1.6 biology

• Chemical energy


  The type of energy stored in glucose
• Respiration


  A series of enzyme controlled reactions that releases chemical energy stored in glucose
• ATP


  Molecule of energy. It is generated when the energy is released from the breakdown of glucose
• Uses of ATP in cellular activities

  • Muscle cell contraction
  • Cell division
  • Protein synthesis
  • Transmission of nerve impulses
• Pyruvate


  Glucose is broken down into two molecules of this, yielding two molecules of ATP
• Aerobic respiration


  Respiration that occurs with oxygen present
• The final products of aerobic respiration

  • Carbon dioxide
  • Water
  • A large number of ATP molecules
• Fermentation


  Respiration in the absence of oxygen
• Lactate


  Pyruvate is converted to this in the absence of oxygen in animal cells producing only two ATP molecules
• Carbon dioxide and ethanol

  Pyruvate is converted to this in the absence of oxygen in plant and yeast cells producing only two ATP molecules
• Cytoplasm


  Where respiration begins and where fermentation is completed
• Mitochondria


  Where aerobic respiration is completed. Cells that require lots of energy require lots of these.
• Aerobic respiration


  Glucose + Oxygen Carbon dioxide + Water + ATP
• Aerobic respiration stages


  1. Glycolysis - Occurs in the cytoplasm, converts glucose into two pyruvate molecules with a small amount of ATP production, oxygen not required

  2. Occurs in the mitochondrion, requires oxygen, converts pyruvate into carbon dioxide and water releasing a large number of ATP
• Fermentation in animals


  Glucose Lactate + ATP
• Fermentation in animals stages

  1. Glycolysis - Exactly the same as aerobic respiration

  2. Pyruvate is converted into carbon dioxide and ethanol and releases no ATP, this is not reversible
• Respirometer


  Can be used to measure the rate (speed) of respiration of an organism, measures the rate of oxygen consumption over a given period of time, the coloured liquid moves up as oxygen is used, any carbon dioxide produced is absorbed by the chemical at the bottom of the tube, the tube on the right is a control with no living thing present