BIOD 102 Biology II Module 5 Exam
Portage Learning (2026/2027)
Section 1: Pharmacokinetics – ADME Principles
Q1: Which definition accurately describes the science of pharmacokinetics?
A. The study of the drug's mechanism of action on specific cellular receptors.
B. The study of the drug's movement through the body involving absorption, distribution,
metabolism, and excretion. [CORRECT]
C. The study of the toxic effects of drugs in animal models.
D. The study of the chemical synthesis of drug compounds.
Correct Answer: B
Rationale: Pharmacokinetics describes "what the body does to the drug" (ADME). Option A
refers to pharmacodynamics, Option C refers to toxicology, and Option D refers to medicinal
chemistry.
Q2: A drug is a weak acid with a pKa of 3.5. According to the pH-partition hypothesis, in which
environment will this drug be predominantly in the unionized (lipophilic) form suitable for
passive diffusion?
A. Gastric lumen (pH 1.5). [CORRECT]
B. Blood plasma (pH 7.4).
C. Renal tubular filtrate (pH 8.0).
D. Duodenal lumen (pH 6.5).
Correct Answer: A
Rationale: Weak acids are unionized in acidic environments (pH < pKa). The gastric lumen (pH
1.5) is significantly more acidic than the drug's pKa, favoring the unionized form. Basic
environments favor the ionized form for weak acids.
.
,Q3: Which of the following factors would decrease the rate of passive diffusion of a drug across
the gastrointestinal mucosa?
A. Increased lipid solubility of the drug.
B. Increased concentration gradient across the membrane.
C. Ionization of the drug molecule. [CORRECT]
D. Increased surface area of the absorption site.
Correct Answer: C
Rationale: Ionized molecules are polar and cannot passively diffuse across the lipid bilayer of
cell membranes. Options A, B, and D all increase the rate of passive diffusion.
Q4: How does a decrease in peripheral blood flow (vasoconstriction) affect the absorption of a
drug administered via intramuscular injection?
A. It increases the absorption rate due to higher local concentration.
B. It decreases the absorption rate by maintaining the concentration gradient.
C. It decreases the absorption rate by reducing the removal of drug from the tissue. [CORRECT]
D. It has no effect on absorption, as blood flow does not impact diffusion.
Correct Answer: C
Rationale: Absorption relies on blood flow to carry the drug away from the injection site,
maintaining a favorable concentration gradient. Reduced blood flow slows this removal, thereby
slowing the overall absorption rate.
Q5: Which anatomical structure is the primary site of drug absorption for most oral medications
due to its large surface area created by villi and microvilli?
A. Stomach.
B. Duodenum (Small Intestine). [CORRECT]
C. Colon.
D. Esophagus.
Correct Answer: B
.
, Rationale: While the stomach absorbs weak acids, the duodenum/small intestine is the primary
site for most drugs due to its massive surface area, extensive blood supply, and neutral pH.
Q6: Which statement correctly contrasts passive diffusion and active transport?
A. Passive diffusion requires ATP; active transport does not.
B. Passive diffusion moves drugs against the concentration gradient; active transport moves
drugs down the gradient.
C. Passive diffusion is non-saturable; active transport is saturable and carrier-mediated.
[CORRECT]
D. Passive diffusion is specific to drug structure; active transport is non-specific.
Correct Answer: C
Rationale: Active transport involves carrier proteins that can become saturated (Tm) and
requires ATP. Passive diffusion does not require energy or carriers and follows the concentration
gradient.
Q7: In the context of drug distribution, what is the primary impact of high plasma protein
binding (e.g., >90%) on a drug's pharmacological activity?
A. It increases the drug's volume of distribution.
B. It increases the drug's glomerular filtration rate.
C. It limits the drug's distribution and pharmacological activity by reducing the free
fraction. [CORRECT]
D. It prevents the drug from undergoing hepatic metabolism.
Correct Answer: C
Rationale: Only the free (unbound) drug can cross membranes, exert pharmacological effects,
and be metabolized or filtered. High binding acts as a reservoir, restricting distribution and
activity.
