n10/4/biolo/hp2/eng/tz0/xx -...
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SecTion a
Answer all the questions in the spaces provided.
1. Gibberellin promotes both seed germination and plant growth. Researchers hypothesize that the gene GID1 in rice (Oryza sativa) codes for the production of a cell receptor for gibberellin. The mutant variety gid1-1 for that gene leads to rice plants with a severe dwarf phenotype and infertile flowers when homozygous recessive. It is suspected that homozygous recessive gid1-1 plants fail to degrade the protein SLR1 which, when present, inhibits the action of gibberellin. The graphs show the action of gibberellin on the leaves and α-amylase activity of wild-type rice plants (WT) and their gid1-1 mutants.
Length of second leaf / cm
12
10
8
6
4
2
0
WT
gid1-1
α-amylase activity /
units seed–1
60
50
40
30
20
10
0
WT
gid1-1
0 10–9 10–8 10–7 10–6 10–5 10–4 0 10–11 10–10 10–9 10–8 10–7 10–6 10–5
Gibberellin concentration / mol dm–3 Gibberellin concentration / mol dm–3
[Source: adapted from M. Ueguchi-Tanaka et al. (2005) ‘Gibberellin-insensitive dwarf1 encodes a soluble receptor for gibberellin’. Nature, 437, pp. 693—698. Adapted by permission from Macmillan Publishers Ltd (c) 2005.]
(a) (i) State which variety of rice fails to respond to gibberellin treatment.
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[1]
(ii) The activity of α-amylase was tested at successive concentrations of gibberellin. Determine the increment in gibberellin concentration that produces the greatest change in α-amylase activity in wild-type rice plants (WT).
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(iii) Outline the role of α-amylase during the germination of seeds.
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(Question 1 continued)
(b) Discuss the consequence of crossing gid1-1 heterozygous rice plants amongst themselves for food production.
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(Question 1 continued)
Most rice varieties are intolerant to sustained submergence under water and will usually die within a week. Researchers have hypothesized that the capacity to survive when submerged is related to the presence of three genes very close to each other on rice chromosome number 9; these genes were named Sub1A, Sub1B and Sub1C. The photograph below of part of a gel shows relative amounts of messenger RNA produced from these three genes by the submergence-intolerant variety, O. sativa japonica, and by the submergence-tolerant variety, O. sativa indica, at different times of a submergence period, followed by a recovery period out of water.
O. sativa japonica O. sativa indica
Sub1A
Sub1B
Sub1C
0 1 3 7 10 R1 R3 0 1 3 7 10 R1 R3submergence recovery submergence recovery
Duration of submergence and recovery / days
[Source: Adapted from “Sub1A is an ethylene-response-factor-like gene that confers submergence tolerance to rice” (2006) Kenong Xu, Xia Xu, Takeshi Fukao, Patrick Canlas, Reycel Maghirang-Rodriguez et al. Nature, 442, pp. 705—708. Adapted by permission from Macmillan Publishers Ltd (c) 2006.]
(c) (i) Determine which gene produced the most mRNA on the first day of the submergence period for variety O. sativa japonica.
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(ii) Outline the difference in mRNA production for the three genes during the submergence period for variety O. sativa indica.
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[2]
(d) Using only this data, deduce which gene confers submersion resistance to rice plants.
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(Question 1 continued)
The OsGI gene causes long-day flowering and the effect of its overexpression has been observed in a transgenic variety of rice. Some wild-type rice (WT) and transgenic plants were exposed to long days (14 hours of light per day) and others to short days (9 hours of light per day).
The shades of grey represent the genotypes of the transgenic plants, where: –/– do not have the overexpressed OsGI gene +/– are heterozygous for the overexpressed OsGI gene +/+ are homozygous for the overexpressed OsGI gene.
Time before flowering / days
180
160
140
120
100
80
60
40
20
0 WT transgenic WT transgenic Short-day light Long-day light
[Source: adapted from R. Hayama, S. Yokoi, S. Tamaki, M. Yano and K. Shimamoto (2003) ‘Adaptation of photoperiodic control pathways produces short-day flowering in rice.’ Nature, 422, pp. 719—722. Adapted by permission from Macmillan Publishers Ltd (c) 2003.]
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(Question 1 continued)
(e) (i) State the overall effect of overexpression of the OsGI gene in plants treated with short-day light.
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[1]
(ii) Compare the results between the plants treated with short-day light and the plants treated with long-day light.
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(iii) State, giving one reason taken from the data opposite, if unmodified rice is a short-day plant or a long-day plant.
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(f) Discuss, using only the data opposite, if OsGI + and OsGI – behave as codominant alleles.
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(g) Evaluate, using all the data, how modified varieties of rice could be used to overcome food shortages in some countries.
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2. (a) The photograph below shows the flowers of Campanula persicifolia. Label structures I, II and III. [3]
green violet
1 cm
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II. . . . . . . . . . . . . . . . . . . . . . . . . . .
III. . . . . . . . . . . . . . . . . . . . . . . . . . .
[Source: photograph provided by IB examiner]
(b) (i) Using the external features shown in the photograph, state the phylum to which this plant belongs.
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(ii) Comment on the hypothesis that the plant shown in the photograph could be pollinated by an animal.
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(c) Outline the use of the binomial system of nomenclature in Campanula persicifolia.
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3. (a) Define the term passive immunity.
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(b) State one use of monoclonal antibodies in diagnosis.
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(c) Define the term pathogen.
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(d) Outline why antibiotics are effective against bacteria but not against viruses.
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SecTion b
Answer two questions. Up to two additional marks are available for the construction of your answers. Write your answers on the answer sheets provided. Write your session number on each answer sheet, and attach them to this examination paper and your cover sheet using the tag provided.
4. (a) State four functions of proteins, giving a named example of each. [4]
(b) Outline the structure of ribosomes. [6]
(c) Explain the process of transcription leading to the formation of mRNA. [8]
5. (a) Draw a labelled diagram of a mature sperm cell. [4]
(b) Outline the role of hormones in the menstrual cycle. [6]
(c) Discuss the cause, transmission and social implications of AIDS. [8]
6. (a) Draw a labelled graph showing a sigmoid (S-shaped) population growth curve. [4]
(b) Describe what is meant by a food chain and a food web. [6]
(c) Explain the relationship between rises in concentration of atmospheric gases and the enhanced greenhouse effect. [8]
7. (a) Draw a labelled diagram of the ultrastructure of Escherichia coli as an example of a prokaryote. [4]
(b) Describe the events that occur in the four phases of mitosis in animals. [6]
(c) Explain the process of aerobic cell respiration after glycolysis has occurred. [8]
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SecTion a
Answer all questions. Write your answers in the boxes provided.
