Energy is the beat of life irrespective of the domains. ATP- the energy currency needs the understanding to explore the beat of life.

Bioenergetics is an important domain in biology. This presentation has explored ATP production and its optimum utilization in biological systems along with certain theories and experiments to give a bird's eye view of this important issue.

1. BIOENERGETICS
ATP-THE ENERGY CURRENCY OF CELL
Presentation by
Dr. N.Sannigrahi, Associate Professor,
Nistarini College, Purulia(W.B) India

2. COURSE CONTENT
ATP-the Energy Currency of Cell
ATP-Synthesis -Mechanism of ATP synthesis,
Substrate level Phosphorylation,
Chemiosmotic mechanism (oxidative and photophosphorylation),
ATP synthases,
Boyer’s conformational model,
Racker’s experiment,
Jagendorf’s experiment;
Role of uncouplers.
ATP-Functions & Importance

3. ATP-THE ENERGY CURRENCY
•ATP-thehighenergybondwasrealizedbyFritzA.Lipmann(1942)forthefirsttimeand
advocatedthemajorlinkintransferofchemicalenergyviaATP-ADPsystem.Energyreleased
fromhydrolysisofATP(Dephosphorylation)againundergoesreversionofATPby
phosphorylation.Theentireprocessisgovernedbyfreeenergychanges.
•▲GofATPhydrolysiswaslargeandnegative-7300cal/mole.
•Ifacompoundinaphysicalorchemicalprocessreleasesfreeenergyvalueofmorethan
5Kcal/molei.e.▲Gis-5kcal/moleormore-vevalue,thenthecompoundistreatedasenergyrich
compoundandif▲Gis-1to-5kcal/molethensuchcompoundistreatedlowenergycompound.
Thebondenergyhavinghighenergyrichiscalledwrigglebond.
•AsfarATPisconcernedhavingtwowrigglebondasdepictedA-S-P-P-P
•ATPwasdiscoveredbyKarlLehmann(Germany)&C.FiskeandY.Subharow(USA)in1929&
LipmannproposedATPasuniversalcarrierofChemicalEnergy.

4. ATP-STRUCTURE

5. HOW DOES ATP SYNTHESISE?
•ATPissynthesisedbothphotosynthesis&Cellularrespiration.
•Duringanabolism
•ATPissynthesisedbyphotosyntheticphosphorylationinpresenceofphotonduringthedaytime
inthechlorophyllcontainingcellsingeneralandchloroplastids(QuantasomesofGranumof
Plastids)inparticular.Thephosphorylationprocessdependsuponthedrainofftheelectronsfrom
theactivatedchlorophyllmoleculesexcitedbyphoton.Itmaybethreetypes-cyclic,non-cyclic
andpseudocyclic.Mostofthegreenplantsperformbynon-cyclicelectrontransportchainfor
phosphorylationwhilechemosyntheticbacteriaprefertocyclicpathways.
•Duringcatabolism
•Cellularrespirationingeneralbutoxidativephosphorylationinparticularalongwiththesubstrate
levelphosphorylationarethetwomainsourcesofhighenergyrichmoleculestoextenddenergy
forsortsofmetabolicactivitiesincell.ThesubstratelevelphosphorylationandATPgeneration
areverylimitedinamountandmostoftheATPsaregeneratedviaoxidationphosphorylation
throughETCforelectrondrainoffthroughchemiosmoticprocess.Thedetailisexploredbelow.

6. ATP SYNTHESIS VIA CELLULAR RESPIRATION

7. METHODS OF CELLULAR RESPIRATION
•CellularRespirationinlivingorganismstakeplaceeitherinabsenceofoxygenorinthepresenceof
oxygen.Respirationwithoutoxygeniscalledanaerobicrespirationhavinglittleefficiencymostly
foundinanaerobicbacteriaandthecellsstarvedduetooxygendeficiency.
•Buttruecellularrespirationisthecompleteoxidationoftherespiratorysubstratesinpresenceof
ambientoxygensupply&herethemaximumnumberofATP-theenergycurrencyisproducedatthe
completeoxidationofbio-fuels-Hydrogen.
•Aerobicrespirationiscomprisingofthefollowingevents-
Glycolysis-consistsofPreparatoryphase&payoffphasetakesplaceinCytoplasm.
CitricacidcycleorTCAcycleofKrebsCycleoccursinMitochondria
TerminalrespirationviaElectronTransportChain(ETC)intheinnermembraneofMitochondriai.e.
cristae.
TheendproductsareCarbondioxide,metabolicwater&energyi.e.ATP.

