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CSEC Biology
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1
Samp
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Paper 1
■■ 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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Samp
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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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/bea
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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]