Download pdf - 2017 Biology-nht Written · PDF fileWritten examination ... sheet provided for multiple-choice questions. Choose the response that is ... to carry out both aerobic and anaerobic respiration

BIOLOGYWritten examination

Friday 2 June 2017 Reading time: 10.00 am to 10.15 am (15 minutes) Writing time: 10.15 am to 12.45 pm (2 hours 30 minutes)

QUESTION AND ANSWER BOOK

Structure of bookSection Number of

questionsNumber of questions

to be answeredNumber of

marksA 40 40 40B 11 11 70

Total 110

• Studentsarepermittedtobringintotheexaminationroom:pens,pencils,highlighters,erasers,sharpenersandrulers.

• StudentsareNOTpermittedtobringintotheexaminationroom:blanksheetsofpaperand/orcorrectionfluid/tape.

• Nocalculatorisallowedinthisexamination.

Materials supplied• Questionandanswerbookof36 pages.• Answersheetformultiple-choicequestions.

Instructions• Writeyourstudent numberinthespaceprovidedaboveonthispage.• Checkthatyourname andstudent numberasprintedonyouranswersheetformultiple-choice

questionsarecorrect, andsignyournameinthespaceprovidedtoverifythis.• AllwrittenresponsesmustbeinEnglish.

At the end of the examination• Placetheanswersheetformultiple-choicequestionsinsidethefrontcoverofthisbook.

Students are NOT permitted to bring mobile phones and/or any other unauthorised electronic devices into the examination room.

©VICTORIANCURRICULUMANDASSESSMENTAUTHORITY2017

SUPERVISOR TO ATTACH PROCESSING LABEL HEREVictorian Certificate of Education 2017

STUDENT NUMBER

Letter

2017BIOLOGYEXAM(NHT) 2

SECTION A – continued

Question 1CellulosebelongstothegroupofbiomacromoleculescalledA. triglycerides.B. polypeptides.C. nucleicacids.D. polysaccharides.

Question 2Whichoneofthefollowingstatementsaboutcelluloseistrue?A. Itiscomposedofthesamemonomerasproteins.B. Itdoesnotprovidestabilitytotheplantcell.C. Itissynthesisedviacondensationreactions.D. Ithasexactlythesamestructureasstarch.

Question 3 Bothplantandanimalcellshaveplasmamembranes.Considerthestructureoftheplasmamembranesofplantcells.TheplasmamembranesofplantcellsA. haveidenticalproteinstotheplasmamembranesofanimalcells.B. haveaphospholipidbilayerstructuresimilartoanimalcells.C. aremadeupmainlyoffatsandstarch.D. containmainlycellulose.

SECTION A – Multiple-choice questions

Instructions for Section AAnswerall questionsinpencilontheanswersheetprovidedformultiple-choicequestions.Choosetheresponsethatiscorrect forthequestion.Acorrectanswerscores1;anincorrectanswerscores0.Markswillnotbedeductedforincorrectanswers.Nomarkswillbegivenifmorethanoneansweriscompletedforanyquestion.

3 2017BIOLOGYEXAM(NHT)

SECTION A – continuedTURN OVER

Question 4Sixmoleculesthatformpartoftheplasmamembraneofananimalcellareshownbelow.

S

R

Whichoneofthefollowingstatementsistrue?A. TheRportionsofthemoleculesareontheoutersurfaceofthecell.B. TheSportionsofthemoleculesrepresentthehydrophilicphosphateheads.C. BoththeSandRportionsofthemoleculesremainfixedinpositionwithinthemembrane.D. TheSandRportionsofthemoleculestogetherallowfortheeasytransportofglucose.

Question 5Thegraphbelowshowsthegrowthrateofdifferenttypesofbacteriawhenthebacteriaareexposedtovaryingconcentrationsofatmosphericoxygen.

100

50

relativegrowth rateof bacteria(per cent)

0 5 10 15 20concentration of oxygen

(per cent of atmosphere)

Bacteria RBacteria SBacteria TBacteria U

Key

Basedonyourknowledgeandtheinformationinthegraph,whichoneofthefollowingstatementsistrue?A. BacteriaRareunabletocarryoutanaerobicrespiration.B. BacteriaUarepoisonedbyahighconcentrationofoxygen.C. BacteriaSareabletocarryoutbothaerobicandanaerobicrespiration.D. BacteriaTareunabletocarryoutbothaerobicandanaerobicrespiration.



Question 6Whichoneofthefollowingdiagramsisacorrectrepresentationofthewaytheionsmoveacrossaplasmamembrane?

A.

C.

B.