1. Theairinurbanareascontainsavarietyofpollutants,includingparticlesofsolidsandgases.The table below shows the pHof rain in urban areas ofNewYork and rural areas nearby.Theconcentrationoffourairpollutantsisalsoshown.Theconcentrationsofgasesaremeasuredinpartsperbillion(ppb).
area Lead /μg m–3
Nitrogen dioxide /ppb
Nitrous oxide /ppb
Sulfur dioxide / ppb pH of rain
Urban 0.09 37.7 39.3 18.7 4.3
Rural 0.04 6.2 0.5 2.3 4.2
[Source:JWGreg,et al.,(2003), Nature,424,pages183–186]
(a) (i) Comparetheacidityofraininurbanandruralareas. [1]
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(ii) Comparethelevelsofatmosphericpollutioninurbanandruralareas. [2]
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(Question 1 continued)
Treeplantinghasbeensuggestedasawayofimprovingairqualityinurbanareas.ThegrowthofPopulus deltoides inurbanand ruralareasnearNewYorkwas investigated. Treesweregrowninpotscontainingthesametypeofsoilinallareas.Highlevelsofmineralnutrientsinthesoilensuredthatlackofnutrientswasnotthelimitingfactorongrowthrates.Thegrowthofthetreesaboveground(shootbiomass)andbelowground(rootbiomass)wasmeasuredafteroneyear.Thebarchartbelowshowstheresultsfortworuralareas(openbars)andfoururbanareas(filledbars).
Rootbiomass/g
Shootbiomass/g
80
60
40
20
0
20
40
LI HV NY1 NY2 NY3 NY4
Sites
[Source:JWGreg,et al.,(2003), Nature,424,pages183–186]
(b) OutlinetheconclusionsthatcanbedrawnaboutthegrowthofPopulus deltoidesfromthedata in thebarchart. [2]
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(Question 1 continued)
(c) DiscusswhetherthedifferencesingrowthratesofPopulus deltoides betweenurbanandruralareascouldbedueto
(i) differencesintheacidityofrain. [1]
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(ii) differencesintheconcentrationofairpollutants. [2]
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(Question 1 continued)
ThehistogramsbelowshowtherangeofozoneexposurebetweenMayandSeptemberinurbanandruralareasnearNewYork.
Num
berofsites
10
5
0
5
030 35 40 45 50 55 Seasonalozoneexposure/ppb
Key:
urbanareas
agriculturalareas
forestedareas
[Source:JWGreg,et al.,(2003), Nature,424,pages183–186]
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Urban
Rural
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(Question 1 continued)
(d) Comparetheseasonalozoneexposuresinurban,agriculturalandforestedareas. [2]
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(Question 1 continued)
The concentrations of ozone and the shoot growth ofPopulus deltoides weremeasured ateightsites.Theresultsareshowninthescattergraphbelow.
Shootbiomass/g
100
80
60
40
20
0 15 25 35 45 55
Ozoneexposure/ppb
[Source:JWGreg,et al.,(2003), Nature,424,pages183–186]
(e) Using the data in the scattergraph and in previous parts of this question, suggest ahypothesis for differences in the growth of Populus deltoides between urban andruralareas.Givereasonsforyourhypothesis. [3]
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2. Themicrographbelowshowsanadulthumanstemcell.
[Source:www.sciencephoto.com/images/download_lo_res.html?id=714420159]
(a) Thecellcyclecanbedividedintotwoparts:interphaseandmitosis.
(i) Identify,witha reason,whether the stemcell in themicrograph is in interphaseormitosis. [1]
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(ii) Deduce twoprocessesthatoccurinhumancellsduringthispartofthecellcycle,butnotduringtheotherpart. [2]
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(Question 2 continued)
(b) Statetwocharacteristicsofstemcells thatcanbeusedtodistinguishthemfromotherbodycells. [2]
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(c) Outline onetherapeuticuseofstemcells. [3]
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3. ThediagrambelowshowsoneDNAnucleotideandpartofasecondnucleotide.
II
I
(a) StatethenamesofstructuresIandII. [1]
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(b) Onthediagramabove,drawthestructuresthataremissingfromthesecondnucleotide. [1]
(c) ThetwonucleotideswouldbepermanentlyseparatedduringDNAreplication.Stateoneprocessduringwhichtheywouldbetemporarilyseparated. [1]
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(d) Outline the method that can be used to amplify small quantities of DNA to obtainlarge enough quantities for DNA profiling. [2]
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4. TriarthuswasatrilobitethatlivedonEarthabout500millionyearsago.Thediagramsbelowshowitsstructure,viewedfromaboveandbelow.ThestructurewasdiscoveredbystudyingfossilsofTriarthus.
[Source:RFortrey,(2000), Trilobite!,page62]
(a) Therearemanyanimals livingonEarth today thatbelong to the samephylumas thetrilobites, but there are no living trilobites. Deduce, with a reason, the phylum towhichTriarthusbelonged. [2]
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(b) Outlinetheevidenceforevolutionprovidedbyfossils. [2]
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(Question 4 continued)
(c) Some trilobites swam in clear, shallowwater and had very large eyes. Suggest howspecieswithlargeeyescouldevolvefromspecieswithsmallereyes. [2]
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SecTion b
Answer two questions. Up to two additional marks are available for the construction of your answers. Write your answers in the boxes provided.
