2023 TYS Answers (ThatBioTutor)

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor. Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:) TYSAnswers2023(ThatBioTutorEdition) IMPTNOTE:- fordifferencesbetween2023and2024syllabus,seethislisthere.- *Shadedblack=outofsyllabusfrom2024onwards Question Ans Question Ans1 D 21 B2 B 22 D3 C 23 D4 C 24 D5 D 25 A6 B 26 C7 B 27 B8 D 28 A9 B 29 C10 D 30 D11 A 31 A12 A 32* A13 A 33* B14 C 34 B15 C 35 D16 C 36 C17 C 37 B18 D 38 A19 B 39 A20 A 40 D

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor. Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Paper2randomanswers:(notcheckedyetbyTBT)-https://drive.google.com/file/d/1qmuJdhwSS1dXvbPPMgsGES5SbCvZlbRY/view?usp=drive_link Q1 a) ● X–pulmonaryartery● Y–rightventricle● Z–tricuspidvalve b) ● Duringventricularsystole,musclesofY,therightventricle,contract.● Asbloodpressureinrightventricleincreasesabovethatoftherightatrium,● CausingZ,thetricuspidvalvetoclose,preventingbackflowofbloodintotherightatrium.● Bloodpressureinrightventricleincreasesabovethatofthepulmonaryartery,pulmonarysemi-lunarvalveisforcedopen,bloodissenttothelungsviathepulmonaryartery. c) ● BloodispumpedfromY,therightventricle,tothelungsviathepulmonaryartery.● Bloodthenreturnstotheleftatriumviathepulmonaryvein,thenenterstheleftventricle,● Andispumpedouttheaortatotherestofthebody.Bloodentersthekidneysviatherenalarteries,● thenbranchesouttoafferentarteriolesofnephrons,enterstheglomeruli,thenefferentarterioles,thenbranchesintobloodcapillaries.

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor. Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q2 ai)Any2points: ● Theyhavethesamelength● Theyhavethesamecentromereposition● Theyhavethesamegeneloci● aii) ● Bodycellsarediploid,hencechromosomeswillbefoundinhomologouspairs● Gametesarehaploid,homologouschromosomeswouldhaveseparatedduringMeiosisI,reductiondivision,hencegametesonlyhaveonecopyofeachchromosome. aiii) Outofsyllabus. b)

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor. Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q3 ai) ● Toreleaseenergythroughaerobicrespiration,● Forcellularactivitiessuchascellgrowth/repair aii) ● Carbondioxide● Water bi) ● Ascelldiameterincreasesfrom10to80µm,meannumberofmitochondriapercellincreasesfrom80to700. bii) Plantcellwithgreaterdensityofmitochondria: ● (choose1)roothaircells/companioncells Reason:(choose1) ● Roothaircells-toreleasealotofenergyviaaerobicrespirationforactivetransportofmineralsaltsfromaregionoflowerconcentrationinthesoiltoaregionofhigherconcentrationintheirlargecentralvacuoles● Companioncells-Toreleasealotofenergyviaaerobicrespirationneededforsievetubeelementstotransportmanufacturedfoodsubstancesduringtranslocationasactivetransportisinvolved Plantcellwithlessdensityofmitochondria:(choose1)Sievetubeelements/Xylemvesselelements Reason:(choose1) ● Sievetubeelements-containnomitochondriatohavemorespaceinthecell,toallowamoreunobstructedflowofsapthroughoutthephloem● Xylemvesselelements-containnocellpartsexceptthecellwall,toallowanunobstructedflowofwaterandmineralsaltsfromtherootstoleaves.

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor. Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q4 a) Feature Liver PancreasIsatargetorganforglucagon ✅ Breaksdownredbloodcells ✅(Outofsyllabus)Isinvolvedinhomeostasis ✅ ✅Producesbile ✅Breaksdownhormones ✅Producesprotease ✅ b) Running: ● Duringtherun,musclesuseupglucoseforaerobicrespirationtoreleaseenergyformuscularcontractions,causingbloodglucoseconcentrationtofall.● Inresponse,cellsoftheisletsofLangerhansinthepancreaswillreleasemoreglucagon,● Whichtravelsthroughthebloodstream,stimulatingthelivertoconvertmoreglycogentoglucose,toraisebloodglucoseconcentrationbacktonormal. Resting: ● Asglucosedemandfrommusclesdecreasesbacktonormal,excessremainingglucoseinthebloodstreamcausesthecellsoftheisletsofLangerhansinthepancreastoreleaselessglucagon,● Andmoreinsulin,increasingthepermeabilityofliverandmusclecellstoglucosesomoreglucosediffusesintothem,andtriggersconversionofglucosetoglycogenin,loweringbloodglucoseconcentrationbacktonormal.