8. CELLULAR RSPIRATION: CHEMICAL OVERVIEW

9. OVERVIEW OF RESPIRATION
Lifewithoutenergyisnevertobeimagined,
Theenergyforliferequiresfordifferenttypesofbiochemicalreactionsasthemetabolismistheelexir
oflifeprocesses,
ATPistheenergycurrencyofcelltodrivethevitality,
Anaerobicreactionproduceenergytoalimitedextentasthepartialoxidationseldomproducelittlebit
energy,
Aerobicrespirationthroughcompleteoxidationordehydrogenationoftherespiratorysubstratesisthe
solesourceofmostofthebiologicalenergysources,
Aerobicrespirationtakesplaceintwositesofcell-Cytoplasm&Mitochondria,
Cytoplasmconductsglycolytictosplitupglucosemoleculestopyruvicacid(3C)compound,ssimple
respiratorysubstratesbytheexpenditureof2ATPsaspreparatoryphase,
ThepayoffphasestartsbythegenerationofATPinitiallytoalesserextentalongwiththeproduction
ofhydrogensourcesinthedifferentformstoproduceenergyintheduestate,
ElectrontransportChain(ETC)ultimatelyplaysthepivotalroleofenergyproductionintheduetime
bythepresenceofoxygenasterminalelectronacceptorandtoproduceATPonthebasisofredox
potential.

10. CELL STRUCTUIRE

11. CELL AND RESPIRATION
•ANAEROBIC RESPIRATION
Inabsenceofoxygen,theaerobicrespirationtakesplaceinsidethecytoplasmofthecell.
Here,glucoseisconvertedintopuruvicacidandthisisbeingusedfortheproductionofthedifferent
compoundsdependingupontheenzymespresentinthecell.
Thepreparatoryphaseneeds2ATPmoleculeforthisconversionandlittleamountofenergyis
producedonlybythesubstratelevelofphosphorylation.
AEROBICRESPIRATION
Therespirationtakesplaceinpresenceofoxygenisaerobicrespirationproducesthedesiredamount
ofenergyandthesitesfortherespirationisasfollows:
GLYCOLYSIS-Cytoplasmofthecellduetopresenceofenzymes,
KREB’SCYCLE-Takesplaceinmitochondriaandmajoramountofcellularenergyisgenerated
here,mitochondrianumberandsizedependsontherequiredwork,mitochondrialnetwork,
intermediatespacewithaqueousmediumliesinbetweenouterandinnermembranes,innermembrane
foldedtoformcristaeextendtomitochondrioninterior,surfaceoftheinnermembranecontainssmall
knob-likeparticles,oxysomeascalledcouplingfactors.

12. GLYCOLYSIS IMAGE

13. SUMMARY OF GLYCOLYSIS
Partialdegradationofmonomers,glucosetokeyintermediates,2molsofacetylCo-A,
6Ccontainingglucoseisprimarilyconvertedinto3Ccontainingpyruvicacidbytheinvestmentof2
ATPsaspreparatoryphaseand4directsATPmolecules(2*2)aresynthesized,calledInvestment
phaseorPreparatoryphase,
Now,3Ccontainingpyruvicacidundergoesdecarboxylationtoproduce2CcontainingacetylCo-A
alongwiththegenerationofNADPH2thatactsasenergysourceintheduecourseinpresenceof
terminalelectronacceptor,oxygen(ViaETC).
Theentireconversionof6Ccompoundto2Ccompoundtakesplacebyanumberofintermediatesteps
eachoneiscatalyzedbythedifferentspecificenzymes,
Thereactionisinitiallyendothermicreactionsfollowedbythedischargeofenergyinthehighenergy
richbond,
ThisisalsocalledEMPasfarasthenamesofthescientistsproposedit.
Attheend,2ATPsarenetproducedalongwith2NADH&2pyruvatemoleculesaresynthesized,
Glucose+2NAD++2ADP+2Pi-->2Pyruvate+2NADH+2H++2ATP+2H2O).The
hydroxylgroupsallowforphosphorylation.Thespecificformofglucoseusedinglycolysisisglucose
6-phosphate.