5. (a) Membraneproteinsvaryintheirpositionswithinthemembraneandintheirfunctions.Outlinethepositionsandfunctionsofproteinsinmembranes. [8]
(b) Explainhowpolarandnon-polaraminoacidshelpchannelproteinsandenzymescarryouttheirfunctions. [5]
(c) Comparecompetitiveandnon-competitiveinhibitionofenzymes. [5]
6. (a) During a period of physical exercise, the rate of urine production falls, but theventilationrateandthebodytemperaturerise.Explainthemechanismsthatareusedtocoolthebodywhenitisoverheated. [5]
(b) Explainhowthecollectingductscanalterthevolumeofurineproducedbythekidney. [5]
(c) Describethestructureoftheventilationsystem,includingthealveoli. [8]
7. (a) Gametes are produced in humans by spermatogenesis and oogenesis. Comparespermatogenesisandoogenesis. [5]
(b) Explain the processes that result in genetic variation in the sperm produced by anadultmale. [5]
(c) Outlinetheprocessofin vitrofertilization(IVF). [8]
8. (a) Allorganisms inanecosystemare involved in thecarboncycle. Outline the rolesoflivingorganismsinthecarboncycle. [8]
(b) Explainhowtriosephosphateisproducedandusedinthechloroplastsofaplant. [5]
(c) Explaintheconditionsthatareneededtoallowaseedtogerminate. [5]
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SECTION A
Answer all questions. Write your answers in the boxes provided.
1. Bottlenose dolphins (Tursiops truncatus) inhabit almost all tropical and temperate oceansbetween45$Nand45$S.Overatwo-yearperiod,aerialsurveyswerecarriedouttoinvestigatethe seasonaldistributionof theseanimalsalong themid-Atlanticandeasterncoastalwatersof theUSA. Sightingswererecordedusingaglobalpositioningsystem(GPS)whileflyinginaregularpatternwithinapproximately65kmoftheshore.Atotalof12760dolphinsweresightedoverthetwo-yearperiodandthedataaresummarizedinthechartbelow.
Eachbarcorrespondstoasinglesurveyandthelengthofthebarcorrespondstothetotalnumberof bottlenose dolphins counted in that survey. The circleswith numbers indicate numbersofdolphins.
[Source:adaptedfromLeighG.Torres,WilliamA.McLellan,ErinMeagherandD.AnnPabst(2005)‘Seasonaldistributionandrelativeabundanceofbottlenosedolphins,Tursiops truncatus,alongtheUSmid-AtlanticCoast.’
Journal of Cetacean Research and Management,7(2),pp.153–161.]
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1 December
1 March
1 June
1 September
Autumn
Summer Spring
Winter25002000
10001500
500
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(Question 1 continued)
(a) Statethelargestnumberofdolphinscountedinasinglesurvey. [1]
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(b) Calculatethemeannumberofdolphinscountedpersurveyforthewinterseason. [1]
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(c) Comparethedataforthedolphinpopulationsinwinterandsummer. [2]
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(Question 1 continued)
Aspartofthesamestudy,coastalaerialsurveyswerecarriedoutoverthesametimeperiodbyflyingparalleltothecoastapproximately500moffshore.Thediagrambelowshowsamapofthesectionofcoastsurveyed.Thebargraphshowstheseasonaldataforsummerandwinteratthecorrespondinglatitudes($N).Atotalof5431bottlenosedolphinsweresightedduringthesesurveys.
Key: summer winter
Latitude/ $ N
36.636.436.236.035.835.635.435.235.034.834.634.434.2
0 100 200 300 400 500 600Meannumberofdolphinscounted
persurvey
[Source:adaptedfromLeighG.Torres,WilliamA.McLellan,ErinMeagherandD.AnnPabst(2005)‘Seasonaldistributionandrelativeabundanceofbottlenosedolphins,Tursiops truncatus,alongtheUSmid-AtlanticCoast.’
Journal of Cetacean Research and Management,7(2),pp.153–161.]
(d) (i) Comparethedistributionofdolphinsinsummerandwinter. [2]
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Cape Lookout 34.6 N
$
Cape Hatteras 35.2 N
$
North Atlantic Sea
Land
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(Question 1 continued)
(ii) Suggestonereasonforthedifferencesindistribution. [1]
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Inadifferentstudy,researchersinvestigatedtheroleofwatertemperatureasapossiblefactorinthedistributionofbottlenosedolphins.Therateofmetabolism(measuredastherateofoxygenuptakeperunitmass)offivecaptiveadultswasmeasuredunderarangeofwatertemperatures.The rateofmetabolismwas found to increasesignificantlywhen thewater temperature fellbelow a certain value known as the lowest critical water temperature (LCTw). Below thistemperaturethebodyusesmoreenergytocombatthecoolingeffectofthesurroundingwater.Thedatafortheseanimalsaresummarizedbelow.
Animal Sex Age / years Mass / kg LCTw /°C
1 male 27 177.3 7.8
2 male 24 191.4 5.7
3 male 26 219.7 5.6
4 male 14 187.0 5.5
5 female 33 178.2 10.6
AdaptedwithpermissionfromL.C.YeatesandD.S.Houser(2008)‘Thermaltoleranceinbottlenosedolphins(Tursiops truncatus).’Journal of
Experimental Biology,211,pp.3249–3257,Table1.doi:10.1242/jeb.020610:TheJournalofExperimentalBiology:jeb.biologists.org
ThegraphbelowsummarizestherelationshipbetweenLCTwandbodymass.
LCT w/°C
11
10
9
8
7
6
5
4160 170 180 190 200 210 220 230
Mass/kg
[AdaptedwithpermissionfromL.C.YeatesandD.S.Houser(2008)‘Thermaltoleranceinbottlenosedolphins(Tursiops truncatus).’
Journal of Experimental Biology,211,pp.3249–3257,Figure4.doi:10.1242/jeb.020610:TheJournalofExperimentalBiology:jeb.biologists.org.]
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(Question 1 continued)
(e) OutlinetherelationshipbetweenbodymassandLCTwformaledolphins. [2]
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(f) SuggestonereasonforthehighLCTwmeasuredforthefemaledolphin. [1]
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(g) Evaluatethehypothesisthatwatertemperaturedeterminestherangeanddistributionofbottlenosedolphinsinthewild. [2]
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(Question 1 continued)
(h) Explainhowan increase inwater temperaturedue toglobalwarmingcouldaffect thedistributionofbottlenosedolphinsalongtheeasterncoastoftheUSA. [2]
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(i) Suggesthowresearchintotherangeanddistributionofbottlenosedolphinscouldbenefitfrominternationalcooperation. [1]
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2. (a) DNAreplication involvesanumberofenzymes includingDNApolymerase. IdentifyoneotherenzymeinvolvedinDNAreplication. [1]
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(b) ExplaintheroleofOkazakifragmentsinDNAreplication. [2]
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(c) Thediagrambelowshowstheprocessoftranscription.
