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.
Glycolysis
Fructose-1,6-bisphosphate
Made from Fructose-6-phosphate by Phosphofructokinase-1 (PFK-1) ★
Phosphofructokinase-1 (PFK-1) ★ rate-limiting · irreversible — Glycolysis
Cofactors: ATP → ADP
Activated by: AMP; ADP; Fructose-2,6-bisphosphate (most potent; made by PFK-2)
Inhibited by: ATP; Citrate
Deficiency: PFK-1 deficiency (Tarui disease) — exercise cramps/myopathy, hemolytic anemia, hyperuricemia
The committed, rate-limiting step. Fed state: insulin → PFK-2 dephosphorylated & active → ↑F2,6-BP → PFK-1 on. Fasting: glucagon → PKA phosphorylates the bifunctional enzyme → FBPase-2 active → ↓F2,6-BP → PFK-1 off (liver).
Condition cards:PFK-1 deficiency (Tarui disease, GSD VII) →
Becomes DHAP via Aldolase A
Aldolase A — Glycolysis
Becomes Glyceraldehyde-3-phosphate via Aldolase A
Aldolase A — Glycolysis