Biology Johor 2009 Answer P1&2

8/8/2019 Biology Johor 2009 Answer P1&2

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CONFIDENTIAL 21BIOLOGY CHEMETRIALSTPM2OO9PAPER

No Answer26 B27 G28 c29 D30 c31 A32 A33 c34 c35 A36 B37 c38 D39 B40 c41 A42 D43 B44 B45 c46 c47 D48 A49 A50 B

No Answer1 c2 D3 c4 B5 c6 D7 A8 D9 A10 G11 B12 c13 A14 c15 c16 D17 B18 A19 B20 D

21 c22 c23 D24 B25 A


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BIOLOGY SCHEMETRIAL STPM2OO9PAPER2

Thealternationetweehaploid ametes nda diploid porophyteeher;tionnaiproouces iploidsporeswhere neof hegenerationssa dominanteneration.F

male : antheridumFemale:archegonium

Body sdifferentiatedntostem, eaves nd ibrous oots.Vascularissue onsists f racheidsndsieve ubes.Dominantporophyte.Freegametophyte. ( Any3)

(ii)(iii)

(bxi)(ii)(iii)

q2= 112,500r0.0004, =0.02.The .frequencyof the cystic fibrosis (recessive)ailere in thepopulations0,02 or2o/o).The frequency f th^e.{ominantnormar) ileren the popurationp)issimply - 0.02= 0.98 or98%).since 2pq equarshe frequency f heterozygotesr carriers,henthe equation il lbe as follows: pq= (2)(.9gi(.02) 0.0+or 1 in25arecarriers.bb=q2=0.4,q=0.63,Since + q = 1, henp must e 1- 0.63= 0.37.2pq= 2 (0.37) 0.63) 0.47.p2or (0.37)2 0.14.Nomutations


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- No Migration- Randommatingmustoccur- Largepopulation- Noselection(AnyTwo)Total

1111z10

b(i)b( i i )

3a(i)a( i i )a(iii)

c

d

- lacoperon- inducibleperon- it is stimulatedo be switched n when actoses present- lacz- glucose ndgalactose- the active epressor olecule inds o heoperator eneandblocksheattachment f RNApolymeraseo thepromoter- thispreventshe ranscriptionfgenes f acZ,lacY and acA so nomRNA anbe made- the nactivatedepressor oleculeanno onger ind o the operatorgene- the operonemains witched n andB-galactosidaseouldbecontinuouslyroduced

111

111111

4 (a)(i)(ii)(iii)

(b)(c) (i)(ii)(iii)

- Thepresence f chlorophyll- Thepresencef cellulose- Thepresence f fucoxanthin- Thepresencef alginic cid- Polysaccharidesn hecellwall redifferent- The storage ompoundsredifferent.- Differencen pigment (AnyTwo)- Movement/motility- A taxon a a group hatcontains rganismshatsharesomebasicfeatureshat ndicateheysharea common ncestry.- Natural classif ication eflects he evolutionaryor phylogeneticrelationshipased nhomologousharacteristics.- ln artificial lassification,he analogous haracters re used toclassifyhe specieswithout ny egardo itsorigin.

Total

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1

111

110

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a. importantoleas structural ndstorage- cellulose-structuralompound- madeof ongchain f B-glucose- unbranchedhain unparallelto achother- !r"u9cross-linkagehatgives tability ndstrength- insoluble- fibers aid n layersndifferent irections ddingurther trengthstarch-storageompoundmixture f amylase ndamylopectinamylase unbranchedhain f a-glucoseormshelix tructureamylopectinbranchedhains f a-glucosecompoundtabilizedy counflessydrogenondcompact nd nsolublereadily ydrolysedo formsugarwhen equired

b i. theesterificationrocessnvolves ondensationeaction- between nemolecule fglycerol nd hreemolecules f fattyacids- threeesterbondsare ormedo produce molecule f triglyc'erideand hreemoleculesfwater

Uc*c:-*o-8---lc 5;:i r-{:;;.-loci:.=--o-d--+c?i:]rcH; = jli:olocx=-o -*ll -1 cti :]r cFi:

rrigfu-ceride

ii. mportance f lecithinn cellmembranetructure- lecithins a typeof phosphoripidsoleculeonsistingfahydrophiliceadand wohydrophobicails- Thecellmembranesmadeupof wophospholipidsayerswiththe hydrophiliceadon heoutside f he bilayer.- The ecithin ilayerormsa boundaryeparatinghecellcontentsfrom heexternal nvironment- Beinghydrophobic,t sselectivelyermeablend egulateshemovementf substancescrosshe membrane.