RNApolymerase
(i) Labelthesenseandantisensestrands. [1]
(ii) DrawanarrowonthediagramtoshowwherethenextnucleotidewillbeaddedtothegrowingmRNAstrand. [1]
5′
3′
3′
5′
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3. (a) Outlinethemechanismsinvolvedinthecontrolofheartbeat. [3]
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(b) Explainhowthedirectionofbloodflowintheheartiscontrolled. [2]
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4. (a) Outlinetheprocessofin vitrofertilization(IVF). [3]
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(Question 4 continued)
(b) Thediagrambelowshowsasmallportionofthetissueinatransversesectionofatestis.
X
(i) IdentifythecelllabelledX. [1]
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(ii) Outlinethefunctionofthiscell. [1]
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(Question 4 continued)
(c) Explainhowmeiosisresultsingeneticvariationingametes. [2]
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SECTION B
Answer two questions. Up to two additional marks are available for the construction of your answers. Write your answers in the boxes provided.
5. (a) Outline,withexamples,thetypesofcarbohydratefoundinlivingorganisms. [4]
(b) Describetheimportanceofhydrolysisindigestion. [6]
(c) Explaintheeffectofinhibitorsontheactivityofenzymes. [8]
6. (a) Describethecharacteristicsofstemcellsthatmakethempotentiallyusefulinmedicine. [5]
(b) Outlineatechniqueofgenetransferresultingingeneticallymodifiedorganisms. [5]
(c) Explaintheuseofkaryotypinginhumangenetics. [8]
7. (a) Describehowplantscarryoutgasexchangeintheleaves. [5]
(b) Outlinethecausesandconsequencesoftheenhancedgreenhouseeffect. [5]
(c) Explaintheroleoflimitingfactorsinphotosynthesis. [8]
8. (a) Outlinewhatismeantbyhomeostasis. [4]
(b) Describehowbodytemperatureismaintainedinhumans. [6]
(c) Explaintheprocessesoccurringinthekidneythatcontributetoosmoregulation. [8]
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SECTION A
Answer all the questions in the spaces provided.
1. During aerobic cell respiration,oxygen is consumedandcarbondioxide isproduced insidecells. This generates concentration gradients between respiring cells and the environment,whichcausediffusionofoxygenandcarbondioxide. Bothoxygenandcarbondioxidearesolubleinwater.Asthetemperaturerises,waterbecomessaturatedatalowerconcentrationofthegas.
Laternula ellipticaisamolluscthatlivesontheseabedinAntarctica.Itsbodytemperatureisalwayssimilartothatoftheenvironmentaroundit.ToinvestigatetheeffectoftemperatureonLaternula elliptica, specimenswerekept in temperature-controlledaquaria. Theoxygenconcentrations ofwater near the gills and in the body fluidsweremeasured, at a range oftemperaturesfrom0°Cto9°C.Thegraphbelowshowsthemeanresults.
Oxygenconcentration
/%
oxygensaturation
4035302520151050
0 2 4 6 8 10 Watertemperature/°C
Key: waterneargills
bodyfluids
[Source:HansOPörtner,LloydSPeckandTimoHirse,“HyperoxiaalleviatesthermalstressintheAntarcticbivalve,Laternulaelliptica:evidenceforoxygenlimitedthermaltolerance”,Polar Biology,2006,29(8),pages688–693]
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(Question 1 continued)
(a) (i) Outline the relationship between temperature and oxygen concentration in thebodyfluidsinLaternula elliptica.
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[2]
(ii) Suggesttworeasonsfortherelationship.
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[2]
(b) In itsnaturalenvironment,Laternula ellipticaburies itself in themudon theseabed.Inthisinvestigation,itwasfoundthatabove6°Citisunabletoburyitself.Suggestareasonforthis.
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[1]
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Theworld’soceanscanabsorblargeamountsofcarbondioxide.ThisprocesshasbeenstudiedinthePacificOceannearHawaii,bymeasuringcarbondioxideconcentrationsintheatmosphereandinsurfacewatereverymonth,fromOctober1988onwards.Thegraphbelowshowsthecarbondioxideconcentrationexpressedaspartialpressures(Pco2).
Pco 2
/µatm
380
370
360
350
340
330
320
310
300
1988 1990 1992 1994 1996 1998 2000 2002Year
Key: atmosphericconcentration
waterconcentration
[ReprintedbypermissionfromMacmillanPublishersLtd:Nature,Dore,et al.,“Climate-drivenchangestotheatmosphereCO2sinkinthesubtropicalNorthPacificOcean”,424,pages754-757,copyright2003.]
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(Question 1 continued)
(c) (i) Describe the trends in atmospheric carbon dioxide concentration, shown inthegraph.
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[2]
(ii) Suggesttworeasonsforthetrendsthatyouhavedescribed.
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[2]
(d) (i) Diffusionof carbondioxideonlyoccurswhen there is a concentrationgradient.Deduce the pattern of carbondioxidediffusion, betweenwater and atmosphere,from1988to2002.
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[2]
(ii) Thegraphprovidesevidenceforthehypothesisthattherewillbenonetdiffusionofcarbondioxidebetweenwaterandatmosphereby2020.Explainthisevidence.
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[1]
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(Question 1 continued)
Theconcentrationofcarbondioxideintheatmosphereiscurrently385ppm(partspermillion).Variations in the concentration of carbon dioxide in the atmosphere can be studied usingice-cores.Anice-corerecordcoveringthelast400000yearshasbeenobtainedfromVostokintheAntarctic.Thegraphbelowshowsthecarbondioxideconcentrationsthatweremeasuredatdifferentdepthsintheice.Atmospherictemperaturesarealsoshownonthegraph.Thesewerededucedfromratiosofoxygenisotopes.TheupperlineonthegraphshowsCO2concentrationsandthelowerlineshowstemperature.
Depthinice-core/m 0 500 1000 1500 2000 2500 2750 3000 3200 3300
CO2/ppm
300
280260
240
220
200
6420–2–4–6–8
Temperature/°C
50000 100000 150000 200000 250000 300000 350000 400000Age/yearsago
[ReprintedbypermissionfromMacmillanPublishersLtd:Nature,LeeR.Kump,“Reducinguncertaintyaboutcarbondioxideasaclimatedriver”,419,pages188-190,copyright2002.]
(e) (i) Statethehighestcarbondioxideconcentrationshownonthegraph.
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[1]
(ii) Statethehighesttemperatureshownonthegraph.
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[1]
(f) Usingthedatainthegraph,deducetherelationshipbetweenatmosphericcarbondioxideconcentrationandtemperature.
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[1]
(g) Usingthedatainthisquestion,explainreasonsforconcernaboutthelong-termsurvivalofAntarcticspecies,suchasLaternula elliptica.
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[3]
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2. (a) Glucoseandgalactoseareexamplesofmonosaccharides.Stateoneotherexampleofamonosaccharide.
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[1]
(b) Theequationbelowshowstheproductionofglucoseandgalactosefromlactose.
(i) Thereareseveraldifferenttypesofcarbohydrate.Statewhichtypeofcarbohydratelactoseis.
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[1]
(ii) Statethetypeofchemicalreactionthatoccurswhenlactoseisdigestedintoglucoseandgalactose.
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[1]
(c) Lactaseiswidelyusedinfoodprocessing.Explainthreereasonsforconvertinglactosetoglucoseandgalactoseduringfoodprocessing.
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...................................................................
2.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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...................................................................
[3]
(d) Simplelaboratoryexperimentsshowthatwhentheenzymelactaseismixedwithlactose,the initial rateof reaction ishighestat48°C. In foodprocessing, lactase isusedatamuchlowertemperature,oftenat5°C.Suggestreasonsforusinglactaseatrelativelylowtemperatures.
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[2]
0 7 1 0
O
OH
H
H
H
H
OHHOHO
O
OH
H
H
H
H
OHHOH
OH
O
H
H
H
OH
OHHH
OH
+lactase
lactose galactose glucose
HOHO
H
H
H OHO
H
OH
OH
HOH
OHOH
CH2CH2 CH2
2CH
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3. Thediagrambelowshowsapairofchromosomesduringmeiosisinacellinthehumantestis.Thepositionoftheallelesofsomegenesisindicated.
A B C
a b c
(a) Deduce,withreasonsforyouranswer,whetherthechromosomesare
(i) autosomesorsexchromosomes.
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(ii) homologousornon-homologous.
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[1]
[1]
(b) Statethestageofmeiosisofacellifitcontainspairsofchromosomesasshowninthediagram.
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[1]
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(c) Attheendofmeiosis,eachofthechromatidsshowninthediagramwillbeinadifferenthaploid cell. The diagrams below represent the chromatids inside the haploid cells.Determinethecombinationsofallelesthatwouldbepresentoneachchromatid.Usethediagramstoindicateyouranswer. [2]
(d) Statethepatternofinheritanceshownbythethreegenes.
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SECTION B
Answer two questions. Up to two additional marks are available for the construction of your answers. Write your answers on the answer sheets provided. Write your session number on each answer sheet, and attach them to this examination paper and your cover sheet using the tag provided.
4. (a) Bloodisaliquidtissuecontainingglucose,urea,plasmaproteinsandothercomponents.Listtheothercomponentsofblood. [5]
(b) Outline how the human body prevents blood glucose concentration from risingexcessively. [5]
(c) Bloodplasma,glomerularfiltrateandurinehavedifferentconcentrationsofsolutes,suchasglucose,proteinandurea.Explaintheprocessesoccurringinthekidneythatcausedifferences in the concentrations of these solutes between blood plasma, glomerularfiltrateandurine. [8]
5. (a) Themainpartsofgrowingplantsareroots,stemsandleaves.Drawaplandiagramtoshowthearrangementoftissuesinthestemofadicotyledonousplant. [5]
(b) Outlinetheadaptationsofplantrootsforabsorptionofmineralionsfromthesoil. [5]
(c) Photosynthesisandtranspirationoccurinleaves.Explainhowtemperatureaffectstheseprocesses. [8]
6. (a) Eukaryoticcellshaveintracellularandextracellularcomponents.Statethefunctionsofone namedextracellularcomponent. [4]
(b) Outline,withanexample,theprocessofexocytosis. [5]
(c) Translation occurs in living cells. Explain how translation is carried out, from theinitiationstageonwards. [9]
7. (a) MostoftheDNAofahumancelliscontainedinthenucleus.DistinguishbetweenuniqueandhighlyrepetitivesequencesinnuclearDNA. [5]
(b) Draw a labelled diagram to show four DNA nucleotides, eachwith a different base,linkedtogetherintwostrands. [5]
(c) ExplainthemethodsandaimsofDNAprofiling. [8]
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Section a
Answer all questions. Write your answers in the boxes provided.
1. Investigatorscarriedoutexperimentstofindtherelationshipbetweentheenergyusedbymice(themetabolic rate)and theiractivity. They found that theamountof timemiceareactivedepends on the time of day, whether they are single or in groups and on the temperatureof their surroundings. Thebarchartbelowshows thepercentageof timemicewereactiveduring three-hourperiodsat threedifferent temperatures.
Activity/%ofthree-hourperiod0 10 20 30 40 50 60 70 80
Timeofday
12:00to15:0015:00to18:0018:00to21:0021:00to00:0000:00to03:0003:00to06:0006:00to09:0009:00to12:00
8 C°
12:00to15:0015:00to18:0018:00to21:0021:00to00:0000:00to03:0003:00to06:0006:00to09:0009:00to12:00
15 C°
12:00to15:0015:00to18:0018:00to21:0021:00to00:0000:00to03:0003:00to06:0006:00to09:0009:00to12:00
31 C°
Key: singlemice groupmice
L.E.MountandJ.V.Willmott(1967)JournalofPhysiology,190,pages371–380.PublishedbyWiley-Blackwell.Usedwithpermission.
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(a) Calculate how many minutes the group mice are active between 21:00and 00:00 at8 C° . [1]
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(b) Outlinetherelationshipbetweenactivityandtemperaturefrom21:00to03:00inallofthemice. [1]
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(c) Animals which are active at night are nocturnal. Suggest one advantage for micebeingnocturnal. [1]
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Theinvestigatorsalsofoundthatthemetabolicrateofthemicechangedatdifferenttimesoftheday.Micewerekeptatoneofthethreeconstanttemperaturesfor24hoursandtheiroxygenconsumptionwasmeasured.Thegraphbelowshowstheresultsforsinglemiceandthemeanvaluesforgroupmice.
