Respiration

• Respiration is a chemical reaction carried out in all living organisms
• Process of Respiration


  1. Energy is released from glucose either in the presence of oxygen (aerobic respiration) or the absence of oxygen (anaerobic respiration)

  2. The reactions ultimately result in the production of carbon dioxide and water as waste products

  3. Energy is transferred in the form of ATP
• The equation for aerobic respiration
• Respiration


  Not to be confused with gas exchange. Gas exchange involves getting oxygen into the cells and carbon dioxide out. Respiration uses the oxygen supplied from gas exchange to release energy in the form of ATP.
• Organisms need energy for

  • Chemical reactions to build larger molecules from smaller molecules
  • Muscle contraction to allow movement
  • Keeping warm (to maintain a constant temperature suitable for enzyme activity)
• ATP


  Adenosine Triphosphate, produced in respiration in the mitochondria, is required for living processes to occur within cells and organisms
• Cellular respiration is an exothermic reaction that is continuously occurring in living cells
• The chemical process of cellular respiration releases energy from glucose
• Comparing Anaerobic & Aerobic Respiration

  • Need for oxygen
  • Products
  • Relative amounts of energy transferred
• Aerobic Respiration


  1. Requires oxygen

  2. Complete breakdown of glucose to release a relatively large amount of energy

  3. Carbon dioxide and water are produced as waste products
• Aerobic Respiration Word Equation

  Glucose + Oxygen → Carbon Dioxide + Water
• Aerobic Respiration Chemical Equation

  C6H12O6 + 6O2 → 6CO2 + 6H2O
• Anaerobic Respiration


  1. Does not require oxygen

  2. Incomplete breakdown of glucose and so releases a relatively small amount of energy

  3. Different breakdown products are formed depending on the type of organism
• Anaerobic Respiration in Animals Word Equation

  Glucose → Lactic Acid
• Anaerobic Respiration in Animals Chemical Equation

  C6H12O6 → 2C3H6O3
• Anaerobic Respiration in Plants and Fungi Word Equation

  Glucose → Ethanol + Carbon Dioxide
• Anaerobic Respiration in Plants and Yeast Chemical Equation

  C6H12O6 → 2C2H5OH + 2CO2
• Practical: Investigating Respiration


  1. Demonstrating the production of carbon dioxide

  2. Demonstrating the production of heat
• Hydrogen Carbonate Indicator


  • Orange in atmospheric CO2 levels
  • Yellow in high CO2 levels
  • Purple in low CO2 levels
• Respiration is an exothermic reaction
• CORMS Evaluation


  • Change
  • Organisms
  • Repeat
  • Measurement 1
  • Measurement 2
  • Same