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Biology LibreTexts

18.3: Aerobic Respiration

Skills to Develop

  • Define aerobic respiration.
  • Give the overall chemical reaction for aerobic respiration.
  • Name the four stages of aerobic respiration.

Aerobic respiration is the aerobic catabolism of nutrients to carbon dioxide, water, and energy, and involves an electron transport system in which molecular oxygen is the final electron acceptor. Most eukaryotes and prokaryotes use aerobic respiration to obtain energy from glucose. The overall reaction is:

\[C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O \label{1}\]

Note that glucose (\(C_6H_{12}O_6\)) is oxidized to produce carbon dioxide (\(CO_2\)) and oxygen (\(O_2\)) is reduced to produce water (\(H_2O\)). This reaction is a strongly driven reactions and "releases" energy as ATP molecules. This type of ATP production is seen in aerobes and facultative anaerobes. Obligate aerobes are organisms that require molecular oxygen because they produce ATP only by aerobic respiration. Facultative anaerobes, on the other hand are capable of aerobic respiration but can switch to fermentation, an anaerobic ATP-producing process, if oxygen is unavailable.

Aerobic respiration involves four stages:

  • glycolysis,
  • a transition reaction that forms acetyl coenzyme A,
  • the citric acid (Krebs) cycle, and an electron transport chain and
  • chemiosmosis.

We will now look at each of these stages.

Summary

  1. Aerobic respiration is the aerobic catabolism of nutrients to carbon dioxide, water, and energy, and involves an electron transport system in which molecular oxygen is the final electron acceptor.
  2. The overall reaction is: C6H12O6 + 6O2 yields 6CO2 + 6H2O + energy (as ATP). Glucose (C6H12O6 ) is oxidized to produce carbon dioxide (CO2) and oxygen (O2) is reduced to produce water (H2O).
  3. This type of ATP production is seen in aerobes and facultative anaerobes.
  4. Aerobic respiration involves four stages: glycolysis, a transition reaction that forms acetyl coenzyme A, the citric acid (Krebs) cycle, and an electron transport chain and chemiosmosis.

Contributors

  • Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS)