BIOLOGY PLUS
Michael O’Callaghan Wesley Hammond
Firstpublished2025
TheEducationalCompanyofIreland
Ballymount Road
Walkinstown
Dublin12
www.edco.ie
AmemberoftheSmurfit WestrockGroupplc
©MichaelO’Callaghan, WesleyHammond,2025
Allrights reserved.Nopartofthispublicationmaybe reproduced,storedina retrievalsystem,ortransmittedinany formor by anymeans,electronic, mechanical,photocopying, recordingorotherwise,withouteithertheprior permissionofthePublisheroralicencepermitting restrictedcopyinginIreland issued by theIrishCopyrightLicensingAgency,63 PatrickStreet,DúnLaoghaire, Co.Dublin.
Editor:UnaMurray
Coverdesign:Design!mage
Bookdesignandlayout:Carole Lynch
Illustrations:Compuscript,Carole Lynch
Whileeverycarehasbeentakentotraceandacknowledgecopyright,the publisherstendertheirapologies foranyaccidentalinfringementwhere copyrighthasproveduntraceable.They wouldbepleasedtocometoasuitable arrangementwiththerightful ownerineachcase.
Disclaimer: Web referencesinthistextbookareintendedasaguide forstudents andteachers. At thetimeofgoingtopress,all webaddresses were activeand containedinformation relevanttothetopicsinthistextbook.However, The EducationalCompanyofIrelandandtheauthorsdonotaccept responsibility for theviewsorinformationcontainedonthese websites.Contentandaddresses maychangebeyondourcontrolandstudentsshouldbesupervisedwhen investigating websites.
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Solutionstothe RevisionQuestionsonExperimentsinthe BiologyPlusInvestigativeLog availableon edcolearning.ie
edco.ie/yd7p
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INTRODUCTION
This Teacher’s ResourceBookiswrittentoaccompanythe BiologyPlus package forthenew LeavingCertificate Biology coursetobeexaminedfrom2027onwards. Inadditiontothetextbook,an InvestigativeLog isincludedwith thepackagesothatstudentscan carryoutand recordtheirpractical investigations.The InvestigativeLog alsoincludesthenew Exam Guide. The ExamGuide provides comprehensive tips forthe new SECSampleExam Papers anda crossreference towhereinthetextbookthe relevantsections forthosesamplequestionscanbe found.Thetextbook, InvestigativeLog and ExamGuide arecomplementedwithawide rangeof digitalmaterial.The digitalresources include PowerPoints,chapterquizzes, interactivequizzes,chaptersummaries,flashcards,mindmaps,and knowledgechecklists.
This Teacher’s ResourceBookcontainsa wealthofteacherplanningtosupportteachers,as wellassolutionstothe revisionquestionsinthetextbook. Revisionquestionsolutionsto InvestigativeLog areonline. Thecontentsofthetextbookare verycloselyalignedwiththeCurriculumSpecification. Thebookisdesigned for bothOrdinaryLeveland HigherLevel students.TheHigherLevelcontentis clearlymarkedwitha redbarand,wherepossible, itisplacedattheendofchaptersorinseparate chapters.
The fourstrandsofthecourse areclearly highlighted(NatureofScience;OrganisationofLife; StructuresandProcessesofLife;andInteractions ofLife).Inaddition,thethreecrosscuttingthemes (Health, TechnologyandSustainability)aredealt withwhere relevant.
Forthetextbookeachchapteropenswiththe LearningIntentions.Thesearebased verycloselyontheCurriculum Specification.Definitionsareclearlydisplayedincolouredpanelsthroughoutthechaptersandareincludedina substantialglossaryatthebackofthebook.
Biologyisa veryvisualsubject.Thebookcontainsa wealthof fullylabelleddiagrams and up-to-datephotographs (manyofwhichareelectronmicroscopeimages).Thesediagramsandimagessupportandenhancethewritten explanationsinthetext.Asmuchaspossible,thetextusesshortsentencesandparagraphstoexplainthetopicsas clearlyaspossible.
