Gluconeogenesis Tournament
Two onboarding diagrams place gluconeogenesis inside carbohydrate metabolism. Then eight MCAT-DoK rounds: where glucose-6-phosphatase lives, the four bypass enzymes in order, the substrates that actually contribute net carbons, the ATP cost of de novo glucose synthesis, and the Cori-cycle inter-organ loop.
Where the Glucose metabolism (gluconeogenesis branch) fits in Metabolism of carbohydrates
Gluconeogenesis is the reverse of glycolysis through the GLUCOSE METABOLISM hub: liver and kidney cells synthesize free glucose from pyruvate, lactate, alanine, and glycerol during fasting. Click the highlighted Glucose metabolism box to enter the tournament.
Click the highlighted Glucose metabolism (gluconeogenesis branch) box to continue.
What this tournament tests
Each task maps to a distinct MCAT cognitive demand. The first two orient you in the broader topology; the next eight test the high-yield mechanism, regulation, sequence and quantitative reasoning that consistently appear on test day.
The Bigger Picture
Locate gluconeogenesis inside Reactome's Metabolism of Carbohydrates overview.
Whole-Pathway Overview
Pan and zoom the WikiPathways gluconeogenesis figure before you play.
Fill in the Blank
Locate glucose-6-phosphatase in the ER lumen of liver / kidney / intestine.
Disruptor
Walk the Von Gierke quartet: hypoglycemia, hepatomegaly, lactic acidosis, hyperuricemia.
Sequence Ordering
Walk the four bypass enzymes from pyruvate to free glucose in order.
Match the Pairs
Pair each gluconeogenic substrate with the metabolic context that delivers it.
Numeric Input
Compute the 6 ATP equivalents per glucose synthesized de novo from 2 pyruvate.
Select All That Apply
Identify which substrates can serve as a NET source of glucose carbons.
Odd One Out
Distinguish the gluconeogenic bypass enzyme from the irreversible glycolytic ones.
Cori Cycle
Recognize the muscle-liver lactate-glucose loop and its alanine-shuttle cousin.
Public leaderboard
Your score posts to a global, persistent leaderboard scored by points first, time as tiebreaker.
Gluconeogenesis in 60 seconds
Gluconeogenesis is the liver and kidney's synthesis of free glucose from non-carbohydrate precursors during fasting. It uses most of the glycolytic enzymes in reverse, plus four irreversible bypass enzymes: pyruvate carboxylase (mitochondrial, biotin-dependent, requires acetyl-CoA), PEPCK (cytosolic, GTP), fructose-1,6-bisphosphatase (cytosolic), and glucose-6-phosphatase (ER lumen of liver / kidney / intestine only).
Skeletal muscle has no glucose-6-phosphatase, which is why it cannot release free glucose to blood. Glucagon drives gluconeogenesis (via cAMP -> PKA -> ACC + glycogen-synthase phosphorylation, and via low F2,6BP); insulin opposes it.
Substrates: lactate (Cori cycle from anaerobic muscle / RBCs), alanine (alanine cycle - amino group carrier from peripheral protein breakdown), glycerol (from adipose lipolysis, enters at DHAP), and propionyl-CoA (from odd-chain FA / branched-chain AAs - the only gluconeogenic fatty-acid contribution).
The big trap: acetyl-CoA cannot become net glucose in mammals. Each turn of the TCA loses 2 C as CO2 before any new OAA is made. So even-chain fatty acids and ketogenic amino acids cannot be net glucose precursors.
FAQ
Why does Von Gierke disease cause hyperuricemia?
Glucose-6-phosphatase deficiency lets G6P accumulate. Excess G6P shunts into the PPP -> ribose-5-P -> nucleotides -> purine catabolism -> uric acid. So Von Gierke is the textbook 'metabolic gout' picture in pediatrics.
Can I make glucose from fat?
Almost never in mammals. Even-chain fatty acids -> all carbons end up as CO2 in the TCA before glucose can be made. Only the propionyl-CoA fragment from ODD-chain fatty acids (or branched-chain AAs) escapes the TCA carbon-loss trap and contributes net carbons via succinyl-CoA.
Do I need an account to play?
No. The tournament is fully public. You get a randomized handle and your score posts to the public leaderboard at the bottom of this page.
Keep going
The opposite direction. Knowing both lets you reason about the F2,6BP regulatory switch.
Glycogenolysis runs alongside gluconeogenesis during fasting. Same hormonal logic.
Overview diagram: Reactome Pathway R-HSA-71387, licensed CC BY 4.0.