PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 1014-1Muscle MetabolismMuscles have high demand for ATPenergy for myosin head recharge, sr Ca++ pump, sarcolemma Na+/K+ATPase…ATP consumption:ATP -> ADP + Pi + Energy Muscles store little ATP yet can sustain activity for long periodsATP must be produced and consumed rapidlyNeed enzymes to make new ATP or restore via phosphorylation of ADP (ADP + P  ATP)14-2Muscle energy supplyMuscle fibers store glycogen as energy sourcepolymer of glucoseAlso import fatty acids, glucose from blood14-3CO2 (waste)Glucose (fuel)oxidativephosphorylationO2AEROBICGeneral CellMetabolismCreatine KinaseADPCREATINECREATINEPHOSPHATE30 + ATP /glucosepyruvateTCAETCH2O (waste)14-4CP is a phosphagenused to rapidly phosphorylate ADP to provide ATP for contractionreversible reaction driven by substrateADPCREATINEPHOSPHATECreatine KinaseATPCREATINEHigh ATP and CreatineHigh ADP and CP14-5ADPATPCKCCPCP CKATPCADPCP selectively reserved to manufacture new ATP quickly for myosin heads (creatine phosphate shuttleCPCPCPCPAt restCCCCADPAt depletion14-6Ultimate source of ATP depends on level of cell activitySustained low to moderate activity low intensity, long durationglucose/fatty acids/pyruvic acid to ATP in mitochondriaATP to CP in mitochondriaCP used to supply myosin headsaerobic14-7Burst activity (pre-anaerobic)high intensity, short durationdirect phosphorylation of ADP by CPlimited by CP storage14-8Prolonged, intense activityCP stores used up fastATP supply limited by : 1. rates of aerobic enzymes, 2. O2 supply from bloodHighest activityCP gonenot enough O2 for aerobic metabolismFiber switches from aerobic toAnaerobic Glycolysis14-9GLYCOGENO2AEROBICCreatine KinaseADPCO2, H2OoxidativephosphorylationGeneral CellMetabolismATPCREATINECREATINEPHOSPHATELACTICACIDNO O2ANAEROBIC2/glucoseglycolysis14-10Aerobic MetabolismAdvantage: high yield of ATPDisadvantage: slow and dependent on blood supply of O2 (which may be limited), makes CO2Mechanism of choice when O2 availableAnaerobic GlycolysisAdvantage: fast ATP production, no rate-limiting O2 requirementDisadvantage: low ATP yield/glucose, toxic byproducts: heat, lactic acidCombination used depends on