When oxygen supply is insufficient โ for example, during an intense sprint โ your cells switch to anaerobic respiration. This happens in the cytoplasm (not the mitochondria) and produces far less ATP per glucose molecule.
In Animals (Including Humans)
glucose โ lactic acid
Lactic acid builds up in muscles, causing the burning sensation and fatigue during intense exercise. It is only a temporary solution โ the body must deal with the lactic acid afterwards.
In Plants and Yeast (Fermentation)
glucose โ ethanol + carbon dioxide
This process is used commercially in brewing (ethanol production) and bread-making (COโ makes dough rise). Note the critical difference: animal cells produce lactic acid, while yeast and plant cells produce ethanol and COโ.
This deep dive covers Anaerobic Respiration: Energy Without Oxygen within Respiration for GCSE Biology. Topic 2: Respiration It is section 4 of 17 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Respiration
Where in the cell does aerobic respiration take place?
Give three uses of energy released from respiration.