Question 1

All catecholamine- secreting cells synthesize dopamine.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following statements is true for the nervous system but NOT the endocrine system?

Accepted Answer

A)  A messenger is transported in the bloodstream.
B)  Effector organs are scattered throughout the body.
C)  There is a special anatomical arrangement between the secretory cell and the target cell.
D)  Communication occurs over long distances.
E)  A messenger communicates to target cells by binding to specific receptors.F) C) and D)
G) B) and E)

Question 3

Catecholamines, such as dopamine, norepinephrine, and epinephrine, are derived from the amino acid

Accepted Answer

A)  leucine.
B)  glycine.
C)  isoleucine.
D)  tyrosine.
E)  glutamate.F) B) and C)
G) C) and E)

Question 4

Which of the following enzymes catalyzes phosphorylation of a protein?

Accepted Answer

A)  adenylate cyclase
B)  tyrosine kinase
C)  phosphodiesterase
D)  phospholipase A2
E)  tyrosine fi- hydroxylaseF) A) and B)
G) A) and C)

Question 5

Describe the factors that affect the magnitude of a target cell's response. Assume that there is a receptor on the cell for the ligand.

Accepted Answer

The first factor that affects a target c...

Question 6

When the alpha subunit of the G protein is activated, it can stimulate ion channels to do what?

Accepted Answer

A)  open only
B)  either open or close
C)  degrade
D)  close only
E)  alter the ion that travels through the channelF) All of the above
G) A) and B)

Question 7

An amplifier enzyme catalyzes the synthesis of a second messenger.

Accepted Answer

A) True 
 B)False

Question 8

Androgens are precursor molecules for the synthesis of

Accepted Answer

A)  cortisol.
B)  cholesterol.
C)  progesterone.
D)  estradiol.
E)  aldosterone.F) B) and C)
G) A) and E)

Question 9

Direct communication between cells in contact with one another is accomplished through

Accepted Answer

A)  paracrine chemical messengers.
B)  endocrine hormones.
C)  gap junctions.
D)  receptors.
E)  ligands.F) B) and D)
G) C) and E)

Question 10

Which of the following will NOT affect the magnitude of a cell's response to a specific hydrophilic ligand?

Accepted Answer

A)  lipid solubility of the ligand
B)  receptor upregulation
C)  ligand concentration
D)  number of receptors
E)  affinity of the receptor for the ligandF) A) and D)
G) C) and D)

Question 11

Cholera is the leading cause of death in children in developing countries, characterized by massive diarrhea. The effects stem from an extracellular toxin that the bacterium Vibrio cholerae releases into the gut. The toxin acts on a _ that overstimulates which causes a cascade of events that leads to electrolytes leaving the cell and causing water to follow them into the lumen of the intestine, resulting in severe diarrhea.

Accepted Answer

A)  protein- P : GTP
B)  G proteins : adenylate cyclase
C)  protein kinases : calmodulin
D)  cAMP : G proteins
E)  calcium : musclesF) A) and E)
G) C) and D)

Question 12

A half- life, in terms of a chemical messenger, refers to

Accepted Answer

A)  the radioactivity of the chemical messenger.
B)  how long the chemical messenger will be effective in the body.
C)  the time it takes for half of the chemical messenger in the blood to be degraded.
D)  the amount of time it takes to cross the plasma membrane.
E)  the amount of time the messenger is bound to a protein.F) B) and D)
G) B) and C)

Question 13

The target cells of the nervous system are

Accepted Answer

A)  glial cells.
B)  other neurons.
C)  all the cell types in the body.
D)  muscle cells.
E)  neurons, muscles, or glands.F) C) and D)
G) A) and E)

Question 14

Tyrosine is one of four amino acids that function directly as chemical messengers.

Accepted Answer

A) True 
 B)False

Question 15

Aspirin decreases inflammation by inhibiting the actions of what enzyme?

Accepted Answer

A)  cyclooxygenase
B)  phospholipase A2
C)  protein kinase A
D)  lipoxygenase
E)  dopa decarboxylaseF) C) and E)
G) A) and E)

Question 16

Aspirin is a nonsteroidal anti- inflammatory drug (NSAID) that relieves pain. Which mechanism best describes how NSAIDs work?

Accepted Answer

A)  When aspirin dissolves in the interstitial fluid it causes a concentration gradient and fluid is pulled from the cell reducing inflammation.
B)  Aspirin decreases the production of thromboxane A2, a chemical involved in blot clot formation, and COX inhibits A2 and, therefore, blood clots do not form and cause pain.
C)  The COX receptors have a greater affinity for aspirin and these speed up the reactions of healing.
D)  Prostaglandins (PG) are eicosanoids that produce pain and inflammation. Cyclooxygenase (COX) is an essential enzyme in the production of PG and aspirin inhibits COX and therefore relieves pain due to the reduced production of PG.
E)  Leukotrienes are eicosanoids that produce pain and inflammation. COX is used in the lipoxygenase pathway and therefore NSAIDs stop the conversion of arachidonic acid to leukotrienes thereby reducing inflammation.F) A) and B)
G) B) and C)

Question 17

Functionally, G proteins are classified into what three types?