14. STRUCTURE OF MITOCHONDRIA

15. MITOCHONDRIA -POWER HOUSE OF CELL
Keydeterminantsofcellularhealth,
Dependsoncelltocell,playsroleinenergydistribution,metabolitebiosynthesis&signaling,
Increasingtheamountofcristaeintheinnermembraneincreasesthecapacityforenergyconversion
andfreeradicalmediatedsignaling,
Electricallyisolatedindividualcristaeprovideaprotectionmechanismtospreadthelimitof
dysfunctionwithinthemitochondria,
alarge,stablemitochondrialreticulumcanprovideastructuralpathwayforenergydistributionand
communicationacrosslongdistancesyetalsoenablerapidspreadingoflocalizeddysfunction,
Highlydynamicmitochondrialnetworksallowforfrequentcontentmixingandcommunicationbut
requireconstantcellularremodelingtoaccommodatethemovementofmitochondria.
Theformationofcontactsitesbetweenmitochondriaandseveralotherorganellesprovidesa
mechanismforspecializedcommunicationanddirectcontenttransferbetweenorganelles.However,
increasingthenumberofcontactsitesbetweenmitochondriaandanygivenorganellereducesthe
mitochondrialsurfaceareaavailableforcontactsiteswithotherorganellesaswellasformetabolite
exchangewithcytosol.

16. TCA CYCLE OR CITRIC ACID CYCLE

17. TCA CYCLE-OVERVIEW
Thetricarboxylicacidcycle(TCA)isaseriesofchemicalreactionsusedinaerobicorganismsto
generateenergyviatheoxidationofacetylcoenzymeA(CoA)derivedfromcarbohydrates,fattyacids
andproteins.
Intheeukaryoticsystem,theTCAcycleoccurscompletelyinmitochondria,whiletheintermediatesof
theTCAcycleareretainedinsidemitochondriaduetotheirpolarityandhydrophilicity.
Undercellstressconditions,mitochondriacanbecomedisruptedandreleasetheircontents,whichact
asdangersignalsinthecytosol.
Ofnote,theTCAcycleintermediatesmayalsoleakfromdysfunctioningmitochondriaandregulate
cellularprocesses.IncreasingevidenceshowsthatthemetabolitesoftheTCAcyclearesubstantially
involvedintheregulationofimmuneresponses.
ThefirststableproductofTCAcycle,Citricacidundergoesdehydrogenationi.e.oxidationandthe
hydrogenionsderivedfromthispathwayultimatelyjoinedwi9ththeoxygen,
Thisultimatelyleadstothegenerationofprotongradientandbymeansofchemiosmosisprocessleads
tothegenerationofATPbyoxidativephosphorylation.
MajorityoftheATPsaregeneratedbythispathwayandleastareproducedbythedirectsubstratelevel
phosphorylation.

18. ATP SYNTHASE
ThemitochondrialATPsynthaseisamultimericenzymecomplexwithanoverallmolecularweightof
about600,000Da.TheATPsynthaseisamolecularmotorcomposedoftwoseparableparts:F
1andF
o.
TheF
1portioncontainsthecatalyticsitesforATPsynthesisandprotrudesintothemitochondrial
matrix.
F0isembeddedinsidethemitochondrialmembraneorthylakoidmembraneorcellmembraneasper
occurrencewhileF1isacomponentfoundtowardsthematrixofthemitochondria,thestromaofthe
chloroplastorwithinthebacterialcell,
F0isamotordrivenbyH+ionstravelacrossthemembrane,
TheisolatedF1cannotmakeATPfromADP&pibutitcanhydrolyzeATPtoADP&Pi----called
ATPase,
Thestrippedmitochondrialparticles(thoselackingF1spheresbutcontainingF0cantransferelectrons
throughETSbuttheylongersynthesizeATPbutadditionofF1spherestothemitochondrialparticles
canrestoretheactivity,
TheF1component(MW=360kdal)contain9polypeptidechainsubunitsoffivekinds-α,β,⅋,φ,ℇ
arrangedintoclusterwithmanybindingsitesforATP&ADP,
TheF0componentisahydrophilicsegmentof4polypeptidechainanditistheprotonchannelof
enzymecomplex.

