Chapter 3: Energy for Cells - Gov 521... · Chapter 3: Energy for Cells ... Light is a form of radiation, consisting of energy ... Questions #15 page 85 2)

Chapter3:EnergyforCells

Title:Oct169:04AM(1of61)

Cells,Matter,andEnergy

Whatisconsideredthebasicunitoflife?

Whatisonethingthatallcellsrequiretomaintainlife?



WhatistheLawofConservationofEnergy?

Whatdolivingthingsusetotransformenergyfromoneformtoanother?


Cells,Matter,andEnergyRememberbacktothelifeprocesseswelookedat...

Whatwasmeantbysynthesisanddecomposition?

Whataboutassimilation?


Cells,Matter,andEnergyWhatarethetwomajorprocessesthatareinvolvedintransferofenergythroughoutanecosystem?

Thesearesimplychemicalreactions...

1) Defineeachoftheseprocessesbasedonwhattheydo

2) Writethesummaryreactionsforbothoftheseprocessesinyournotebooks


Cells,Matter,andEnergyPhotosynthesis

CellRespiration


SolarEnergy

Photosynthesizers

Herbivores

Carnivores

TopCarnivores

Decom

posers

thermalenergyreturnedtotheatmosphere

energytransformedtoheat

Conservationofenergystatesthatenergycannotbecreatedordestroyed.Thisdiagramseemstoindicatealossofenergy...explainhowthisispossible.



ReadPages6871

Definethefollowingterms:

Energy PotentialEnergy KineticEnergy ChemicalEnergy Metabolism



Homework

ReviewPages6871

CompleteQuestions#14and610onpage72


Photosynthesis

Definephotosynthesis,andwritethesummaryreaction.


PhotosynthesisandtheCarbonCycleDrawaquicksketchofthemajorpartsofthecarboncycle,includingtheroleofphotosynthesis.


LightWaveModel: Lightisaformofradiation,consistingofenergy

waves.Thedistancebetweenpeaksofawave(wavelength)andthenumberofwavespersecond(frequency)determinethepropertiesoftheenergy.

Visiblelightisafairlynarrowbandwithinthisspectrum,rangingfromwavelengthsofabout800400nm(nanometers).

Whitelightconsistsofamixtureofallofthesewavelengths.Thecolorweperceiveobjectstobeisaresultofthelightthatiseitherabsorbedorreflectedfromtheirsurfaces.


Light400nm800nm


ThePhotonModelofLightInthismodel,lightisthoughtofastinyparticles,or"packets",ofenergy,calledphotons.

Inthismodel,frequencyisthoughtofastheamountofenergycontainedinanindividualphoton...thehigherthefrequency,thegreatertheavailableenergy.

So,lightwithahigherfrequencycarriesmoreenergythanlightwithlowerfrequency.

(Thiscanbeseeneasilywhenyoulookatpenetrationoflightunderwater.)


ThePhotonModelofLightThedeeperyougounderwater,themorelightisabsorbed.Lightwithhigherfrequency(moreenergy)penetratesdeeperthanlowerfrequencylight.

Inthevisiblespectrum,whichcolorsarelowestinfrequency?Whichcolorswouldyoulosefirstasyoudescendunderwater?

Whatcolorwouldyouexpectobjectstoappearonceyougetintodeeperwater?(Stillshallowenoughthatsomesunlightreachesyou.)


LossofColoratDepth

Inshallowwater,mostcolorsarestillvisible


LossofColoratDepth

Indeeperwater,everythingtakesonabluishvioletappearance.


LightandPigmentsIfanobjectappearstobegreen,whatdoesthattellusaboutthelightthatisstrikingthatobject?

Whatisapigment?

Ifanobjectappearstobegreen,whatdoesthattellusaboutthepigmentsthatitcontains?


ChloroplastsandEnzymesSketchthestructureofthechloroplast.

Whichpartofthechloroplastcontainsthepigment chlorophyll?


ChloroplastsandEnzymesWhatare enzymes?