[max ]

[max4]


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Chemoautotroph PhotoautotrophDoneby bacteria

Donebygreenplantsor organismswhichhas hechlorophylligment

Synthesise rganiccompoundsromcarbon

dioxide ndwaterSynthesiserganic ompoundsrominorganicompoundsuchas carbon

dioxide,waterEnergy fromoxidation finorganic ubstancesuchas H2S, mmoniand ron

Energy upply from he(sun)light

6(a)

36(b)

Saprophytic rganisms an be defined s: organismshat obtaintheirnutritionaleeds romdeadanddecaying rganicmaterialsCannot ynthesiseheirown oodSecreteenzymes uch as amylese, roteases,ipasewhichdigesttheir oodextracellularyAbsorb he digested roductshroughhe cellsurfacesGiveexample:Mucor,Rhizopus,mushroomEcologicallymportant ecauseheyact asa decorhposerBreakdown he deadorganism ndwasteproductThe decomposedmaterialwhichcontains hemicalelements anbe reused absorbed)y he saprophytesndotherautotrophs.

t15

Obligateparasite FacultativeparasiteUnableo live ndependently

without he presence f a host orsupply f nutrient

Able o live ndependentlywithouthe presence f a host

forsupplyof nutrientUnableo reproducendependently Able o reproduceindependently

e.g.TapewormIaenia solium) e.g.bootlaceungus(Armillaria e.llea)

Alwaysexistas an obligateparasite

Whenunderstressfulcondition;t canbe an

obligate arasite.(Any2) Max2 mark (Any2) Max2 marks

Total

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7(a)| -d issociat ionofcarbonicacidinttreerytnI Il9 concentrationf hydrogenons esultingnreductionf hepHI - tli: results.n he oxyhaemoglobinissociatingo release aemoglobinI w!i9ncombines ith heexcess ydrogenons oformhaemoglo-binicI acid HHb , as a buffering ffect| - increasinghe carbon ioxide oncentrationncreaseshe rateofI oxyhaemoglobinissociation| - thus ncreasinghe carbon ioxide oncentrationeducesheaffinity fI haemoglobinowards xygen, process alledBohr'seffect| - Bohr's ffect esultsna shiftof heoxygen issociationurveofI haemoOlobino the right(b) | - thebreathingycle scontrolledy hebreathingentreocatedn heI medulla blongata| - tnis.nreathingentre onsist f he nspiratoryentre nd heexpiratoryI centre| - the nspiratoryentre endsmpulseso theouter ntercostal usclesI anddiaphragmringing bout ontractionhile he nnerntercostalI muscleelaxes| - ttris esultsnan ncreasen he horacicavity olume, ringing boutI inspiration| - alveolus ndbronchiolesxpands uringnspirationtimulatingheI stretcheceptors ithinhewallsof healveoli ndbronchioleso sendI impulseso the expiratoryentre| - theexpiratoryentre endsnhibitorympulseso the nspiratoryentre| - the nspiratoryentrehenstops endingmpulseso thediaphragmI andouter ntercostalsuscle ausinghem o relax.| - thisbrings bouta decreasen horacicavity olume esultingnI expiration| - when hevolumen he alveolusndbronchiolesre educed,heI stretcheceptorsreno onger timulatedo ire nhibitorympulsesoI the expiratoryentre| - inspiratoryentre nceagain endsmpulseo thediaphragmndouterI intercostal uscle ringing bout ontractionnd nspiration| - thecycle s repeated