19. ATP SYNTHASE

20. ATP SYNTHASE-FUNCTION
ThecylindricalstalkbetweenF0&F1includesmanyproteinsincludingenzymecomplexsensitiveto
oligomycin,anantibioticthatblocksATPsynthesisbyinterferingtheutilizationofprotongradient,
Thestalkisthecommunicatingportionoftheenzymecomplex,
F0F1ATPaseiscalledATPasebecause,inisolatedform,ithydrolysesATPtoADPplusPi,
AsitisimportantbiologicalroleinintactmitochondriatoproduceATPfromADPandPi,itisbetterto
calledasATPsynthetase.
PaulBoyerproposedasimplecatalyticmechanismtopredictthatF-ATPaseimplementsarotational
mechanisminthecatalysisofATP,
EachcatalyticsiteoftheF-ATPasewouldachieveandchangethreeconformationsduringacomplete
360ºturnoverandacyclewouldbecompletedatathreedifferentcatalyticsitewitharotationof120º,
WhenanucleotidebindstoATPase,itundergoesaconformationalchangeinordertobetightlybound
toATP,
AnotherconformationalchangebringsthereleaseofATP,
Theseconformationalchangeareaccomplishedbyrotatingtheinnercoreoftheenzyme,
Thecoreitselfispoweredbytheprotonmotiveforceconferredbyprotonscrossingthemitochondrial
membrane.

21. INNER MEMBRANE OF MITOCHONDRIA

22. BOYER’S CONFORMATIONAL MODEL
•TheF1unitabout80AngstromsfromtheF0subunitandbothareconnectedtotheYsubunitwhich
spanstothe⅋3β3ring.energytransduction(necessarytocapturethenegativefreeenergychange
associatedwithcollapseoftheprotongradienttodrivethepositivefreeenergychangeforATP
synthesis)occurbetweenthetwosubunits.
•BoyerintheabsenceofthecompletestructureofF1F0ATPSynthaseswasabletodeducefrom
experimentalevidencethatthe⅋3β3complexwhichcanbeviewedasthreeαβdimers(withcatalysis
occurringbetweensubunitsofindividualdimerswhereATPandADPbind)havethreedifferent
interconvertibleconformationdefinedasloose(L),Open(O)andtight(T)stateswiththenamesofthe
strengthofsubstratetobindineachdimer.
•O-openstatewithverylowaffinityforsubstratesandhasnocatalyticactivity,
•L-Loosestatewithlowaffinityforsubstratesandhasnocatalyticactivity,
•T-tightstatewithhighaffinityforsubstrateandwithhighcatalyticactivity.
•Thethreestatesdonotrotatewithrespecttothecentralaxis,butconformationallydependingontheir
interactionwithYsubunitwhichbindsperpendicularlyinthecentraljunctionofthe⅋3β3ringcause
theconformationoftheO,LandTstatestochangeinsituwiththeorientationoftherotatingY
subunit.

23. BOYER’S CONFORMATIONAL MODEL
TheconversionoftheLOTconformations,theirbindingsubstrate(ADP&Pi),theconversionof
boundADP&Piandthereleasedoftheproductisdoneasparthefollowingmethod:
TheCollapseoftheprotongradient(i.e.theprotonmotiveforce)causestheYsubunittorotatelikea
crankshaftrelativetotheF1subunit,forcingtheβsubunittochangetheconformationfromtheTto
theO(releasingATP)andthentotheL(bindingADP&Pi)states.
TheYsubunitdoesnotappeartoundergoanysignificantconformationalchangeonATPhydrolysisas
evidencedbytritiumexchangestudiesofamideproteins.
Tovisualizetherotationoftheenzyme,MasasukeYoshidaandhiscolleaguesattheTokyoInstituteof
Technologyattachedanactinfilamentlabeledwithafluorescentdyetothebaseoftheγsubunitusing
anotherproteinasa"glue."
TheythenattachedtheF1complexupsidedowntoaglasssurface.Iftheγsubunitrotateswithrespect
tothecatalyticcomplex,theactinfilamentshouldswingaroundwithit.Sincethefilamentisvery
longcomparedtotheATPsynthase(about1μm),itsrotationshouldbevisibleinafluorescence
microscope.
Inotherwords,thefluorescentlytaggedactinfilament,whichislargeenoughtovisualizeinalight
microscope,reportstherotationoftheγsubunit.•

24. ELECTRON TRANSPORT CHAIN & TERMINAL
RESPIRATION

25. BOYER’S CONFORMATIONAL MODEL
•WhenATPwasaddedtothemodifiedenzyme,theactinfilamentswereseentoswingaroundina
circleatasmuchas4revolutionspersecondinafluorescencemicroscope.Demonstrationofthe
rotarymotionoftheγsubunitmadeitpossibletoputtogetheramodelofhowtheATPsynthase
works.
•Gammasubunitisintheformofaxle,itrotateswhenprotonsflow,
•ATPsynthetaseisknownasthesmallestMOLECULAR MOTORinthelivingcells,
•ConformationalCouplingcanexplainprotontranslocationcoupledtoATPcleavageandactive
transportofmetabolitescoupledtomembranepotential,protongradientsofATPcleavage.
•Thismodelcanexplainhowtheconformationalmodelwherethemolecularmotorplayavery
significantrolefortheproductionofATPinthisregardtodrivethebiologicalpathwayswhichare
mostlyenergydependentprocess.

26. RACKER’S EXPERIMENT,
•EfraimRacker-identifiedandpurifiedFactor-1(F1),thefirstpartoftheATPsynthaseenzymetobe
characterized.
F1isonlyapartofalargerATPsynthasecomplex.Itisaperipheralmembraneproteinattachedto
componentFo,whichisintegraltothemembrane.
RackerwasabletoconfirmPeterD.Mitchell'shypothesisthatcontrarytopopularopinion,ATP
synthesiswasnotcoupledtorespirationthroughahighenergyintermediatebutinsteadbya
transmembraneprotongradient.
RACKER’SEXPERIMENT:RackerandStoeckeniusbuiltanartificialsystemconsistingofa
membrane,abacterialprotonpumpactivatedbylight,andATPsynthase.Theymeasuredthe
concentrationofprotonsintheexternalmediumandtheamountofATPproducedinthepresenceand
absenceoflight.
Inthepresenceoflight,theconcentrationofprotonsincreasedinsidethevesicles,suggestingthat
protonsweretakenupbythevesicles.Inthedark,theconcentrationofprotonsreturnedtothestarting
level.ATPwasgeneratedinthelight,butnotinthedark.
Inthepresenceoflight,theprotonpumpwasactivatedandprotonswerepumpedtoonesideofthe
membrane,leadingtotheformationofaprotongradient.Theprotongradient,inturn,powered
synthesisofATPviaATPsynthase.

27. RACKER’S EXPERIMENT

28. JAGENDORF’S EXPERIMENT
•ProtongradientisessentialforATPsynthesisandthisistobeconfirmedbythisexperimentasstated
below.PeterMitchellin1961proposedCHEMIOSMOTICTHEORY.
•Membranepotentialwithhighnegativechargesandpositivechargesoperatingontheopposite
surfacesofthemembranescangenerateenergyrichbondbetweenADPandPitosynthesizeATPs,
•Thebasicprincipleofchemiosmosisisthationconcentrationdifferencesandelectricpotential
differencesacrossmembranesareasourceoffreeenergythatcanbeutilizedbythecell,
•Earlyevidencesupportingachemi-osmoticmechanismofphotosyntheticATPformationwas
providedbyanexperimentcarriedoutbyAndréJagendorf'sandco-workers,
•Jagendorf'scontinuedtocarryoutnovelexperimentsthatdeepenedourunderstandingofhowATP
formationislinkedtothecaptureoflightenergyinaprocesscalledphotophosphorylation,
•Mitchell'sChemiosmotichypothesisisthemostwidelyacceptedtheorythatadvocatesthattheproton
gradientistheonlyprerequisiteforthesynthesisofATPinpresenceofADPandiPintheavailability
ofATPsynthetase.ThisalsoconclusivelyprovedthatlightdoesnotrequireforthesynthesisofATPas
itwasproposedthatthelightenergyisrequiredforthesynthesisofATPduringthelightreactionof
photosynthesisduringthephotosyntheticphosphorylation.

