33. Which enzyme converts acetaldehyde to acetate in alcohol catabolism? (A) Alcohol dehydrogenase (B) Aldehyde dehydrogenase (C) Catalase (D) CYP2E1

42. At the molecular level, insulin signaling is initiated primarily through activation of which mechanism? (A) G‑protein–coupled receptor signaling (B) Ligand‑gated ion channel opening (C) Receptor tyrosine kinase autophosphorylation (D) Nuclear hormone receptor binding