cp 9&10

• Aerobic uses oxygen; anaerobic doesn't
• Aerobic happens in mitochondria; anaerobic in the cytoplasm
• Aerobic produces carbon dioxide and water; anaerobic releases lactic acid
• Photosynthetic pigments


  Different solubilities in solvents
• Coloured liquid moving along capillary tube in a respirometer

  1. Insects remove oxygen from the air as they respire

  2. Carbon dioxide they release is absorbed by the soda lime

  3. Drop in air volume reduces the pressure
• Respirometer


  Device used to investigate the factors affecting the rate of aerobic or anaerobic respiration
• Core practical 9 - Investigate the factors affecting the rate of aerobic or anaerobic respiration using a respirometer


  • IV - temperature - thermostatically controlled water bath (20,25,30,35,40oC)
  • DV - volume of oxygen uptake - mm3 per min per gram
  • Controls - Mass of organism - measure with a balance
  • Volume of air - keep the boiling tube the same size
  • Volume of CO2 absorbed - use the same mass of soda lime
  • Age/Species of insect
  • Compare the results to a control tube that contains no organism
  • Calculate the volume using (pi)r2h
• Purpose of syringe and 3 way valve

  To investigate the effect of temperature on the rate of respiration
• Water bath


  Maintains a constant temperature for the respiration experiment
• Core practical 10 - Investigate the effect of different wavelengths of light on the rate of photosynthesis
• Very similar to the respiration core practical