Glycolysis Tournament
Ten MCAT-DoK rounds. The tournament begins with an interactive onboarding step that locates glycolysis inside the broader Metabolism of Carbohydrates map. Then identify PFK-1 on a real Reactome diagram, order the glycolytic intermediates, match enzymes to their reactions, compute net ATP yield, predict the metabolic fallout of arsenate poisoning at GAPDH, and read the canonical hexokinase vs glucokinase kinetics curves.
Where the Glucose metabolism (glycolysis) fits in Metabolism of carbohydrates
Glycolysis is the entry point of carbohydrate catabolism. On this overview, the Glucose metabolism panel shows how glycolysis connects to glycogen breakdown, gluconeogenesis, the pentose phosphate pathway, and pyruvate. To enter the tournament, click the highlighted Glucose metabolism box.
Click the highlighted Glucose metabolism (glycolysis) box to continue.
What this tournament tests
Each of the ten rounds maps to a distinct MCAT cognitive demand for AAMC content category 1A (Bioenergetics & Carbohydrate Metabolism). Together they cover the high-yield enzymology, regulation, intermediate sequence, ATP accounting, and quantitative kinetics that consistently appear on test day.
Visual Labeling
Identify PFK-1, the regulated step, on the live Reactome glucose-metabolism diagram.
Fill in the Blank
Recall PGK as the enzyme of the first substrate-level phosphorylation in glycolysis.
Disruptor
Predict the integrated effect of arsenate poisoning on net ATP yield per glucose.
Hot Spot
Click GAPDH - the unique NADH-producing step and the molecular target of arsenate.
Data Interpretation
Read hexokinase vs glucokinase Michaelis-Menten curves and reason about hepatic glucose buffering.
Sequence Ordering
Order glycolytic intermediates from G6P to PEP - the backbone of every regulation question.
Match the Pairs
Pair each glycolytic enzyme with the reaction it catalyzes (and spot the gluconeogenesis trap).
Numeric Input
Compute the canonical net ATP yield per glucose from glycolysis alone.
Select All That Apply
Identify which allosteric signals activate PFK-1 (AMP, F2,6BP, ADP) and which inhibit it.
Odd One Out
Tell glycolytic enzymes apart from look-alikes in the pentose phosphate pathway.
Public leaderboard
Your score posts to a global, persistent leaderboard scored by points first, time as tiebreaker.
Glycolysis in 60 seconds
Glycolysis is the cytosolic pathway that converts glucose -> 2 pyruvate, producing a net 2 ATP and 2 NADH per glucose. It happens in every cell, with or without oxygen.
The three irreversible (regulated) steps are catalyzed by hexokinase / glucokinase, phosphofructokinase-1 (PFK-1), and pyruvate kinase. PFK-1 is the rate-limiting enzyme: inhibited by ATP and citrate, activated by AMP and fructose-2,6-bisphosphate.
The only oxidoreductase is GAPDH, which oxidizes glyceraldehyde-3-phosphate to 1,3-BPG, producing NADH. This step is also where arsenate sabotages glycolysis: it substitutes for Pi, forming an unstable acyl-arsenate that hydrolyzes spontaneously - bypassing the PGK substrate-level phosphorylation downstream and collapsing net ATP yield.
Hepatocytes use glucokinase (high Km, ~10 mM) instead of hexokinase, so they only phosphorylate glucose meaningfully when blood glucose is high - acting as a postprandial glucose buffer rather than competing with the brain during fasting.
FAQ
What is the rate-limiting step of glycolysis?
Phosphofructokinase-1 (PFK-1). It catalyzes the committed step (F6P -> F1,6BP) and is the most heavily regulated enzyme in the pathway.
Why does the liver use glucokinase?
Glucokinase has a high Km (~10 mM), so its activity scales with blood glucose. The liver only phosphorylates glucose aggressively after meals, allowing it to buffer postprandial surges into glycogen.
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.
Where does the diagram come from?
It is the Reactome 'Glucose metabolism' pathway (R-HSA-70326), licensed CC BY 4.0. We render the original SVG and overlay quiz hotspots on the actual entity bounding boxes.
Keep going
Continue the cellular respiration story: TCA enzymology, NADH/FADH2/GTP/CO2 yield per turn, and feedback regulation.
130+ topic games across Biochem, Bio/Molecular, Gen/Org Chem, Physics, Psych/Soc.
Diagram: Reactome Pathway Glucose metabolism (R-HSA-70326), licensed CC BY 4.0.