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10Total 15

I(a) whena myelinatedeurones sufficientlytimulated,naction otentialisgenerated.thissetsup a local urrent hich epolarizesheadjacentegionthe nflux fsodiumons rom heextracellularluid ntoone egion f heaxoncreates localcircuitnthat egionthe ncreasensodiumons n heaxoplasmepelshecationso moveto theadjacent egionwhich smorenegativelyhargedthis ncreaseshemembraneotentialn headjacentegion ndopensup sodium oltage ated hannelssodiumonsdiffusento he neurone nd hemembranesdepolarizedwhen he hresholdevelsexceeded, newaction otentialsgeneratedthe ocal urrent t one egion,herefore,nduces newaction otentialin headjacentegionwhich eepsmovingna fonryardirection

11111111Max:7

7


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yhgna nervempulse rrives ta synapticnob, alcium ated hannelsin hepresynaptic embranepensca" ionsdiffuse uicklyromsynapticleftor extracellularluid nto hesynapticnobthis nflux f ca2*causeshesynapticesicleo fusewith hepresynapticmembranevesicleselease eurotransmitteroleculesnto hesynaptic leftbyexocytosisneurotransmitterolecules iffuseacross he cleft and bind to thereceptors nthepostsynaptic embranethisbindingriggersheopening f sodium hannelsNa* ions diffuse into the postsynaptic eurone,depolarisinghepostsynapticembranea new potential, nownas excitatory ostsynaptic otential Epsp) isgeneratedif the EPSP s arge nougho reachhe hresholdevel, n actionpotentialsgeneratednd s ransmittedlonghepostsynapticeurone.

111111111Max:8

| - Genemutations he changen hesequencefnucleotideases f heI DNA hatcorrespondso a particularen6 nan organismI - alsoknown spointmutation.| - frameshiftmutation nd missensemutation redifferentormsof geneI mutation.| - Chromosomalutations hechangen hestructuref hechromosomeI alsoknown schromosomalaberration| - or he.cl?ngen he number f hechromosomesnan organism.| - aneuploidyndeuploidy hich onsists f allopolyploidyndI autopolyploidyredifferentormsof chromosomalutation.I maxII| - Th.eour. ossibleways hatgenemutatiornanoccurare hroughI substitution,nversion,nsertion,nddeletion.II - ]l'r *?litution,a.nucleotideasepair s replacedy another asepair ntheDNAnucleotideequencef hegene.- and heyareusuallymissence utationss henewnucleotideasealters negenetic ode o a differentode,which aystillcode oran

amino cidbut t sa differentminoacid.- an example fgenetic isorderaused ysubstitutionssickle-cellanaemia, here hebase hyminen hecode orglutamic cid ssubstitutedy he baseadeninen hegene hatcodesor heB-polypeptidehain.- in nversion,woor morenucleotideasepairs avebeen eversedn heDNAbase equence ithinhegene.- thealtered enetic odemay esultna differentmino cid n hepolypeptidehainand he ormationfa non-functionalrotein.- in nsertion, nextranucleotideasepair s nsertednto heDNAbasesequencef a genecausinghewhole ase equenceo be shifted neplacebackward.- in deletion, nucleotideasepair sdeletedrom he DNAbase

(a)

11,|I1

(b )

t


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sequence f a genecausinghewholebaseseffiplace onryard.- both nsertionnddeletion re rameshift utation ndevery ingletriplet odeafter he nsertion rdeletion oint saltered.- insertionsnd deletions re usuallymoreharmfulhansubstitutionndinversionbecause of the frameshiftmutationswhich often lead toproduction f non-functionalroteins.- B-Talassaemia ajol sa genetic isorder ausedby he deletion f abase n heB-globinllele nd his resultsna lackof B-polypeptidehainsof hehaemoglobinolecule.- Down yndromesanexamprefaneuproidyhat s nstead f46 maxchromosomeshereare47 chromosomesn he ndividuar.- it sa result f non-disjunctionuringmeiosis.- the wochromosomesumber 1fat to separateuring naphaseoranaphasel of meiosis.- thegametes roduced ontain 4 chromosomes2 copiesofchromosome1)and22 chromosomesnochromosome1)- whena sperm ontaining3chromosomesuseswithan ovumcontaining 4 chromosomesnd hezygoteormed ontainshreechromosome1, risomy.- the ndividual aybe a maleor emale sually ith lat,broadaces,slanted yes,shortpalmsandarementallyetirded.

