Aerobic system

• stages:

  1. aerobic glycolysis
  2. krebs cycle
  3. electron transport chain
• aerobic glycolysis:

  • sarcoplasm
  • converts glycogen into pryuvic acid by enzyme PFK
  • resynthesises 2 moles of ATP
  • link reaction catalysed by coenzyme a, producing acetyle coA - allows access to mitochondria
• aerobic glycolysis:

  glycogen = (GPP) glucose = (PFK) pryuvic acid = (coenzyme a) acetyle coA
• krebs cycle:

  • matrix of mitochondria
  • acetyle coA combines with oxaloacetic acid to form citric acid, which is oxidised
  • carbon dioxide, hydrogen and energy for 2 moles of ATP are released
• krebs cycle:

  acetyle coA = (oxaloacetic acid) citric acid = (oxidised) = krebs cycle

  = carbon dioxide

  = hydrogen ion

  = 2 moles of ATP
• electron transport chain:

  • hydrogen atoms are carried through ETC along the cristae by NAD and FAD splitting ions and electrons
  • hydrogen ions (H+) are oxidised and removed as water (h2o)
  • hydrogen electrons carried by NADH2 release energy for 30 moles of ATP
  • FADH2 release energy for 4 moles of ATP
  • overall yield of 34 moles of ATP

  when all stages complete one moles of glucose yields is 38 moles of ATP
• krebs cycle - second stage of aerobic system producing energy to resynthesises 2 ATP in the matrix of the mitochondria
• electron transport chain - third stage of aerobic system producing energy to resynthesises 34 moles of ATP in the mitochondrial cristae
• Electron transport chain:

  H+ (ions) = oxidised = water (h20)

  H- (electrons) = NAD & FAD

  = reduced FAD = 4 moles of ATP

  = reduced NAD = 30 moles of ATP
• type of reaction: aerobic

  site: cytoplasm, matrix and cristae of mitochondria

  fuel: glycogen/glucose and triglycerides (FFAS)

  enzymes: GPP, PFK, coenzyme a and lipase

  yield: 1:38

  by products: co2 and h20

  intensity: low-moderate/sub-maximal intensity

  duration: 3+ minutes
• strengths:

  • large yield store: triglycerides, FFAs, glycogen and glucose
  • high ATP yield and long duration of energy production
  • no fatiguing byproducts
• weaknesses:

  • delay for oxygen delivery and complex series of reactions
  • slow energy production limits activity to sub-maximal intensity
  • triglycerides or FFAs demand around 15% more oxygen for breakdown
• • glycogen stores are large and fuel aerobic system for a significant period of time
  • however, long distance/endurance athletes want to preserve glycogen as it can be broken down aerobically and anaerobically
• aerobic systems and FFA's

  triglycerides or fats can be metabolised aerobically as free fatty acids (FFA's). This provides a huge potential fuel store which conserves glycogen and glucose for high intensity sections

  • lipase converts triglycerides into FFA's and glycerol.
  • FFA's are converted into acetyle CoA following the same path into the krebs cycle.
  • a higher energy yield so more preferable In long distance atheltes.
  • However, FFA's require 15% more oxygen to metabolise