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.
Carbohydrate digestion & absorption
Undigested sugar reaches the colon
Made from At the brush border: maltose, α-limit dextrins, lactose, sucrose by Anything not digested passes on
Anything not digested passes on — Carbohydrate digestion & absorption
Deficiency: Carbohydrate malabsorption — from enzyme deficiency, saturated transporters, or mucosal damage (celiac disease, Crohn's, post-infectious)
Undigested disaccharides and indigestible carbohydrate reach the large intestine, draw water in osmotically, and are fermented by colonic bacteria to CO₂, CH₄ and H₂ (p20) — which is what the hydrogen breath test detects.
Condition cards:Carbohydrate malabsorption / osmotic diarrhea →Post-infectious (temporary) carbohydrate malabsorption →Celiac disease (gut damage causing malabsorption) →