Metabolicrate/mlO2kg
–1min–1
130
120
110
100
90
80
70
60
50
40
30
20 12:00 15:00 18:00 21:00 00:00 03:00 06:00 09:00
Timeofday
Key: singlemiceat8 C° singlemiceat15 C° singlemiceat31 C°
groupmiceat8 C° groupmiceat15 C° groupmiceat31 C°
L.E.MountandJ.V.Willmott(1967)Journal of Physiology,190,pages371–380.PublishedbyWiley-Blackwell.Usedwithpermission.
(d) Statetherelationshipbetweentemperatureandmetabolicrate. [1]
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(e) Comparetheresultsforthesinglemiceat15 C° withthoseforthegroupmiceat15 C° . [2]
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(f) Suggestonereasonwhytheresultsdifferforsinglemiceandgroupmice. [1]
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(g) Explainwhyoxygenconsumptionisusedasameasureofmetabolicrate. [2]
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(h) Usingthedatafrombothgraphs, evaluatethehypothesis that increased activity causesan increase inmetabolic rate inmice. [2]
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(i) Thereactionsofrespirationtakeplaceinthemitochondriaofthemicecellsasshowninthefollowingmicrograph.
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2. Thediagrambelowshowstwonucleotideslinkedtogethertoformadinucleotide.
I
II
(a) (i) IdentifythechemicalgrouplabelledI. [1]
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(ii) StatethetypeofbondlabelledII. [1]
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(b) DistinguishbetweenthesenseandantisensestrandsofDNAduringtranscription. [1]
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(c) ComparetheDNAfoundinprokaryoticcellsandeukaryoticcells. [2]
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3. (a) Definethetermexcretion. [1]
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(b) Explaintheprocessofultrafiltration. [2]
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(c) Thediagrambelow showspart of the humankidney. The arrow shows the directionof blood flow.
I II
Bloodflow
ComparethecompositionofthefluidsfoundintheregionslabelledIandIIbygivingonedifferenceandone similarity. [2]
Difference: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Similarity: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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4. Thefoodwebbelowshowssomeof thefeedingrelationshipsfoundbetween theorganismslivinginornearariverinEngland.
Heron Kingfisher
Trout
CarnivorousStonefly
CarnivorousCaddis Dragonfly
MayflyRiverlimpetFreshwater
shrimp
Leech
Diatomsandotheralgae
(a) Identifyanorganisminthefoodwebthatis
(i) anautotroph. [1]
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(ii) bothasecondaryandtertiaryconsumer. [1]
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(b) Explainhowtheflowofenergyinthefoodwebdiffersfromthemovementofnutrients. [2]
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(c) Discussreasonswhythelevelsofapyramidofenergydifferinsize. [2]
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Section b
Answer two questions. Up to two additional marks are available for the construction of your answers. Write your answers in the boxes provided.
5. (a) Outlinetheeffectoftemperatureandsubstrateconcentrationontheactivityofenzymes. [4]
(b) Distinguish between competitive and non-competitive enzyme inhibition of chemicalreactions,givinganexampleofeach. [5]
(c) Explainthelight-independentreactionsofphotosynthesis. [9]
6. (a) Outlinethevariousstagesofthecellcycle. [4]
(b) Describe the differences in the structures of dicotyledonous plants andmonocotyledonousplants. [5]
(c) Define the term transpiration andexplain the factors thatcanaffect transpiration inatypical terrestrialplant. [9]
7. (a) DescribethecausesofDownsyndrome. [5]
(b) Describehowhumanskincolourisdeterminedgenetically. [5]
(c) Explainthecausesofsickle-cellanemia. [8]
8. (a) Outlinetheroleoftheskinintemperatureregulation. [5]
(b) Outlinetheroleofhormonesintheprocessofbirthinhumans. [4]
(c) Explaintheprinciplesofvaccination. [9]
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2. Two foodsweremeasuredwith a calorimeter to determine the energy in each. Five trialson potato chips and five trials on walnuts were performed. The resultsareshownin thetablebelow.
Trial Potato chip / kJ g–1 Walnut / kJ g–1
1 22.4 24.12 21.7 23.83 21.9 25.24 22.0 28.05 22.0 27.9
Mean 22.0 missingvalueStandarddeviation 0.1 2.0
(a) Calculatethemeanenergyforthewalnut. [1]
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(b) Explainhowthisdatashowswhichfoodhadthegreatestvariationinitsenergycontent. [2]
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(c) Bothpotatochipsandwalnutscontainlipids.Stateonefunctionoflipids. [1]
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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3. (a) Bloodtransportsmoleculesthroughoutthebody.Statewherethebloodabsorbs
(i) hormones. [1]
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(ii) carbondioxide. [1]
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(b) Describethreefeaturesofalveolithatadaptthemtogasexchange. [3]
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(c) Explainhowthestructureofcapillariesrelatestotheirfunctions. [3]
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
0716
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4. Thediagramshowsacrosssectionofaleaf.
X
�������
Y Z
(a) IdentifythetissueslabelledX,YandZ.
(i) X: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [1]
(ii) Y: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [1]
(iii) Z: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [1]
(b) Outlinetwoadaptationsofxerophytesthathelptoreducetranspirationfromtheleaves. [2]
1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(This question continues on the following page)
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(Question 4 continued)
(c) Angiospermophyta have vascular tissue (xylem and phloem) that bryophyta lack.Suggestadvantages thatvascular tissueconfers. [3]
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SECTION B
Answer two questions. Up to two additional marks are available for the construction of your answers. Write your answers in the boxes provided.
5. (a) Listthegeneralfunctionsofnon-membraneproteins. [4]
(b) Outlinethedigestion,absorptionandassimilationofproteinsinhumans. [6]
(c) Actin and myosin are two proteins found in muscles. Explain how skeletal musclecontracts,includingtheinteractionoftheseproteins. [8]
6. (a) Describetherelationshipbetweengenes,polypeptidesandenzymes. [4]
(b) Outlinecontrolofmetabolicpathways. [6]
(c) Discusstheuseoflactaseintheproductionoflactose-freemilk. [8]
7. (a) Outlinepollination,fertilizationandseeddispersal. [4]
(b) Comparetheprocessesofspermatogenesisandoogenesis. [8]
(c) Describetheconsequencesofoverpopulationofaspecies. [6]
8. (a) Outlinehowthreepropertiesofwaterenhanceitsusebylivingorganisms. [6]
(b) DescribetheroleofADHinosmoregulation. [4]
(c) Explainhowwaterismovedfromrootstoleavesinterrestrialplants. [8]
1016
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SECTION A
Answer all the questions in the spaces provided.
