Glycolytic system

• type of reaction - anaerobic

  site of reaction - sarcoplasm

  by products - lactic acid

  intensity - high intensity e.g 400m/800m runner

  duration - up to 3 minutes dependent on exercise
• enzymes involved:

  • glucose phosphorylase (GPP)
  • phosphofructokinase (PFK)
  • lactate dehydrogenase (LDH)
• 1. Phosphocreatine and ATP stores fall after 10 seconds.
  2. If glucose levels dip enzyme, glucose phosphorylase (GPP) breaks down stored glycogen for more glucose, to maintain its concentration.
  3. ADP and phosphate level rise and trigger the release of phosphofructinase (PFK) to breaks down glucose to extract energy for continued ATP resynthesis
  4. This forms pyruvic acid - for every 1 mole of glucose broken down there is a net gain of 2 moles of ATP
  5. lactate dehydrogenase (LDH) is released which catalyses the conversion of pyruvic acid into lactic acid
• anaerobic glycolysis:

  glycogen (GPP) = glucose (PFK) = pyruvic acid + energy
• lactate pathway:

  pyruvic acid (LDH) = lactic acid

  energy + 2P + 2ADP = 2 ATP (endothermic)
• phosphofructokinase (PFK) - an enzyme which catalyses the breakdown of glucose
• anaerobic glycolysis - the partial breakdown of glucose into pryuvic acid
• lactase dehydrogenase (LDH) - an enzyme which catalyses the conversion of pyruvic acid into lactic acid
• glucose phosphorylase - an enzyme which catalyses the breakdown of glycogen into glucose
• OBLA = the onset on blood lactate accumulation, the point at which blood lactate levels rise and fatigue sets in
• glycogen (GPP) = glucose (PFK) = pyruvic acid (LDH) = lactic acid

  = 2 ATP
• advantages:

  • no delay of oxygen and large fuel stores in liver, muscle and blood stream
  • relatively fast breakdown of ATP resynthesis
  • provides energy for high intensity activities for up to 3 minutes
  • lactic acid can be recycled into fuel for further energy production
• weaknesses:

  • fatiguing bi-product lactic acid, reduces pH and inhibits enzyme production
  • relatively low ATP yield and recovery can be lengthy