Respiration
Aerobic respiration
Aerobic respiration is how a cell fully burns glucose using oxygen — releasing a large batch of ATP, plus carbon dioxide and water.
It runs in stages: glycolysis in the cytoplasm, then the link reaction and Krebs cycle, and finally oxidative phosphorylation on the inner mitochondrial membrane — where most of the ATP is actually made.
Because oxygen is the final electron acceptor, glucose is oxidised completely. That is why aerobic respiration gives far more ATP from one glucose than any anaerobic pathway.
Where students slip up
Two mix-ups: fermentation does NOT use oxygen (it's the anaerobic backup), and most ATP comes from the mitochondria, not from glycolysis — which nets only 2 ATP.
Why it helps in the exam: The ATP tally and 'which organelle' are repeat favourites.
Where this connects
The point of making all this ATP is to spend it. Pumping ions against their gradient across a membrane is one of the largest bills a cell pays.
Where the ATP gets spent →Quick check
Most ATP in aerobic respiration is produced at the:
- ACytoplasm, during glycolysis
- BRibosomes
- CInner mitochondrial membrane
- DNucleus