Numerous mnemonics, tips and ‘Did youknow?’ panelscomplementthecontentandwillhelpstudentsto recall informationand relatethecontentto real-worldsituations.
Allthe practicalinvestigations areincludedincolouredpanels,normallyclosetotheendofeachchapter(forease ofaccess).Inmanyoftheinvestigations,the resultsareindicatedorpredicted(ifnotstateddirectly).Inaddition,the investigations(includingthoseinEcology)are availabledigitallyas onlinevideos
Substantial summaries areincluded foreachchapter.Thesesummariesarehelpful forexam revision.
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Alargenumberof revisionquestions areincludedattheendofeachchapter.Thesequestionstendto followthe sequenceofthecontentofeachchapter,andtheyareclearlydelineatedasOrdinaryorHigherLevelquestions.In addition,wherepossible,thequestionsarearrangedsothatthemoredifficultquestionsareattheend.
A very substantialindex isincludedtoallowstudentstoaccessinformationeasily.
DIGITALRESOURCES
Planning
Editableplanningdocuments
Solutions
Textbooksolutions: Chapter by chaptersolutionsto RevisionQuestions
MyInvestigativeLog: Chapter by chaptersolutionstoActivity: RevisionQuestionsonExperiment
The BiologyPlusdigital resourcesprovidesupplementarycontenttoenhance yourlearningexperience.
Linkstothe resourcesare referencedthroughoutthetextbookusingthe followingicons:
MindMap
MindMaps arevisual representationsthat outlineandconnectconceptsinaclear andorganisedmannertoaidin reviewing coursematerial.
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Editable PowerPoint presentationsprovide chaptersummaries,highlighting keytopics, definitionsandexperimentsinthetextbook. PowerPoint
Investigation Video
The InvestigationVideos arein-depthvisualdemonstrationsof experimentstoenhancepracticalunderstandingandprovideexamtips. Dedicatedecologyvideospresented by biologistÉannaNíLamhna.
Knowledge Checklist
Each KnowledgeChecklist isa listofessentialconcepts,topics anddefinitionstobemastered beforemovingontothenext unit,ensuringstudentsareon track.
KNOWLEDGECHECKLIST
CHAPTER13 ENZYMES
Do youknow…? ✔
1. Thechemicalnatureofanenzyme.
2. Whatbiomoleculeenzymesaremadefrom.
3. Howtoexplainhowanenzymeisabiologicalcatalyst.
4. Howtostatetheshapeofanenzyme.
5. Howtolisttwo factorsthataffectenzymeactivity.
6. Howtodescribewhatismeant by optimumactivityin relationtoenzymes.
7. Howtodefinethetermssubstrateandproduct.
8. Howtodescribeacatabolicenzymeandnameanexample.
9. Howtodescribeananabolicenzymeandnameanexample.
10 Howtodrawagraphshowinghowtemperatureaffectsenzymeactivity.
11. HowtodrawagraphshowinghowpHaffectsenzymeactivity.
12. Howtodefinetheterm‘denaturedenzyme’.
13. Howtodefinetheterm‘immobilisedenzyme’.
14 Howtodefinetheterm‘bioprocessing’.
15. Howtodefinetheterm‘bioreactor’.
16 Howtolistthreeadvantagesofimmobilisedenzymes.
17 Howtonametheenzyme,substrateandproductpresentintheexperimentshowinghow pH,temperatureandheatdenaturationaffectthe rateofenzymeactivity.
