Pharmacology Second Messenger System/ Pharmacodynamics
Second messengers are molecules that relay the signals received at receptors on the cell surface to target molecules in the cytosol or nucleus. This Pharmacology second messenger system/ Pharmacodynamics quiz is perfect for helping you see just how much you know about second messengers and how they achieve their function. Give it a shot and see how high your score is.
Questions and Answers
- 1.
What do lipid-soluble drugs, steroids and thyroid hormones bind to?
- A.
Cytokine receptors
- B.
Intracellular receptors
- C.
Tyrosine kinase receptors
- D.
G protein-coupled receptors
- E.
Transmembrane ion channels
Correct Answer
B. Intracellular receptorsExplanation
Lipid-soluble drugs, steroids, and thyroid hormones are able to pass through the cell membrane due to their hydrophobic nature. Once inside the cell, they bind to intracellular receptors located in the cytoplasm or nucleus. This binding activates the receptor, leading to changes in gene expression and cellular processes. Therefore, intracellular receptors are the appropriate target for these types of molecules.Rate this question:
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- 2.
What inhibitory constraint is relieved by the binding on the transcription-activating domain of the intracellular receptor?
- A.
Hsp-30
- B.
Hsp-60
- C.
Hsp-70
- D.
Hsp-90
- E.
None of the above
Correct Answer
D. Hsp-90Explanation
The binding of hsp-90 on the transcription-activating domain of the intracellular receptor relieves an inhibitory constraint.Rate this question:
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- 3.
What inhibitors of TK receptors bind to the extracellular domain?
- A.
Small permeant molecules
- B.
Monoclonal antibodies
- C.
Both
- D.
Neither
Correct Answer
B. Monoclonal antibodiesExplanation
Monoclonal antibodies are able to bind to the extracellular domain of TK receptors. This is because monoclonal antibodies are specifically designed to recognize and bind to specific antigens, such as the extracellular domain of TK receptors. On the other hand, small permeant molecules are typically unable to bind to the extracellular domain of TK receptors as they are too small to effectively interact with the receptor. Therefore, the correct answer is monoclonal antibodies.Rate this question:
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- 4.
What inhibits a receptor's TK activity in the cytoplasm?
- A.
Small permeant molecules
- B.
Monoclonal antibodies
- C.
Both
- D.
Neither
Correct Answer
A. Small permeant moleculesExplanation
Small permeant molecules can inhibit a receptor's TK activity in the cytoplasm. These molecules are able to pass through the cell membrane and interact with the receptor, preventing its tyrosine kinase (TK) activity. This inhibition can occur by directly binding to the receptor and disrupting its function or by interfering with the signaling pathways involved in TK activity. Monoclonal antibodies, on the other hand, are not typically small enough to freely enter the cytoplasm, and therefore do not directly inhibit TK activity.Rate this question:
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- 5.
What receptors involve JAK and STAT molecules and are activated by growth hormone, erythropoietin and interferon?
- A.
Cytokine receptors
- B.
Intracellular receptors
- C.
Tyrosine kinase receptors
- D.
G protein-coupled receptors
- E.
Transmembrane ion channels
Correct Answer
A. Cytokine receptorsExplanation
Cytokine receptors involve JAK and STAT molecules and are activated by growth hormone, erythropoietin, and interferon. Cytokine receptors are a type of cell surface receptor that play a crucial role in the immune system and mediate the effects of various cytokines. When a cytokine binds to its corresponding receptor, it activates the JAK-STAT signaling pathway, leading to the activation of specific genes and cellular responses. Therefore, cytokine receptors are the correct answer in this case.Rate this question:
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- 6.
What is not a function of transmembrane ion channels?
- A.
Cardiac conduction
- B.
Muscle contraction
- C.
Neurotransmission
- D.
Secretion
- E.
None of the above
Correct Answer
E. None of the aboveExplanation
Transmembrane ion channels are proteins that allow the passage of ions across cell membranes. They play crucial roles in various physiological processes, including cardiac conduction, muscle contraction, neurotransmission, and secretion. Therefore, "none of the above" is the correct answer because all of the mentioned functions are indeed associated with transmembrane ion channels.Rate this question:
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- 7.
How much time elapses between the ligand binding and the cellular response?
