Anaerobic Respiration and Fermentation
Without oxygen, cells ferment glucose for quick ATP.
About this topic
Without enough oxygen, cells can still release a little energy through glycolysis alone, producing 2 ATP per glucose. In animals, pyruvate is converted to lactic acid (lactate fermentation), causing muscle fatigue during hard exercise; the oxygen debt is repaid afterwards. In yeast and plants, alcoholic fermentation produces ethanol and CO₂.
Fermentation is used for bread, beer, wine and yoghurt. It is much less efficient than aerobic respiration, but works fast.
During a sprint, your muscles use oxygen faster than blood supplies it, so cells switch to lactate fermentation to keep making a little ATP. The lactate builds up, and afterwards you keep breathing heavily to repay the oxygen debt as the liver converts lactate back into glucose. In yeast, fermentation gives ethanol and carbon dioxide, which makes bread dough rise and produces beer and wine.
Fermentation is also used for yoghurt and cheese, where bacteria turn lactose into lactic acid. Anaerobic respiration releases far less energy than aerobic, only 2 ATP versus about 30. Muscle soreness after exercise is often blamed on lactic acid, but research suggests it is mostly caused by tiny tears in muscle fibres.
Key ideas
- Lactic acid in muscles
- Ethanol and CO₂ in yeast
- Yields much less ATP
Quick check
Use cases: where Anaerobic Respiration and Fermentation helps
- Homework: review the key idea behind Anaerobic Respiration and Fermentation before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Anaerobic Respiration and Fermentation without notes.
- Visual learning: play with the interactive lab to see how Anaerobic Respiration and Fermentation changes when you adjust its inputs.
- Teaching a friend: explain Anaerobic Respiration and Fermentation in your own words, then compare your version with the key ideas.
Biology underpins medicine, farming, conservation and biotechnology.
Frequently asked questions
What is Anaerobic Respiration and Fermentation?
Without oxygen, cells ferment glucose for quick ATP.
What will I learn in Anaerobic Respiration and Fermentation?
Lactic acid in muscles. Ethanol and CO₂ in yeast. Yields much less ATP.
Is Anaerobic Respiration and Fermentation part of Biology?
Yes. It is one of 150 Biology topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Anaerobic Respiration and Fermentation lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Anaerobic Respiration and Fermentation?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.