,BIOD 351 Module 1 | Pharmacology | Portage Learning
| Questions & Verified Answers | 2026 Edition
1. Which term best describes the study of how a drug moves through the body, specifically examining
absorption, distribution, metabolism, and excretion?
A) Pharmacodynamics
B) Pharmacokinetics
C) Toxicology
D) Pharmacy
Correct Answer: Pharmacokinetics
Rationale: Pharmacokinetics is defined as what the body does to the drug, encompassing the four
phases of ADME: Absorption, Distribution, Metabolism, and Excretion. Pharmacodynamics, in contrast,
describes what the drug does to the body. Toxicology studies harmful effects, while pharmacy focuses
on preparation and dispensing.
2. A medication administered orally undergoes significant first-pass metabolism. Which organ is
primarily responsible for this effect?
A) Kidneys
B) Liver
C) Lungs
D) Small intestine
Correct Answer: Liver
Rationale: The liver is the primary site of first-pass metabolism. Orally administered drugs are absorbed
from the gastrointestinal tract and transported via the portal vein to the liver before reaching systemic
circulation. The liver's enzyme systems metabolize a significant portion of the drug, reducing its
bioavailability.
3. Which of the following is NOT one of the four phases of pharmacokinetics?
,A) Absorption
B) Distribution
C) Biotransformation
D) Excretion
Correct Answer: Biotransformation
Rationale: The four phases of pharmacokinetics are Absorption, Distribution, Metabolism, and Excretion
(ADME). Biotransformation is another term for metabolism, not a separate phase. Metabolism refers to
the chemical alteration of drugs by the body, primarily in the liver.
4. A drug has a half-life of 6 hours. If 240 mg is administered, how much of the drug remains in the body
after 18 hours?
A) 120 mg
B) 60 mg
C) 30 mg
D) 15 mg
Correct Answer: 30 mg
Rationale: 18 hours represents three half-lives (18 ÷ 6 = 3). After each half-life, the drug concentration
decreases by half: 240 mg → 120 mg → 60 mg → 30 mg. This exponential decay is a fundamental
principle of pharmacokinetics governing drug elimination.
5. What does the term "bioavailability" measure?
A) The total amount of drug excreted by the kidneys
B) The percentage of the administered drug dose that reaches the systemic circulation
C) The speed at which a drug is absorbed from the gastrointestinal tract
D) The maximum concentration of a drug in the bloodstream
, Correct Answer: The percentage of the administered drug dose that reaches the systemic circulation
Rationale: Bioavailability is the percentage (or extent) of the administered drug dose that reaches the
systemic circulation unchanged. It is influenced by factors such as first-pass metabolism, drug
formulation, and route of administration. Intravenous administration provides 100% bioavailability.
6. Which organ is the main contributor to drug excretion?
A) Liver
B) Kidneys
C) Colon
D) Lungs
Correct Answer: Kidneys
Rationale: The kidneys are the primary organs responsible for drug excretion. They filter drugs and their
metabolites from the bloodstream into the urine. Other routes of excretion include the liver (bile),
lungs, and skin, but the kidneys play the dominant role.
7. An agonist drug is best defined as one that:
A) Binds to a receptor and blocks activation
B) Binds to a receptor and triggers a response
C) Increases the metabolism of other drugs
D) Decreases the absorption of other drugs
Correct Answer: Binds to a receptor and triggers a response
Rationale: An agonist binds to a receptor and triggers a response, effectively "turning on" the receptor.
Agonists mimic the action of endogenous ligands. Antagonists, in contrast, bind to receptors and block
activation without producing a response.
8. An antagonist drug is best defined as one that:
| Questions & Verified Answers | 2026 Edition
1. Which term best describes the study of how a drug moves through the body, specifically examining
absorption, distribution, metabolism, and excretion?
A) Pharmacodynamics
B) Pharmacokinetics
C) Toxicology
D) Pharmacy
Correct Answer: Pharmacokinetics
Rationale: Pharmacokinetics is defined as what the body does to the drug, encompassing the four
phases of ADME: Absorption, Distribution, Metabolism, and Excretion. Pharmacodynamics, in contrast,
describes what the drug does to the body. Toxicology studies harmful effects, while pharmacy focuses
on preparation and dispensing.
2. A medication administered orally undergoes significant first-pass metabolism. Which organ is
primarily responsible for this effect?
A) Kidneys
B) Liver
C) Lungs
D) Small intestine
Correct Answer: Liver
Rationale: The liver is the primary site of first-pass metabolism. Orally administered drugs are absorbed
from the gastrointestinal tract and transported via the portal vein to the liver before reaching systemic
circulation. The liver's enzyme systems metabolize a significant portion of the drug, reducing its
bioavailability.
3. Which of the following is NOT one of the four phases of pharmacokinetics?
,A) Absorption
B) Distribution
C) Biotransformation
D) Excretion
Correct Answer: Biotransformation
Rationale: The four phases of pharmacokinetics are Absorption, Distribution, Metabolism, and Excretion
(ADME). Biotransformation is another term for metabolism, not a separate phase. Metabolism refers to
the chemical alteration of drugs by the body, primarily in the liver.
4. A drug has a half-life of 6 hours. If 240 mg is administered, how much of the drug remains in the body
after 18 hours?
A) 120 mg
B) 60 mg
C) 30 mg
D) 15 mg
Correct Answer: 30 mg
Rationale: 18 hours represents three half-lives (18 ÷ 6 = 3). After each half-life, the drug concentration
decreases by half: 240 mg → 120 mg → 60 mg → 30 mg. This exponential decay is a fundamental
principle of pharmacokinetics governing drug elimination.
5. What does the term "bioavailability" measure?
A) The total amount of drug excreted by the kidneys
B) The percentage of the administered drug dose that reaches the systemic circulation
C) The speed at which a drug is absorbed from the gastrointestinal tract
D) The maximum concentration of a drug in the bloodstream
, Correct Answer: The percentage of the administered drug dose that reaches the systemic circulation
Rationale: Bioavailability is the percentage (or extent) of the administered drug dose that reaches the
systemic circulation unchanged. It is influenced by factors such as first-pass metabolism, drug
formulation, and route of administration. Intravenous administration provides 100% bioavailability.
6. Which organ is the main contributor to drug excretion?
A) Liver
B) Kidneys
C) Colon
D) Lungs
Correct Answer: Kidneys
Rationale: The kidneys are the primary organs responsible for drug excretion. They filter drugs and their
metabolites from the bloodstream into the urine. Other routes of excretion include the liver (bile),
lungs, and skin, but the kidneys play the dominant role.
7. An agonist drug is best defined as one that:
A) Binds to a receptor and blocks activation
B) Binds to a receptor and triggers a response
C) Increases the metabolism of other drugs
D) Decreases the absorption of other drugs
Correct Answer: Binds to a receptor and triggers a response
Rationale: An agonist binds to a receptor and triggers a response, effectively "turning on" the receptor.
Agonists mimic the action of endogenous ligands. Antagonists, in contrast, bind to receptors and block
activation without producing a response.
8. An antagonist drug is best defined as one that:
