Chapter 2 The Molecules of Cells：2章细胞的分子.ppt

chapter2:themoleculesofcells,topicoutline,thermodynamicsfirstlawsecondlawsteadystatevsequilibriumchemistryatomsandmoleculeschemicalreactionswateracidsandbasesbiologicalmolecules,definitions,energypotentialkineticchemicalmatterandenergyareinterconvertible.workspontaneouschangevsnon-spontaneouschangedocharacteristicsofliferequirework?,typesofenergyinbiologicalsystems,kineticenergy-energyofmotion,workdonepotentialenergy-storedenergy,canbereleasedtodoworkarcherdrawsbowstringback-usedkineticenergytensionnowinbowstringrepresentspotentialenergyreleaseofbowstringconvertspotentialenergytokineticenergy,energy(contd),thermodynamics,asystem:someportionoftheuniversethatyouwishtostudy,thesurroundings:theadjacentpartoftheuniverseoutsidethesystem,i.e.everythingbutthesystem,changesinasystemareassociatedwiththetransferofenergy,naturalsystemstendtowardstatesofminimumenergy,1stlawofthermodynamics,totalenergyinuniverseisconstantenergycannotbecreatedordestroyedenergycanbeconvertedfromoneformtoanotherthepathwayofconversionisirrelevant,theenergychangebetweenidenticalinitialandfinalstatesisequalwhenitcomestoenergy-youcantgetahead!,2ndlawofthermodynamics-youcantbreakeven,either!,noconversionis100%efficient.totalusefulenergyinaclosedsystemdecreasesasconversionsoccur.closedsystemsgofromcomplextosimple.entropymeasureofdisorderclosedsystemstendtotheirhigheststateofdisorderentropyoftheuniverseincreaseswitheveryconversion,2ndlawofthermodynamics,randomnessisspontaneousinaclosedsystem,beakeronlefthasdifferentcoloredmarblesseparatedfromeachotherhighlyorderedsystemlowentropy,examplesofentropy,lowentropy,highentropy,beakeronrighthasdifferentcoloredmarblesscatteredamongsteachotherhighlydisorderedsystemhighentropy,otherexamples?,summary-thermodynamics,firstlaw:energycannotbecreatedordestroyed,butitcanbechangedfromoneformtoanother.secondlaw:energycannotbechangedfromoneformtoanotherwithoutlossofusableenergy,gradientsacasestudy,whatisagradient?typespressuretemperaturechemicalwhatdoesthe2ndlawsayaboutgradients?,equilibriums-closedsystemsgotoequilibrium,universe-200atomshydrogen182helium-18allothers1/2,human200atomshydrogen-126oxygen-51carbon19nitrogen3allothers-1,whathappensifyouachieveequilibrium?,equilibriumvssteadystate,livingthingsgofromsimpletocomplex.evolutiongoesfromsimpletocomplex.how?arebiologicalsystemsnotsubjecttothe2ndlaw?,basicchemistry,matterelements.atomscompoundsmolecules,modelofanatom,modelofanatom,periodictableofelements,atomicsymbolatomicnumberatomicmass(weight).,atoms,chemicalreactions,electronshellsvalence(outer)shelloctetruleionicbondscovalentbonds,atomswillstrivetofilltheirouter(valence)orbitals,ifanatomhas1valencee-,itshappytogiveitawayexample:sodium,1valencee-,atomswillstrivetofilltheirouter(valence)orbitals,andifanatomhas7valencee-,itshappytopickuponeex.chlorine,7valencee-,ionicbonds,ionscanhaveimportantbiologicalfunctions.,covalentbonding,carbon(c)4,hydrogen(h)1,methanech4,eachpairofelectronsrepresentstheformationofacovalentbond.,asidefromsinglecovalentbonds,double,ortriplecovalentbondscanform.,review,ionicbondsoccurwhene-aresharedina+/-arrangementcovalentbondsexistwhenoneatomshares1ormoree-withanotheratom.onecovalentbondmeans2e-areinvolved.alwaysinvolvesapairofe-,oxidation/reduction,oxidation-lossofelectronreduction-gainofelectronexamples?,wateristhemostabundantmoleculeinlivingthings.waterhasspecialtraitsthatmakeitimportanttolife.,waterandlife,watermolecules:2-hcovalentlybondedto1-o.covalent=sharede-.butissharingequal?,chemistryofwater,amazingstuff!shouldnotbealiquidatroomtemphighlypolarmolecule.,water,hydrogenbondspolarity,hydrogenbonding,positivelychargedhydrogenend,negativelychargedoxygenend,hydrogenbonds,covalentbondsbetweenhydrogenandoxygen,characteristicsofwater:,liquidatroomtemperatureuniversalsolventforpolarmoleculeswatermoleculesarecohesivewatermoleculesareadhesivetemperatureofwaterchangesslowlyabsorbsheatuponvaporizationreleasesheatuponfreezingfrozenwaterislessdense,waterasasolventhowitworks,dissociationofwatermolecules,waterdissociatesandreleaseshydrogenions(h+)