- A.
Milliseconds
- B.
Several seconds to minutes
- C.
Hours
- D.
Days
- E.
Weeks
Correct Answer
A. MillisecondsExplanation
After the ligand binds to its receptor on the cell surface, it triggers a series of intracellular signaling events that lead to the cellular response. These signaling events occur rapidly and can be completed within milliseconds. Therefore, the time that elapses between ligand binding and the cellular response is in the order of milliseconds.Rate this question:
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- 8.
Where are G protein-coupled receptors activated by G proteins?
- A.
Extracellular domain
- B.
Intracellular regions
- C.
Seven membrane domains
- D.
All of the above
- E.
None of the above
Correct Answer
B. Intracellular regionsExplanation
G protein-coupled receptors (GPCRs) are activated by G proteins in their intracellular regions. GPCRs span the cell membrane and have three main regions: the extracellular domain, the intracellular loops, and the seven transmembrane helical domains. The extracellular domain is responsible for ligand binding, while the intracellular regions interact with G proteins to initiate intracellular signaling cascades. Therefore, the intracellular regions of GPCRs play a crucial role in G protein activation and subsequent cellular responses.Rate this question:
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- 9.
Which of the following is an effector that generates intracellular second messengers?
- A.
Enzymes
- B.
Ion channels
- C.
GTP-alpha
- D.
A and B
- E.
All of the above
Correct Answer
D. A and BExplanation
Enzymes and ion channels are both effectors that can generate intracellular second messengers. Enzymes, such as protein kinases or phospholipases, can catalyze reactions that produce second messengers like cyclic AMP or inositol trisphosphate. Ion channels, on the other hand, can allow the entry or exit of ions, which can trigger the release of second messengers like calcium ions. Therefore, both enzymes and ion channels are capable of generating intracellular second messengers.Rate this question:
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- 10.
Which of the following is not a second messenger?
- A.
Beta-arrestin
- B.
CAMP
- C.
CGMP
- D.
IP3
- E.
DAG
Correct Answer
A. Beta-arrestinExplanation
Beta-arrestin is not considered a second messenger. Second messengers are molecules that transmit signals within cells, and they are typically small molecules or ions. Examples of second messengers include cAMP, cGMP, IP3, and DAG. Beta-arrestin, on the other hand, is a protein involved in the desensitization and internalization of G protein-coupled receptors. It acts downstream of second messenger signaling pathways and is not itself a second messenger molecule.Rate this question:
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- 11.
Stimulation of G protein-coupled receptors results in responses that last how long?
- A.
Milliseconds
- B.
Several seconds to minutes
- C.
Hours
- D.
Days
- E.
Weeks
Correct Answer
B. Several seconds to minutesExplanation
Stimulation of G protein-coupled receptors results in responses that last several seconds to minutes. This is because G protein-coupled receptors activate intracellular signaling pathways that initiate a cascade of events leading to cellular responses. These responses typically involve the activation of second messengers, such as cyclic AMP or calcium ions, which can have short-lived effects on cellular processes. Therefore, the duration of the response is relatively short-lived and typically lasts for several seconds to minutes.Rate this question:
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- 12.
What is the molecular weight of most drugs?
- A.
1-10
- B.
100-1000
- C.
10000-100000
- D.
Cannot determine
Correct Answer
B. 100-1000Explanation
Most drugs have a molecular weight in the range of 100-1000. This is because drugs are typically small molecules that need to be able to penetrate cell membranes and interact with specific targets in the body. Larger molecules may have difficulty crossing cell membranes and may not be as effective in their intended function. Additionally, very small molecules may not have the necessary complexity to interact with specific targets. Therefore, the molecular weight range of 100-1000 is generally ideal for drugs.Rate this question:
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- 13.
What is the binding of a drug to a nonregulatory molecule such as plasma albumin is called what?
- A.
Partial agonist
- B.
Inert binding site
- C.
Antagonist
- D.
Agonist
- E.
None of the above
Correct Answer
B. Inert binding siteExplanation
The binding of a drug to a nonregulatory molecule such as plasma albumin is called an inert binding site. This means that the drug is not interacting with a regulatory molecule or receptor, but rather binding to a nonfunctional site on the albumin molecule. This type of binding does not elicit a physiological response and does not affect the activity of the drug.Rate this question:
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- 14.