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor. Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q5 ai) ● WatermovesoutofcellBbyosmosis,formingathinfilmofmoisture,whichevaporatesintowatervapourintheintercellularairspaces.● Asthiscontinuestooccur,waterpotentialofcellBdecreases,andisnowlowerthanthatofcellA.● WaterflowsfromaregionofhigherwaterpotentialincellAtoaregionoflowerwaterpotentialincellB,downthewaterpotentialgradient,viaosmosis.● WatermovesfromxylemvesselsintocellAtoreplacethewaterlost,increasingitswaterpotentialtobehigherthancellBonceagain. aii) ● Whenaplantwilts,morewaterislostviatranspirationthanisabsorbedattheroots,mesophyllcellsexperienceanetlossofwater,causingtheirlargecentralvacuolestoshrink.● Severewaterlosswouldcauseitsplasmamembrane/cellsurfacemembranetopullawayfromthecellwall● Thecellisnowplasmolysed b) ● Seawaterhasahighconcentrationofsalt,andlowwaterpotential.● Waterpotentialofthesoilcouldbecomelowerthanthatoftheplants'roothaircells,waterleavesviaosmosisinsteadofenteringtherootsoftheplant.● morewaterislostviatranspirationthanisabsorbedattheroots,mesophyllcellsexperienceanetlossofwater,causingtheirlargecentralvacuolestoshrink,theplantwilts.● Thiscausestheguardcellstoclosestomata,plantswillnotbeabletotakeinsufficientcarbondioxide/Thisreducestotalleafsurfacearea,plantswillnotreceivesufficientsunlightforphotosynthesis,henceeventuallydie.

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor. Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q6 a) ● P–larynx● Q–bronchi● R–trachea b) ● Whenbreathingin,thediaphragmcontractsandflattens,whiletheribcagemovesupwardsandoutwardsduetothecontractionofexternalintercostalmuscles.● Boththeseactionsincreasethoracicvolume,causingairpressureinlungstofallbelowatmosphericpressure,causingairtoflowintothelungs. c) Tar: ● Tarisacarcinogen,whichincreasestheriskoflungcancer.● Taralsoparalysescilia,sodustparticlesandpathogenstrappedinmucuscannotbeexpelled.Thiscanresultinchronicbronchitisandemphysema. Carbonmonoxide: ● Carbonmonoxidebindsirreversiblywithhaemoglobinsuchthatitcannottransportoxygenanymore,reducingtheabilityofbloodtotransportoxygen.● Carbonmonoxidealsodamagesinnermostlayerofbloodvessels,increasingtheratefattydepositsaccumulateinarteries,henceincreasingchancesofheartattacks.

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor. Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q7. a)Oceans b(i) Landuse Massofcarbonreleasedintotheatmospherein1990/millionsoftonnes Massofcarbonreleasedintotheatmospherein2015/millionsoftonnes Urban 0.0 0.5 Industrialfarming 2.9 64.3 Small-holderfarming 20.7 49.1 Undevelopedland 12.0 13.6 Tallshrubs 4.1 9.2 Degradedpeatswamp 12.1 9.4 b(ii) ● (49.1-20.7)/20.7*100=137%(3sf) b(iii) ● Aspeatismadeofdeadplantremainsthathavenotfullydecomposed,whenpeatisdrained,microorganismsfeedonthepeatanddecomposeit,● Releasingcarbondioxideasdecomposersundergoaerobicrespiration.● Thepeatswampforestusedtoaccumulatecarboncompoundsinthepeatunderthelivingvegetationforindefiniteperiodsoftime,butadrainedoneonlystorescarboninthelivingvegetation.● Asitisnowreleasingmorecarbondioxidetotheatmospherethanittakesin,itisnowacarbonsource.

Credit:WrittenbythecollectiveeffortofourtutorsatThatBioTutor. Youarewelcometosharethesewithanyoneyou’dlike!Justdon’tsellthemforprofit:)Q8Either ai)Any3points: ● Menstrualcyclelengthvariesbetweenwomenofdifferentages/evenwithinthesameage,anddonothaveafixedduration.● Themeanmenstrualcyclelengthisatitsmaximumatage21years,whereitlasts30days.● Meanmenstrualcyclelengthgenerallydecreasesfromabout30daysto26.7daysaswomenagefrom18to45years.● Themaximumcyclelengthforwomenaged18to45was31dayswhiletheminimumcyclelengthwas26.7days.● (Anyothervalidtrend/observationind