Aerobic and Anaerobic Respiration

• Cellular respiration is an endothermic reaction which is continuously occurring in living cells
• The energy transferred during respiration supplies all the energy needed for living processes
• Respiration in cells can take place aerobically (using oxygen) or anaerobically (without oxygen)
• Aerobic respiration needs lots of oxygen
• Aerobic respiration goes on all the time in plants and animals
• Most of the reactions for aerobic respiration take place in the mitochondria
• Aerobic respiration equations:

  • glucose + oxygen --> carbon dioxide + water
  • $C_6H_12O_6 +$$6O_2 --> 6CO_2 +$$6H_2O$
• Anaerobic respiration takes place if there isn't enough oxygen
• When you do vigorous exercise, and your body can't supply sufficient energy to your muscles, they start doing anaerobic respiration as well as aerobic respiration
• Anaerobic respiration:

  • glucose --> lactic acid
• Anaerobic respiration is the incomplete breakdown of glucose, which makes lactic acid
• Anaerobic respiration does not transfer nearly as much energy as aerobic respiration
• Anaerobic respiration is only useful in emergencies, like during exercise when it allows you to keep using your muscles for a bit longer
• Anaerobic respiration in plants and yeast is slightly different
• Plant and yeast cells can respire without oxygen too, but they produce ethanol and carbon dioxide instead of lactic acid
• Anaerobic respiration in plant and yeast cells:

  • glucose --> ethanol + carbon dioxide
• Anaerobic respiration in yeast cells is called fermentation
• Fermentation has economic importance in the manufacture of bread and alcoholic drinks
• Organisms need energy for:

  • keeping warm
  • chemical reactions to build larger molecules
  • movement