Aerobic energy system

Specification Aerobic energy system – simplified biochemistry in the breakdown, release and regeneration of ATP in glycolosis, the Kreb cycle and Electron transport chain, role of mitochondria, use in sporting situations – oxygen deficit, Excess Post-exercise Oxygen Consumption, including fast and slow components of the recovery process – VO2 max-limiting factor to performance.

Summary of Aerobic Energy Production Glycolysis with oxygen, Glycogen  Pyruvate + 2 moles of ATP  Pyruvate turns into Acetyle Co-Enzyme A  Mitochondria- matrix(Krebs Cycle) When glycogen runs out, Triglycerides are used. Fats  Beta Oxidation  Krebs cycle 2 moles of ATP are made in the Krebs cycle, CO2 is produced Hydrogen is removed, and this is transferred to the Mitochondira- Cristae (Electron transport system)

Electron transport system Water is formed when electrolytes and hydrogen are combined with oxygen through a series of enzyme reactions Resynthesis of ATP – 34 moles of ATP ‘Large amount’

From mark scheme/How majority of energy used in a marathon (Part of 14 mark question) A. Majority produced by the aerobic system/oxygen B. Glycolysis/Anaerobic glycolysis C. Carbohydrates/glycogen/glucose D. Broken down into pyruvate/ pyruvic acid E. Some ATP produced/2 ATP F. Krebs cycle G. Fats/triglycerides/fatty acids/glycerol H. Beta oxidation I. Oxidation of acetyl-coenzyme-A/Citric acid/ production of CO2 J. Electron transport chain K. Water/H2O formed/hydrogen ions formed (H+)/hydrogen/protons L. Large quantities of ATP produced or resynthesised/34-36 ATP

Krebs Cycle A. Pyruvic acid combines with acetyl CoA/acetyl coenzyme A B. Fatty acids combine with acetyl CoA/acetyl coenzyme A C. Beta oxidation occurs D. Forms oxaloacetic acid E. Oxaloacetic acid combines with coenzyme A F. Forms citric acid G. Oxidation of citric acid/ hydrogen ions/ H+ removed from citric acid H. Production/removal of carbon dioxide I. Hydrogen ions/H+/H2 passed onto the electron transport chain/electron transfer chain J. Resynthesis of 2 ATP/energy to form 2 ATP molecules

Advantages – More ATP can be produced – 36 ATP molecules No fatiguing bi-products, only CO2 & H2O) Large stores of glycogen and triglycerides means exercise lasts a long time. Disadvantages – Complicated system, which takes a while for enough O2 to be available to meet the demands of the activity & to make sure FFA and glycogen are broken down. FFA transportation to muscles is low – needs 15% more O2 to be broken down than glycogen.

EPOC Excess Post-exercise Oxygen Consumption +Oxygen Debit

Four tasks that need to be done Replenishment of ATP Removal of lactic acid Replenishment of myoglobin with oxygen Replenishment of glycogen

Definition EPOC explanation – volume of oxygen consumed in recovery above the resting rate

Fast component B. The alactacid/alactic (debt/component) C. Re-saturation of myoglobin/haemoglobin with oxygen D. Re-synthesise ATP/PC levels E. Uses 2-4 litres of oxygen F. Completed in 2-3 minutes G. 50% PC stores replenished within 30 seconds/75% within 60 seconds

Slow component Lactacid oxygen debt The portion of oxygen required to remove lactic acid from the muscle cells and blood

Slow component – oxygen functions Removal of lactic acid – Lactic acid  pyruvate  CO2, water, muscle glycogen, blood glucose, protein Maintenance of elevated heart and respiratory rates – Keep increased heart rate so oxygen can get to muscles, saturate myoglobin, resynthesize muscle phosphates and remove lactic acid Replenishment of glycogen stores – Carb window Elevated body temperature – Speeds up process.

Factors that affect V02

Q. Lifestyle – lack of exercise/smoking/poor diet/fitter/ R. Training – continuous/aerobic/fartlek improves VO2 max/stamina/endurance training S. Age – VO2 max decreases with age T. Physiology – number of slow twitch fibres/capillary density/number of mitochondria/haemoglobin content/surface area of alveoli/red blood cell count/efficiency of heart or equivalent U. Physiology – any other example named in point T V. Genetics – inherited factors of physiology limit possible improvement W. Gender - men generally have approx. 20% higher VO2 max than women X. Body composition – higher percentage of body fat decreases VO2 max/poor diet reduce VO2 max/overweight/obese