1. Migratingbirdsmustrefuelalongthewayinordertocontinueflying.Afieldstudywasconductedamongfourdifferentspeciesofmigratingbirdsknowntostopathighqualityandlowqualityfoodsites.Twotechniqueswereusedtoassessfoodqualityinthestopoversites.Birdswerecapturedandweighedatthetwosites.Bloodsamplesweretakenfromthebirdstodeterminenutrientlevelsintheirblood.Thetwotechniqueswerecomparedfortheireffectiveness.
Thetablebelowshowsdatacollectedfromthetwositesduringoneseason.
Site 1 Site 2
SpeciesN
(number captured)
Mean bird mass / g
N(number captured)
Mean bird mass / g
Hermitthrush 46 29.8 28 28.3
White-throatedsparrow 47 27.9 48 27.2
Americanrobin 8 78.3 10 77.6
Magnoliawarbler 30 8.4 10 8.2
[Source:adaptedfromCGuglielmo,et al.,(2005),Physiological and Biochemical Zoology,78(1),pages116–125]
(a) Considering all the birds sampled, identifywhich specieswas sampled themost andwhichwassampledtheleast. [1]
Most: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Least: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(b) Using the data fromthe table, calculate the percentage difference inmeanbirdmassfor thehermitthrushesrefuelingatSite1compared to thoserefuelingatSite2.
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[1]
(This question continues on the following page)
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(Question 1 continued)
Amethodwasused todetermine theaveragemasschange ingramsperhour( )g h 1 duringthe study. Graph A represents a summary of data collected during one season whereasGraphBrepresentsasummaryofdatacollectedover17years.
GraphAoneseasonsummary
GraphB17-yearsummary
Averagemass
change/gh–1
4.0
3.0
2.0
1.0
0.0
–1.0
–2.0
Averagemass
change/gh–1
1.00.80.60.40.20.0
–0.2–0.4–0.6
HT WS AR MW HT WS AR MW Species Species
Key: Site1 Site2
HT: HermitthrushWS: White-throatedsparrow
AR: AmericanrobinMW: Magnoliawarbler
[Source:adaptedfromCGuglielmo,et al.,(2005),Physiological and Biochemical Zoology,78(1),pages116–125]
(c) Comparethe17-yearsummarydataforthehermitthrushandthemagnoliawarbler.
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[2]
(d) EvaluatetheoneseasondataforthehermitthrushandtheAmericanrobinwithregardtoaveragemasschangeperhouratSite1.
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(This question continues on the following page)
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(Question 1 continued)
Among birds, high triglyceride concentration in blood plasma indicates fat depositionwhereas high butyrate concentration in blood plasma indicates fatutilization and fasting.The following data summarizes triglyceride levels and butyrate levels measured for thesame groups of birds.
Triglyceridelevels Butyratelevels
Concentration/arbitraryunits
1.81.61.41.21.00.80.60.40.20.0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0 HT WS AR MW HT WS AR MW
Species Species
Key: Site1 Site2
HT:HermitthrushWS:White-throatedsparrow
AR: AmericanrobinMW:Magnoliawarbler
[Source:adaptedfromCGuglielmo,et al.,(2005),Physiological and Biochemical Zoology,78(1),pages116–125]
(e) Describe, using the triglyceride levels graph, the results at Site 1 and Site 2 for allof thebirds.
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[2]
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(Question 1 continued)
(f) ExplainthedifferencesinthetriglyceridelevelandbutyratelevelforthehermitthrushatSite1andSite2.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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[2]
(g) Scientists have hypothesized that the food quality is better at Site 1 than at Site 2.Evaluatethishypothesisusingthedataprovided.
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[2]
(h) Suggestoneadvantageandonedisadvantageforbloodsamplingratherthanweighingbirds toassess foodqualityatstopoversites.
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
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2. (a) Thescanningelectronmicrographbelowshowsthesurfaceofthenuclearenvelopewithnumerousnuclearpores.
X
0.2µm
[Source:adaptedfromDNelsonandMCox,(2000),Lehninger Principles of Biochemistry,thirdedition,page35]
(i) Calculatethepowerofmagnificationoftheimage.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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[1]
(ii) StatethediameteroftheporelabelledX.
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[1]
(b) Listtwoexamplesofhowhumanlifedependsonmitosis.
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[1]
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(Question 2 continued)
(c) Describetheimportanceofstemcellsindifferentiation.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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[3]
(d) Thegraphsbelowshowthenormalmenstrualcycle.
Estrogenpgml–1plasma
Progesteronengml–1plasma
300
200
100
0
8
4
0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 Time/day
[Source:adaptedfromwww.mivf.com.au/ivf/infertility/images/cyclediagram.GIF]
(i) Predict, with a reason, how the graphs will change if the woman becomespregnant.
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[2]
(ii) Listtworolesoftestosteroneinmales.
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[1]
0 7 1 0
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3. (a) OutlinethebondingbetweenDNAnucleotides.
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[2]
(b) Explain how chemical bonding between water molecules makes water a valuablecoolant in livingorganisms.
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[2]
(c) Stateawordequationforanaerobiccellrespirationinhumans.
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4. (a) Explainwhycarriersofsex-linked(X-linked)genesmustbeheterozygous.
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[2]
(b) (i) Labelthediagrambelowwhichshowsabasicgenetransfer. [2]
II.
IV.
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(ii) Statetwogeneraltypesofenzymesusedingenetransfer.
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SECTION B
Answer two questions. Up to two additional marks are available for the construction of your answers. Write your answers on the answer sheets provided. Write your session number on each answer sheet, and attach them to this examination paper and your cover sheet using the tag provided.
5. (a) Outlinethestructureofaribosome. [4]
(b) Distinguish between fibrous and globular proteins with reference to one example ofeachprotein type. [6]
(c) Explaintheroleofauxininphototropism. [8]
6. (a) Outlinetheprocessofglycolysis. [5]
(b) Describehowpancreaticcellsdirectlyaffectbloodglucoselevels. [5]
(c) Explainwhydiabetescouldbedetectedthroughtheanalysisofurine. [8]
7. (a) Drawalabelleddiagramofamaturesperm. [5]
(b) Outlinetheformationofchiasmataduringcrossingover. [5]
(c) ExplainhowanerrorinmeiosiscanleadtoDownsyndrome. [8]
8. (a) Describe the relationship between the rise in the concentration of atmosphericcarbondioxideand theenhancedgreenhouseeffect. [5]
(b) Outlinetheprecautionaryprinciple. [5]
(c) Antibiotic resistance in bacteria is an example of evolution in response toenvironmentalchange.Usinganotherexample,explainhowanenvironmentalchangecanleadtoevolution. [8]
1 0 1 0
1
SECTION A
N 1 1 /4/BIOLO IIfP2 IENG/TZOIXX
Answer all questions. Write your answers in the boxes provided.