D.

ions on either side of plasma membraneion pumpion channel

Key

RS

R Splasma membrane

plasma membrane

plasma membrane

plasma membrane

R S

R S R S

ADP + PiATP ADP + PiATP

ADP + PiATP

ADP + PiATP

ADP + PiATP

Question 7Whenahydrophilicsignallingmoleculereachesatargetcell,whichsequenceofstepsoccurs?A. bindingtoglycolipidoncellsurface,transduction,responseB. bindingtoproteinreceptoroncellsurface,transduction,responseC. bindingtocytoplasmicreceptormolecule,transduction,responseD. bindingtoendoplasmicreticulumreceptormolecule,stimulationofgeneregulator,transduction,

response

Question 8 Whenratsarestressed,theyreleaseachemicalthatappearstocauseotherratsnearbytobecomeanxious.ThischemicalisaA. neurotransmitter.B. pheromone.C. pathogen.D. enzyme.



Question 9 Totestthehypothesisthatauxinproducedintheapicaltipinhibitsthelateralgrowthofbranchesinpeas, astudentsetupanexperimentasshowninthediagrambelow.

gel containing auxin applied tocut end

decapitation –apical tip removed

normal pea plant

decapitation –apical tip removed

normal pea plant

lateral branch

10 days

10 days

Treatment 1

Treatment 2

apicaltip

apicaltip

WhichoneofthefollowingisacontrolforTreatment2?

A. apeaplantwiththebottomleavesremoved

B. anintactpeaplantwithmanyleaves

C. adecapitatedpeaplantwithafoilcapplacedonthecutend foil cap coveringcut end

D. adecapitatedpeaplanttowhichagelcontainingnoauxinisappliedtothecutend

gel containingno auxin appliedto cut end



Question 10Whichoneofthefollowingstatementsaboutthetransmissionofanervesignalistrue?A. AnerveimpulseisfacilitatedbyNa+/K+pumpsonthemembraneoftheneuron.B. Calciumionsareinvolvedinthetransmissionoftheimpulsealongtheneuron.C. Thegreaterthestimulus,thegreaterthesizeofthenerveimpulse.D. Neurotransmittersareactivelytransportedacrossthesynapse.

Question 11WhenapoptosisisinitiatedbyDNAdamageinacellA. theplasmamembraneruptures,releasingthecellcontents.B. acascadeofreactionsoccursinthecytoplasm.C. allenzymeactivitywithinthecellisinhibited.D. uncontrolledreplicationofthecelloccurs.

Question 12Thelymphaticsystemplaysanimportantroleindefendingthehumanbodyagainstdisease.Whichoneofthefollowingistrueofthelymphaticsystem?A. Lymphnodesprovideanaturalbarrieragainsttheentryofpathogensintotheinternalenvironment.B. Lymphcontainshydrochloricacid,whichkillsmanybacteria.C. Cellswithinthelymphnodesdetectantigens.D. Lymphcontainsmucustotrapbacteria.



Use the following information to answer Questions 13 and 14.Inextremelyrarecases,injectionofaninfluenzavaccinemaycauseanallergicreaction,whichusuallyoccurswithinafewhoursofthevaccinebeingadministered.Theflowchartbelowoutlinesthekeystagesinanallergicresponse.

Step Pbody tissues

exposed to allergen

Step QB cells stimulated

Step RB plasma cellsproduce IgEantibodies

Step S

Step Vsigns of allergy, for

example, runny nose

?

Step Useveral physiologicaleffects, for example,

increased mucussecretion

Step Tcells release

histamine

Question 13WhichoneofthefollowingstatementsbestsummarisesStepS?A. CytotoxicTcellsareactivated.B. SecretedIgEantibodiesbindtomastcells.C. ComplementproteinsstimulateT-helpercells.D. SecretedIgEantibodiesattachtomacrophages.

Question 14AnotherexampleofaphysiologicaleffectatStepUandaresultingsignofallergyatStepVcouldbeA. capillariesbecomingpermeableandleaky,causingswelling.B. increasingnumbersofphagocytes,leadingtorednessoftheskin.C. vasodilationoftheskinbloodvessels,leadingtopalenessoftheskin.D. relaxationofthesmoothmusclesinlungtubules,causingbreathingdifficulties.

Question 15Guillain-Barrésyndromeisahumanautoimmunediseasethataffectsthenervoussystem.ThereisnocureforGuillain-Barrésyndrome,butresearchershavedevelopedatreatmentthatcanreducethesymptomsofGuillain-Barrésyndromeinpatients.WhichoneofthefollowingcouldbeausefultreatmentforGuillain-Barrésyndrome?A. vaccinationwithanattenuatedformoftheGuillain-BarrépathogeninordertodevelopBmemorycellsB. injectionofphagocyticcellsthathavebeendevelopedtorecogniseanddestroytheGuillain-Barré

pathogenC. repeatedremovalofthepatient’sbloodandfilteringofantibodiesbeforereturningthebloodtothe

patient’sbodyD. administrationofhigher-than-normaldosesoftheantibioticpenicillinwithinthefirst48hoursof

symptomsofGuillain-Barrésyndromebeingnoticed



Question 16 CanolaisaneconomicallyimportantcropplantinAustralia.Pathogensthatreducecanolaproductionareaconcerntogrowers.Onesignificantdiseaseisblackleg,causedbythefungus Leptosphaeria maculans. A detailedexaminationofinfectedcanolastemshasshownthepresenceofthefungus.ThestructureoftheL. maculanspathogenconsistsofA. asingleproteinmolecule.B. cellswithoutDNAmolecules.C. aproteincoatenclosingRNAmolecules.D. cellswithacellwallandanuclearmembrane.

