The ATP ledger for one glucose
"The ATP ledger for one glucose" is a free, interactive Class 11 Biology simulation for NEET, built on the lesson "The respiratory balance sheet" in Respiration in Plants. Keep oxygen on and slide through the stages. Notice that NADH piles up for three stages while the ATP count stays tiny. Per glucose: glycolysis nets 2 ATP and 2 NADH; the link reaction adds 2 NADH; Krebs' cycle adds 6 NADH, 2 FADH₂ and 2 ATP; the ETS turns 10 NADH and 2 FADH₂ into 34 ATP. Total 38, on the textbook's assumptions; fermentation gives 2.
From the lesson The respiratory balance sheet in Respiration in Plants. Change the values and watch what happens.
The idea behind it
NCERT §12.5
- The net ATP from one glucose can be calculated, but only as a theoretical exercise resting on four assumptions.
- Assumption one: the pathway runs as one orderly sequence, glycolysis then the TCA cycle then the ETS, each substrate forming the next.
- Assumption two: the NADH made in glycolysis is moved into the mitochondria and undergoes oxidative phosphorylation.
- Assumption three: no intermediate is drawn off to make another compound. Assumption four: only glucose is respired, with no other substrate entering at any intermediate stage.
- None of these holds in a living cell: all the pathways run at once, substrates enter and leave as needed, ATP is used as needed, and enzyme rates are controlled in many ways.
- On these assumptions the net gain is 38 ATP per glucose in aerobic respiration: 10 NADH × 3 = 30, 2 FADH₂ × 2 = 4, plus 2 net ATP from glycolysis and 2 from the TCA cycle.
- Fermentation, by contrast, nets only 2 ATP per glucose.
Questions
2 answers
- What does the "The ATP ledger for one glucose" simulation show?
- Keep oxygen on and slide through the stages. Notice that NADH piles up for three stages while the ATP count stays tiny.
- Is this simulation free?
- Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "The respiratory balance sheet" in Respiration in Plants (Class 11 Biology).
Embed this simulation
Free, with a link back
Teaching this idea? Put the simulation on your own page or LMS with this code.