1. Stem cells in the bone marrow can be forced into blood vessels in a process called mobilization.Mobilization of stem cells from the bone maffow into the blood vessels represents the basis formodern bone marrow transplantation procedures.
To test the effect of light on the mobilization of stem cells, mice were subjected to a simulated"jetlag" by advancing the light-dark cycle by 12 hours. This was done by subjecting mice toa 24-hour light period before the results shown in the graph were recorded. The results werecompared to the stem cells in control mice under normal conditions of 12 hours of light (E)and 12 hours of darkness (I)
Key: ---o- Control --*-- Jet lag
100
80
Stem cells 60per ml blood
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20
0 2 4 6 8 r012t416 1820222426
fSource: adapted from S Méndez-Fercer, et al., (2008), Nature,452, pages 4424471
(a) (i) State the maximum number of stem cells per ml blood in the control mice. tll
Time / hours
(ii) Determine the number of hours of light needed to release the maximum numberof stem cells in blood in control mice. tll
(This question continues on the following page)
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-3- N 1 1 /4/B IOLO/HP2IEN G IT ZO IXX](Question I continued)
(b) Distinguish between the trends shown in the number of stem cells per ml blood by themice subjected to jet lag and the control mice. t2l
(c) Other studies suggest that a greater number of blood stem cells for transplantation maybe obtained if they are harvested during darkness. Evaluate this hypothesis. t2l
(This question continues on thefollowing page)
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N11/4/BIOLOIHP2IENG/TZOIXX I-4-(Question I continued)
One important chemical in the mobilization of stem cells is a protein, CXCLI2, which maintainsthe stem cells inside the bone maffow. The breakdown of CXCLI2 causes the mobilizationof stem cells to the blood vessels.
The graph below shows the mobilization of stem cells and the production of mRNA lor CXCLI2when the bone maffow is treated with two different chemicals (isoprenaline and clenbuterol).
Control
isoprenaline
clenbuterol
100 50mRNA for CXCLI2
(% of control)
50Stem cells released
100
fSource: adapted from S Méndez-Ferrer, et al., (2008), Nature,452,pages 4424471
(d) Explain how the amount of mRNA for CXCLl2 gives an indication of the amount ofprotein CXCLI2 produced. tll
(e) Compare the effect of isoprenaline and clenbuterol with the normal release of stem cellsand the production of mRNA for CXCLl2. t3l
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(This question continues on page 6)
(Question I continuedfrom page 4)
Type I diabetes is an autoimmune diseasep cells in the islets of Langerhans. Isletpancreas after leaving the bone maffow.
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resulting from destruction of the insulin-producingregeneration can occur when stem cells reach the
N11/4/BIOLOIHP}IENG/TZOIXX I
Studies have shown a link between CXCLI2 and type I diabetes. Mice predisposed to developthe disease were given an inhibitor of CXCLI2 for 3 weeks. The incidence of diabetes wasmeasured after 28 weeks and compared to control mice that were not given the inhibitor.
70
60
50
40
30
Key:- + - Control--r- with inhibitor
Incidenceof diabetes
t%
t0
0 20 25Age lweeks
fSource: adapted from Q Leng, et al., (2008), BMC Immunologt,9,page 571
(Ð (Ð Outline the effect of CXCLl2 inhibition on the incidence of diabetes.
(This question continues on thefollowing page)
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-7- N 1 1 /4/BIOLO/HP2IEN G IT ZO IX](Question I continued)
(ii) Suggest how the breakdown of CXCLI2 in the bone marrow may be related todiabetes. tll
(g) Evaluate the possible use of isoprenaline in the treatment of diabetes. t2l
(h) Research is being conducted into treatment for diabetes based on stem cells. Discuss theethical issues involved in stem cell research. t3l
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r I-8- N 1 1 /4/BIOLO/HP2IEN G IT ZO IXX
(a) The diagram shows the structure of the leaf of a dicotyledonous plant. Label I and II. t2l
[Source: adapted from www,emc.maricopa.edu ffacuhyllarabee/BIOBK/BioBookPLANTANALhtml]
(b) Outline the function of II. ttl
L
-9- N 1 1 /4/BIOLO/HP2IEN G IT ZO IXX](a) Predict the genotypic and phenotypic ratios of the possible offspring of a male hemophiliac
and a female carrier using suitable symbols for the alleles in a Punnett grid. t3l
Genotypic ratio:
Phenotypic ratio:
(b) Hemophilia is a disorder where the ability to control blood clotting or coagulationis impaired. Describe the process of blood clotting. t2l
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N11/4/BIOLO/HP2IENG ITZOIXX1- 11-
(Question 4 continued)
(a) State the process occurring at X and Y. t2l
X:
Y
(b) Suggest one type of organism that can be involved in process Z. tll
(c) Explain the relationship between the rise in concentration of atmospheric carbon dioxideand the enhanced greenhouse effect. t3l
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-t2-SECTION B
N11/4/BIOLO/HP2/EN GITZOIXX I
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Answer two questions. Up to nvo additional marl<s are availablefor the construction of your answers.Write your answers in the boxes provided.
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6. (a)
(b)
(c)
7. (a)
(b)
(c)
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8. (a)
(b)
(c)
5. (a) Draw a labelled diagram of the digestive system.
(b) Many people cannot digest lactose and benefit from a diet containing no lactose. Outlinethe production of lactose-free milk.
(c) Explain how the kidney helps to retain useful substances in the blood and eliminatesubstances which the body does not need.
Describe the production of semen.
Explain the structure and function of the placenta.
Outline the hormonal control of birth.
Deflne the terms chromosome, gene, allele and genome.
Compare the genetic material of prokaryotes and eukaryotes.
Explain the process of DNA replication.
Draw the absorption spectrum of chlorophyll.
Explain the process of photophosphorylation in chloroplasts.
Outline how the glucose produced as a result of photosynthesis is transported and storedin plants.
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