Applied Exercise Physiology Review Guide Exam I February 4 2014 1 What is ATP How does it function How is ATP formed the special carrier molecule of free energy Adenosine Triphosphate ATP Energy Currency o No ATP no conversion of energy Two major functions o 1 Extract potential energy from food and conserve it within the bonds o 2 Extract and transfer the chemical energy in ATP to power biological of ATP work ATP H2O ATPase catalyst ADP Pi Phosphorus G energy o Hydrolysis reversible reaction Very limited supply of ATP 2 3 seconds Creatine Phosphate o A high storage form of ATP which allows you to work past the amount of ATP o Creatine Kinase is triggered when there are high levels of ADP o ADP initiator triggers how much creatine phosphate will be created o More available than ATP but still a limited amount 6 8 seconds o Simple one step fast reaction that doesn t require the presence of oxygen occurs outside the mitochondria in the sarcoplasm o Macronutrients are stored in the body which allow us to move past the ATP and Creatine Phosphate 2 Differentiate between aerobic and anaerobic metabolism Aerobic presence of oxygen o Muscle cells can contract repeatedly without fatigue Anaerobic absence of oxygen o Muscle cells must rely on other reactions that do not require oxygen to o Fatigue fuel muscle contraction created during anaerobic metabolism in the cells impairment of muscle contractions due to waste products The proportion between aerobic and anaerobic metabolism changes depending on o The more intensely we exercise the greater the need for anaerobic ALWAYS use ATP engage creatine phosphate and then engage anaerobic glycolysis exercise intensity metabolism 3 Describe glycolysis A series of 10 enzymatically controlled chemical reactions create two molecules of pyruvate from the anaerobic breakdown of glucose Lactate forms when NADH oxidation does not keep pace with its formation in glycolysis IMPORTANT Where energy costs us and where NAD is involved 1 ATP to use glucose from the blood we do not always use glucose from the blood we also use glycogen from muscle which saves us 1 ATP glycogen glucose 6 phosphate fructose 6 phosphate 2 3 phosphoglyceraldehydes 2 1 3 diphosphoglycerate 2 3 phosphoglycerate 2 phospho enol pyruvate 2 pyruvic acid lactate or lactic acid o Glucose 6 phosphate fructose 6 phosphate 1ATP o 2 3 phosphoglyceraldehydes 2 1 3 diphosphoglycerate NAD NADH o 2 phospho enol pyruvate 2 pyruvic acid 2ATP o 2 pyruvic acid lactate or lactic acid NADH NAD We store glycogen a couple predominant places muscle and liver Occurs in the cytoplasm Helps if oxygen is available but it doesn t need it Glycogenolysis breaking down the glycogen molecule Pyruvic acid or pyruvate is the end product of glycolysis Grossed 4 ATP but net total is different since some ATP are lost in the process o Net total 2 if taken as glucose from the blood o Net total 3 if taken from glycogen 4 Describe the Krebs Cycle and ETS Aerobic energy metabolism Phase 1 acetyl CoA breakdown Phase 2 o In the mitochondria the Krebs Cycle generates hydrogen atoms during o Significant quantities of ATP regenerate when these hydrogens oxidize via the aerobic process of electron transport oxidative phosphorylation ETC All values are doubled when computing the net gain of hydrogen and carbon dioxide because two molecules of pyruvate form from one glucose molecule in glycolysis o Kreb s Cycle produces 1 FADH2 3 NADH 1 ATP o Accounting for 2 pyruvic acid molecules the total outcome is 2 FADH2 6 NADH 2 ATP Electron Transport Chain o Every NADH electron will yield 3 ATP 5 Compare and contrast the three energy systems Energy Sources o Fat Big energy source predominately stored as adipose tissue throughout the body Less accessible for cellular metabolism since it must first be reduced from its complex form triglyceride to the simpler components of glycerol and free fatty acids Triacylglycerol molecule glycerol and fatty acid o Can be stored directly within muscle as lipoprotein complexes or circulating free fatty acids Fatty acid prepares to enter the citric acid cycle through beta oxidation in the mitochondria oxygen required o All it does is break off 2 carbons until the entire FA degrades to acetyl CoA for direct entry into the citric acid cycle o The hydrogens released during FA catabolism oxidize through the respiratory chain Energy release too slow for intense exercise o Carbohydrate At rest taken up by the muscles and liver and converted into glycogen In the liver glycogen can be converted into glucose and transported to the muscles via the blood Energy release much quicker than fat ideal for intense exercise Not a great source of fuel costly to use and replace Must be broken down into amino acids before being converted to o Protein glucose Energy Systems o ATP PCr Makes the most ATP independent of time o Glycolytic lactic acid anaerobic o Oxidative aerobic Makes the most ATP per minute 6 Describe oxygen deficit and oxygen debt during light and heavy exercise Oxygen deficit period during which the level of oxygen consumed is below that required to supply all that ATP necessary to do that amount of work oxygen which would have been consumed at rest during that time amount of oxygen consumed during recovery excluding the Oxygen debt There will ALWAYS be an oxygen deficit but can be decreased through training Heavy aerobic exercise requires a longer time to achieve steady state larger oxygen deficit Larger oxygen deficit larger oxygen debt 7 Describe what occurs in the phases of oxygen debt specifically the alactaid and lactaid portions 2 phases to recovery o Fast component Alactaid Acid Oxygen consumed drops off quickly coincides with the replenishment of ATP strong positive relationship 30 seconds 75 ATP replacement 60 seconds 90 ATP replacement o Slow component Lactaid Acid Need to replace depleted glycogen and remove excess lactic acid Some lactate does replace glycogen levels are dependent upon the severity of the glycogen depleted the more glycogen depleted the more lactate goes to produce glycogen 8 How is lactate formed during glycolysis What are the conditions under which it is formed When energy demands exceed the oxygen supply in the ETC a back up occurs NADH H is inhibited and donates its hydrogens to pyruvate reducing pyruvate temporarily to lactate Conditions o Low muscle oxygen o Accelerated glycolysis o Recruitment of fast twitch muscle fibers o Reduced rate of lactate removal from the blood 9 What
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