Aerobic and anaerobic respiration

• Cellular respiration is an exothermic reaction which is continuously occurring in living cells.
• The energy transferred supplies all the energy needed for living processes.
• Respiration in cells can take place aerobically (using oxygen) or anaerobically (without oxygen), to transfer energy.
• Organisms need energy for:

  • chemical reactions to build larger molecules
  • movement
  • keeping warm
• Aerobic respiration is represented by the equation:

  glucose + oxygen --> carbon dioxide + water

  C6H12O6 + O2 --> CO2 + H2O
• Anaerobic respiration in muscles is represented by the equation:

  glucose --> lactic acid
• As the oxidation of glucose is incomplete in anaerobic respiration much less energy is transferred than in aerobic respiration.
• Anaerobic respiration in plant and yeast cells is represented by the equation:

  glucose --> ethanol + carbon dioxide
• Anaerobic respiration in yeast cells is called fermentation and has economic importance in the manufacture of bread and alcoholic drinks.