In Exercises 4762, find the determinant of the matrix. Expand by cofactors using the row or column that appears to make the computations easiest. 32110203
DietaryFats • Lipids:HDL,LDL,VLDL • Triglycerides:Actualfats • Phospholipids:Cellmembrane • Sterols:Cholesterol,testosterone Primaryenergysourceatrest&duringlow-intensityexercises • Mostconcentratedformofenergy Triglycerides Consistof3fattyacidtailsandoneglycerolhead Comprisesnearly95%offatindiet “triacylglycerol”–technicalterm Usuallycontainsacombinationofdifferentfattyacids Oils–predominantlypoly-andmonounsaturatedfattyacids • Vegetableoils–10-13%saturatedfattyacids • Coconutoil–92%saturatedfattyacids,6%monounsaturated,and2% polyunsaturated FattyAcids Chainsofcarbon&hydrogenwithcarboxylgroup(COOH)atoneend • Lengthvariesfrom4-24carbonbonds Saturatedfattyacids • Containsinglecarbonbond • Fromanimals • Solidatroomtemp Unsaturatedfattyacids • 1ormoredoublebonds • Plantsource • Liquidaroomtempandsolidatcoldtemp Monounsaturated • Onedoublebond Polyunsaturated • Twoormoredoublebonds Weconsumeabout16-18carbonbonds UnsaturatedFormation • Cis–groupsonsamesideofdoublebonds -allowsfattyacidstobend -facilitatesmovementacrosscellmembrane • Trans–groupsonoppositesidesofdoublebonds -producedsyntheticallythough“hydrogenation” TransFat Hydrogenation • Usedincommercialfoodprocessingtomakeliquidoilsmoresolid • Doublebondsonunsaturatedfatbroken,andhydrogenatomsadded • Canbefullorpartialsaturation Polyunsaturated • Doublebondbetweencarbonscountedfromlastcarboninchainfarthest fromcarboxylgroupcarbon • Omega-3,6and9 Omega-3fattyacids Alpha-linoleicacid(ALA) • Essentialfattyacid;cannotbemanufacturedbybody • Ex:soy,canola,andflaxseedoils,leafygreenveggies,fattyfish,andfishoil Eicosapentaenoicacid(EPA) • Marine(oily)fish-(salmon,mackerel,sardines) Docosahexaenoicacid(DHA) • Maincomponentofmembranephospholipase • SamesourcesasEPA Omega-6fattyacids Linoleicacid:notmanufacturedbythebody • Essentialfattyacidinmanyvegetableoils Arachidonicacid-foundinanimals • Precursortoprostaglandins&otherrelatedhormonecompounds Recommendedratio:omega-6:omega-3–4:1 • TypicalWesterndietsare15:1(animalfats) Oleicacid-Omega-9monounsaturatedfattyacid(ex.Oliveoil) • Helpsreducetheriskofheartdiseaseifsubstitutedforsaturatedandtrans fat Sterols&Phospholipids Compriseremaining5%offatsinfoods Sterols-ex:cholesterol,cortisol,vitaminD,andsexhormones • Groupoffatswithfourringstructure • ContainsoneormoreOHgroups&nocarbonyl(=C=O)orcarboxyl(COOH) groups Cholesterol–animalfoods • Cellmembranecomponent Phospholipids • Structuresimilartotriglyceridesbutincludesphosphateinglycerolhead withonly2fattyacids • Structuralcomponentofalllivingtissues Digestionoffats Occursprimarilyinsmallintestine Mixwithbilesalts&digestiveenzymesbeforecrossingintestinalcellmembranes Pancreaticlipase-breaksdownlargefattyacids • Monoglyceridesandfreefattyacids Absorptionoffats Exogenouspathway • Crossintomucosalcellsthroughpassivediffusion • Monoglycerideresynthesizedintotriglycerides Short-(4carbon)&medium-(6-10carbon)absorbedasfreefattyacids • Freefattyacidchainsisboundtoalbumininthebloodstream(non dissolvable) Majorityofdietaryfatsarelong-chainfattyacids Triglycerideincorporatedintochylomicronmolecule • Largetransportmoleculecontainingfats Chylomicroncomposition(lipoprotein) • Triglycerides–92% • Phospholipids–12% • Cholesterol–3% • Proteins–2% Chylomicronsreleasedslowlyintolymphaticvessels&enterbloodstream • Presentinbloodstream–1.5hoursaftermeal • Triglyceridemetabolizedbylipoproteinlipase -fattyacidsandglycerolabsorbedbyadiposeandmuscletissuecells -clearedfrombloodstreamafter12hrfast Chylomicronremnants-formedafterremovaloftriglyceridecore • Takenupbytheliverandremovedfromcirculation Storageoffats Esterification • Fattyacidsreformedintotriglyceridesforstorageinadipocytes • StimulatedbyinsulinandmediatedbyLPL Storedassubcutaneous&visceralfat&intramusculartriglycerides • Ex:myocardialandtypeIskeletalmuscle • Ex:Anhydrous Efficientstorageformofenergy Metabolismoffats Lipolysis-Fatsmobilizedfromstorage&brokendownintoglycerol&fattyacids • Catalyzedbyhormone-sensitivelipase(HSL) • Postabsorptivestate,fasting,starvation,stress,andexercise Fattyacids&glycerolcirculateinblood&takenupbyappropriatetissues • Mostofglyceroltakenupbyliver–metabolizedtoglucoseorreassemble intotriglycerides • Freefattyacids–boundtocarrierproteinandtransportinblood Fattyacidsdistributedtoothertissuesinbodyandmetabolized • Utilizationdependentonnumberofreceptorsites&transportmechanisms incellmembrane • Ex:heartmusclecellshavehighercapacityfatutilizationvs.TypeImuscles fiberwhicharehigherthanTypeII Provideahighsourceofenergybutmetabolicprocesscomplexandslow Metabolismofintracellularfats Fattyacidchainsconvertedtofattyacyl-CoA • Occursinoutermitochondriamembrane Fattyacyl-CoAtranslocatetoinnermitochondrialmatrix • Co-Aremovedandfattyacidattachedtocarnitinemolecule • Re-joinedwithCoAonceinsidemitochondria • Catalyzedbycarnitineacyltransferaseenzymes Increaseduptakeincellswithlargenumberofwell-developedmitochondria Beta-oxidation: • Fattyacidchainsconvertedtoacetyl-CoA&entersKrebscycle • Eachacetyl-CoA–generates10ATP;1NADHandFADHR • Ex:Palmitate-icecarbonfat:8acetylCoAand80ATP Ketones Conversionofacetyl-CoAtoketonebodies • Acetoacetate,acetone,&Β-hydroxybutyrate Upto185gofketonesproduceddailybyliver • Supplies2-6%ofbody’stotalenergyneedsafterovernightfast • Plasmalevels–<0.05MO/L Acceleratedfattyacidoxidation • Increasesproductionofketones • Ketosis Plasmalevels–>0.06MO/L Ketoacidosis–associatedwithdiabeticcomaanddeath Starvation,restrictionofcarbs,impairedmetabolism;Ketonesbecometheprimary sourceofenergyforbrain(76weeks,70%ofenergy) Restrictionofcarbsindiet • Gluconeogenesisoccursinfirst2-3days • After3days,glucoseprimarilymanufacturedfromglycerol Affectonathleticperformance • Lowglycogenstores • Inabilitytosustaintrainingandortrainathighintensities