Question 17Scientistsperformedanexperimentinwhichtheyobservedtheinteractionofredbloodcells(RBCs),antibodiesandtheinfluenzavirus.Differentcombinationsoftheseweremixedtogetherinsmallcontainerscalledwells.Twodifferentantibodiesweretested.Theresultsareshownbelow.

Components added to the well

Interaction Observation

Well A RBCs noclumpingofredbloodcells

Well B

+

virus RBCs clumpingofredbloodcells

Well C virus

+

+

Antibody type 1

RBCs

noclumpingofredbloodcells

Well D virus

+

+

Antibody type 2

RBCs

clumpingofredbloodcells

Source:adaptedfromCentersforDiseaseControlandPrevention(www.cdc.gov/)

Whichoneofthefollowingwouldbeareasonableconclusiontodraw?A. Antibodytype1isnotspecifictothesurfaceproteinsofthevirus.B. Antibodytype2preventsinteractionbetweentheRBCsandthevirus.C. InWellB,theRBCsandthesurfaceproteinsofthevirusdonotinteractwitheachother.D. InWellC,theantigen–antibodyinteractioninterfereswiththeRBCsbindingtothevirus.



Use the following information to answer Questions 18 and 19.Considerthefollowingphotographofonioncellsundergoingcelldivision.Thesecellswerefoundinagrowingroottip.

R

S

N

M

Source:PIYAPONGTHONGDUMHYU/ Shutterstock.com

Question 18Whichoneofthefollowingisacorrectstatement?A. HomologouschromosomesarepairedinthecelllabelledR.B. EachchromosomeinthecelllabelledMwillcontainonemoleculeofDNA.C. SeparatedsisterchromatidsaremovingtooppositepolesofthecelllabelledS.D. ThenucleusofthecelllabelledNhashalfthenumberofchromosomescomparedtoitsparentnucleus.

Question 19 Thestageofcelldivisionatwhichthenuclearenvelopearisesfromfragmentsoftheparentnuclearenvelope,andthenucleolireappear,isshownbythecelllabelledA. M.B. N.C. R.D. S.

Question 20 Considercellsdividingbymeiosis.ThecellsproducedA. aretheresultofonenucleardivisionandtwodivisionsofthecytoplasm.B. havethesamenumberofchromosomesastheparentcell.C. aregeneticallyidenticaltoeachother.D. arehaploid.



Question 21 Duringmeiosis,theprocessofcrossingoverA. involvestheexchangeofgeneticmaterialbetweennon-sisterchromatidsofhomologouschromosomes.B. occursbetweensectionsofnon-homologouschromosomes.C. resultsinlessgeneticvariationinthegametes.D. occursduringthesecondmeioticdivision.

Question 22SynthesisofDNAmoleculesisrequiredintheproductionofnewcells.WhichoneofthefollowingisacorrectstatementaboutthesynthesisofDNAmolecules?A. DNAprimersactasastartingpointforthesynthesisofnewDNAmolecules.B. ThesynthesisofDNAmoleculesoccursintheG2stageofthecellcycle.C. OnlyonestrandoftheoriginalDNAmoleculeactsasatemplate.D. DNApolymerasejoinsnucleotidestoagrowingstrandofDNA.

Use the following information to answer Questions 23 and 24.Ricinisanaturallyoccurring,powerfulpoisonthataffectseukaryoticorganisms.Largemammalsthatingestsmallamountsofricincandiewithinthreetofivedays.Studieshaveconcludedthatricinstopsthemovementofaribosomealongaspecificmolecule.ThisspecificmoleculehasbeenlabelledMoleculeXinthediagrambelow.

ribosome Molecule X

direction of ribosome movement

Question 23WhatisthenameofMoleculeX?A. rRNAB. tRNAC. mRNAD. pre-mRNA

Question 24EukaryoticorganismsdiefromricinpoisoningbecausethericinimmediatelycausesA. nervedamagetomotorneurons.B. theprocessofmitosisinthecellstostop.C. irreversibledamagetoDNAinthenucleiofcells.D. theprocessofproteinsynthesisinthecellstostop.



Question 25 AsectionofaDNAstrandhasthebasesequenceAGCGCATAGCAA.DuringDNAreplicationtoformthecomplementaryDNAstrand,amutationinvolvingasinglebasesubstitutionoccurredinthelasttripletofthissection.ThismutationwasthenpassedontothemRNAwhentranscriptionofthecomplementarystrandoccurred.ThebasesequenceofthemRNAcontainingthemutationcouldbeA. AGCGCAUAGCAAB. AGCGCAUAGUAAC. UCGCGUAUCGUUD. UCGCGUAUCAUU

Question 26 Considerthediagramofthechromosomesbelow.

