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Fitness and respiration


Respiration is the process by which energy is released from glucose.

Aerobic respiration

Aerobic respiration requires oxygen. It happens in cells when glucose reacts with oxygen. Here are the word and symbol - higher only - equations:

glucose + oxygen    →    carbon dioxide + water (+ energy)

C6H12O6 + 6O2    →    6CO2 + 6H2O (+ energy)

Energy is shown in brackets in each equation because it is not a chemical substance.

Anaerobic respiration

Anaerobic respiration does not need oxygen. It happens when there is not enough oxygen for aerobic respiration. Here is the word equation:

glucose    →    lactic acid (+ energy)

Much less energy is released by anaerobic respiration than by aerobic respiration.

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