Accepted Answer

A)  alpha, beta, and gamma
B)  slow, fast, and opened or closed
C)  those that affect ion channels, stimulatory G proteins, and inhibitory G proteins
D)  first, second, and third messengers
E)  those that affect proteins, those that affect enzymes, and those that affect specific genesF) A) and C)
G) B) and E)

Question 18

Steroid hormones are derived from the hormone testosterone.

Accepted Answer

A) True 
 B)False

Question 19

The chemical messenger of the nervous system is and chemical messenger of the endocrine system is .

Accepted Answer

A)  hormone : neurotransmitter
B)  neurotransmitter : hormone
C)  autocrines : paracrines
D)  neurohormone : adrenocorticoid
E)  neurotransmitter : neurohormoneF) None of the above
G) C) and E)

Question 20

Thyroid hormones alter the transcription of mRNA in the target cell.

Accepted Answer

A) True 
 B)False

Exam 5: Chemical Messengers

Correct Answer
verified

All catecholamine- secreting cells synthesize dopamine.

Correct Answer
verified

Direct communication between cells in contact with one another is accomplished through

Correct Answer
verified

The chemical messenger of the nervous system is and chemical messenger of the endocrine system is .

Correct Answer
verified

Steroid hormones are derived from the hormone testosterone.

Correct Answer
verified

Which of the following statements is true for the nervous system but NOT the endocrine system?

Correct Answer
verified

Tyrosine is one of four amino acids that function directly as chemical messengers.

Correct Answer
verified

When the alpha subunit of the G protein is activated, it can stimulate ion channels to do what?

Correct Answer
verified

Which of the following will NOT affect the magnitude of a cell's response to a specific hydrophilic ligand?

Correct Answer
verified

Which of the following enzymes catalyzes phosphorylation of a protein?

Correct Answer
verified

A half- life, in terms of a chemical messenger, refers to

Correct Answer
verified

Catecholamines, such as dopamine, norepinephrine, and epinephrine, are derived from the amino acid

Correct Answer
verified

Androgens are precursor molecules for the synthesis of

Correct Answer
verified

Functionally, G proteins are classified into what three types?

Correct Answer
verified

Aspirin decreases inflammation by inhibiting the actions of what enzyme?

Correct Answer
verified

Aspirin is a nonsteroidal anti- inflammatory drug (NSAID) that relieves pain. Which mechanism best describes how NSAIDs work?

Correct Answer
verified

The target cells of the nervous system are

Correct Answer
verified

Thyroid hormones alter the transcription of mRNA in the target cell.

Correct Answer
verified

An amplifier enzyme catalyzes the synthesis of a second messenger.

Correct Answer
verified

Describe the factors that affect the magnitude of a target cell's response. Assume that there is a receptor on the cell for the ligand.

Correct Answer
verified
The first factor that affects a target c...
View Answer

Exam 5: Chemical Messengers

Correct AnswerverifiedShow Answer

All catecholamine- secreting cells synthesize dopamine.

Correct AnswerverifiedShow Answer

Direct communication between cells in contact with one another is accomplished through

Correct AnswerverifiedShow Answer

The chemical messenger of the nervous system is and chemical messenger of the endocrine system is .

Correct AnswerverifiedShow Answer

Steroid hormones are derived from the hormone testosterone.

Correct AnswerverifiedShow Answer

Which of the following statements is true for the nervous system but NOT the endocrine system?

Correct AnswerverifiedShow Answer

Tyrosine is one of four amino acids that function directly as chemical messengers.

Correct AnswerverifiedShow Answer

When the alpha subunit of the G protein is activated, it can stimulate ion channels to do what?

Correct AnswerverifiedShow Answer

Which of the following will NOT affect the magnitude of a cell's response to a specific hydrophilic ligand?

Correct AnswerverifiedShow Answer

Which of the following enzymes catalyzes phosphorylation of a protein?

Correct AnswerverifiedShow Answer

A half- life, in terms of a chemical messenger, refers to

Correct AnswerverifiedShow Answer

Catecholamines, such as dopamine, norepinephrine, and epinephrine, are derived from the amino acid

Correct AnswerverifiedShow Answer

Androgens are precursor molecules for the synthesis of

Correct AnswerverifiedShow Answer

Functionally, G proteins are classified into what three types?

Correct AnswerverifiedShow Answer

Aspirin decreases inflammation by inhibiting the actions of what enzyme?

Correct AnswerverifiedShow Answer

Aspirin is a nonsteroidal anti- inflammatory drug (NSAID) that relieves pain. Which mechanism best describes how NSAIDs work?

Correct AnswerverifiedShow Answer

The target cells of the nervous system are

Correct AnswerverifiedShow Answer

Thyroid hormones alter the transcription of mRNA in the target cell.

Correct AnswerverifiedShow Answer

An amplifier enzyme catalyzes the synthesis of a second messenger.

Correct AnswerverifiedShow Answer

Describe the factors that affect the magnitude of a target cell's response. Assume that there is a receptor on the cell for the ligand.

Correct AnswerverifiedThe first factor that affects a target c...View AnswerShow Answer

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Correct Answer
verified
The first factor that affects a target c...
View Answer