29. JAGENDORF’S EXPERIMENT

30. JAGENDORF’S EXPERIMENT
AndreT.Jagendorf's&EarnestUribePlacedchloroplastsextractedfromcellsindarkness,thereby
eliminatinglightabsorption&electrontransferasasourceofenergyforphotosynthesis.•Inthedark,
thylakoidswerefirstincubatedinamediumofpH4untilboththeexteriorandinteriorofthevesicles
hadph4.
Then,thethylakoidvesicleswerequicklytransferredtoamediumwithpH8.Atthispoint,therewas
apHgradient,withtheinteriorofthethylakoid(pH4)havingahigherH+concentrationthanthe
exterior(pH8).
When ADP was added, ATP was made, even in the dark. This is convincing evidence linking a pH
gradient to ATP synthesis.
PeterMitchell’shypothesisthataprotongradientcandrivethesynthesisofATPwasproposedbefore
experimentalevidencesupporteditandwasthereforemetwithskepticism.Inthe1970s,biochemist
EfraimRackerandhiscollaborator,WaltherStoeckeniustestedthehypothesis.

31. ROLE OF UNCOUPLERS.
Uncouplersareamphiphiliccompounds(whicharesolublebothinwaterandlipids).Theyareagents
withconjugateddoublebondswhichallowthemtodiffuseacrossthemembraneinboththe
protonatedformandtheunprotonatedform,andthusdissipatetheelectrochemicalprotongradient.
Uncouplerswhichtransferprotonsacrossthemembraneareknownasprotonophores.
TheydisruptsphosphorylationbydissociatingthereactionsofATPsynthesisfromtheelectron
transportchain.TheydirectlybypassestheATPsynthasebyallowingpassiveprotoninflux,without
affectingelectronflow,butATPsynthesisdoesnotoccur.
Theresultisthatthecellormitochondrionexpendsenergytogenerateaprotonmotiveforce,butthe
protonmotiveforceisdissipatedbeforetheATPsynthasecanrecapturethisenergyanduseittomake
ATP.
Uncouplersincreasestheprotonpermeabilityoftheinnermitochondrialmembraneanddissipatesthe
protongradient.Uncouplersarecapableoftransportingprotonsthroughmitochondrialandchloroplast
membranes.Bothmammalianandplantmitochondriacontainuncouplingprotein(UCP).Thisprotein
facilitatesthemovementofprotonsacrosstheinnermembraneandthereforepartiallyuncouples
electrontransportanddecreasestheATPyieldofrespiration.Electronflowwithoutaccompanying
phosphorylationissaidtobeuncoupled

32. ROLE OF UNCOUPLERS.
•Uncouplingproteins(UCPs)occurintheinnermitochondrialmembraneanddissipatetheproton
gradientacrossthismembranethatisnormallyusedforATPsynthesis
•Additionofuncouplersresultsincontinuationofelectrontransportandprotonpumping,without
generationofanyprotongradient.ATPsynthesisdoesnotoccurwithoutaffectinguptakeofoxygen.
Intheabsenceofprotongradient,however,protonsaretransportedinreversedirectionthroughATP
synthasesattheexpenseofATP.
•ProtonatedDNP(aweakacid)diffusesfromhighprotonconcentrationsideofthemembranetolow
protonconcentrationsidewhereitgetsdissociatedtogenerateprotonsresultingindissipationof
protongradient.
•Membraneispermeabletobothprotonatedandanionicformsofthese.•E.g.FCCP(trifluoromethoxy
carbonylcyanidephenylhydrazone),averyefficientmitochondrialuncouplers.Otherexamplesof
uncouplers-Carbonylcyanidephenylhydrazone(CCP)2,4-dinitrophenol(DNP),Carbonylcyanidem-
chlorophenylhydrazine(CCCP).

33. ATP YEILD FROM COMPLETE OXIDATION OF GLUCOSE
•GLYCOLYSIS ( CYTOSOL)
Phosphorylation of glucose: -1
Phosphorylation of Fructose 6-phosphate -1
Dephosphorylation of 2 moles of 1,3 DPG +2
Dephosphorylation of 2 moles of PEP +2
2 NADH formed in the oxidation of 2 moles of G-3-P
•CONVERSION OF PYRUVATE INTO ACETYL CO -A ( Inside Mitochondria)
2 NADH are formed
•CITRIC ACID CYCLE( Inside Mitochondria)
2 moles of GTP from 2 moles of Succinyl–CoA +2
6 NADH formed in the oxidation of 2 moles of isocitrate, α-ketoglutarateand malate,
2FADH2 formed in the oxidation of 2 moles of succinate

