Download pdf - Lab 3: Cellular Respiration - Harvard University

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Lab3:CellularRespirationCellrespirationreferstotheprocessofconvertingthechemicalenergyoforganicmoleculesintoaformimmediatelyusablebyorganisms.Glucosemaybeoxidizedcompletelyifsufficientoxygenisavailableandissummarizedbythefollowingreaction:

𝐶𝐶"𝐻𝐻$%𝑂𝑂" + 6𝑂𝑂% 𝑔𝑔 → 6𝐶𝐶𝑂𝑂% 𝑔𝑔 + 6𝐻𝐻%𝑂𝑂 + 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑔𝑔𝑒𝑒

Allorganisms,includingplantsandanimals,oxidizeglucoseforenergy.Often,thisenergyisusedtoconvertADPandphosphateintoATP.Itisknownthatpeasundergocellrespirationduringgermination.Dopeasundergocellrespirationbeforegermination?Usingyourcollecteddata,youwillbeabletoanswerthisquestionconcerningrespirationandnon-germinatedpeas.UsingtheCO2GasSensor,youwillmonitorthecarbondioxideproducedbypeasduringcellrespiration.Bothgerminatedandnon-germinatedpeaswillbetested.Afteryourpreliminaryinvestigation,youwillinvestigatehowvariousfactorsmayinfluencetherateofcellularrespiration.

OBJECTIVES

Inthisexperimentyouwill

• UseaCO2GasSensortomeasureconcentrationsofcarbondioxideduringcellrespiration• Determinewhethergerminatingpeasandnon-germinatingpeasrespire• Comparetheratesofcellrespirationingerminatingandnon-germinatingpeas• Designyourownexperimentstomeasureratesofrespirationofdifferentseedsandorganismsas

wellastheeffectofseveralvariablesincludingsalinity,germinationtime,andtemperature

MATERIALS

LabQuest2 GerminatedandNon-germinatedPeasVernierCO2GasSensor VariousSeeds(bothGerminatedandNon-germinated)250mLRespirationChamber IceThermometer HotWaterBathCrickets Mealworms


PROCEDURE

1. EnsureyourCO2GasSensoryisproperlyconnectedtotheLabQuest2andchoose“New”fromtheFileMenutosetupanewexperiment.

2. RecordtheroomtemperatureinTable1.Askyourinstructorforthecurrenttemperature3. Preparefordatacollectionbychangingthecollectionmodeto“TimeBased”.Settheintervalto4

seconds/sampleandthedurationto300secondsasinthepicturebelow:

4. Obtain25germinatedpeasandblotthemdrybetweentwopiecesofpapertowel.Placethe

germinatedpeasintotherespirationchamberasshowninthefigureonthepreviouspage5. PlacetheshaftoftheCO2GasSensorintheopeningoftherespirationchamberasinFigure16. Waitonetotwominutes,thenstartdatacollection.Datawillbecollectedfor5minutes.7. Whendatacollectionhasfinished,agraphofcarbondioxidegasvs.timewillbedisplayed.8. RemovetheCO2GasSensorfromtherespirationchamber.Returnthepeastothecontainerwhere

youfoundthem9. UseanotebookornotepadtofanairacrosstheopeningsintheprobeshaftoftheCO2GasSensor

for1minute10. Shaketherespirationchamberaroundforaminutetocompletelyrefreshtheairinsidethe

chamber11. Repeatsteps4thru10usingnon-germinatedpeas12. Performalinearregressiontocalculatetheratesofrespiration

a. Gotothegraphanddisplayallrunsb. ChooseCurveFitfromtheAnalyzemenu.Thenselectyourfirstrun(Germinated)c. SelectLinearfortheFitEquation.Thelinear-regressionstatisticsforthesetwodata

columnsaredisplayedfortheequationintheform

𝑒𝑒 = 𝑚𝑚𝑚𝑚 + 𝑏𝑏

Wherexistime,yisCO2concentration,mistheslope,andbisthey-intercept

d. Entertheslope,m,astherateofrespirationinTable2onthenextpage13. Performstep12againforyoursecondrun(non-germinated)


DATA

OPENINQUIRY

Nowthatyouhavedataforbothgerminatedandnon-germinatedpeas,whataresomefactorsthatmayeffectthatratesofrespirationofpeas/seeds?Designyourexperimentstotestoneormorevariablesincludingthingssuchastemperature,timeofgermination,light,typeofseeds,etc.Afterdeterminingwhichvariablesyouwouldliketotest,comeupwithahypothesisandrunyourexperiment!Besuretorecordalloftherelevantdatainyourownlabnotebook.

QUESTIONS

1. Doyouhaveevidencethatcellrespirationoccurredinpeas?Explain.

2. Whatistheeffectofgerminationontherateofcellularrespirationinpeas?

3. Whydogerminatedpeasundergocellrespiration?

4. Wouldyouconsidernon-germinatedseeds“Alive”?

5. Listthreefactorsthatcouldpossiblyaffecttherateofcellularrespiration.


SAVINGANDEXPORTINGYOURDATA

1. Onceyouhavecompletedacquiringallofyourdata(bothguidedandopeninquiry)andperformedthelinearregressiononallofyourdataruns,select“File”,“Save…”,andthengiveyourfileanameusingthefollowingformat:

MMDDYY_School_LQ###(ex.112119_OB_LQ202)2. Select“Save”andyourfilewillbesaved.Youwillthenbereturnedtothemainscreen3. Select“File”againandthistimeselect“Email”asshownbelow:

4. Select“Graph…”andthenenterthefollowingemailaddress:

5. Onthe“Subject”line,enteryourschool,LabQuestNumber,andexperimentnameusingthe

followingformat:School_LQ###_RespGraph.Itshouldlooksimilartheoneintheimageabove.Onceyouarefinished,select“Send”

6. Repeatsteps3-5exceptthistimeselect“Email”and“TextFile…”instead.Underthesubjectline,replacetheword“Graph”with“Data”.Itshouldlooksomethinglike“BLA_LQ202_RespData”

Graphoutputexample

Textoutputexample

SCHOOLCODES

OB=J.D.O’Bryant

KD=KennedyHCA

TB=TechBostonAcademy

BLA=BostonLatinAcademy