Howdoenzymesfunctiontocontrolchemicalreactions?


ChloroplastsandEnzymesThe"lockandkey"model ofenzymeaction

Whyareenzymesnotconsidered"rawmaterials"inareaction?


StagesofPhotosynthesis

Photosynthesisisactuallyaseriesofreactionsratherthanasingleprocess.Wewillbelookingatasimplifiedversion,butunderstandthatineachofthestepsweexamineisinfactmadeupofseveralsmallersteps.

Thetwomainstagesofphotosynthesisarethe LightReactionsandtheDarkReactions ,ortheCalvinCycle.

Thelightreactionstakeplaceonthesurfaceofthethylakoidmembranes,whilethedarkreactionsoccurinthestroma.


LightandDarkReactions


LightReactions

Thelightreactionsrequiresunlightenergy.

Assunlightstrikeschlorophyllonthesurfaceofthechloroplast,theenergyabsorbedpowersareactionthatbreaksdownawatermolecule,releasingtheoxygen.

Thehydrogenfromthewaterissplitintoprotonsandelectrons.Theelectronshaveabsorbedthereactionenergy,andarethenpassedalongaseriesofcarriermoleculesonthesurfaceofthethylakoid.Thisiscalledanelectrontransportchain.

Eachtimetheelectronispassedfromonecarriertoanother,someoftheenergyitcontainsislost.


LightReactions

Illustratethe"hotpotato"versionoftheETC.


LightReactions

Theenergyfromtheelectronsisusedtocreatehighenergymolecules,suchasATPandNADPH 2,inthestroma.

Thelightreactionsconsistoftwooftheseelectrontransportchains,orphotosystemsattheendofthefirstchain,theelectronsaregivenbacktoasecondmoleculeofchlorophyll,whichabsorbssunlightandreenergizesthembeforesendingthemtothesecondelectrontransportchain.Attheendofthesecondchain,theelectronsarejoinedwiththeprotons,creatingmorehighenergymolecules.

Asinglethylakoidwillcontainmanyphotosystems,alloperatingsimultaneously.


LightReactions

Summarizethelightreactions:


DarkReactions(CalvinCycle)

Thenamedarkreactionscanbemisleading.Whilethelightreactionscanonlyoccurinsunlight,thedarkreactions canoccurwithoutthepresenceoflight,butdarknessisn'tnecessary...thisprocessisgoingonallthetime.

12setsoflightreactionsarerequiredtoprovideenoughhighenergymoleculesforeachsetofdarkreactions.


DarkReactions(CalvinCycle)Thesereactionsoccurinthestroma.

Sixcarbondioxidemoleculesareabsorbedfromtheair,andputtogethertoformtwomoleculesofPGAL,whicharethencombinedtoformasinglemoleculeofglucose.

Duringthisprocess,severalotherthingshappen:

thehighenergymoleculescreatedduringthelightreactionsareuseduptopowerthereactions thehydrogensfromthebrokenwatermoleculesareaddedtothecarbondioxide,sinceglucosealsocontainshydrogen theexcessoxygenandhydrogenarereleasedaswater(6waterreleasedpercycle)


PhotosynthesisSummarizethestagesofphotosynthesis,andthemajoreventsthattakeplaceduringeachstage.


DarkReactions(CalvinCycle)Let'saddupalltheparts:*rememberhowmanywaterwerebrokenduringthelightreactions

oxygen

carbondioxide

water

glucose

LightReactions DarkReactions TOTALS


Question#16,Page81Readthisquestionandanswerpartsa,b,andc.


LokenTimer2.swf

Question#16,Page81(a)Atwhattemperaturewasthealgaemostactive?


Question#16,Page81(b)Whatcanbeinferredfromthefactthattherewasnochangeincolorinthealgaeat2 ?


Question#16,Page81(c)Howwasthetemperaturerelatedtotherateofphotosynthesisinthesealgae?


