Aerobic v Anaerobic

Specification Point 2.36
  • Describe the differences between aerobic and anaerobic respiration

differences between aerobic & anaerobic respiration, Edexcel IGCSE Biology

Aerobic Respiration

Specification Point 2.37
  • Know the word equation and the balanced chemical symbol equation for aerobic respiration in living organisms
  • Aerobic respiration requires oxygen
  • It is the complete breakdown of glucose to release a relatively large amount of energy for use in cell processes
  • It produces carbon dioxide and water as well as the useful energy

Glucose       +       Oxygen       →       Carbon dioxide       +       Water

C6H12O6       6O2       6CO2       6H2O

Anaerobic Respiration

Specification Point 2.38
  • Know the word equation for anaerobic respiration in plants and in animals
  • Anaerobic respiration does not require oxygen
  • It is the incomplete breakdown of glucose to release a relatively small amount of energy for use in cell processes
  • It produces different breakdown products depending on the type of organism it is taking place in

Anaerobic Respiration in Animals

  • Mainly takes place in muscle cells during vigorous exercise

Glucose       →      Lactic acid

  • The lactic acid builds up in muscle cells and lowers the pH of the cells
  • This could denature the enzymes in cells so it needs to be removed
  • This happens by oxidising the lactic acid (combining it with oxygen)
  • When this happens it can be broken down to carbon dioxide and water
  • This is the reason we continue to breath heavily even after finishing exercise – we need to continue getting larger amounts of oxygen into the blood to combine with the lactic acid produced
  • This is known as ‘repaying the oxygen debt’

Anaerobic Respiration in Plants & Yeast

  • We take advantage of the products of anaerobic respiration in yeast by using it in bread making (where the carbon dioxide produced helps dough to rise) and in brewing (where the ethanol produced makes beer)

Glucose → Ethanol + Carbon dioxide

Edexcel IGCSE Biology Notes

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Author: Caroline

Based in the stunning Cayman Islands, our resident environment expert Caroline is Head of Science at a local secondary school. When she’s not teaching or writing our Biology resources, she’s volunteering for the Department of Environment, helping monitor turtle nests and release hatchlings into the wild. A true biologist!