Drugs that bind and activate the receptor directly or indirectly are?
- A.
Partial agonist
- B.
Inert binding site
- C.
Antagonist
- D.
Agonist
- E.
None of the above
Correct Answer
D. AgonistExplanation
An agonist is a type of drug that binds and activates a receptor directly or indirectly. It produces a biological response by mimicking or enhancing the effects of endogenous substances that bind to the same receptor. This activation can lead to various physiological responses in the body. Therefore, the correct answer in this case is agonist.Rate this question:
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- 15.
Drugs that bind to a receptor and prevent the binding of other molecules are?
- A.
Partial agonist
- B.
Inert binding site
- C.
Antagonist
- D.
Agonist
- E.
None of the above
Correct Answer
C. AntagonistExplanation
An antagonist is a drug that binds to a receptor and prevents other molecules from binding. It acts by blocking the receptor's activation and inhibiting the biological response that would normally occur. This is in contrast to an agonist, which binds to a receptor and activates it, and a partial agonist, which activates the receptor but with less efficacy than a full agonist. An inert binding site does not have any effect on the receptor or its function. Therefore, the correct answer is antagonist.Rate this question:
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- 16.
What binds and activates the receptor but does not evoke a full response?
- A.
Partial agonist
- B.
Inert binding site
- C.
Antagonist
- D.
Agonist
- E.
None of the above
Correct Answer
A. Partial agonistExplanation
A partial agonist is a substance that binds to a receptor but only activates it partially, resulting in a weaker response compared to a full agonist. It can bind to the receptor and block the binding of other substances, but it does not fully activate the receptor to produce a maximal response. This makes it different from an antagonist, which solely blocks the receptor without any activation. Therefore, a partial agonist can bind and activate the receptor to some extent, but it does not evoke a full response.Rate this question:
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- 17.
If EC50 is small then?
- A.
Potency is high
- B.
Potency is low
- C.
Affinity is high
- D.
Affinity is low
- E.
None of the above
Correct Answer
A. Potency is highExplanation
If EC50 is small, it indicates that a small concentration of a drug or compound is required to elicit a response. This suggests that the drug or compound is highly potent, meaning it has a strong effect at low concentrations. Therefore, the correct answer is "potency is high".Rate this question:
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- 18.
If Kd is small then?
- A.
Potency is high
- B.
Potency is low
- C.
Affinity is high
- D.
Affinity is low
- E.
None of the above
Correct Answer
C. Affinity is highExplanation
When Kd is small, it means that the dissociation constant is low. In terms of drug-receptor interactions, a low Kd indicates a high affinity between the drug and the receptor. This means that the drug has a strong binding ability to the receptor, resulting in a high affinity. Therefore, the correct answer is "affinity is high".Rate this question:
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- 19.
Which of the following displays a hyperbolic curve?
- A.
Graded dose-binding relationship
- B.
Graded dose-response relationship
- C.
Quantal dose-response relationship
- D.
A and B
- E.
B and C
Correct Answer
D. A and BExplanation
The correct answer is "A and B" because both the graded dose-binding relationship and the graded dose-response relationship can display a hyperbolic curve. In a graded dose-binding relationship, the response increases gradually with increasing dose until it reaches a maximum level, after which it plateaus. Similarly, in a graded dose-response relationship, the response also increases with increasing dose, but it may not reach a plateau and can continue to increase. Both of these relationships can be represented by a hyperbolic curve.Rate this question:
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- 20.
Efficacy can be determined by?
- A.
Graded dose-response curve only
- B.
Quantal dose-response curve only
- C.
Both
- D.
Neither
Correct Answer
A. Graded dose-response curve onlyExplanation
Efficacy can be determined by the graded dose-response curve only because it provides a quantitative measure of the response to different doses of a drug. This curve plots the response (e.g. the magnitude of a therapeutic effect) against the dose of the drug administered. It allows for the determination of the maximum effect that can be achieved with the drug (efficacy), as well as the dose at which 50% of the maximum effect is achieved (potency). On the other hand, the quantal dose-response curve is used to determine the proportion of individuals in a population that respond to a drug at different doses, but it does not provide information about the magnitude of the response.Rate this question:
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