X

Source:IaremenkoSergii/Shutterstock.com

ThestructureslabelledXareA. centromeres.B. spindlefibres.C. sisterchromatids.D. homologouschromosomes.



Use the following information to answer Questions 27 and 28.Tryptophanisanaminoacidthatisproducedbymanybacteria.GenesthatcodefortheproductionoftryptophanarefoundonbacterialDNAandtogetherarecalledthe trpoperon.Intheprocessofgeneregulation,arepressorprotein(trprepressor)bindstothetrpoperon.Whensuchbindingoccurs,theprocessoftryptophanproductionstops.Thisisillustratedinthediagrambelow.

trp repressorbinds to trp operon

trp repressor

production oftryptophan unable to

proceed

trp operon

DNA strand

Question 27 Whenthetrprepressorbindstothetrpoperon,whichoneofthefollowingenzymeswouldbeblockedfromfunctioningnormally?A. RNApolymeraseB. DNApolymeraseC. endonucleaseD. DNAligase

Question 28Whichoneofthefollowingfactorswouldincreasetheconcentrationofthetrprepressorinbacterialcells?A. lowconcentrationoftryptophanB. highconcentrationoftryptophanC. highconcentrationofDNAligaseD. lowconcentrationofDNApolymerase



Use the following information to answer Questions 29 and 30.HaemophiliaAisarecessivegeneticdisorder.Humanswiththisdisordertendtobleedmorethannormalbecauseoneoftheproteinsneededinbloodclottingismissing.ThegenecontrollingtheproductionofthisproteinisfoundontheXchromosome.Thisgenehastwoalleles.

Question 29AfemalecarrierofhaemophiliaAA. willbehomozygouswithrespecttothisgene.B. hasonecopyofeachoftheallelesofthisgene.C. willhavethesamegenotypeasafemalewithhaemophiliaA.D. passesthealleleforhaemophiliaAtoallofherdaughters.

Question 30 ConsiderthechildrenofafatherwhosebloodclotsnormallyandamotherwhoisacarrierofhaemophiliaA.Whichoneofthefollowingisacorrectstatementaboutthechildrenoftheseparents?A. EachchildwillhaveanequalchanceofinheritinghaemophiliaA.B. Daughterswillhavea50%chanceofinheritinghaemophiliaA.C. Alldaughterswillbehomozygouswithrespecttothisgene.D. Sonswillhavea50%chanceofinheritinghaemophiliaA.

Question 31Inapopulation,atraitwillbemorelikelytoshowcontinuousvariationifA. thetraitisinfluencedbymanygenes.B. genescontrollingthetraitarecloselylinked.C. thereisalowmutationrateinthegenecontrollingthetrait.D. theenvironmenthaslittleeffectontheexpressionofthetrait.



Use the following information to answer Questions 32 and 33.Thepresenceofhornsandthecolourofhairingoats(Capra hircus)aregeneticallyinherited.Inaparticularbreedofgoats,haircolourmaybebrownorwhite.Thesegoatsmayhavehornsorhornsmaybeabsent.

Question 32 Crossesbetweenindividualgoatswereperformedandthephenotypesoftheoffspringwererecorded.Theresultsofthecrossesareshowninthetablebelow.

Cross Phenotypes of parents Phenotype(s) of offspring

1 brown×white brown

2 brown×brown somebrownandsomewhite

3 white×white white

4 horns×nohorns nohorns

5 horns×horns horns

6 nohorns×nohorns somewithhornsandsomewithnohorns

Basedontheinformationprovided,whichoneofthefollowingconclusionscanbemade?A. Allgoatswithbrownhairhavethesamegenotypewithrespecttohaircolour.B. Thebrown-hairedparentincross1isheterozygouswithrespecttohaircolour.C. Allgoatswithhornshavethesamegenotypewithrespecttothepresenceorabsenceofhorns.D. Thetwoparentswithouthornsincross6havedifferentgenotypeswithrespecttothepresenceor

absenceofhorns.

Question 33 Todetermineifthegeneforhaircolourandthegeneforthepresenceorabsenceofhornsarelinked,thefollowingcrosseswerecarriedout.

Cross Phenotypes of parents Phenotypes of offspring and ratio

1 brownhair,nohorns× whitehair,horns

allhavebrownhair,nohorns

2 brownhair,nohorns× brownhair,nohorns

9brownhair,nohorns:3brownhair,horns:3whitehair,nohorns:1whitehair,horns





EvidencethatthegenesarelinkedwouldbeprovidedbyA. cross1.B. cross2.C. cross3.D. cross4.