18. Howtostatewhyonlyone factorshouldchangeinanexperiment.
19 Howtostatehow youmightchangethetemperature.
20. Howtostatehow youmight keepthetemperatureconstant.
21. Howtostatehow youmightchangethepH.
22. Howtostatehow youmight keepthepHconstant.
23. Howtostatewhy youusedwashingupliquid.
24 Howtonamethesourceofcatalase.
25. Howtodescribehow youmeasuredtheenzymeactivity.
26. Howtostatehow youmightdenatureanenzymeintheheatdenaturationexperiment.
27. Howtodefinetheactivesite.
28. Whatismeant by enzymespecificity.
29. Howtoexplainhowanenzyme works(inducedfitmodel/activesitetheory).
30. Examplesofenzymesusedin foodandbeverageindustry.
31. Examplesofenzymesusedinmedicineindustry.
32. Examplesofenzymesusedinpharmaceuticalindustry.
33. Examplesofenzymesusedinbiofuelindustry.
Quizzes
InteractiveQuizzes andFlashcards provideengagingactivitiesdesigned foractive recalland reinforcementof key factsanddefinitions.
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3D Models
3DModels areinteractivemodelsto enhanceunderstanding,improvespatial awareness,andtomakecomplexconcepts easiertovisualiseand remember.
ChapterSummary
Each ChapterSummary givesaconcise overview ofimportantpoints, summarising keyinformation coveredinthechapter.
CHAPTER SUMMARY
● Anatomyisthestudyofthestructureofan organismoritsparts.
● Physiologyisthestudyofthefunctionsand processesofanorganismoritsparts.
● Thepairoflungsislocatedinthethoraciccavity.
● Breathinginthroughthenosefilters,moistensand warmstheair.
● Thepharynxisthethroat.Theepiglottisandlarynx areinthepharynx.
● Theepiglottiscloses overthetrachea,which prevents foodfromenteringthetrachea (windpipe)andlungs.
● Thelarynx(voicebox)producesvibrationsto createsound.
● Thetracheaismadeofmuscle,elasticfibresand ringsofcartilage–thesepreventthetubefrom collapsinginwards.
● Mucusinthebreathingtracttrapsdust,bacteria andviruses.
● Thepleuralmembraneisadoublemembranethat surroundsthelungsand reducesfrictionduring breathing.
● Thealveoliareairsacs foundattheendsof bronchiolesthatallowgasexchange: Oxygendiffusesfromthealveoliinto red bloodcells Carbondioxideandwaterdiffusefromthe bloodplasmaintothealveoli
● Adaptationsofalveoli: Largesurfacearea forgasexchangeasthey aresonumerous Thinwalls foreasiergasexchange Moistsurfaces(helpswithdiffusion)
● Inhalationmeansbreathingout.Itusesenergyand isactive.
● Stepsinvolvedininhalation: Thebrain registersthelevelsofcarbon dioxide.
• Thediaphragmcontracts,whichmovesthe diaphragmdown.
• Theintercostalmusclesalsocontract,which allowstheribstobepulledupandout.
• The volumeofthechestcavity(thorax) increasesandtheairpressureinthe chestcavitydecreases.
• Airisnow forcedintothelungs(inhalation)
CHAPTER28
THEBREATHINGSYSTEM
● Exhalationmeansbreathingout.Itdoesnotuse energyandispassive.
● Stepsinvolvedinexhalation: Thediaphragm relaxesandmovesup. Theintercostalmuscles relaxandtheribsmove downandin. The volumeofthechestcavity(thorax) decreasescausingtheairpressureinthechest cavitytoincrease. Airispushedoutofthelungs(exhalation).
● The rateofhumanbreathingismainlycontrolled by themedullaoblongatainthebrain: Carbondioxideisanacidicgas. Increasedconcentrationsofcarbondioxide decreasethebloodpH.
• Themedullaoblongatainthebraindetects thislowpH,whichcausesustobreathe faster anddeeper,especiallywhen we exercise.
● Carbondioxideoperatesasacontrolling factorin gasexchangeinbothplantsandanimals.
Chapter Quiz
Thereisa ChapterQuiz (self-assessmentquiz)atthe endofeachchaptertotest understandingand reinforce learning.
PLANNING
Schemeof Work
Introductiontothe BiologyPlus Schemeof Work
ThisSchemeof Workhasbeendesignedtohelp youplananddeliverthenewLeavingCertificateBiology specificationusingthe BiologyPlus textbookanditsfull rangeofsupporting resources.Itprovidesa ready-to-use framework forteaching,saving youtimewhileensuringfullspecificationcoverage.
