• The energy released from the breakdown of ATP to ADP + P is converted to kinetic and heat energy.• The bond then needs to be re-built to be broken down again to create more energy.• There are four ways that this is done in the body: 1. ATP System 2. Phosphocreatine system 3. Lactic Acid System 4. Aerobic Energy System
Phosphocreatine System• Phosphocreatine is found in the sarcoplasm.• When the enzyme ‘creatine kinase’ is present: Phosphocreatine --------------> P + Creatine + Energy• For every molecule of PC broken down, 1 molecule of ATP is produced.• No fatiguing by-products are released• Occurs between approximately 3-10 seconds of exercise.
ATP production in the lactic acid system• Involves the partial breakdown of glucose.• The enzyme ‘Phosphofructokinase’ is released when levels of phosphocreatine drop, and begin to break down the glucose molecules.• These molecules break down into two pyruvic acid molecules.• When oxygen is not present, pyruvic acid is converted into lactic acid by the enzyme ‘lactate dehydrogenase’.• For every mole of glycogen broken down, 2 molecules of ATP are gained.
The Aerobic System NO PYRUVIC ACID LACTIC ACID OXYGEN H2O 2 ATP OXYGEN ELECTRON TRANSPORT CHAINACETYL-COENZYME A KREBS CITRIC ACID CYCLE 34 ATP= Pyruvate Dehydrogenase
The Aerobic System• If Oxygen is present then the pyruvic acid will convert into oxygen, and then into acetyl co-enzyme A and then (due to PDH) into citric acid until proceeding on to Krebes Cycle.• In the Krebes cycle, 2 molecules of ATP are created.• Then after entering the “electron transport chain” 34 molecules of ATP are created. Water is a by-product.• Takes place in the mitochondria.
The relationship of: intensity, hydrogen and oxygen More Muscle More ATP hydrogen is More oxygen Exercise More glucose contraction must be released in is required to becomes is broken requires more resynthesized the electron combine withmore intense down ATP transport the hydrogen chain
Energy From Fats and Proteins FATS• Fat is stored in adipose tissue as triglycerides.• Requires more oxygen than the breakdown of glycogen.• The presence of lactic acid inhibits the fat breakdown. PROTEINS• Our bodies only rarely use proteins for ATP re-synthesis.• Only used when the body is in a state of exhaustion.
SUMMARY ATP-PC SYSTEM LACTIC ACID AEROBICSite of reaction Sarcoplasm Sarcoplasm Sarcoplasm + MitochondriaOxygen present Anaerobic Anaerobic AerobicFuel used Phosphocreatine Carbohydrates Carbohydrate and FatActive enzyme Creatine Kinase Phosphofructokinase Phosphofructokinase + LipaseEnzyme activated by ATP increase Decrease in PC levels Decrease in insulin levelsRelative speed Very fast Fast SlowBy-products None Lactic Acid Carbon Dioxide and WaterEffects of by-products None Inhibits enzyme None as easily expelled from bodyEnergy Yield 1 2 38Threshold 3-10 seconds 1-2 minutes Unlimited in sub-maximal exercise
OBLA (onset of blood lactate accumulation) • The point where blood lactate concentration rises to approximately 4mmol/l. • It is also the point where lactic acid cannot be removed quickly. • The lactate threshold is reached at a certain VO max. For elite athletes this will be at about 2 70-80%.
Excess post-exercise oxygen consumption (EPOC) “The amount of oxygen consumed during recovery above that which would have ordinarily been consumed at rest.” Made up of two main components: • Alactacid Component – The fast replenishment stage • Lactacid Component - The slow replenishment stageStage Time Oxygen used Function 1 Function 2 Function 3Alactacid Completed Up to 4 litres Re-saturate Resynthesise ResynthesiseStage within 2-3 myoglobin ATP PC minutes with oxygenLactacid Can take up 5-10 litres Lactic acid Replenishment Re-balanceStage to 2 hours removal of muscle body glycogen temperature stores
Energy sources used in aerobic energy systemGLYCOLYSIS BETA OXIDISATIONCarbohydrates Fats ProteinsStored in the muscle as Stored in adipose tissue as Stored in muscle cellsglycogen triglyceridesGlucose Fatty Acids Amino Acids ATTACHES TO FATTY ACIDS AND TRANSPORTED IN BLOOD OXYGEN ACETYL - COENZYME Glucose = 38 ATP Fatty Acids = 130 ATP THROUGH AEROBIC ENERGY SYSTEM