Calculate the ATP yield from complete oxidation of one glucose molecule.
How to lay out the answer. Follow the frame, then write it in your own words.
1 · Open in two lines. One glucose is fully oxidised to 6 CO2 and 6 H2O through glycolysis, the link reaction and the TCA cycle. Most ATP comes from NADH and FADH2 by oxidative phosphorylation.
2 · Draw the ATP table. [Table: stage, product, ATP by older and newer values, with the totals]
3 · Add up each stage.
Glycolysis: 2 ATP + 2 NADH.
Pyruvate → acetyl-CoA: 2 NADH.
TCA cycle (2 turns): 6 NADH + 2 FADH2 + 2 GTP.
4 · Give both totals. Older values (NADH 3, FADH2 2): 38, or 36 with the glycerol-phosphate shuttle. Newer values (2.5, 1.5): 32, or 30.
5 · Significance. Aerobic oxidation gives 16 to 19 times more ATP than glycolysis alone (2 ATP).
6 · Nutrition link. Needs niacin, riboflavin, thiamine and pantothenic acid, plus iron and copper for the electron transport chain.
7 · Close in one line. Sum up that most of glucose's energy is captured in the mitochondria by oxidative phosphorylation.
Scoring tip: Always show the table. Write both totals and say which values you used.
Write-up practice
The check looks for key words only. It does not grade your answer and never writes it for you.