Learn / Metabolism
Metabolic pathways
Every FMK pathway as a clickable map. Pick one pathway to hammer it — next step, enzyme, regulator, cofactor, and the facts that get tested (NADPH and who needs it, rate-limiting steps, deficiencies) — or set it to all pathways for a mixed drill. Every answer says which enzyme and which pathway.
Cholesterol synthesis · Cytosol / smooth ER — mainly liver. Enzymes sit beside the arrows; a ★ marks the rate-limiting step. The map scrolls inside its panel.
Zoom
Cholesterol synthesis
Vitamin D
Made from Cholesterol (C27) by 7-Dehydrocholesterol → UV-B (skin) → 25-OH (liver) → 1,25-(OH)₂ (kidney, 1α-hydroxylase)
7-Dehydrocholesterol → UV-B (skin) → 25-OH (liver) → 1,25-(OH)₂ (kidney, 1α-hydroxylase) — Cholesterol synthesis
Condition cards:Vitamin D deficiency: rickets (child) / osteomalacia (adult) →