The route of drug administration that gives the most rapid onset of the pharmacological effect is

Correct Answer: B

Rationale: Intravenous injection (B) gives the most rapid onset, delivering drug directly into the bloodstream, bypassing absorption (e.g., morphine in seconds). Intramuscular (A) and subcutaneous (original E) are slower due to tissue absorption. Intradermal (C) is slowest, for local effects. Peroral (D) involves GI absorption, delaying onset (e.g., 30-60 min). IV's immediacy suits emergencies, avoiding first-pass metabolism, though it risks rapid toxicity, requiring precise dosing and monitoring.

Correct Answer: C

Rationale: CYP3A4 (C) is expressed in both intestinal epithelium and kidney, metabolizing many drugs (e.g., midazolam), impacting first-pass and systemic clearance. CYP2D6 (A) is primarily hepatic. CYP1A1/2 (B) is in liver/lung, inducible by smoking. CYP2E1 (D) is hepatic, ethanol-related. No original E. CYP3A4's dual presence reduces bioavailability (e.g., cyclosporine), mediates interactions (e.g., with grapefruit juice), and is critical in drug metabolism studies, influencing dosing and efficacy.

Correct Answer: B

Rationale: Glucose is best described as a monosaccharide (B), a single sugar unit (C₆H₁₂O₆) not hydrolyzable into simpler carbohydrates, serving as an energy source (e.g., dextrose IV). A sugar (A) is broader. Disaccharides (C, e.g., sucrose) and polysaccharides (D, e.g., starch) hydrolyze. Oligosaccharides (original E) are 3-10 units. Glucose's simplicity drives its rapid absorption, critical in hypoglycemia treatment, distinguishing it in carbohydrate chemistry and pharmacokinetics.

Correct Answer: B

Rationale: Plasmids carry optional genes (B), circular double-stranded DNA in bacteria (e.g., antibiotic resistance genes), not essential for growth (C). They're not single-stranded (A) or linear (D). No original E. These extrachromosomal elements enable bacterial adaptability, critical in resistance spread (e.g., beta-lactamases), impacting antibiotic efficacy, a major pharmacology and public health concern.

Correct Answer: C

Rationale: CD4+ T cells recognize antigens bound to MHC class II molecules on antigen-presenting cells (APCs) (C), like macrophages, triggering helper T-cell responses (e.g., cytokine release). MHC class I (A) is for CD8+ cells. Free antigens (B) don't activate T cells directly. No option D or original E. This MHC II restriction drives adaptive immunity, critical in vaccine design and immunosuppressive drugs (e.g., cyclosporine), shaping immune pharmacology.