2024 Specimen Paper Answers (ThatBioTutor)

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor.Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:) SpecimenPaper2024(ThatBioTutorEdition) Question Ans Question Ans1 D 21 D2 B 22 C3 A 23 A4 B 24 B5 D 25 C6 C 26 B7 B 27 B8 B 28 D9 B 29 D10 C 30 C11 C 31 C12 A 32 B13 D 33 A14 D 34 C15 B 35 B16 D 36 A17 A 37 C18 A 38 C19 D 39 A20 A 40 B NeedpersonalisedguidanceforOLevelPureBio?Learnmorehere:www.thatbiotutor.comFormoretips:www.youtube.com/@thatbiotutor

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor.Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:) Q1. ai)Protease aii)● Thestomachhasahighlyacidicenvironment, duetopresenceofhydrochloricacid,whichisatpH2,theoptimumpHfortheproteaseinthestomach,● whilethesmallintestinehasaslightlyalkalineenvironmentduetohigherpHofbileandpancreaticjuiceandintestinaljuice. bi)Liverandmusclecells. bii)Glycogen c) ● Deaminationoccursattheliver, whereaminogroupsareremovedfromexcessaminoacidsandconvertedintourea.● Urealeavestheliverviathehepaticvein, entersakidneyviatherenalartery, whereitisforcedoutalongwithmostofthebloodplasmaduringultrafiltrationfromglomerulusintotheBowman’scapsule.● Ureatravelsthroughtheproximalconvolutedtubule,loopofHenle,distalconvolutedtubule,collectingduct.● Itistransportedinurinetothebladderviaaureter, thenexcretedwhenurineleavesthebodyviatheurethra. NeedpersonalisedguidanceforOLevelPureBio?Learnmorehere:www.thatbiotutor.comFormoretips:www.youtube.com/@thatbiotutor

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor.Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q2.ai)● Thenetmovementofparticlesfromaregionofhigherconcentrationtoaregionoflowerconcentration,● downaconcentrationgradient. aii)● Thereisahigherconcentrationofoxygeninthealveolarairspacethaninthebloodcapillarieswhichcarrydeoxygenatedblood,creatingaconcentrationgradient. aiii)● Deoxygenatedbloodfromthebodyflowsintotherightatrium, thenpastthetricuspidvalveintotherightventricle.● Itispumpedoutofthepulmonaryarterytothelungs,whichbranchesintocapillariessurroundingalveoli.● Oxygenatedbloodthenreturnstotheheartviathepulmonaryvein, enteringtheleftatrium. bi)● Theloweroxygenconcentrationintheairwouldleadtoagentlerconcentrationgradientbetweenairinthealveoliairspaceandthebloodplasma,● Diffusionrateofoxygendecreases,hencetherewouldbereducedoxygenuptakefromthealveoliintotheblood. bii)● Moreredbloodcellswouldincreasetheratethatoxygencanbetransportedfromlungstomuscles,● somusclescanundergohigherratesofaerobicrespiration, releasingmoreenergyformuscularcontractions, allowingathletestosustainlongerperiodsofintenseactivitywithlessfatigue, enhancingtheirperformance. NeedpersonalisedguidanceforOLevelPureBio?Learnmorehere:www.thatbiotutor.comFormoretips:www.youtube.com/@thatbiotutor

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor.Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q3. ai)(Chooseanyoneoftheshapes) aii)(Chooseeithertoporbottomstrand) bi)Mutation bii)(Anyone)● Ultravioletradiation/Nuclearradiation/Gammarays/Tar c) ● TohavethebloodgroupOphenotype, onemusthavethegenotypeI O I O , andmusthaveinheritedarecessiveI O allelefromeachparent.● AnindividualwithbloodgroupABhasI A andI B alleleswhicharecodominant, anddoesnothaveanI O allele.● TheywouldnotbeabletopassonanI O alleletotheiroffspring, hencetheiroffspringcanneverbebloodtypeO. NeedpersonalisedguidanceforOLevelPureBio?Learnmorehere:www.thatbiotutor.comFormoretips:www.youtube.com/@thatbiotutor

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor.Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q4. ai)Watervapour aii)Aerobicrespiration b) ● Fromthegraph:● Waterfromfood=1300cm³● Waterfromdrink=1360cm³● Waterproducedinthebody=320cm³● Totalwatergain=1300+1360+320=2980cm³. c)Choose2: ● Incoldclimate,thebodywillnotneedasmuchwaterintaketocompensateforwaterlostthroughsweat,● decreasingone’sthirst, hencewaterintakefromdrinkswoulddecrease. ● Waterlostthroughtheskinwoulddecrease.● Inacoldclimate,sweatglandsbecomelessactiveandsecretelesssweat, lesswaterinsweatevaporates, lesslatentheatislost,inordertokeepthebodywarm. ● Duetoanincreaseinmetabolicrateinresponsetointernalbodytemperaturebeingtoocold,● higherrateofaerobicrespirationproducesmorewaterasaby-product, hencemorewaterisproducedinthebody/hencemoreexcesswaterwillbeexcretedinurine. ● Coldairislesshumidthanwarmair, increasingtheevaporationrateofwaterfromthethinfilmofmoistureofthealveoli,● somorewaterislostatthelungsduringexhalationaswatervapour. NeedpersonalisedguidanceforOLevelPureBio?Learnmorehere:www.thatbiotutor.comFormoretips:www.youtube.com/@thatbiotutor

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor.Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)d) ● 190dm 3 =190,000cm³ofwaterisfilteredthroughthekidneyseachday. FromFig.4.1,760cm³ofwaterisexcretedfromthebodythroughurineeachday.● Thisdemonstratesthatmostwaterfilteredthroughthekidneyisreabsorbedbackintothebloodattheproximalconvolutedtubule,loopofHenle,distalconvolutedtubule,andcollectingduct. Onlyasmallamountofwaterstaysinthefiltrateandbecomesurine. NeedpersonalisedguidanceforOLevelPureBio?Learnmorehere:www.thatbiotutor.comFormoretips:www.youtube.com/@thatbiotutor

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor.Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q5. ai)Hormones aii)Targetorgans bi) Personwithoutdiabetes:J Reason:FromFig.5.1,personJ’sbloodglucoselevelswerestableandkeptwithinthenormalrangeatapproximately5units, showingtheirpancreasissecretingsufficientinsulinandtheirtargetorgansarerespondingtoinsulin. Personwhoproducesnoinsulin:H Reason:FromFig.5.1,personHhadpersistentlyhighbloodglucose,intherangeof9to19units, andfluctuatedgreatlycomparedtopersonsGandJ. Thisshowstheirpancreasproducesnoinsulinandisunabletobringdownbloodglucoseconcentrationtoregularlevels. c) ● Afterbeingbreathedintothetrachea,bronchi, andintobronchioles, insulinmoleculesenterthealveoli,● Wheretheydissolveintothethinfilmofmoistureliningthealveolarairspace, thendiffuseintothebloodplasma. NeedpersonalisedguidanceforOLevelPureBio?Learnmorehere:www.thatbiotutor.comFormoretips:www.youtube.com/@thatbiotutor

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor.Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q6. a) ● Forallofthefivespecies,thereareagreaternumberofstomatapermm 2 onthelowerepidermiscomparedtotheupperepidermis. bi) ● ThisistoensurechangesinmassduetowaterlossisonlyduetotranspirationattheleavesofshootA, andnotbyevaporationfromthewatersurface. bii) ● Totalmassofwaterlossafter48hours=214.5g−211.8g=2.7g● Totalmassofwaterlossperday=2.7g/2 =1.35g● Massofwaterlostpercm 2 ofleafsurfaceareaperday=1.35g/45cm 2 =0.03g/cm 2 /day biii) Species:C Explanation:FromTable6.1,speciesChasthehighestconcentrationofstomata,241stomatapermm 3 onitsleaves,allowingmorewatervapourtodiffuseoutperleafarea,increasingtranspirationrate, hencelosingthemostwaterpercm 2 ofleafareaperday. biv)(Anyone) ● Hairsonleafsurface/Rolledleafstructure/Sunkenstomata/Thicknessofthewaxycuticle NeedpersonalisedguidanceforOLevelPureBio?Learnmorehere:www.thatbiotutor.comFormoretips:www.youtube.com/@thatbiotutor

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor.Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q7.a) b) ● From10°Cto35°C, astemperatureincreases,clottingtimedecreasessteadilyfrom86to30s.● Clottingtimeisthelowestattheoptimumtemperatureof35°C.● From35°Cto45°Cclottingtimeincreasessharplyfrom30to58s. c) ● Plateletspromotebloodclottingatthesiteofinjury, sealingthewoundtopreventlossofbloodandpreventingtheentryofharmfulmicroorganisms.● Whenbloodvesselsaredamaged,plateletsareactivated,whichtriggertheconversionofsolublefibrinogenintoinsolublefibrin,● Forminglonginsolublefibrinthreadswhichtrapredbloodcells, formingaclotatthesiteofinjury. Pathogensareunabletoenter