11

(c) I1111

maxl4

7


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l0(a) | Thereare hreeways o obtain desired ene:(i) | frl Producinghegene rommRNA y using everseranscriptase- when a gene is active/expressed,t can producea few thousandmolecules f mRNAwhicharecomplementaryo the gene.A probeis used o identifyhe required RNA.

- From he mRNA,a copyof theoriginal ene/DNA an be producedby using etrovirus. heenzymenvolveds reverseranscriptase.

- DNAproducedhisway sknown s complementaryNAor oDNA.(2)Synthesisinghe desired eneartificially- The sequence f bases n a gene can be determinedrom the

sequence f amino cids n heproteinhat t codesor . | 1- Basedon that knowledge, gene can be synthesised y usingnucleotidesnd oininghem n he ight rder. | 1(3) cutting the desiredgene rom he donor'sDNA by usingrestriction

endonucleases.- Restrictionndonucleasesre enzymes roduced y bacteriao cut

up the DNAof viruseswhichattackhem:Rest+ietionndonucleasesare used o cuta donor'sDNA o obtainhedesired ene.

- Restrictionnzymesut DNAat specific asesequerrcesnown s | 1restriction ites. More than 2000 restrictionenzymeshave beendiscovered,achwith tsspecific estrictionites. 1- Restrictionitesarepolindromes.hismeans he basesequqnce f Ione strand reads he same as its complementarytrand n the Iopposite irection. I t

- Restrictionenzymes make staggeredcuts, producingsingle-stranded tickyendswhichcanbe used o oin up DNA ragments yhydrogen onding. | 1

- By using estrictionndonucleases,he DNAof donororganismscutinto many fragments f various engths. he fragments re thenseparatedymeans fge lelectrophoresis.

- The DNA ragmentwhichcontainshe desired ene s identified y | 1usinga geneprobe.t is calledhe argetDNA.Total 11 maximum7) | 1

- Thedesiredgene s oined o a fragment f DNAknownas a vector.

11

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(a)(ii)

Two commonly used vebacteriophageambda A) DNA.- Bacterial plasmids are cut by using the same restrictionendonucleases thoseused o cut he donorDNAso as to producecomplementaryticky nds.

- The argetDNA s oined o thebacterial lasmid r phageA DNAbymeans of their sticky ends. The deoxyribose ugars and thephosphateroups re igated yusingDNA igase.- The resultingecombinant NAmolecules rethen ransferredntohost cells, usually E. coli bacteria.This is done by addingrecombinant NA moleculeso a culture lask containing . cof.

calcium onsare addedand he lask s warmed. uch a treatmentgives rise to pores n the cell surfacemembrane f E colr, husallowinghe recombinant NAmoleculeso enter.The processscalledransformation/transduction.- lf bacteriophage s usedas a vector,nsertion f recombinantNAisdoneby nfecting . coliwithhephage.

Total5(1) Recombinant NA technology as been used to make bacteriaproduce umulinhumannsulin)or usebydiabetics.(2) Farm animals have been engineered o be ,,pharmaceuticalfactories",.e.made o producearehumanproteins uchas q-1-antitrypsinnzyme ndhuman rowth ormoneor reating iseaseslikeemphysemanddwarfism.

(3) Diseases uchas haemophiria,ystic ibrosis,muscular ystrophyand cancerare causedby defective enes.Recombinant NAtechnologys used n gene herapyor treating uchdiseases yreplacingefective eneswithnormalgenes.Total3

(b)

t (

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Biology Johor 2009 Answer P1&2