respiration

• Respiration is a chemical reaction carried out in all living organisms to release energy from glucose
• Respiration


  The process of releasing energy from glucose
• Respiration occurs


  With oxygen (aerobic) or without oxygen (anaerobic)
• The waste products of aerobic respiration are carbon dioxide and water
• Respiration


  A chemical reaction carried out in all living organisms to release energy from glucose
• Respiration can occur with oxygen (aerobic) or without oxygen (anaerobic)
• Waste products of aerobic respiration

  Carbon dioxide and water
• Energy transfer during respiration


  Energy is transferred in the form of ATP (adenosine triphosphate)
• Difference between respiration and gas exchange


  Respiration releases energy from glucose using oxygen, while gas exchange involves getting oxygen into the body and removing carbon dioxide
• Uses of energy in living organisms


  • Chemical reactions
  • Muscle contraction
  • Maintaining body temperature
  • Growth and cell division
  • Active transport
  • Passage of nerve impulses
  • Protein synthesis
• Cellular respiration is an exothermic reaction as it releases heat
• ATP


  A molecule that is produced during respiration and provides energy in living organisms
• Role of ATP


  Releases energy for cellular processes
• ATP is produced during both aerobic respiration and anaerobic respiration, however, less ATP is produced in anaerobic respiration
• Difference in reactants between aerobic and anaerobic respiration


  Aerobic respiration includes oxygen, anaerobic respiration does not include oxygen
• Aerobic respiration produces more ATP than anaerobic respiration
• Aerobic respiration


  The process of releasing energy from glucose in the presence of oxygen
• Anaerobic respiration


  The process of releasing energy from glucose in the absence of oxygen
• Waste product of anaerobic respiration in animals

  Lactic acid
• Anaerobic respiration occurs in the absence of oxygen
• Glucose is the source of energy for both aerobic and anaerobic respiration
• Anaerobic respiration involves the incomplete breakdown of glucose into lactic acid which is later broken down further as oxygen becomes available
• Word equation for aerobic respiration


  Glucose + Oxygen → Carbon Dioxide + Water (+ energy)
• Balanced chemical equation for aerobic respiration

  C6H12O6 + 6O2 → 6CO2 + 6H2O
• In the balanced chemical equation for aerobic respiration, one molecule of glucose combines with six molecules of oxygen
• Reactants of aerobic respiration


  • Glucose
  • Oxygen
• Products of aerobic respiration


  • Carbon dioxide
  • Water
• Anaerobic respiration


  The chemical reaction in cells that breaks down nutrient molecules to release energy without using oxygen
• Anaerobic respiration does not require oxygen
• When anaerobic respiration mainly occurs in animals


  In muscle cells during vigorous exercise
• Word equation for anaerobic respiration in animals


  Glucose → Lactic Acid
• Balanced chemical equation for anaerobic respiration in animals

  C6H12O6 → 2C3H6O3
• Buildup of lactic acid in muscle cells


  Oxygen debt
• Fermentation


  Anaerobic respiration in yeast cells, producing ethanol and carbon dioxide
• Word equation for anaerobic respiration in plants and fungi


  Glucose → Alcohol + Carbon Dioxide
• Balanced chemical equation for anaerobic respiration in plants and yeast


  C6H12O6 → 2C2H5OH + 2CO2
• Purpose of the core practical: Investigating respiration


  To demonstrate the production of carbon dioxide and heat energy during respiration using different organisms
• Apparatus required for the core practical: Investigating carbon dioxide production in seeds


  • Boiling tubes
  • Rubber bungs
  • Hydrogen carbonate indicator solution
  • Cotton wool
  • Glass beads
  • Germinating seeds
  • Boiled/dead seeds
• Role of the hydrogen carbonate indicator when investigating respiration in seeds


  Detects changes in carbon dioxide levels by changing colour
• Expected results from hydrogen carbonate indicator in a tube containing dead or boiled seeds


  Indicator would remain orange because dead or boiled seeds would not be respiring so no carbon dioxide would be produced