If cells can respire anaerobically, why do humans need oxygen?

Cells can indeed respire - or release energy - without oxygen, using anaerobic respiration. Here, energy is released from glucose to generate a substance called lactic acid. This is a good temporary solution for our cells if the oxygen supply is interrupted, or if cells are respiring at such a high rate that the oxygen supplied can't keep up. However, lactic acid build-up can harm a cell: it reduces the pH, which affects enzymes and other cellular processes. Therefore anaerobic respiration cannot be used for a prolonged period of time without having damaging effects on a cell. To remove lactic acid, it must be oxidized to CO2 and water at a later point - and this requires oxygen. Of course, when sufficient oxygen supply is restored, aerobic respiration can be used, which doesn't produce lactic acid.

SJ
Answered by Samuel J. Biology tutor

24115 Views

See similar Biology GCSE tutors

Related Biology GCSE answers

All answers ▸

Why does a mutation in the genetic code change the structure of a haemoglobin molecule?


What are the names given to the body's first and second line of defence against disease? Name an example for each and how it works to prevent disease.


Describe a simple food chain and the trophic levels within it


Describe 2 ways in which the body prevents entry of microorganisms into the body


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning