Aerobic Respiration

Aerobic Respiration

Key Stages of Respiration:

  • Respiration produces ATP.


  • The first stage of anaerobic and aerobic respiration.
  • Takes place in the cytoplasm.
  • Involves the phosphorylation of glucose to glucose phosphate using ATP, production of triose phosphate, and oxidation of triose phosphate to pyruvate.
  • Results in a net gain of ATP and reduced NAD.
  • In anaerobic respiration, pyruvate can be converted to ethanol or lactate using reduced NAD, with oxidised NAD used in further glycolysis.

Aerobic Respiration:

  • Pyruvate from glycolysis enters the mitochondrial matrix by active transport.
  • Pyruvate gets oxidised to acetate, producing reduced NAD.
  • Acetate combines with coenzyme A in the link reaction to produce acetylcoenzyme A.
  • Acetylcoenzyme A reacts with a four-carbon molecule, releases coenzyme A, and produces a six-carbon molecule that enters the Krebs cycle.
  • The Krebs cycle generates reduced coenzymes and ATP by substrate-level phosphorylation, and carbon dioxide is lost.
  • ATP synthesis by oxidative phosphorylation is associated with the transfer of electrons down the electron transfer chain and passage of protons across inner mitochondrial membranes, catalysed by ATP synthase.
  • Other respiratory substrates include breakdown products of lipids and amino acids, which enter the Krebs cycle.

Additional Information:

  • Aerobic respiration involves all stages, while anaerobic respiration is just glycolysis.
  • A flow chart is recommended to show each reaction and where in the cell it takes place.