andhydroxideions(oh-).,acidsandbases,acids-releasehydrogenions(h+)insolution.hclh+cl-bases-takeuphydrogenions(h+)orgiveoffhydroxideions(oh-)insolution.naohna+oh-,phameasureofacidity,ifph7,base,7=neutral,buffers-substancesthathelptoresistchangeinph.whyimportant?,waterfinalnotes,hydrophilic-polarhydrophobicnon-polaramphipathic-containhydrophilicandhydrophobicparts,organicmoleculesarefoundinlivingthings.thechemistryofcarbonaccountsforthechemistryoforganicmolecules.macromolecules(polymers),organicmoleculescarbonbased,organicmolecules,monomer,polymer,macromolecules(polymers)andmonomers.,polymermonomercarbohydratemonosaccharidesproteinaminoacidnucleicacidnucleotide,dehydrationsynthesisorcondensationreactionsvshydrolysis,a,b,oh,h,+,+hohorh2o,covalentbonds,ifthereactioniscarriedoutmultipletimesyoucreateapolymer!,+h2omolecules,condensation,hydrolysis,dehydration(condensation)builds.hydrolysisbreaksdown.,whatdotheydo?structureactasenzymestospeedreactionsserveascarriersactasantibodiestransportersandchannels,proteins,proteins-polymersofaminoacids.,peptidebonds,proteins-levelsoforganization.,tertiary(3)structure3d,1structureandenvironmentfactorsr-groupshydrogenbondinghydrophobicinteractionsionic(salt)bridgesdisulfidebondsnativevsdenaturedremember:aproteinsfunctionisaresultofitsform!,catalyst?speedsupreactionproteinsthemodel:,enzymesbiologicalcatalysts,e=enzymes=substratep=product,classesofenzymes,1.oxidoreductases2.transferases3.hydrolases4.lyases5.isomerases6.ligases,enzymeslowerenergyofactivation,eabarrier,reactants,1,products,2,enzyme,figure5.5a,enzymes-lowertheenergybarrier,enzyme-substratecomplexes,everyreactioninacellrequiresaspecificenzyme.enzymesarenamedfortheirsubstrates:substrateenzymelipidlipaseureaureasemaltosemaltaseribonucleicacidribonuclease,activesite,wheredoesenzymebindtosubstrate?howdoesenzymerecognizeitssubstrate?,inducedfitmodel,inducedfitmodel,enzymaticreaction,cellchemistry,enzymesinvolvedinalmostallchemicalreactions.anabolismthebuildingreactions.ex.proteinsynthesiscatabolismthebreakdownreactions.ex.proteindigestionmetabolismsumofallreactions,factorsaffectingenzymaticspeed,rememberformfollowsfunction!factorssubstrateconcentration-toapointenvironmenttemperaturephsaltconcentrationanythingthataffectsformaffectsfunction!,temperatureoptimumphoptimum,inhibitionmodels,inhibition-reducedactivitycompetitivee+s+ies+eie+poriorp2non-competitive(allosteric)e+s+inoorreducedese+noproductorreducedproductex.feedbackinhibition,feedbackinhibition,non-competitive(allosteric)inhibitionallostericsitevsactivesite,feedbackinhibition2,feedbackinhibition3,problem,ethanolethyleneglycol,enzymecofactors,cofactors-maybenecessaryforsomeenzymestocarryouttheirfunctions.twotypes:metalions.excopper(cu+2)oriron(fe+2)coenzymesorganicmolecules,mustbepresentforotherenzymestofunction.exvitamins,levelsofproteinstructurequaternary(4)structure,multiplechains:interactionsofmorethanonepolypeptidechaintoformthecomplete,functionalprotein.ex.hemoglobinandantibodies,generally,c:h:oina1:2:1ratio(ch2o)nfunctionsquickenergyandshort-termenergystorage.exglycogen,starchstructure.ex.cellulosepolymer=polysaccharidesex.starchmonomers=monosaccharidesex.glucose,carbohydrates,nomenclature,basedonnumberofcarbons3c=triose4c=tetrose5c=pentose,etc,structureofglucose,disaccharides,polymerizationofcarbohydrates,polysaccharides,starch,glycogen,cellulose,lipids,non-polarbiologicalmoleculesfunctionsenergystorage:fatsandoils.waterproofing:waxesandoilsinsulation:fatlayers(blubber)cushioning:fatlayers(solesofyourfeet)regulatingmetabolism:steroidscomponentofcellmembranes:phospholipids,lipidstructure(triglyceride),glycerolbackbonefattyacidtailsfatsvsoils,x3,triglycerideformation,hh-cohh-cohh-cohh,glycerol,fattyacids,hh-coh-coh-coh,+h20,+3h20,triglyceride,whattypeofreactionformsatriglyceride?,dehydrationsynthesis,+h20,+h20,saturatedvs.unsaturatedfats,saturatedvs.unsaturatedfats,fattyacids:cisvs.trans,-linolenicacid,trans-linolenicacid,phospholipids,themajorstructuralcomponentofcellmembranes,phospholipidbehavior,phospholipids,soapsandemulsifiers,steroids-hormonesandstr