FactorsAffectingPhotosynthesisWhatotherfactorsdoyouthinkmightaffectphotosynthesis?


CellularRespirationWhatiscellularrespiration?

Wheredoescellrespirationtakeplaceinthecell?


CellularRespirationDrawthestructureofthemitochondria.


HomeworkQuestions#15page85

1) ListthreeactivitiesthattakeplaceinthecellthatrelyonmoleculesofATP

Anythreeactivitiesthatrequirethecelltouseenergyforexample:

proteinpumpsmovementdigestionendocytosisrunningchemicalreactionsmakingcomplexmolecules(synthesis)etc.


HomeworkQuestions#15page85

2) MakeadiagramofATPandshowhowenergyisreleasedfromthismolecule.

AR

PP

P

AdenineRibose

Phosphate

Highenergyphosphatebond

ATP,oradenosinetriphosphate,containshighenergyphosphatebonds.Whenthethirdphosphateisremoved,theenergyinthebondisreleased,andADP(adenosinediphosphate)isproduced.


Homework3) Whatisglycolysis?Wheredoesitoccur?

Glycolysisinvolvessplittingamoleculeofglucoseintotwopyruvicacidmolecules.Thisstageofcellrespirationtakesplaceinthecytoplasm.


Homework4) Identifythemainphasesofcellrespiration.Whichoftheseproduces

themostATP?

Thefourmainphasesofcellrespirationare:

Glycolysis PyruvicAcidBreakdown(PAB)orthetransitionreaction Krebscycle ElectronTransportChain(PAB)

TheETCproducesmostoftheATP


Homework5) Howisoxygenimportantforthereleaseofenergyinaerobic

cellularrespiration?

OxygenactsasthefinalelectronacceptorattheendoftheETC.

Oxygenwillcombinewiththeelectronsandprotons(hydrogen)toformmoleculesofwater.


StagesofCellularRespirationTheprocessofcellularrespirationcanbedividedintofourstages,eachoccurringinaspecificareawithinthecell.

1) Glycolysis

2) PyruvicAcidBreakdown(PAB),alsocalledthe transitionreaction

3) KrebsCycle

4) ElectronTransportChain


StagesofCellularRespirationTheprocessofcellularrespirationcanbedividedintofourstages,eachoccurringinaspecificareawithinthecell.

1) Glycolysis takesplaceinthecytoplasm.Thisisthebreakinginhalfofglucosetoformtwomoleculesofpyruvicacid,orpyruvate.

Itdoestakesomeenergytostartthingsoff.Atthebeginningofglycolysis,twoATPareusedtotriggerthereaction.However,fourATPareproducedattheendofglycolysis,foratotalgainoftwoATP.

Inaddition,therearetwootherhighenergymoleculesformed,calledNADH2.ThesepasstheirhydrogensontoanothermoleculecalledFADH2inthemitochondria.Thehydrogenswillbeusedlaterintheelectrontransportchain


StagesofCellularRespirationSo,tosummarizeGlycolysis:

glucosesplitsintotwomoleculesofpyruvicacid,orpyruvate. twoATPused,fourATPproducedtotalgain:twoATP. twoNADH2formed,whichswitchtotwoFADH2


StagesofCellularRespiration

2) PyruvicAcidBreakdown alsocalledthetransitionreaction.

Thisisashortstagethattakesplaceaspyruvateistransferredfromthecytoplasmandintothemitochondria.

CO2isreleased,andthetworemainingcarbonsarejoinedtoacoenzyme*toformAcetylcoenzymeA,oracetylCoA.Inaddition,anotherhighenergymolecules(NADH 2)areformed.

(RememberthoughthatPABhappenstwiceforeveryglucose,soreallytherearetwoCO2andtwoNADH 2producedbythisstage!)



*Acoenzymeisamoleculethatallows,orhelps,enzymestocontroltheirchemicalreactions.Manyenzymescanotactwithoutthepresenceofacoenzyme.