34. BALANCE SHEET OF RESPIRATION

35. ATP YEILD FROM COMPLETE OXIDATION OF GLUCOSE
•OXIDATIVE PHOSPHORYLATION
2NADH formed in Glycolysis ; each yield 2 ATP ( assuming transport of NADH by malate–
oxaloacetate -aspertate shuttle) +6
2 NADH formed in oxidative decarboxylation of pyruvate; each yields 3 ATP +6
2 FADH formed in the citric acid cycle; each yields 3 ATP +4
6 NADH formed in the citric acid cycle; each yields 3 ATP +18
•------------------------------------------------------------------------------------------------------------------------
NET YIELD PER GLUCOSE +38 ATP

36. FUNCTIONS OF ATP
Hydrolysisistheprocessofbreakingcomplexmacromoleculesapart.Duringhydrolysis,wateris
split,orlyses,andtheresultinghydrogenatom(H+)andahydroxylgroup(OH–)areaddedtothe
largermolecule.ThehydrolysisofATPproducesADP,togetherwithaninorganicphosphateion(Pi),
andthereleaseoffreeenergy.
Tocarryoutlifeprocesses,ATPiscontinuouslybrokendownintoADP,andlikearechargeable
battery,ADPiscontinuouslyregeneratedintoATPbythereattachmentofathirdphosphategroup.
Water,whichwasbrokendownintoitshydrogenatomandhydroxylgroupduringATPhydrolysis,is
regeneratedwhenathirdphosphateisaddedtotheADPmolecule,reformingATP.
Obviously,energymustbeinfusedintothesystemtoregenerateATP.Wheredoesthisenergycome
from?Innearlyeverylivingthingonearth,theenergycomesfromthemetabolismofglucose.
Inthisway,ATPisadirectlinkbetweenthelimitedsetofexergonicpathwaysofglucosecatabolism
andthemultitudeofendergonicpathwaysthatpowerlivingcells,
unctionsofATPTheATPisusedforvariouscellularfunctions,includingtransportationofdifferent
moleculesacrosscellmembranes.OtherfunctionsofATPincludesupplyingtheenergyrequiredfor
themusclecontraction,circulationofblood,locomotionandvariousbodymovements.

37. FUNCTIONS OF ATP

38. FUNCTIONS OF ATP
AsignificantroleofATPapartfromenergyproductionincludes:synthesizingthemulti-thousandtypes
ofmacromoleculesthatthecellrequiresfortheirsurvival.ATPmoleculeisalsousedasaswitchto
controlchemicalreactionsandtosendmessages.
•IMPORTANCE OFATPMOLECULE INMETABOLISM
1.TheseATPmoleculescanberecycledaftereveryreaction.
2.ATPmoleculeprovidesenergyforboththeexergonicandendergonicprocesses.
3.ATPservesasanextracellularsignalingmoleculeandactsasaneurotransmitterinbothcentraland
peripheralnervoussystems.
4.Itistheonlyenergy,whichcanbedirectlyusedfordifferentmetabolicprocess.Otherformsof
chemicalenergyneedtobeconvertedintoATPbeforetheycanbeused.
5.ItplaysanimportantroleintheMetabolism–alife-sustainingchemicalreactionsincludingcellular
division,fermentation,photosynthesis,photophosphorylation,aerobicrespiration,proteinsynthesis,
exocytosis,Endocytosisandmotility.

39. THANKS FOR YOUR JOURNEY
•ACKNOWLEDGEMENT :
1.Googleforimages
2.Differentwebpagesforcontentandenrichment,
3.PrinciplesofBiochemistry-Lehninger,
4.Biochemistry-ReginaldHGarrett,
5.FundamentalsofBiochemistry-Jain,Jain&Jain
6.PlantPhysiology-Taiz&Zeiger
7.PlantPhysiology-Mukherjee&Ghosh
8.AppliedPlantPhysiology-ArupKumarMitra
9.AtextbookofBotany-Hait,Bhattacharya&Ghosh
10.PlantPhysiology-Devlin
•Disclaimer:Thispresentationhasbeenpreparedforonlinefreestudymaterialsforacademic
domainwithoutanyfinancialinterest.