Theplanislaidoutchapter by chapterinlinewiththespecification’sunifyingstrandandthreestrandsofcontent. Eachchapterentryincludes:
● LearningOutcomes–directlinkstothespecificationso youcanseeexactlywhatiscovered. Forthefull wordingoftheLearningOutcomesoncurriculumonline.ie,pleaseseethelinkbelow.
edco.ie/zb2c
● LearningIntentions–student-friendlygoalstoguideteachingandlearning.
● SuggestedClassTime–inboth40-minuteand1-hour formats,tosuitdifferenttimetables.
● Investigations–practicalactivitiesfromthespecificationwithclearlinkstotheBiologyPlusInvestigativeLog.
● BiologyinPracticeInvestigation–integrationpointsthroughoutthe yeartohelp youplan forthe20hoursof investigative work required fortheproject,withguidanceontiming, resources,andassessment.
● AssessmentOpportunities–end-of-chapterassessments,digitalquizzes,andothertoolstocheckunderstanding.
● Resources–afulllistof availablematerials,including PowerPoints,mindmaps,flashcards,digitalanimations, 3Dmodels,andknowledgechecklists.
Theplanisflexible. Youcan followitasacomplete yearplanoradaptittofit your ownsequenceandpace.Itintegrates digitalandprint resources,ensuringthatlessonsareengagingandaccessible forallstudents,while keepingpractical investigationsandexamskillsatthecore.
By followingthisSchemeof Work, youcanbeconfidentthatstudentswillmeetallspecification requirements, includingthe20-hourBiologyinPracticeInvestigation,whilebenefitingfromthestructured,student-friendly approachof BiologyPlus.
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TEACHERPLANNING
UnifyingStrandNatureofScience
End-of-chapter
Understandthenatureofscientificknowledge
Appreciatehowscientists wo rk Appreciatehowscientificideasaremodified ove rtime
Conduct re search re levanttoascientificissue
Re alisethatscienceisaglobalenterprisethatdependsonclear communication,internationalcon ve ntions,peer re viewand re producibility
Re cognisebias
Evaluatedifferentsourcesofinformation(includingsecondarydata)
Understandthatasourcemaylackdetailorshowbias
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment
Digital ● End-of- chapter quiz
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment
Digital ● End-of- chapter quiz
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1
Re cognisequestionsthatareappropriate fo rscientificin ve stigation
Po setestable hy pothesesandcomparestrategies fo rin ve stigating hy potheses
2 INVESTIGATINGIN
Design,planandconductin ve stigations
Explainhow yo uconsidered re liability,accuracy,precision,error, fa irness,safety,integrityandselectionofsuitableequipment
Produceandselectqualitativeandquantitativedata Analysedatatoidentifypatterns, re lationships,anomalous observationsandtodrawandjustifyconclusions
Apply yo urlearningandskillstosolvingproblemsinunfamiliarcontexts
Communicate yo ur re sultsandin ve stigationstoa ra ngeofaudiences
Evaluatemedia-basedargumentsconcerningscienceandtechnology
Re searchandpresentinformationonthecontributionofscientiststo scientificdisco ve ryandin ve ntion
Re searchandevaluatetheimpactofscientificdisco ve ryandin ve ntion onsocietyundertheheadings:economic,social,sustainabilityand ethical
3
UnifyingStrandNatureofScience
LearningIntentions In ve stigationsAssessment
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment Digital ● End-of- chapter quiz
Mindmap Po we rPoint Flashcards Knowledge Checklist Digitalanimation
End-of-chapter assessment Digital ● End-of- chapter quiz
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ChapterLOs
Appreciate: Whatmodelsare Theevolvingnatureofmodels Thevalueofmodels Usethe fo llowingconceptstoexplainbiologicalphenomena: Sy stems Interdependence Unityoflife Diversityoflife — Fo rmfitsfunction Tr ansferofinformation Tr ansferofmatter Tr ansferofenergy
