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■■ Sample examination Paper 11 Agroupofstudentssetouttoinvestigatewhetherlightwasneededfor

photosynthesis.Belowisanoutlineoftheprocedurethestudentsused.

Procedure: a Coveraportionofoneleafonapottedplantwithapieceofblackorsilver

paper.

b Afterafewdaysremovetheleaffromtheplant.c Placetheleafinboilingwaterforabout30seconds.d Removeleafandplaceitinatesttubewithenoughalcoholtocovertheleaf.e Placethetubeinahotwaterbathandboiltheleafuntilitisdecolourized.f Removetheleafandsoftenitinhotwater.g Spreadtheleafonawhitetile.h Addpotassiumiodide(iodine)solutiontotheleaf.i Makeobservations.

a) Statetwoflawsinthestudents’procedureandexplainwhytheyareimportantforafairexperiment. [4]

b) Describewhatobservationswouldbeexpectediftheexperimenthadbeendonecorrectly. [2]

c) Explaintheimportanceof:i) decolourizingtheleaf,andii) boilingtheleafatthestartoftheexperiment. [4]

d) Whatwasthepurposeofthepotassiumiodide(iodinesolution)? [1]

silver paper

green leaf

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1 2 a) Thetablebelowshowssomeofthefoodsrequiredinthedietofhumans,someoftheimportantsourcesofthesefoodsandsomeoftheimportantfunctionsinthebody.Copyandcompletethetablebyfillingintheblankspaces.

Food Two examples of good sourcesof the food

One important function in the body

Protein Used for growth

Carbohydrates

Sugar

Fat Provides the body with energy

Calcium and phosphorus

Cheese

Iron

Fish liver Prevents rickets

Vitamin C Cherries

[15]

b) Namethetestyouwouldusetoshowthatafoodcontainsprotein. [1]c) Whatcolourchangewouldshowthatproteinwaspresent? [1]d) Whatisthedifferencebetweenheterotrophicandautotrophicnutrition? [2]

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3 Thegraphbelowshowsthepulserateofanathletebefore, during and after runningarace.Carefullyexaminethegraphthenanswerthequestionsthatfollow.

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70–2 0 1 2 3 4 5 6 7 8 9 10 11

Time/minutesPu

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a) i) Howlongdidittaketheathletetoruntherace? [1]ii) Byhowmuchdidtheirpulserateincreaseduringtherace? [1]

b) i) Suggestwhytheirpulserateincreasedbetweentime22and0minutes. [1]

ii) Howdoestheincreasedpulseratebenefittheathlete’smuscles? [2]c) Explainwhythepulseratedidnotgobacktonormalimmediatelyafterthe

race. [3]

4 Cylindersofpotatowerecuteach5cmlonganduniformincircumference.TencylinderswereplacedinsolutionAandteninsolutionB,andwereleftforonehour.Afterthistimethecylinderswereremovedfromthesolutionsandwerere-measured.Theresultsareshowninthetablebelow.

Potato cylinders in Solution A Potato cylinders in Solution B

Appearance Soft/limp Hard/firm

Average length 4.8 cm 5.2 cm

a) Explainwhytencylinderswereusedineachsolutioninsteadofjustone. [2]

b) Fromtheseresults,commentonthepossiblenatureofsolutionsAandBandaccountforthechangesinthepotatocylinders. [2]

c) i) Nametheprocesswhichcausedthechangesinthepotatocylinders. [1]ii) Giveoneexampleinplantlifeandoneinanimallifewherethisprocess

occurs.Ineachcase,stateitsimportancetotheorganism. [4]iii)Explainhowthisprocessisdifferentfromtheprocessthatisemployedby

plantstotakeupmineralsfromthesoil. [2]iv) Explainhowthisprocessisdifferentfromtheprocessofoxygenleaving

agreenleafofaplant. [2]

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1 5 Alargebirdcageatthezoowassweptoutandthedebrisfromthefloorwastippedontomoistgardensoil.Withinashorttime,manyseedlingsappearedatthisspot.Thereweretendifferentspeciesandtheycontinuedtogrowsteadilyduringwarmdaysandnights.Afterthreetofourweeks,someseedlingshadgrownlargerandothershaddisappeared,leavingonlythreespecies.

a) Givetwopossibleoriginsoftheseedlings. [2]b) Statetwofactorsmentionedintheaccount,whichhelpedthegermination

process. [2]c) Statetwootherfactorsthatareessentialforthecontinuedgrowthofthe

seedlingsafterinitialgermination. [2]d) Suggesttwohypotheses(reasons)toexplainwhy,afteraperiodoftime,

therewasachangeinthissmallcommunitysuchthatonlythreespeciesremained. [4]

Free-response questions

6 a) Withtheaidofaclearlylabelleddiagram,describetheeventsthattakeplacewithinthehumanheart,fromthetimethebloodenterstheright atriumuntilitleavesviatheaorta. [7]

b)Distinguishbetweenlymph,tissuefluidandplasmaintermsofcompositionandlocation. [6]

c) Distinguishbetweenarteries,veinsandcapillariesintermsoftheirstructureandfunction. [7]

7 a) Withtheuseofillustrationsdescribethemechanismfortakingairintothelungs. [7]

b)Thealveoliarethegaseousexchangesurfaceofthelungs;thisissynonymoustothegillsofafish.

i) Givefourfeaturesofagaseousexchangesurfacethatmakeitmoreefficient.Ineachcasestatehowitmakesthegaseousexchangemoreefficient. [4]

ii) Drawandannotateadiagramofafishgillshowingthegilllamellaeandrakers.[4]

c)Differentiatebetweenanaerobicandaerobicrespirationinhumans. [5]