Manyvitaminsactascoenzymes,whichiswhytheyareneededinthediet...withoutthevitamins,someoftheenzymesthatcontrolcellfunctioncannotoperatecorrectly.


StagesofCellularRespirationSo,tosummarizePyruvicAcidBreakdown:

pyruvicacidmovesintomitochondria CO2givenoff(oneperpyruvate,so2total) NADH2formed(oneperpyruvate,so2total) AcetylCoAformed(2)


StagesofCellularRespiration3) Krebscycle takesplaceinthe matrixofthemitochondria.

Thisstageinvolvesacyclicreactionamoleculeoxaloacetate isjoinedtotheacetylCoAtoformcitricacid.(TheKrebscycleisalsocalledtheCitricacidcycle.)

Aseriesofreactionshappens,splittingthismoleculeapartseveralotherthingshappenaswell:

asingleATPisformed,aswellasfourotherhighenergymolecules(NADH 2andFADH 2)

twocarbondioxidemoleculesarereleased

threewatermoleculesareabsorbed(rememberhydrolysis?)



Attheendofthecycle,anewmoleculeofoxaloacetateisformed.(Thisiswhyit'scalledacycle...themoleculeyoustartwithisreformedattheend,soitcanbereused.)

*Remember:twopyruvicacidsareformedduringglycolysis,sotheKrebscyclehappenstwiceforeachglucose.

So,intotal,howmanyofeachareusedorformed:

Water:3usedpercyclex2cycles=6waterused

Carbondioxide:2formedpercyclex2cycles=4CO2formed

ATP:1formedpercyclex2cycles=2ATP


StagesofCellularRespirationSo,tosummarizeKrebsCycle:

AcetylCoAbrokendown CO2givenoff(2percycle,so4total) Waterused(3percycle,so6total) ATPformed(1percycle,so2total) NADH2andFADH2formed(4percycle,so8total)


StagesofCellularRespiration4) ElectronTransportChain takesplaceonthe cristaeofthe

mitochondria.(Rememberthelightreactionsinphotosynthesis?TheyarealsoanETC,andwheredotheyhappen?WhatdoesthattellyouaboutETCs?)

AnETCneedsenergizedelectrons.Wheredothesecomefrom?

ThehighenergymoleculesformedduringPABandKrebscycle.Thesemoleculesreleasehydrogen,losingenergyastheydo.ThehydrogenspasstheirelectronsontotheETC,andtheyarepassedalongthechain,losingabitofenergywitheachtransfer.Inall,12ofthesemoleculeshavebeenformed,eachgivingH 2.

Thisenergyisusedtoformatotalof32ATPmolecules.


StagesofCellularRespiration4) Onefinalstepneedstobeexplained...whathappenstoallofthose

electronsattheendoftheETC?

Rememberwheretheycamefrom?NADH2andFADH2

Hydrogenatoms...attheendtotheETC,theelectronsarejoinedupwiththeprotonsagaintoformhydrogen.However,hydrogenisadangerouselementtohavearound.Thecellcombinesthehydrogenwithoxygentoformwater.

Sincetherewereatotalof24hydrogenspassedtotheETC,12oxygensareneedetoformatotalof12H2O...inotherwords,6O2moleculesareused.


StagesofCellularRespirationBytheway,youareNOTexpectedtorememberthis,butthereisareasononly32ATPgetmadeby12pairsofelectronsrunningthroughtheETC...thisisforthoseofyouwhorealizethat32doesn'tdivideby12.

ThereareactuallytwoETCs...onetakestheelectronsfromNADH2,theotherfromFADH2.EachpairofelectronsfromaNADH2resultsin3ATPbeingproduced,whileeachFADH2resultsinonly2ATP.

Ifyouaddthemallup,therewereatotaloffourFADH2andatotalofeightNADH2.