.
Portage Learning (2026/2027)
Section 1: Pharmacokinetics – ADME Principles
Q1: Which definition accurately describes the science of pharmacokinetics?
A. The study of the drug's mechanism of action on specific cellular receptors.
B. The study of the drug's movement through the body involving absorption, distribution,
metabolism, and excretion. [CORRECT]
C. The study of the toxic effects of drugs in animal models.
D. The study of the chemical synthesis of drug compounds.
Correct Answer: B
Rationale: Pharmacokinetics describes "what the body does to the drug" (ADME). Option A
refers to pharmacodynamics, Option C refers to toxicology, and Option D refers to medicinal
chemistry.
Q2: A drug is a weak acid with a pKa of 3.5. According to the pH-partition hypothesis, in which
environment will this drug be predominantly in the unionized (lipophilic) form suitable for
passive diffusion?
A. Gastric lumen (pH 1.5). [CORRECT]
B. Blood plasma (pH 7.4).
C. Renal tubular filtrate (pH 8.0).
D. Duodenal lumen (pH 6.5).
Correct Answer: A
Rationale: Weak acids are unionized in acidic environments (pH < pKa). The gastric lumen (pH
1.5) is significantly more acidic than the drug's pKa, favoring the unionized form. Basic
environments favor the ionized form for weak acids.
.
,Q3: Which of the following factors would decrease the rate of passive diffusion of a drug across
the gastrointestinal mucosa?
A. Increased lipid solubility of the drug.
B. Increased concentration gradient across the membrane.
C. Ionization of the drug molecule. [CORRECT]
D. Increased surface area of the absorption site.
Correct Answer: C
Rationale: Ionized molecules are polar and cannot passively diffuse across the lipid bilayer of
cell membranes. Options A, B, and D all increase the rate of passive diffusion.
Q4: How does a decrease in peripheral blood flow (vasoconstriction) affect the absorption of a
drug administered via intramuscular injection?
A. It increases the absorption rate due to higher local concentration.
B. It decreases the absorption rate by maintaining the concentration gradient.
C. It decreases the absorption rate by reducing the removal of drug from the tissue. [CORRECT]
D. It has no effect on absorption, as blood flow does not impact diffusion.
Correct Answer: C
Rationale: Absorption relies on blood flow to carry the drug away from the injection site,
maintaining a favorable concentration gradient. Reduced blood flow slows this removal, thereby
slowing the overall absorption rate.
Q5: Which anatomical structure is the primary site of drug absorption for most oral medications
due to its large surface area created by villi and microvilli?
A. Stomach.
B. Duodenum (Small Intestine). [CORRECT]
C. Colon.
D. Esophagus.
Correct Answer: B
.
, Rationale: While the stomach absorbs weak acids, the duodenum/small intestine is the primary
site for most drugs due to its massive surface area, extensive blood supply, and neutral pH.
Q6: Which statement correctly contrasts passive diffusion and active transport?
A. Passive diffusion requires ATP; active transport does not.
B. Passive diffusion moves drugs against the concentration gradient; active transport moves
drugs down the gradient.
C. Passive diffusion is non-saturable; active transport is saturable and carrier-mediated.
[CORRECT]
D. Passive diffusion is specific to drug structure; active transport is non-specific.
Correct Answer: C
Rationale: Active transport involves carrier proteins that can become saturated (Tm) and
requires ATP. Passive diffusion does not require energy or carriers and follows the concentration
gradient.
Q7: In the context of drug distribution, what is the primary impact of high plasma protein
binding (e.g., >90%) on a drug's pharmacological activity?
A. It increases the drug's volume of distribution.
B. It increases the drug's glomerular filtration rate.
C. It limits the drug's distribution and pharmacological activity by reducing the free
fraction. [CORRECT]
D. It prevents the drug from undergoing hepatic metabolism.
Correct Answer: C
Rationale: Only the free (unbound) drug can cross membranes, exert pharmacological effects,
and be metabolized or filtered. High binding acts as a reservoir, restricting distribution and
activity.
.
