AICE Biology Lab Review - SchoolWorld an Edline Solution：丽斯生物学实验室审查schoolworld一艾里尼溶液.ppt

aicebiologylabreview biologicalmolecules enzymes b biologicalmolecules a carryouttestsforreducingandnon reducingsugars includingsemi quantitativeuseofthebenedict stest theiodineinpotassiumiodidesolutiontestforstarch theemulsiontestforlipidsandthebiurettestforproteins benedict stest reducing nonreducingsugars round1 results aqua blue negative greentoyellowtoorange positive note todetectthesimplesugarsucrose youmustdoround2test lefttoright benedict sreagent bnr potatoextract bnr onionextract bnr 5 glucose bnr testingforsimplesugars benedict sreagent round1 procedure addbenedictsreagenttosample placeinwaterbathuntiljustboiling benedict stest reducing nonreducingsugars round2 anegativeresultinroundonedoesnotmeananabsenceofcarbohydrates sucroseisanon reducingsugar canonlybedetectedbydoinground2ofbenedict stesting acidhydrolysis procedure performround1ofbenedict stesting negativeresultindicateseithernocarbohydrateornon reducingsugars sucroseorstarch howwouldyoutestforthepresenceofstarch performround2ofbenedict stestingtoseeifyouhavesucroseifstarchtestisnegative sampleprocedureforbenedict stestfornonreducingsugar inatesttubeplace5cm3solution add3cm3benedict sreagenttothesolutioninthetesttubeandplacethetubeintheboilingwaterbathforfiveminutes add1cm3dilutehydrochloricacidtothesolutionsolutioninyourtesttube notethetimeandplaceinthewaterbathafter10 minutes removethetubefromthewaterbath coolitunderthetap neutralizetheacidbyaddingsolidsodiumbicarbonate alittleatatime untiltheadditionofoneportionproducesnofizzing withadroppingpipetteplace3cm3benedict ssolutionintesttube returntothewaterbathandheatforfiveminutes acolorchangeindicatesthattherewasnonreducingsugarpresent howwouldyouverifythatyoursolutionwassucrose notstarch benedict stesting samplequestion1 solutionsoffourfoodsubstancesaretestedforsugars thetableshowsthecoloursofthesolutionsaftertesting whichfoodisanon reducingsugar benedict stesting samplequestion2 foursugarsolutionsweretestedwithastandardbenedictssolution thetableshowsthecolourofthesolutionsaftertesting whatisthebestinterpretationoftheresults testingforstarchiki iodineinpotassiumiodide results yellow orange negative purple black positive lefttoright ikionly starchsolution starchsolution iki emulsiontestingforlipids sampleprocedure add2cm3fatoroiltoatesttubecontaining2cm3ofabsoluteethanol dissolvethelipidbyshakingvigorously addanequalamountofcoldwater observation acloudywhitesuspension basisoftest lipidsareimmisciblewithwater addingwatertoasolutionofthelipidinalcoholresultsinemulsionoftinydropletsinthewaterwhichreflectlightandgiveawhite opalescentappearance testingforpolypeptides proteins biuret sreagent lefttoright biuret sreagent brr water brr eggalbuminsolution eggalbuminsolution brr results denim blue negative lavender positive identifyeachsample foodtestsarecarriedoutonfourunknownchemicals thechartbelowshowstheresultsofeachtest key positiveresult x negativeresult c enzymes c followthetimecourseofanenzyme catalysedreactionbymeasuringratesofformationofproducts forexample usingcatalase orratesofdisappearanceofsubstrate forexample usingamylase enzymes d investigateandexplaintheeffectsoftemperature ph enzymeconcentrationandsubstrateconcentrationontherateofenzyme catalysedreactions andexplaintheseeffects practicequestion1 thecurvexshowstheactivityofanenzymeat20oc curvesatodshowtheeffectofdifferentconditionsontheactivityoftheenzyme whichcurveshowstheeffectofincreasingthetemperatureby10ocandaddingextrasubstrate enzymespracticequestion2 thegraphsshowtheeffectsoftemperatureandphonenzymeactivity whichstatementexplainstheenzymeactivityatthepointshown a atp hydrogenbondsareformedbetweenenzyme substrate b atq thekineticenergyofenzymeandsubstrateishighest c atr peptidebondsintheenzymebegintobreak d ats thesubstrateiscompletelydenatured enzymespracticequestion3 thegraphshowstheeffectofsubstrateconcentrationontherateofanenzyme controlledreaction theenzymeconcentrationisconstant whichstatementaboutthegraphiscorrect