energy systems

• how long do ATP stores in muscle last

  3-4 seconds
• what enzyme breaks the last bond in ATP and what are the products?

  • ATPase
  • ADP and Pi with energy released
• what are the 3 energy systems?

  • ATP-PC system
  • anaerobic glycolytic system
  • aerobic system
• what is the fuel of the ATP-PC system?

  phosphocreatine
• how does the ATP-PC system work?

  • enzyme creatine kinase detects high levels of ADP
  • creatine kinase breaks down phosphocreatine to phosphate and creatine, energy is released
  • this energy is used to convert ADP to ATP in a coupled reaction
• give advantages of the ATP-PC system

  • ATP can be resynthesised quickly
  • PCr stores can be resynthesised quickly
  • no fatiguing by-products
  • can increase time ATP-PC system is used by use of creatine supplementation
• give disadvantages of the ATP-PC system

  • PCr stores last for 10 seconds
  • 1 ATP is resynthesised from 1 PCr breakdown
  • PCr resynthesis can only take place when there is oxygen
• where does anaerobic glycolysis take place?

  sarcoplasm of the muscle cell
• how does the anaerobic glycolytic system work?

  • enzyme glycogen phosphorylase breaks down glycogen into glucose
  • enzyme phosphofructokinase breaks down glucose into pyruvic acid and energy is released to resynthesize 2 ATP
  • enzyme lactate dehydrogenase breaks down pyruvic acid into lactic acid
• give advantages of the anaerobic glycolytic system

  • quick ATP resynthesis due to few chemical reactions
  • can be used for a sprint finish
• give disadvantages of the anaerobic glycolytic system

  lactic acid is produced, this denatures enzymes and prevents them from increasing the rate of chemical reactions taking place
• what are the stages of the aerobic energy system?

  • anaerobic glycolysis phase
  • krebs cycle
  • electron transport chain
• what happens during the anaerobic glycolysis phase?

  • phosphofructokinase breaks down glucose into pyruvate
  • pyruvate is then oxidised into acetyl-coenzyme-A by enzyme pyruvate dehydrogenase
  • acetyl-coenzyme-A combines with oxaloacetic acid to form critic acid
• what happens during the krebs cycle?

  • oxidation of critic acid, hydrogen atoms are moved and enter the electron transport chain
  • production of carbon dioxide due to carbon and oxygen combining and then is carried to the lungs to be breathed out
  • energy is released to resynthesize 2 ATP
• what happens during the electron transport chain

  • hydrogen ions and electrons combine with oxygen to form water
  • energy is released to resynthesize 34 ATP
• give advantages of the aerobic energy system

  • produces 36 ATP
  • no fatiguing by-products
• give disadvantages of the aerobic energy system

  • dependent on oxygen
  • takes longer to produce energy than other energy systems
• how long does the ATP-PC system last?

  up to 10 seconds
• how long does the anaerobic glycolytic system last?

  between 10 seconds to 3 minutes
• how long does the aerobic energy system last?

  more than 3 minutes
• how is lactate formed?

  • lactic acid breaks down quickly and releases hydrogen ions
  • the remaining compound combines with sodium or potassium ions and forms salt lactate
• what is lactate threshold?

  the point during exercise at which lactic acid quickly accumulates in the blood
• what is lactate threshold expressed as?

  a percentage of our VO2 max
• what when does OBLA?

  occurs when concentration of lactate is around 4 milimoles per litre
• what factors affect the rate of lactate accumulation?

  • exercise intensity
  • muscle fibre type
  • rate of blood lactate removal
  • respiratory exchange ratio
  • fitness of performer
• what is buffering?

  a process which aids the removal of lactate and maintains acidity levels in the blood and muscle