Question 34Radio-isotopicdating(radiometricdating)isusedtodeterminetheageoffossilsandtheirsurroundingrocks.Whichstatementaboutradio-isotopicdatingistrue?A. Radio-isotopicdatingtechniquesareonlyreliablewhendatingfossilsthatwereformedlessthan

20millionyearsago.B. Radio-isotopicdatingcalculationsassumethatthebreakdownofaradioactiveisotopeoccursata

constantrate.C. Carbonisthebestelementtoprovideusefulradio-isotopicdatingevidenceforcalculatingtheageofall

fossils.D. Radio-isotopicdatingtechniquescannotprovideanestimateofhowmanyyearsagoafossilwas

formed;theyareonlyusefultocompareifonefossilisolderthananother.

Question 35Researchersstudiedthephylogeneticrelationshipbetweentwoamphibianspecies,SpeciesGandSpeciesH.Basedonmolecularhomology,whichoneofthefollowingwouldbeusefulevidencetohelpdeterminetherelationshipbetweenthetwospecies?A. Therateofaparticularmetabolicreaction,catalysedbythesameenzyme,isconsiderablyfasterin

SpeciesGthaninSpeciesH.B. Thestructureoftheeyemusclesissignificantlydifferentbetweenthetwospecies.C. Theaminoacidsequenceofaparticularproteinisthesameinbothspecies.D. ThemoleculetRNAispresentinbothspecies.

Question 36 ComparativegenomicsA. isatoolusedbyscientiststostudyevolutionarychange.B. comparesthebiogeographicaldistributionofpresent-dayspecies.C. isthestudyofthehomologousandanalogousstructuresofdifferentspecies.D. reliesontheabilityofscientiststoseparatedifferentcarbohydratesfromthecellsofdifferentspecies.

Question 37 Severalspeciesofflightlessbirdscanbefoundondifferentlandmassesoftheworld.ExamplesincludetheAfricanostrich,theAustralianemuandtheNewZealandkiwi.Recentstudieshavemadescientistsrethinktheevolutionaryrelationshipbetweenflightlessbirds.Scientistsnowhypothesisethattheseflightlessbirdshaveevolvedbyconvergentevolution.ThissuggeststhatA. thelossoftheabilitytoflydevelopedindependentlyineachofthethreebirdspecies.B. eachofthethreebirdspeciesoccupiesverydifferentecologicalniches.C. theostrich,theemuandthekiwisharearecentcommonancestor.D. therateofmutationineachofthethreebirdspeciesishigh.



Question 38 Whichofthefollowingcharacteristicsaresharedbybothhominoidsandhominins?A. colourvision,omnivorous,nails,opposablethumbs,simpletooluse,livingingroupsB. colourvision,carnivorous,highlydevelopedsenseofsmell,forward-facingeyes,solitarylivingC. poorvision,eatsonlyfruit,poorsenseofsmell,claws,highlydevelopedhearing,livingingroupsD. well-developedperipheralvision,herbivorous,poorsenseofsmell,forward-facingeyes,

well-developedhearing,livingingroups

Question 39 Thediagrambelowshowsthreeviewsoftheskeletonofahomininspecies.

Source:3drenderings/Shutterstock.com

Basedonyourknowledgeandtheinformationprovidedinthediagram,whichoneofthefollowingisacorrectstatement?A. ThespeciesshowninthediagramisolderthanAustralopithecus afarensis.B. Thespeciesshowninthediagramhasapelvicstructureallowingbipedallocomotion.C. Thespeciesshowninthediagramhasaslopingforeheadsimilartomodern-dayhumans.D. Thespeciesshowninthediagramhasprominentbrowridgessimilartothoseseeninallhominin

species.


END OF SECTION ATURN OVER

Question 40 FossilbonesofthehomininspeciesHomo floresiensis werediscoveredinacaveontheIndonesianislandofFlores.Thefossilboneshavebeendatedfromabout100000to60000yearsago.Thissuggeststhatthisspecieslivedatthesametimeasmembersofourownspecies,Homo sapiens.ScientistslookedforevidenceofculturalevolutioninthecavewherethefossilremainsofH. floresiensis werefound.EvidenceofculturalevolutioncouldincludeA. footprintsindicatingthatH. floresiensiswasbipedal.B. handbonesthatindicatethatH. floresiensishadanopposablethumb.C. anaveragebodysizeinH. floresiensisthatissmallerthanthatofH. sapiens.D. H. floresiensis beingfoundwithvariousfossilisedburntanimalboneswithcutmarksonthem.


SECTION B – Question 1–continued

Question 1 (6marks) Haemoglobinisthemoleculeinredbloodcellsthatdeliversoxygentocellsthroughoutthebody.Inadults,haemoglobinnormallyconsistsoffoursub-units:twosub-unitsofbeta-globinandtwosub-unitsofalpha-globin.Eachsub-unitisboundtoaniron-containingmoleculecalledhaem.Thehaemmoleculebindstooxygen.

a. Namethegroupofbiomacromoleculesthathaemoglobinbelongsto. 1mark

b. Sickle-celldisease(SCD)isagroupofblooddisorders.PeoplewithSCDmayhavejust asinglenucleotidechangeintheHBBgene–thesegmentofDNAthatcodesforthe beta-globinofthehaemoglobin.Thisresultsinanalteredhaemoglobinmolecule.

