Anaerobic Glycolytic System

• Anaerobic Glycolytic System:

  • produce high-powered energy for high-intensity effort
  • how long the system lasts depends on the fitness of the individual and the intensity of the exercise
  • can last up to 2-3 mins
  • it resynthesised ATP from the break down of the fuel glucose (supplied from the digestion of carbs and is stored in the muscles and liver as glycogen)
• How it provides energy:

  • when PC stores are low the enzyme glycogen phosphorylase is activated to break down glycogen into glucose
  • glucose is then broken down into pyruvic acid by the enzyme phosphofructokinase (PFK)
  • this process takes place in the sarcoplasm of the muscle cell where O2 isn't available
  • the pyruvic acid is further broken down into lactic acid by the enzyme lactate dehydrogenase (LDH)
  • 2 ATP molecules are produced for 1 molecule of glucose broken down
  • (4 ATP molecules are actually produced but 2 are used to provide the energy for glycolysis)
• Advantages of the Anaerobic Glycolytic System:

  • its quick: ATP can be resynthesised quickly due to its very few chemical reactions and lasts for longer than the ATP-PC System
  • in the presence of O2, lactic acid can be converted back into the liver glycogen or used as a fuel through oxidation into CO2 + H2O
  • can be used for sprint finishes (i.e to produce an extra burst of energy)
• Disadvantages of the Anaerobic Glycolytic System:

  • lactic acid as the by-product -> denatures (inhibits) enzymes and prevents them increasing the rate at which chemical reactions take place
  • only a small amount of energy (2 ATP) can be released from glycogen under anaerobic conditions (5% as opposed to 95% under aerobic conditions)