1. ATP ENERGY PRODUCTION

2. Energy The body needs a constant supply of energy to perform every day tasks such as respiration and digestion. Energy is the capacity to perform work and is measured in joules or calories. 2

3. Calorie, Joule and Watt Calorie is the amount of heat energy needed to raise the temperature of 1 gram of water through 1 o C. A Kilocalorie (kCal)is 1000 calories. Joule = 4.2 kCal. A Watt is equivalent to the use of one joule per second. Power is the work performed per unit of time and is measured in watts. 3

4. Work Work is defined as force x distance. It can be measured in calories and joules. Food Food is chemical energy. It is converted into movement (kinetic energy). Or is stored as potential energy. 4

5. Energy release in the body Energy release in the body is complicated. There is only one usable form of energy in the body – adenosine triphosphate (ATP). All food we eat has to be converted into ATP. ATP is a high energy phosphate compound made up of adenosine and 3 phosphates. The bonds that hold the compound together are a source of a lot of potential energy. ATP = adenosine-phosphate-phosphate-phosphate 5

6. When a compound is broken down( the bonds between the molecules are broken) the energy is released. ATP is broken down to adenosine diphosphate (ADP) and free phosphate, releasing the stored energy. ATP → ADP + P + Energy The energy released from the breakdown of ATP to ADP and P is converted to kinetic and heat energy. 6

7. Methods of ATP production Once ATP has been broken down to release energy it has to be put back. There are three ways that this is achieved in the human body: 1 The phosphocreatine system (ATP/PC) or alactic system. 2 The lactic acid system or anaerobic glycolysis. 3 The aerobic system. Each method is good at supplying energy for particular energy demands and duration. Systems 1 and 2 are anaerobic they take place without oxygen System 3 is aerobic: it requires oxygen to work. 7

8. The ATP Molecule Adenosine Energy Adenosine Triphosphate (ATP) The breakdown of ATP: P P P P P P ATP = ADP + energy for biological work + P (ADP = Adenosine Diphosphate) Energy for cellular function

10. ATP Production by Phosphocreatine or Alactic System Phosphocreatine is a high- energy phosphate compound. It is found in the sarcoplasm of the muscle. Potential energy is stored in the bonds of the compound. Phosphocreatine → P+ Creatine + Energy creatine kinase 10

11. Creatine kinase is activated when the level of ADP in the muscle cell increases. It is when the stores of ATP start to diminish. The energy released by the breakdown of PC is used to convert ADP to ATP. Energy has to be liberated by the breakdown of PC before ATP can be formed. Stores of PC in the muscles are enough to sustain all out effort for about ten seconds. 11

12. This is the only system capable of producing ATP quickly. During activities that demand large amounts of energy over a short period of time As PC is stored in the muscle it is readily accessible as an energy source. Energy for ATP can be obtained extremely quickly. No fatiguing by products are released. 12

14. ATP production by the lactic acid system or Glycolysis Also anaerobic taking place in the sarcoplasm. The energy needed comes from the food we eat. It involves the partial breakdown of glucose. Breakdown of PC does not rely on the availability of oxygen. It is much more complex than Phosphocreatine. It therefore stores more energy. 14

15. The Glycolytic System Involves the breakdown (lysis) of glucose by glycolytic enzymes. Glucose comes from the digestion of carbs & breakdown of glycogen during glycogenolysis. Glycogen is made from glucose during glycogenisis. Glycolysis produces pyruvic acid which is then converted to lactic acid in the absence of oxygen.

16. Glucose is broken down anaerobically (in absence of oxygen). Because there is no O 2 lactic acid is formed. Breakdown of bonds in glucose release energy. The energy is used to synthesise ATP. The lactic acid system takes longer to produce energy than the ATP/PC system. It supplies energy for high intensity activities for about a minute. The 400m is a good example. 16

17. Outline of Lactic Acid System (anaerobi glycolysis) Production of energy for resynthesis of ATP 17

18. ADENOSINE TRIPHOSPHATE (ATP) Formed in the breaking down ofGLUCOSE This in turn is broken down by a chemical reaction to give PYRUVIC ACID If there is insufficient oxygen LACTIC ACID accumulates This causes FATIGUE in the muscles. & H +

19. LACTIC ACID SYSTEM Glycogen made from glucose from digested food present in all cells of the body – muscles, liver When glycogen breaks down it releases pyruvic acid and energy. This energy is used to re-build ATP from ADP and P This system is anaerobic – no O 2 Pyruvic acid is easily removed when O 2 is available No O 2 = Pyruvic acid is converted into lactic acid Muscles fail to contract fully - fatigue

20. The lactic acid builds up due to the shortage of O 2 = oxygen debt  needs to be paid back once exercise has finished. Takes about 20 – 60 mins to remove accumulated lactic acid after maximal exercise Lactic acid build-up makes muscles feel tired & painful  exercising anaerobically can only be done for short periods of time.

