Aerobic respiration vs Anaerobic respiration: what's the difference?
GCSE Biology
Both release energy from glucose; the difference is whether oxygen is used and how much energy is released.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Aerobic respiration vs Anaerobic respiration — side by side
| Aerobic respiration | Anaerobic respiration | |
|---|---|---|
| Oxygen | Used | Not used |
| Energy released | Large amount | Small amount |
| Products (in muscle cells) | Carbon dioxide + water | Lactic acid |
| Products (in yeast) | — (aerobic gives CO₂ + water) | Ethanol + carbon dioxide (fermentation) |
| Complete breakdown of glucose? | Yes | No (incomplete) |
Exam tip — how to tell them apart: AERobic needs AIR (oxygen) and gives more energy. Anaerobic = "an" (without) air → lactic acid in animals, ethanol in yeast.
Common trap: In animals anaerobic respiration produces lactic acid (not ethanol) — ethanol/CO₂ is the yeast (fermentation) version.
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