The following anticancer drugs are considered highly emetogenic:

Correct Answer: D

Rationale: Cisplatin (D) is considered highly emetogenic, causing severe nausea and vomiting in most patients due to its action on the chemoreceptor trigger zone and GI tract, requiring aggressive antiemetic prophylaxis (e.g., 5HT3 antagonists, dexamethasone). Cyclophosphamide (A) is moderately to highly emetogenic, depending on dose, but less than cisplatin. Methotrexate (B) is mildly emetogenic at standard doses. 5-Fluorouracil (C) causes moderate nausea. Interleukin-2 (original E) is variably emetogenic, not a cytotoxic drug. Cisplatin's alkylating action on DNA is potent against testicular and ovarian cancers, but its emetic potential, linked to serotonin release, makes premedication critical for patient tolerability.

Correct Answer: C

Rationale: The correct answer is that distribution depends on the unbound drug concentration gradient between blood and tissue (C). Only free (unbound) drug can cross membranes into tissues, driven by the concentration gradient, as per Fick's law of diffusion. Option A is false; blood flow (e.g., high to brain, low to fat) significantly affects distribution, as seen with anesthetics. Option B is incorrect; tissue solubility (lipid vs. aqueous) determines partitioning, like thiopental in fat. Option D is wrong; strong plasma protein binding (e.g., warfarin) reduces free drug, limiting distribution. Option E (original) about half-life is unrelated. This gradient-driven process explains rapid onset in highly perfused organs and prolonged effects in poorly perfused ones, critical for therapeutic targeting and avoiding toxicity.

Correct Answer: D

Rationale: Quantal dose-response curves (D) provide information about variation in drug sensitivity within a population, plotting the percentage of subjects responding (e.g., pain relief) against dose, revealing ED50 and variability (e.g., standard deviation). Maximal efficacy (A) measures the maximum effect (graded curves). Therapeutic index (B) is TD50/ED50, assessing safety, not sensitivity spread. Drug potency (C) compares doses for equal effects (e.g., ED50), not population variation. Graded curves (original E) measure continuous responses, not all-or-none. Quantal curves, used in clinical and preclinical studies, highlight interindividual differences (e.g., genetic polymorphisms), guiding dosing adjustments for diverse populations.

Correct Answer: D

Rationale: The Ames test detects mutagenesis in bacteria (D), using Salmonella strains to identify reverse mutations from chemicals (e.g., aflatoxin), a rapid screen for potential carcinogens due to mutation-cancer correlation. Options A and B (carcinogenesis) require animal models, not bacteria. Option C (teratogenesis) involves developmental toxicity, not the Ames focus. Option E (original) is redundant with D. Developed by Bruce Ames, this assay's simplicity and sensitivity make it a cornerstone in genotoxicity screening, though positive results need animal confirmation for carcinogenicity, balancing cost and predictive power.

Correct Answer: A

Rationale: Blood flow to the tissue is an important determinant (A), as highly perfused organs (e.g., brain, heart) receive drugs faster, influencing onset (e.g., anesthetics). Solubility (B) affects partitioning (e.g., lipophilic drugs into fat), but blood flow drives initial delivery. Concentration (C) sets the gradient, but flow dictates access. Tissue size (D) impacts total drug amount, not rate. Option E (original) is true but A is primary. This perfusion-limited distribution explains rapid effects in critical organs and slower accumulation in fat, guiding drug design and dosing schedules.