Glycolytic stoichiometry: For every one molecule of glucose fully processed through glycolysis, how many molecules of pyruvate are produced?

Introduction / Context:
Glycolysis converts one six-carbon glucose into two three-carbon pyruvate molecules. Understanding this stoichiometry is fundamental for calculating ATP and NADH yields and for linking glycolysis to the TCA cycle and fermentation.

Given Data / Assumptions:

• Glucose has six carbons; pyruvate has three carbons.
• Carbon is conserved during glycolysis.
• No carbon is lost as CO2 in the ten glycolytic steps.

Concept / Approach:
The pathway splits fructose-1,6-bisphosphate into two triose phosphates that are processed in parallel. Therefore, all subsequent steps occur twice per glucose, leading directly to two pyruvate molecules.

Step-by-Step Solution:
Aldolase cleaves the 6-carbon compound into two 3-carbon molecules (G3P and DHAP). Triose phosphate isomerase interconverts DHAP and G3P, funneling both into G3P. Each G3P is processed to pyruvate, producing two pyruvate per original glucose. Thus, select “2.”

Verification / Alternative check:
Net yield per glucose: 2 pyruvate, 2 ATP (net), and 2 NADH under standard accounting.

Why Other Options Are Wrong:
1 ignores the split; 3 or 4 would require carbon loss or gain; 6 is impossible given carbon balance.

Common Pitfalls:
Forgetting the aldolase split makes all later steps double per glucose.

Final Answer:
2.