between the signal molecule and enzyme.
C)  The cells facilitate a direct protein-protein interaction between the signal molecule and enzyme.
D)  Binding of the signal molecule to its receptor initiates a signal transduction pathway leading to enzymatic activity.E) A) and B)
F) B) and C)

Question 6

You are performing an experiment to assay phosphorylation of a substrate by a protein kinase.Based on the data in the table below,what do these experimental results suggest?

Accepted Answer

A)  GTP is not required for phosphorylation.
B)  The substrate can undergo autophosphorylation.
C)  The substrate is not required for phosphorylation.
D)  The protein kinase is required for phosphorylation.E) B) and D)
F) All of the above

Question 7

You are having lunch with an elderly friend when suddenly he begins to experience chest pain and tightness.He reaches into his pocket,gets out one of his nitroglycerin tablets and quickly takes it.After the episode passes,your friend asks you how the nitroglycerin helps his angina.You explain that nitroglycerin gets converted by cells to NO causing the smooth muscle cells of the blood vessel to relax and increase blood flow to the heart.He pushes you for a more detailed explanation,so you explain further that

Accepted Answer

A)  NO activates guanylyl cyclase,which catalyzes the synthesis of cGMP,which acts as an intracellular messenger in a pathway leading to smooth muscle relaxation.
B)  NO activates a protein kinase which catalyzes the synthesis of cGMP,which acts as an intracellular messenger in a pathway leading to smooth muscle relaxation.
C)  NO inhibits guanylyl cyclase,which allows the build up of cGMP,which acts as an intracellular messenger in a pathway leading to smooth muscle relaxation.
D)  NO activates cGMP,which catalyzes the synthesis of guanylyl cyclase,which acts as an intracellular messenger in a pathway leading to smooth muscle relaxation.E) C) and D)
F) A) and D)

Question 8

Vasopressin is a hormone that is primarily released when the body is low on water.Release of vasopressin causes the kidneys to conserve water by concentrating urine and decreasing urine output.However,vasopressin also has additional functions in other tissues such as the brain and blood vessels,which are not directly involved in urine production.How could it be possible for vasopressin to trigger different responses in different tissues?

Accepted Answer

A)  Vasopressin can bind to,and act on,different receptor subtypes,leading to different cellular responses in different tissues.
B)  Vasopressin can be released at different times to result in different effects.
C)  Because vasopressin is a hormone,it can be sent to specific regions of the body leading to specific effects.D) None of the above
E) A) and C)

Question 9

A small number of surface receptors can ultimately generate a large intracellular response,as each step of the pathway is often expanded by signal _________.

Accepted Answer

A)  amplification
B)  transduction
C)  dampening
D)  splittingE) None of the above
F) All of the above

Question 10

Which of following statements about G proteins associated with G-protein-coupled receptors is false?

Accepted Answer

A)  G proteins provide a link between the receptor and effector protein.
B)  G proteins can propagate the signal by either the G α\alphaα or the G β\betaβ  γ\gammaγ components.
C)  G proteins are heterotrimeriC.
D)  Associated G proteins become active by exchanging GTP for GDP.
E)  Activated G protein diffuses away from the receptor. F) D) and E)
G) B) and E)

Question 11

Your research project involves the characterization of a particular signal transduction pathway.Specifically,you have been studying a receptor tyrosine kinase and protein X,which initiates downstream events.You are certain that protein X is part of the signal transduction pathway,but have been unable to identify a direct protein-protein interaction between the receptor tyrosine kinase and the protein X.What should you do next?

Accepted Answer

A)  Try to identify a coactivator protein.
B)  Try to identify proteins that act downstream of protein X.
C)  Try to identify an adapter protein that can interact with both the receptor and protein X.
D)  Confirm the interaction between the receptor tyrosine kinase and its signal molecule.E) None of the above
F) C) and D)

Question 12

___________ among cells is a hallmark of multicellular organisms.

Accepted Answer

A)  Communication
B)  Transport
C)  Linkage
D)  IdentityE) A) and B)
F) B) and C)

Question 13

A researcher is trying to produce a new cancer drug to be tested on small tumors.The tumor has to be localized in a small area of the body and cannot have metastasized (spread to other areas of the body) .Furthermore,this drug must prohibit the signaling from one tumor cell to another tumor cell.Given the above information,this new drug will prohibit

Accepted Answer

A)  direct physical contact between tumor cells.
B)  autocrine signaling between tumor cells.
C)  paracrine signaling between tumor cells.
D)  endocrine signalizing between tumor cells.E) All of the above
F) None of the above

Question 14

Located on or within the cell are _________ proteins,each of which has a three dimensional shape complementary to that of a specific signal molecule.