ExplainhowasinglenucleotidechangeintheHBBgenecanalterthestructureofthehaemoglobinmoleculeinpeoplewithSCD. 2marks

SECTION B – Short-answer questions

Instructions for Section BAnswerallquestionsinthespacesprovided.Writeusingblueorblackpen.


SECTION B – continuedTURN OVER

c. RecentadvancesinDNA-editingtechniqueshavegreatpotentialtocureconditionssuchasSCD.OnesuchtechniqueinvolvestheuseofRNA.RNAisamoleculecloselyrelatedtoDNA.

CompletethetablebelowtoprovideacomparisonbetweenDNAandRNA. 3marks

DNA RNA

Names of nucleotide bases present

Function 1

Function 2


SECTION B – continued

Question 2 (4marks)Atransmissionelectronmicrographofpartofacellisshownbelow.Thenucleusofthecellhasbeenlabelled.

X

nucleus

Source:JoseLuisCalvo/Shutterstock.com

Thecellshownaboveisasecretorycell.Thesecretoryproductofthecellissynthesisedbyanorganelle,partofwhichisenclosedbythecirclelabelledX.

a. Namethisorganelle. 1mark

b. Describethetransportationpathwaytakenbythesecretoryproductfromtheorganellenamedinpart a.untilitleavesthecell. 3marks



Question 3 (5marks)a. i. Giveanexampleofacatabolicreactionthatoccursinacell. 1mark

ii. Justifywhythisreactionisclassifiedasacatabolicreaction. 1mark

b. AproteincalledAMP-activatedproteinkinase(AMPK)hasbeenshowntocontrolmetabolicreactionsincells.AMPKregulatesthelevelofATPinthecell,controllingtherateofbothanabolicandcatabolicreactionssothatthelevelofATPremainsoptimalforcellularactivities.

i. Completethefollowingtableusingthewords‘increases’or‘decreases’toindicatehow therateofcellularreactionsiscontrolledbyAMPKwhenthelevelofATPwithinthe cellfalls. 1mark

Type of cellular reaction

Catabolic Anabolic

Rate of cellular reaction

ii. Giveareasonforeachofyouranswerstopart b.i. 2marks



Question 4 (7marks)Thesmokeproducedduringafireisusuallymoredangerousthantheheat.Twoofthemanytoxicchemicalsinthesmokeofafirearecarbonmonoxideandhydrogencyanide.Carbonmonoxidemoleculesbindtohaemoglobinmoleculesintheblood,reducingtheblood’scapacitytotransportoxygen.Thiscausesasignificantreductioninoxygensupplytothecellsofthebody.

a. Oxygenisrequiredfortheprocessofcellularrespiration.Thethreestagesofthisprocessarelistedinthetablebelow.

Completethetablebynamingthemissinginputsandoutputsofeachstageofcellular respirationwhennormaloxygenlevelsareavailable. 3marks

Stage Inputs Outputs

glycolysis

ADP+PiNAD++H+

ATPNADH

Krebscycle

ADP+PiNAD++H+

FAD+2H+

ATPNADHFADH2

electrontransportchain

ADP+PiNADHFADH2

ATPNAD++H+

FAD+2H+

b. Suggestwhybloodlactate(lacticacid)levelsmightbeusedtodiagnosecarbonmonoxidepoisoning. 1mark



c. Hydrogencyanideisaninhibitoroftheenzymecytochromecoxidase,animportantenzymeintheelectrontransportchain.

Explainhowamoleculesuchashydrogencyanidemayactasaninhibitoroftheenzymecytochromecoxidase. 2marks

d. Refertothegeneralbiochemicalpathwayshownbelow.

Enzyme AA

Enzyme BB

Enzyme CC

Enzyme DD E

DescribewhathappenswhenanyoneoftheenzymesA,B,CorDinthepathwayisinhibited. 1mark



Question 5 (7marks) a. Onthediagramofthechloroplastbelow,uselabelledarrowstoindicatethepositionsofthe

followingstructures:• grana• stroma 2marks

Region B Region A

Source:BlueRingMedia/Shutterstock.com



b. Twostudentssetupanexperimenttomeasurethereactionrateofthelight-dependentstageofphotosynthesis.Thylakoidmembraneswereremovedfromchloroplastsandsuspendedinsolution.Themembraneswerethenexposedtodifferinglightintensitiesandtherateofthereactionwasmeasured.StudentAwasgiventhylakoidmembranesfromRegionAand StudentBwasgiventhylakoidmembranesfromRegionB.Bothfollowedthesamemethod.

Theresultsobtainedbybothstudentsareshownbelow.

