What is the net gain of glycolysis?

• A. 2 ATP, 2 NADH
• B. 4 ATP, 2 NADH
• C. 2 ATP, 2 NAD+
• D. 0 ATP, 2 NADH

Answer: (A)

Glycolysis converts one glucose into two pyruvate and generates energy in the form of ATP and reducing equivalents. It starts by spending two ATP to prime the glucose, then yields four ATP later through substrate-level phosphorylation, giving a net gain of two ATP per glucose. In parallel, two molecules of NAD+ are reduced to NADH as glyceraldehyde-3-phosphate is oxidized, and since two molecules of that intermediate come from one glucose, you end up with two NADH. So the overall net products of glycolysis per glucose are two ATP and two NADH (plus two pyruvate).