Accepted Answer

A)  amplification
B)  monoclonal
C)  transmembranal
D)  receptor
E)  messengerF) A) and E)
G) C) and E)

Question 15

What characteristics do all cell surface receptors share?

Accepted Answer

A)  They are composed of hydrophilic proteins.
B)  They all must bind to a molecule to be activated.
C)  They all result in creation of an ion channel.
D)  They include the activation of a G protein.E) A) and B)
F) A) and D)

Question 16

Most cells are in physical contact with other cells at all times by forming permanent connections called

Accepted Answer

A)  cell junctions.
B)  gated ion channels.
C)  enzymatic receptors.
D)  G-protein-coupled receptors.
E)  cell surface markers.F) C) and E)
G) B) and E)

Question 17

The class of cell surface receptors that acts indirectly on plasma membrane-bound enzymes or ion channels is called

Accepted Answer

A)  G-protein-coupled receptors.
B)  gated ion channels.
C)  enzymatic receptors.
D)  second messenger receptors.E) B) and C)
F) All of the above

Exam 9: Cell Communication

Adjacent cells can signal others by direct contact,while nearby cells that are not touching can communicate by the release of __________ signals.

Correct Answer
verified

Located on or within the cell are _________ proteins,each of which has a three dimensional shape complementary to that of a specific signal molecule.

Correct Answer
verified

The class of cell surface receptors that acts indirectly on plasma membrane-bound enzymes or ion channels is called

Correct Answer
verified

Correct Answer
verified

Most cells are in physical contact with other cells at all times by forming permanent connections called

Correct Answer
verified

Correct Answer
verified

Protein kinases,enzymes which add phosphate groups to proteins,are an example of ______________ receptors.

Correct Answer
verified

Correct Answer
verified

The space into which neurotransmitters are released is called a chemical

Correct Answer
verified

You are performing an experiment to assay phosphorylation of a substrate by a protein kinase.Based on the data in the table below,what do these experimental results suggest?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Which of following statements about G proteins associated with G-protein-coupled receptors is false?

Correct Answer
verified

___________ among cells is a hallmark of multicellular organisms.

Correct Answer
verified

A small number of surface receptors can ultimately generate a large intracellular response,as each step of the pathway is often expanded by signal _________.

Correct Answer
verified

What characteristics do all cell surface receptors share?

Correct Answer
verified

Correct Answer
verified

Exam 9: Cell Communication

Adjacent cells can signal others by direct contact,while nearby cells that are not touching can communicate by the release of __________ signals.

Correct AnswerverifiedShow Answer

Located on or within the cell are _________ proteins,each of which has a three dimensional shape complementary to that of a specific signal molecule.

Correct AnswerverifiedShow Answer

The class of cell surface receptors that acts indirectly on plasma membrane-bound enzymes or ion channels is called

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Most cells are in physical contact with other cells at all times by forming permanent connections called

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Protein kinases,enzymes which add phosphate groups to proteins,are an example of ______________ receptors.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The space into which neurotransmitters are released is called a chemical

Correct AnswerverifiedShow Answer

You are performing an experiment to assay phosphorylation of a substrate by a protein kinase.Based on the data in the table below,what do these experimental results suggest?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which of following statements about G proteins associated with G-protein-coupled receptors is false?

Correct AnswerverifiedShow Answer

___________ among cells is a hallmark of multicellular organisms.

Correct AnswerverifiedShow Answer

A small number of surface receptors can ultimately generate a large intracellular response,as each step of the pathway is often expanded by signal _________.

Correct AnswerverifiedShow Answer

What characteristics do all cell surface receptors share?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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Correct Answer
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