Student A Student B

reactionrate

light intensity

reactionrate

light intensity

i. Whatcouldthestudentshavemeasuredintheirexperimenttoindicatethereactionrate? 1mark

ii. Statetwofactorsthateachstudentmustcontrolwhensettinguptheirexperimentsothattheycancomparetheirresultsandknowthattheirresultsarevalid. 2marks

iii. Eachstudentsetuptheirexperimentinanidenticalmanner.

Explainthedifferencesobservedintheirresults. 2marks



Question 6 (8marks)a. Innateimmunityhelpsprotecthumansfrominvadingpathogens.

Howdoestheskinhelpprotecthumansfrominvadingpathogens? 1mark

Researchsuggeststhatthemicroorganismsthatnormallyliveontheskinhaveaverycomplexandbeneficialrelationshipwiththeirhosts. Staphylococcus epidermidis is oneofthemostcommonspeciesofbacteriaonhumanskin.Toinvestigatethepossiblebeneficialroleofthisbacterium,scientistsdesignedanexperimentasfollows.Twogroupsofmicewereused.ThemiceinGroup1hadS. epidermidisappliedtotheirskin.ThemiceinbothGroup1andGroup2wereinfectedwithapathogenicfungus.Themicewereleftforseveraldays,andthenscientistsmeasuredthelevelsofantigen-presentingcells(APCs)andcytotoxicTcells(Tccells)intheskinofthemicefrombothgroups.

b. DescribetheroleofAPCsinanimmuneresponse. 2marks

c. InwhichtypeofimmuneresponsewouldtheTccellsandAPCsplayapart? 1mark



d. InadditiontothelevelsofAPCsandTccells,thegrowthofthepathogenicfunguswasalsomeasuredinallofthemice.Theresultsofthisexperimentaresummarisedinthetablebelow.

Mice Level of APCs Level of Tc cells Growth of the pathogenic fungus

Group1 high high nogrowthonskin

Group2 low low funguscoveringalargeareaofskin

i. Stateahypothesisthatthisexperimentistesting. 1mark

ii. Explainwhichgroupofmiceservedasacontrolinthisexperiment. 1mark

iii. Explainthedifferenceingrowthofthepathogenicfungusinthetwogroupsofmice. 2marks



Question 7 (8marks) Researchersstudyingtheprocessoffloweringinaplanthypothesisedthattheonsetoffloweringiscontrolledbytheregulationofaspecificgene.Theresearchersdecidedtosequencethegene.

a. Whatinformationisobtainedfromgenesequencing? 1mark

AportionoftheDNAoftheplantwasamplified.TheDNAamplificationmixturewasmadeupofthespecificgenesegment,asupplyoffournucleotidebases,Taq polymeraseandDNAprimers.Thetemperatureofthemixturewaschangedasfollows.

Step Temperature

1 94°C

2 55°C

3 72°C

b. DescribewhathappenstotheDNAwhenthemixtureisheatedduringStep1.Nametheendproductofthisstage. 2marks

c. WhatisthefunctionoftheDNAprimersinthemixture? 1mark

d. Explainwhythetemperaturewasreducedto55°CinStep2andthenincreasedto72°CinStep3. 3marks



e. Theresearchersrepeatedthisamplificationprocessthreemoretimesinseparatemicrotubes.Theythencarriedoutgelelectrophoresisonsamplesfromeachofthefourmicrotubes.Theirresultsareshownbelow.

Microtube1

Microtube2

Microtube3

Microtube4

directionof travel

loadingwells

SuggestapossiblereasonwhytheresultsforMicrotube3aredifferentfromtheresultsfortheotherthreemicrotubes. 1mark



Question 8 (7marks) Considerthefollowingpedigree.

1 2

1 2 3 4 5 6

3 4

I

II

III

2 31

IndividualII-4displaysatraitthatisinherited.TheinheritanceofthistraitisX-linkeddominant.ItisknownthatthistraitisalsofoundinindividualswithinthisfamilyingenerationsIandIII.

a. i. Inthepedigreeabove,shadeinallindividualswhomustalsodisplaythesametraitasindividualII-4. 1mark

ii. Giveareasonforshadinginthoseindividuals. 1mark



b. A different inheritedtraitwasinvestigatedinafamily.Individualsdisplayingthistraithavebeenshadedinthepedigreebelow.

1 2

1

2 31

2 3 4 5 6

4

3 4

I

II

III

i. Determinethemodeofinheritanceofthistrait. 1mark

ii. Givetwopiecesofevidencetosupportyouranswertopart b.i. 2marks

iii. IfindividualsIII-3andIII-4haveachild,whatistheprobabilitythatthischildwillhavethetrait?Showyourworking. 2marks


SECTION B – continued

Question 9 (5marks) InAfrica,themalaria-carryingmosquitoAnopheles gambiae hasbeenthefocusofa mosquito-eradicationcampaignusingtheinsecticidepyrethroid.Researchersfoundthatallele1ofgeneL1014producesresistancetopyrethroidinthesemosquitoes;however,allele2doesnotproduceresistancetopyrethroid.Researchersstudiedthefrequencyofbothoftheseallelesoveraperiodoftime.Intheparticularpopulationofmosquitoeswherethisstudywascarriedout,anintenseprogramofpyrethroidsprayingwasbegunin2008andwasmaintaineduntil2011.Theresultsoftheallelefrequencystudiesarepresentedinthetablebelow.

