Respiration

• Aerobic respiration

  1. Enzyme-controlled chemical reactions in the mitochondria

  2. Glucose and oxygen carried by blood and diffuse into cells

  3. Glucose reacts releasing stored energy
• Anaerobic respiration

  1. Shorter series of enzyme-controlled reactions

  2. Partially breaks down glucose

  3. Releases some energy

  4. Can occur without oxygen
• Oxygen debt

  Amount of oxygen needed to remove toxic lactic acid produced in anaerobic respiration
• Respiratory system

  Obtains sufficient oxygen for respiration and removes waste gases carbon dioxide and water
• Inspiration

  1. Intercostal muscles contract lifting ribs up and out

  2. Diaphragm contracts and flattens

  3. Chest cavity increases in volume and decreases in pressure, air is sucked in
• Expiration

  1. Intercostal muscles relax and ribs move down and in

  2. Diaphragm relaxes and domes up

  3. Chest cavity decreases in volume and increases in pressure, air is forced out
• Alveoli

  • Good blood supply
  • Large surface area
  • Thin walls
  • Moist lining
• As red blood cells and plasma in blood capillary flow around alveolus

  Oxygen diffuses into the capillary and carbon dioxide diffuses out
• Thermometer to record temperature changes
• Thermos flask to reduce heat lost through the sides
• Investigating respiration in germinating peas

  1. Peas respire releasing heat, temperature goes up

  2. Peas boiled, no respiration by peas but temperature still increases slightly due to respiring microbes

  3. Boiled and disinfected peas, temperature does not increase as no respiration occurs
• Glucose + Oxygen


  Carbon dioxide + Water + Energy (released as ATP)
• anaerobic respiration

  Lactic acid + Energy (less ATP produced, partial breakdown as no oxygen available)