So, 4FADH2x2ATPperFADH2=8ATP8NADH2x3ATPperNADH2=24ATP

8+24=32ATPfromtheETC


SummaryofCellRespiration


SummaryofRespirationCompletethefollowingchart:

TOTALSPABGlycolysis

glucose

water

carbondioxide

oxygen

ATP

KrebsCycle ETC


SummaryofRespirationCompletethefollowingchart:

TOTALSPABGlycolysis

glucose

water

carbondioxide

oxygen

ATP

KrebsCycle ETC

0 0 0

+2x2=+4+1x2=+2

1/2x12=6

0

0 0 3x2=6

0

+1x12=+12

1 0 0 0

2+4=+2 0 +1x2=+2 +32

6

+6

+6

1

+36


Homework

ReviewSection3.3onAerobicRespiration.

Practicewritingoutthestagesinorder,includingthemajorstepsofeach

BepreparedtoreviewallstepsonTuesday.

Mr.HigginbothamwillbeavailableforhelpduringnoonhouronMonday...therearenoclassesduetocareerday,butanyonewhowouldliketospendsometimereviewingiswelcometobringlunchuptotheroomandrunthroughthestagesoraskquestions.


Carbon

Oxygen

Hydrogen

NAD

FAD

CoA

Oxaloacetate

ATP

Title:Nov19:40AM(61of61)

Page 1: Oct 16-9:04 AMPage 2: Oct 16-9:05 AMPage 3: Oct 16-9:05 AMPage 4: Oct 16-9:05 AMPage 5: Oct 16-9:05 AMPage 6: Oct 16-9:05 AMPage 7: Oct 16-9:05 AMPage 8: Oct 16-9:05 AMPage 9: Oct 16-9:05 AMPage 10: Oct 16-9:05 AMPage 11: Oct 16-9:05 AMPage 12: Oct 16-9:05 AMPage 13: Oct 16-9:05 AMPage 14: Oct 16-9:05 AMPage 15: Oct 16-9:05 AMPage 16: Oct 16-9:05 AMPage 17: Oct 16-9:05 AMPage 18: Oct 16-9:05 AMPage 19: Oct 16-9:05 AMPage 20: Oct 16-9:05 AMPage 21: Oct 16-9:05 AMPage 22: Oct 16-9:05 AMPage 23: Oct 16-9:05 AMPage 24: Oct 16-9:05 AMPage 25: Oct 16-9:05 AMPage 26: Oct 16-9:05 AMPage 27: Oct 16-9:05 AMPage 28: Oct 16-9:05 AMPage 29: Oct 16-9:05 AMPage 30: Oct 16-9:05 AMPage 31: Oct 16-9:05 AMPage 32: Oct 16-9:05 AMPage 33: Oct 16-9:05 AMPage 34: Oct 16-9:05 AMPage 35: Oct 16-9:05 AMPage 36: Oct 16-9:05 AMPage 37: Oct 16-9:05 AMPage 38: Oct 16-9:05 AMPage 39: Oct 16-9:05 AMPage 40: Oct 16-9:05 AMPage 41: Oct 16-9:05 AMPage 42: Oct 16-9:05 AMPage 43: Oct 16-9:05 AMPage 44: Oct 16-9:05 AMPage 45: Oct 16-9:05 AMPage 46: Oct 16-9:05 AMPage 47: Oct 16-9:05 AMPage 48: Oct 16-9:05 AMPage 49: Oct 16-9:05 AMPage 50: Oct 16-9:05 AMPage 51: Oct 16-9:05 AMPage 52: Oct 16-9:05 AMPage 53: Oct 16-9:05 AMPage 54: Oct 16-9:05 AMPage 55: Oct 16-9:05 AMPage 56: Oct 16-9:05 AMPage 57: Oct 16-9:05 AMPage 58: Oct 16-9:05 AMPage 59: Oct 16-9:05 AMPage 60: Oct 16-9:05 AMPage 61: Nov 1-9:40 AM

Documents

Chapter 3: Energy for Cells - Gov 521... · Chapter 3: Energy for Cells ... Light is a form of radiation, consisting of energy ... Questions #15 page 85 2)