Allele frequencies for gene L1014 in A. gambiae

Allele type Frequency in 2007 Frequency in 2011

1 36.4% 77.7%

2 63.6% 22.3%

Itisconsideredthatthisdataprovidesevidencethattheprocessofnaturalselectionhasoccurred intheA. gambiae species.

a. Usingtheinformationabove,explainhownaturalselectionhasoperatedinthispopulationoftheA. gambiae mosquito. 3marks

b. Basedontheinformationabove,hasthegenepoolofthispopulationoftheA. gambiae mosquitobeenalteredbythesprayingofthisinsecticide?Explainyouranswer. 2marks


SECTION B – Question 10–continuedTURN OVER

Question 10 (9marks)Sixdifferentbeetlespecieshavebeenstudiedbyscientists.ThesixspeciesarefoundwithincavesinthenorthernpartofSpain(seemap).AllsixspeciesbelongtothegenusGeotrechus.Therelativepositionsofthesixspecieswithintheregionareshowninthediagrambelow.

location of beetle species

S

ST

U

V

Species SSpecies USpecies W

SUW

W

Species TSpecies VSpecies X

TVX

X

Key

a. ScientistsusedDNAsequencesandproteinstructurestohelpclassifythesixbeetlespecies.

Describeotherevidencethescientistscouldusetohelpclassifythebeetlesintodifferentspecies. 2marks

b. Thescientistsgatheredinformationtoconstructaphylogenetictreeforthesixbeetlespecies.

Whatinformationisdisplayedinaphylogenetictree? 1mark



Byexaminingfossilevidenceinthearea,thetimingoftheappearanceofeachofthespecieshasbeendetermined.Thisisshowninthetablebelow.

Location of beetle species Species present Time period in which species were found

(millions of years ago)

R

RR

RR

R

R

R SpeciesR 24

SS

S

R

R

R

R

R SpeciesRS SpeciesS

16

T

SS

S

R

R

R

R SpeciesRS SpeciesST SpeciesT

8

U

V

TS

S

R

R

R SpeciesRS SpeciesST SpeciesTU SpeciesUV SpeciesV

6

W

X

U

TS

S

V

S SpeciesST SpeciesTU SpeciesUV SpeciesVW SpeciesWX SpeciesX

2

Source:adaptedfromAFaille,CBourdeau,XBellesandJFresneda,‘Allopatricspeciationillustrated: ThehypogeangenusGeotrechusJeannel,1919(Coleoptera:Carabidae:Trechini),

withdescriptionoffournewspeciesfromtheEasternPyrenees(Spain)’, inArthropod Systematics & Phylogeny,73(3)2015,p.453



c. ScientistscomparedDNAsequencesinfourmitochondrialgenesandtwochromosomalgenesfoundinthenucleusofthebeetles.

IdentifythetwobeetlespeciesthatwouldhavetheleastnumberofdifferencesintheirDNAsequences.Explainyouranswer. 3marks

d. Scientistsexplainedtheappearanceofthesixbeetlespeciesbysuggestingthat,overtime,allopatricspeciationhadoccurred.

Describetheprocessofallopatricspeciation. 3marks


Question 11 (4marks)Coralreefsarefoundinoceansaroundtheworld.Coralsareanimalsthatbuildupcalciumcarbonateskeletons.Single-celledalgaelivewithinthecoraltissues.QueenslandscientistshavereportedthatmanyofthecoralsinaregionoftheGreatBarrierReefhaverecentlybecomebleached.Bleachingoccurswhenthesingle-celledalgaeleavethecoraltissuesduetoenvironmentalchanges.Coralsturnwhitewithoutthealgaeandmaydie.Thisbleachinghasbeenattributedtoanincreaseinwatertemperatureandacidity.Twoapproacheshavebeenproposedtohelpreversethebleachingoccurringinthecoralreefs.

Approach 1Scientistsselectivelybreedcoralscontainingsingle-celledalgaewithinalaboratorysetting.Particularcoralswithalgaearethenreintroducedintothecoralreef.

a. Explainhowselectivebreedingmayhelpreversethebleachingofthecoral. 2marks

Approach 2Single-celledalgaefromthecoralreefareexposedtomutagenswithinalaboratorysetting.Someofthesealgaearereintroducedbackintothecoralreefs.

b. i. Whatwouldbethepurposeofexposingthesingle-celledalgaetomutagens? 1mark

ii. Whatisadisadvantageofthisapproach? 1mark

END OF QUESTION AND ANSWER BOOK