BIOD 351 Pharmacology Module 2 Exam –
Pharmacodynamics 2026/2027 UPDATE Portage Learning
UPDATED ACTUAL Questions and CORRECT Answers
1. Which of the following best defines pharmacodynamics?
A. The movement of a drug through the body
B. What the body does to a drug
C. What a drug does to the body
D. The process of drug excretion
Answer: C
Rationale: Pharmacodynamics is the study of the biochemical and physiological effects of
drugs on the body and their mechanisms of action.
2. The ability of a drug to bind to a specific receptor is referred to as:
A. Affinity
B. Efficacy
C. Potency
D. Intrinsic activity
Answer: A
Rationale: Affinity describes the strength of the attraction between a drug and its receptor.
,3. A drug that binds to a receptor and produces a maximal biological response is
a:
A. Full agonist
B. Antagonist
C. Inverse agonist
D. Partial agonist
Answer: A
Rationale: Full agonists bind to receptors and mimic the regulatory molecules to activate
the receptor to its maximum potential.
4. What is the term for the maximum effect a drug can produce?
A. Selectivity
B. Potency
C. Threshold
D. Efficacy
Answer: D
Rationale: Efficacy (or intrinsic activity) refers to the maximal effect an agonist can
produce regardless of the dose.
5. Which parameter on a dose-response curve indicates the drug’s potency?
A. The maximal height of the curve
B. The slope of the curve
C. The baseline level
D. The horizontal position (EC50)
Answer: D
Rationale: Potency is determined by the concentration (EC50) or dose (ED50) of a drug
required to produce 50% of the maximum effect.
, 6. A competitive antagonist has which effect on the agonist’s dose-response
curve?
A. Shifts the curve to the right without affecting the maximum response
B. Shifts the curve to the left
C. Decreases the maximal response (Emax)
D. Increases the slope of the curve
Answer: A
Rationale: Competitive antagonists compete for the same binding site, requiring higher
doses of agonist to achieve the same effect, shifting the curve rightward (increasing EC50).
7. Non-competitive antagonists are characterized by:
A. A rightward shift in the EC50 only
B. A decrease in the maximal response (Emax)
C. Binding reversibly to the active site
D. Increasing the drug’s potency
Answer: B
Rationale: Non-competitive antagonists bind irreversibly or to an allosteric site, effectively
reducing the number of functional receptors and lowering the maximal response.
8. Which of the following describes an ‘inverse agonist’?
A. A drug that blocks the effect of an agonist
B. A drug that stabilizes the receptor in an inactive state and reduces constitutive activity
C. A drug that binds to a different site than the agonist
D. A drug that binds to the receptor but produces no response
Answer: B
Rationale: Inverse agonists reduce the baseline or ‘constitutive’ activity of receptors that
are active even in the absence of an agonist.
Pharmacodynamics 2026/2027 UPDATE Portage Learning
UPDATED ACTUAL Questions and CORRECT Answers
1. Which of the following best defines pharmacodynamics?
A. The movement of a drug through the body
B. What the body does to a drug
C. What a drug does to the body
D. The process of drug excretion
Answer: C
Rationale: Pharmacodynamics is the study of the biochemical and physiological effects of
drugs on the body and their mechanisms of action.
2. The ability of a drug to bind to a specific receptor is referred to as:
A. Affinity
B. Efficacy
C. Potency
D. Intrinsic activity
Answer: A
Rationale: Affinity describes the strength of the attraction between a drug and its receptor.
,3. A drug that binds to a receptor and produces a maximal biological response is
a:
A. Full agonist
B. Antagonist
C. Inverse agonist
D. Partial agonist
Answer: A
Rationale: Full agonists bind to receptors and mimic the regulatory molecules to activate
the receptor to its maximum potential.
4. What is the term for the maximum effect a drug can produce?
A. Selectivity
B. Potency
C. Threshold
D. Efficacy
Answer: D
Rationale: Efficacy (or intrinsic activity) refers to the maximal effect an agonist can
produce regardless of the dose.
5. Which parameter on a dose-response curve indicates the drug’s potency?
A. The maximal height of the curve
B. The slope of the curve
C. The baseline level
D. The horizontal position (EC50)
Answer: D
Rationale: Potency is determined by the concentration (EC50) or dose (ED50) of a drug
required to produce 50% of the maximum effect.
, 6. A competitive antagonist has which effect on the agonist’s dose-response
curve?
A. Shifts the curve to the right without affecting the maximum response
B. Shifts the curve to the left
C. Decreases the maximal response (Emax)
D. Increases the slope of the curve
Answer: A
Rationale: Competitive antagonists compete for the same binding site, requiring higher
doses of agonist to achieve the same effect, shifting the curve rightward (increasing EC50).
7. Non-competitive antagonists are characterized by:
A. A rightward shift in the EC50 only
B. A decrease in the maximal response (Emax)
C. Binding reversibly to the active site
D. Increasing the drug’s potency
Answer: B
Rationale: Non-competitive antagonists bind irreversibly or to an allosteric site, effectively
reducing the number of functional receptors and lowering the maximal response.
8. Which of the following describes an ‘inverse agonist’?
A. A drug that blocks the effect of an agonist
B. A drug that stabilizes the receptor in an inactive state and reduces constitutive activity
C. A drug that binds to a different site than the agonist
D. A drug that binds to the receptor but produces no response
Answer: B
Rationale: Inverse agonists reduce the baseline or ‘constitutive’ activity of receptors that
are active even in the absence of an agonist.
