biology...january 2011 biology assessment unit as 1 assessing molecules and cells [ab111] tuesday 11...
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INSTRUCTIONS TO CANDIDATES
71
Centre Number
Candidate Number
TotalMarks
For Examiner’s use only
QuestionMarks Number
1
2
3
4
5
6
7
8
6397.05R
Thetotalmarkforthispaperis75.SectionAcarries60marks.SectionBcarries15marks.Figuresinbracketsprinteddowntheright-handsideofpagesindicatethemarksawardedtoeachquestionorpartquestion.
YouareremindedoftheneedforgoodEnglishandclearpresentationinyouranswers.Useaccuratescientificterminologyinallanswers.Youshouldspendapproximately20 minutesonSectionB.YouareexpectedtoanswerSectionBincontinuousprose.QualityofwrittencommunicationwillbeassessedinSection B,andawardedamaximumof2marks.
INFORMATION FOR CANDIDATES
WriteyourCentreNumberandCandidateNumberinthespacesprovidedatthetopofthispage.Writeyouranswersinthespacesprovidedinthisquestionpaper.Answeralleightquestions.YouareprovidedwithPhotograph 1.4forusewithQuestion4inthispaper.Donotwriteyouranswersonthisphotograph.
TIME
1hour30minutes.
ADVANCED SUBSIDIARY (AS)General Certificate of Education
January 2011
Biology
AssessmentUnitAS1assessing
MoleculesandCells
[AB111]
TUESDAY 11 JANUARY, MORNING
1115
62
AB
11
1
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Section A
1 Thestatementsinthetablebelowrefertosomeofthefeaturesfoundinprokaryoticandeukaryoticcells.Somefeaturesmaybefoundonlyinonetypeofcellorinbothcelltypes.
Ifafeatureispresent,placeatick(✓)intheappropriateboxand,ifthefeatureisabsent,placeacross(✗)intheappropriatebox.(Donotleaveanyboxesempty.)
Feature Prokaryotic cell Eukaryotic cell
Plasmid
Ribosome
Golgiapparatus
[3]
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2 Thediagrambelowrepresentsaplantcellimmersedinabathingsolutionwithasolutepotentialof–1200kPa(ψexternal).Thesolutepotential(ψs)andpressurepotential(ψp)ofthecellarealsoshown.
ψs = –1400 kPa
ψexternal = –1200 kPa
ψp = 500 kPa
(a) Calculatethewaterpotential(ψcell)ofthecell.
Answer________________________[1]
(b) Describeandexplainthemovementofwaterbetweenthecellanditsbathingsolution.
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(c) Drawadiagramofthecelltoshowitsfinalappearanceinthebathingsolution.
[2]
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3 (a) Readthefollowingpassagewhichdescribestheprimarystructureofaproteinandwritethemostappropriateword(s)intheblankspacestocompletetheaccount.
Proteinsarepolymers,consistingoflongchainsof
joinedtogetherby
reactionstoformnumerous bonds.The
sequenceofmonomersinaproteinisknownasitsprimarystructure
andisencodedinthe ofanorganism. [4]
(b) Proteinsarecomplexmoleculeswithaleveloforganisationbeyondtheprimarystructure.Describehowafinaloverallshapeisproducedinaprotein.
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(c) DescribethecolourchangewhichindicatesthepresenceofproteininafoodsamplewhenitistestedwithBiuretreagent.
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4 Photograph1.4 isanelectromicrographofpartsoftwoadjacentspongymesophyllcellsfoundintheleafofageraniumplant.
(a) (i) IdentifythestructureslabelledAtoD.
A_________________________________
B_________________________________
C_________________________________
D_________________________________ [4]
(ii) Explainthepositionofthenucleiinthesemesophyllcells.
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(b) Usethescalebartocalculatethemagnificationofthiselectronmicrograph.(Showyourworking)
Answer________________________[3]
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5 (a) Thediagrambelowrepresentsthefluidmosaicmodelofthecellsurfacemembrane.
A
B
C
D
(i) IdentifythestructureslabelledAtoD.
A_____________________________________
B_____________________________________
C_____________________________________
D_____________________________________ [4]
(ii) PlaceanX on the diagramtoindicatetheoutersurfaceofthemembrane.Giveareasonforyouranswer.
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(b) Thetablebelowshowstheeffectofchangingconditionsonthreedifferentmechanismsofmembranetransport.
Effect of changing conditions on rate of movement
Change in conditions
Mechanism1
Mechanism2
Mechanism3
Increasedoxygenlevels
Rateincreases
significantly
Noeffectonrate
Noeffectonrate
Additionofcyanide(arespiratorypoison)
Ratedecreasessignificantly
Noeffectonrate
Noeffectonrate
Increasednumbersofmembranecarriers
Rateincreases
Rateincreases
Noeffectonrate
Usingtheinformationinthetable,identifyeachmechanismofmembranetransportand,ineachcase,giveareasonforyouridentification.
(i) Mechanism1
Identification _____________________________________________
Reason__________________________________________________
_______________________________________________________[2]
(ii) Mechanism2
Identification _____________________________________________
Reason__________________________________________________
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(iii)Mechanism3
Identification _____________________________________________
Reason__________________________________________________
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BLANK PAGE
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6 (a) TheenzymeBamHIisarestrictionendonucleasewiththerecognitionsiteGGATCCcuttingDNAintofragmentsbetweenthebasesGG.