21. Accumulation of Lactic Acid Lactic acid affects muscular contraction by: 1. Inhibiting the secretion of calcium that enables the coupling of actin and myosin protein filaments = protein filaments cant attach to each other. The sliding of the muscle protein filaments = not possible. 2. Inhibiting the action of the glycolytic enzymes = glucose not being broken down. Glucose is the food fuel for both anaerobic and aerobic glycolysis.

22. Fatigue When glycogen is broken down anaerobically lactic acid is produced. If lactic acid accumulates it lowers the pH (H + ). pH affects action of phosphofructokinase. It also affects lipoprotein kinase that breaks down fat. The body’s ability to synthesise ATP is temporarily reduced causing fatigue. 22

23. Production of ATP using the Aerobic System Needs oxygen. At the onset of exercise there isn’t enough O 2 to break down food fuels. So the 2 anaerobic systems are used. As heart rate and rate of ventilation increase more oxygen gets to the working muscles. Within 1-2 minutes the muscles are being supplied with enough O 2 to allow effective aerobic respiration. 23

24. Stage 1:Aerobic glycolysis Aerobic glcolysis is the same as anaerobic glycolysis. Glucose is broken down to pyruvic acid. As O 2 is now present the reaction can proceed further than in anaerobic glycolysis. Lactic acid is not produced. Two molecules of ATP are synthesised at this stage. 24

25. Stage 2: The TCA/Citric acid/Krebs’ Cycle The pyruvic acid produced in the 1st stage diffuses into the matrix of the mitochondria. A complex cyclical series of reactions now occurs. During the cycle three important things happen: 1.carbon dioxide is formed. 2.oxidation takes place-hydrogen is removed from the compound. 3.Sufficient energy is released to synthesis 2 molecules of ATP. 25

26. The Kreb’s Cycle. The pyruvic acid is taken by the enzyme acetyl CoA into the Kreb’s cycle in the mitochondria Glycogen Pyruvic acid 2 ATP Lactic acid Kreb’s cycle *Sarcoplasm* *Mitochondria* 2 ATP 2CO 2 Removed via lungs Acetyl CoA

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28. Stage 3:The Electron transport chain/electron transport system The H 2 atoms removed in stage 2 are transported by coenzymes to the inner membrane of the mitochondria. The electrons are passed along by electron carries combining with O 2 and H 2 ions to form water. Energy is released which combines ADP with phosphate to form ATP. The energy yield from the electron transport chain forms 34 molecules of ATP. The total yield of ATP from aerobic respiration is therefore 38 molecules of ATP. 28

29. The aerobic system of synthesising ATP is the most efficient. The byproducts (CO 2 and H 2 O) are easily expelled from the body. However the reactions involved in this system depend on the availability of O 2. 29

30. Electron transport chain Involves water (perspiration), heat and large amounts of ATP being released. Aerobic system breaks down carbs rather than fats to release energy (fats produce more ATP than carbs but require more O 2 to produce equivalent amount of ATP.) Aerobic system is fatigue resistant = primary source of ATP for endurance activities. Aerobic production of ATP happens in the mitochondria.

31. The ETC. Krebs cycle Hydrogen ETC O2 H2OH2O 34ATP Mitochondria matrix. Mitochondria cristae

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33. Characteristics of the 3 Energy Systems Energy System Aerobic/ Anaerobic Fuel/ Energy Source By-product Exercise intensity Duration Sporting Examples NOTES ATP/ PCAnaerobicATP/ PCCreatineHigh (Flat Out) 10 – 15 Seconds Sprinting, athletic field events, weight- lifting. Small muscular stores of ATP and PC are exhausted quickly leading to a rapid decline in immediate energy. Lactic Acid Anaerobic Glycogen Glucose Pyruvic Acid/ Lactic Acid High Intensity Up to 3 minutes 400m 800m Racket sports. Lactic acid is a by- product and can cause rapid fatigue. Aerobic Fat/ glucose mixture Water/ CO 2 Low3 minutes onwards Long distance running/ cycling. This system is limited by availability of O 2