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Respiration

Respiration is the process of breaking down glucose, typically in living cells, for the purpose of releasing energy.

There are two types of respiration:

  • Aerobic: Completely breaks down glucose, uses oxygen, and releases more energy.
  • Anaerobic: Partially breaks down glucose, doesn't use oxygen, and releases less energy.

Aerobic Respiration

Aerobic Respiration happens in the mitochondria of living cells, and breaks down glucose in the presence of oxygen into carbon dioxide and water. This can be represented with the following chemical equation:

glucose + oxygen => carbon\,dioxide + water\,(+\,energy)

or the following symbol equation:

C_6H_{12}O_6 + 6O_2 => 6CO_2 + 6H_2O\,(+\,ATP)

Anaerobic Respiration

Anaerobic Respiration happens with a lack of oxygen, as does not completely break down the glucose molecule. As less bonds are broken, less energy is released. It can happen in both muscles, and plants/yeast.

In Muscles

When there is not enough oxygen available to the muscles to perform aerobic respiration during heavy exercise, they will begin to anaerobically respire - using stored glucose which gets broken down into lactic acid. This can be represented with the following chemical equation:

glucose => lactic\,acid\,(+\,energy)

or the following symbol equation:

C_6H_{12}O_6 => 2C_3H_6O_3\,(+\,ATP)

In Plants and Yeast

Anaerobic Respiration can also happen in plants and some microorganisms (such as yeast where it can be used to rise bread). It will break glucose down into ethanol and carbon dioxide. This can be represented with the following chemical equation:

glucose => ethanol + carbon\,dioxide\,(+\,energy)

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