AP生物-LAB-5-WRITE-UP

1、APBIOLOGYCellRespirationLabWrite-upOBJECTIVES?Tounderstandrespiration,dormancy,andgermination.?Knowhowarespirometerworksintermsofthegaslaws;thegeneralprocessesofmetabolisminlivingorganisms;?Howtherateofcellularrespirationrelatestotheamountofactivityinacell.?Calculatetherateofcellrespirationfromexper

2、imentaldata?Relategasproductiontorespirationrate?Testtherateofcellularrespirationingerminatingversusnongerminatedseedsinacontrolledexperiment;and?Testtheeffectoftemperatureontherateofcellrespirationingerminatingversusnongerminatedseedsinacontrolledexperiment.PROCEDURE?Setuptwowaterbaths,oneatroomtem

3、perature,theotheroneat10degreeCelsius?Forrespirometer1,Countout50germinatingpeasandplacethemintothegraduatedcylinder.Forrespirometer2,putin50drypeasand110plasticbeads.Forrespirometer3,onlyputin150plasticbeads.(nowthevolumesoftherespirometersshouldbethesame)Andthefirstsetofrespirometerisready.Prepare

4、anothersetofgerminatingpeas,driedpeasplusbeads,andplasticbeads.Toassemblethesixrespirometers,obtainsixvials,eachwithanattachedstopperandpipette.Placeasmallpieceofcottoninthebottomofeachvialand,usingadropper,moistenthecottonwith15%KOH.Makesurethattherespirometervialsaredryontheinside.DonotgetKOHonthe

5、sidesoftherespirometer.PlaceasmallwadofnonabsorbentcottonontopoftheKOH-soakedabsorbentcotton.Placethefirstsetofgerminatingpeas,drypeasplusbeads,andbeadsinvials1,2,and3.Placethesecondsetinvials4,5,and6,respectively.Insertthestopperfittedwiththecalibratedpipette.Placeaweightedcollaroneachendofthevial.

6、Makeaslingofmaskingtapeattachedtoeachsideofeachofthewaterbathstoholdthepipettesoutofthewaterduringanequilibriumperiodofsevenminutes.Vials1,2,and3shouldrestintheroomtemperaturebathandtheothervialsshouldrestinthe10degreeCelsiuswaterbath.?Aftertheequilibriumperiodofsevenminutes,immerseallsixrespiromete

7、rentirelyintheirbaths.?Allowtherespirometerstoequilibrateforthreemoreminutesandthenrecord,tothenearest0.01mL,theinitialpositionofwaterineachpipette.Checkthetemperatureinbothbathsandrecorditinthedatatable.Every5minutesfor20minutes,takereadingsofthewater'spositionineachpipetteandrecordthedata.DATA

8、Temp(C)Time(min)BeadsAloneGerminatingPeasDrypeasandBeadsReadingtimeXDiff.ReadingtimeXDiff.CorrectedDiff.ReadingtimeXDiff.CorrectedDiff.10°C05.3-5.3-5.3-55.30.05.30.00.05.30.00.0105.30.015RoomTemp05.6-5.4-5.7-55.60.05.70.00.0105.60.0155.60.05.6-0.10

9、.10303i7。/ 1Z_510Time (min)Oxygen consumption ovar time86 4 L I o c ptDEnsuco U86AX。2.o.Geirrnnating Peas 4 0 CDry peas and Beads IOCGerminatingat room temp Dry peas plus beads at room temp15Fromthedatawecollectedandthegraphabove,wewanttofindbetweentherateoftherespirationandthetemperature,aswellasth

10、edifferenceinrespirationratebetweengerminatingpeasanddrypeas.Thisactivityusesanumberofcontrols,byusingtheidealgaslaw,PV=nRT,wekepttheairpressureandthevolumeofmaterialsineachrespirometerconstant.Thatway,wecanfigureouttheeffectoftemperatureontherespiration.Watermovedintotherespirometer'spipettesbe

11、causepressuredecreasedwhentheamountofoxygenwasdecreased(orconsumed).Bymeasuringtheamountofwaterinthepipette,wecanknowtheamountofoxygenconsumedbythepeas.Thevialhadtobecompletelysealedsothatgasescouldn'tescapeandwatercouldn'tleakintotherespirometer.Thegraphshowedthatasthetimegoeson,theamountof

12、oxygenconsumedincreases.Drypeasstartedconsumingoxygenslowerthangerminatingpeas.Andgerminatingpeasgenerallyconsumedmoreoxygenthandrypeas.Italsotellsusthattheamountofoxygenconsumedisgreaterinwarmerwaters,forbothgerminatinganddrypeas.ConditionShowCalculationsHereRate(mLO2/minute)GerminatingPeas/100C(0.

13、3-0.0)/100.03mL/minGerminatingpeas/Roomtemperature(545.7)/150.047mL/minDryPeas/100C(0.2-0.0)/100.02mL/minDryPeas/RoomTemperature(5.7-(5.5+5.6)/2)/150.01mL/minThistableshowedthatthegerminatingpeasinroomtemperaturehaveahighestrespirationrateoverall,whichmeansgerminationcanincreasethepeaseedsrespiratio

14、neffectively.Andthedrypeasdidn'tturnoutthewayweexpected,whichwethoughttheratewassupposedtobehigheratawarmertemperature.Instead,theyhaveahigherrateat100C.Itisnecessarytocorrectthereadingsfromthepeaswiththereadingsfromthebeads,becausethebeadsservedasacontrolgroup.It'simportanttofindthechangein

15、rateofrespirationbycomparingwiththebeads.ThepurposeofKOHisthisexperimentistoremovetheC02,sothatthepressureofCO2wontaffectthereading.possiblegraphfor口2consumptionbygerrnfnatingpeasastemperaturecontinuesincreasingThisgraphhereshowsthepredictionoftherateofoxygenconsumptionastemperatureincreases.Thecons

16、umptionwoulddropdramaticallybecausewhenthetemperaturegetstoohigh,theenzymewillbedenaturedandendtherespirationprocess.ConclusionInthisexperiment,wehopedtoseeawarmertemperaturecanincreasetherateofrespiration(oxygenconsumption),andgerminatingpeashaveagreaterrateofrespirationandconsumemoreoxygenthandryp

17、eas.Theactualexperimentalresultwasfairlyclosetoourexpectation.Thedatashowedthatthetemperaturedoesaffecttherateofrespirationdirectly,butonthedrypeas,wesawanoppositeresult.Ithinkthepossiblecauseoferroristhattheremightbealeakonthestopper,sowatermovedintothepipetteandcausedthisinaccuracy.Inaddition,thedatawascol