ThebasesononestrandofalengthofDNA,120nucleotides,isrepresentedinthethreelinesbelow.
AATGGGTACGCACAGTGGATCCACGTAGTATGCGATGCGT
AGTTGATAGATAGATAGATAGATAGATAGATATTTTATCG
TGCTGTACGGATCCGGAAGTGGCGATGAGGATCCATGCAA
(i) HowmanyfragmentswouldbeproducedifthislengthofDNAwascutwiththerestrictionendonucleaseBamHI?
Answer [1]
(ii) TheDNAstrandabovecontainsamicrosatelliterepeatsequence(MRS).Identifythesequenceandstatethenumberofrepeats.
• Microsatelliterepeatsequence__________________________
• Numberofrepeats__________________________________ [2]
(iii) ExplainwhymicrosatelliterepeatsequencesareusefulforforensicanalysisofDNA.
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(b) DNAsamplesfromthemembersofaparticularfamilywereanalysedforrestrictionfragmentlengthpolymorphisms(RFLPs).ThedarkbandsintheautoradiographbelowrepresentRFLPmarkers.Theautoradiographhas15lanesmanyofwhichareusedforcomparison.
15lanescontainsamplesfromthefollowingsources.
• Lanes8,9,10,12,13and14arefrommembersofthesamefamily
• Lanes1,2,7,11and15containaseriesofDNAfragmentsofdifferentlengthusedforcalibration
• Lane3isacontrolcontainingknownRFLPmarkers(producingbandsatthesamelocationseachtime)
• Lanes4,5and6arefromunrelatedindividuals
(i) ExplainwhythesonanddaughterhavedifferentRFLPmarkers.
_________________________________________________________
_______________________________________________________[1]
Image of DNA samples has been removed due to copyright issues.
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(ii) Usingtheinformationintheautoradiograph,identifythegrandparentsasthewife’sparents(maternal)orthehusband’sparents(paternal).Explaintheevidenceforyourchoice.
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(iii) Usetheautoradiographtoidentifymatcheswithanyoftheunrelatedindividuals(4,5and6)andanyofthefamilymembers.
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(iv) ExplainwhyRFLPmatchesmaybefoundbetweenunrelatedindividuals.
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7 Thisquestionisaboutthedigestionofjellybyprotein-digestingenzymes.
(a) Jellycontainstheproteingelatine,whichisbrokendowntoaminoacidsbyprotein-digestingenzymes.Statethetypeofreactionwhichtakesplaceduringdigestion.
___________________________________________________________[1]
(b) TheprocedureusedforaninvestigationoftheeffectofpHontheactivityoftwoprotein-digestingenzymesisoutlinedbelow.
1. FivebuffersolutionswerepreparedatpH4,6.4,7.4,8,and9. 2. 10stripsofjellywerecutfromajellyblock.Eachstripwas
approximately1to2mminthickness. 3. Eachstripwastrimmedtoarectangleof10by20mmandthe
surplusjellydiscarded.TrimmedstripswereplacedinseparatePetridishes.
4. 10cm3ofeachofthefivebuffersolutionswasaddedtotwoofthePetridishes,sothattwoPetridisheshadpH4,twohadpH6.4,etc.ThePetridishesweredividedintotwosets,eachsethavingonedishateachpH.
5. 10cm3ofenzymeAwasaddedtoonesetofthePetridishesand10cm3ofenzymeBwasaddedtothesecondsetofPetridishes.
6. AllPetridisheswereleftatroomtemperaturefor90minutes. 7. Theareaofthejellyremainingwasmeasuredandtheresultsare
showninthetablebelow.
Area of jelly remaining/mm2
pH Enzyme A Enzyme B
4 0 200
6.4 100 190
7.4 171 98
8 190 48
9 200 0
(i) Plottheaboveresults,usinganappropriategraphicaltechnique.(Usethegraphpaperopposite.) [5]
(ii) Describethetrendsevidentinthegraph.
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(c) ExplainwhypHinfluencestheactivityofanenzyme.
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(d) Thereareseveralpotentialproblemswiththedesignofthisexperiment.Suggestfour possibleproblemsintheprocedureused.
1. ___________________________________________________________
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2. ___________________________________________________________
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3. ___________________________________________________________
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4. ___________________________________________________________
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Section B
Quality of written communication is awarded a maximum of 2 marks in this section. [2]
8 (a) Giveanaccountofthestructureofthenucleicacids,DNAandRNA. [8]
(b) DescribetheprocessofDNAreplication. [5]
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(a) Giveanaccountofthestructureofthenucleicacids,DNAandRNA.
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(b) DescribetheprocessofDNAreplication.
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THIS IS THE END OF THE QUESTION PAPER
Permissiontoreproduceallcopyrightmaterialhasbeenappliedfor.Insomecases,effortstocontactcopyrightholdersmayhavebeenunsuccessfulandCCEAwillbehappytorectifyanyomissionsof acknowledgementinfutureif notified.
111562
6397.02
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GCE Biology Advanced Subsidiary (AS)Assessment Unit AS 1: Molecules and CellsJanuary 2011
Photograph 1.4(For use with Question 4)
NUCLEUS
NUCLEUS
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D
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0.5 Õm © Dr Jeremy Burgess/Science Photo Library
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