U4.1 U4.2
4 BIOLOGICAL REASONING 2x40-minute classes Or (1hourand 20minutes)
Strand1OrganisationofLife
ChapterLOs
1.1.1 Outlinetheelevencharacteristicsoflivingthings
Distinguishbetweentissues,organsandorgansystems
Distinguishbetweenanabolicandcatabolic re actions
5 THE CHARACTERISTICS OFLIFE 3x40-minute classes Or (2x1-hourclasses)
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment Digital ●
End-of- chapter quiz
Digitalanimation
Mindmap Po we rPoint Flashcards Knowledge Checklist
3DModelAnimal CellStructure
End-of-chapter assessment In ve stigative Log Digital ● End-of- chapter quiz
In ve stigation1a: To in ve stigateanimal cellsusingalight microscope In ve stigation1b: To in ve stigateplantcells usingalightmicroscope
Strand1OrganisationofLife
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LearningIntentions
Explainthestructureandfunctionsofavirus Discussthedifficultyofdefiningviruses Discusstheeconomicandmedicalimportanceofviruses
Outlinethedomainsoflife:archaea,bacteriaandeukarya Explainhowclassificationsystemsevolve
Explaintheimportanceanduseofclassificationsystems Outlinethetaxonomicclassificationofthesixkingdomsoflife
Explainprokaryoticandeukaryoticclassification
Understandwhatismeant by phylogeny
Understandthatemergingevidenceenhancessystemsofclassification
Describethecomplexityofmulticellularorganismsfromcellto organismlevel
Understandthestructuresandorganelles(andtheirfunctions)of animalandplantcells
Understandthedifferentfieldsofmicroscopy(opticalandelectron microscopy)
Understandtheuseandfunctionofalightmicroscope
In ve stigate,usingprimaryandsecondarydata,thestructuresand organellesofanimalandplantcells
Re sources
In ve stigationsAssessment
Strand1OrganisationofLife
Mindmap Po we rPoint Flashcards Knowledge Checklist 3DModel Phospholipid Structure (C ell Membrane) Digitalanimation
End-of-chapter assessment
In ve stigation2a: Te sting fo rthepresence orabsenceofstarch
In ve stigative Log Digital ●
End-of- chapter quiz
In ve stigation2b: Te sting fo rthepresence orabsenceof re ducing sugars In ve stigation2c: Te sting fo rthepresence orabsenceofprotein In ve stigation2d: Te sting fo rthepresence orabsenceoflipid In ve stigation3: To in ve stigate quantitativelythelevel of re ducingsugarsina ra ngeof fo odsamples
Mindmap Po we rPoint Flashcards Knowledge Checklist Digitalanimation
End-of-chapter assessment Digital ●
End-of- chapter quiz
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LearningIntentions
Outlinethestructuresandmetabolic ro lesofcarboh yd ra te,lipidand proteinandidentifynutritionalsourcesofeach
Re cognisethe ro lesofmineralsinbiologicalprocesses
Outlinethe ro leofvitamins(onewater-solubleandone fa tsoluble)in biologicalprocesses
Outlinethemain ro lesofwaterinlivingthings Te sting fo rthepresenceorabsenceofstarch, re ducingsugarsand protein To in ve stigatequantitativelythelevelof re ducingsugarsina ra nge of fo odsamples
ChapterLOs
8
Biomolecules–The ChemicalsofLife
6x40-minute classes Or (4x1-hourclasses)
Outlinethe ro leof AT PinmetabolicpathwaysHL HL Outlinethe ro leofNAD+andNADP+inmetabolicpathways
1.2.8
9 Tr ansferMolecules
2x40-minute classes Or (1hourand 20minutes)
Strand1OrganisationofLife
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment Digital ●
End-of- chapter quiz
Digital3Dmodel StructureofDNA Digitalanimation
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment Digital ●
End-of- chapter quiz
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LearningIntentions
DescribethebasicstructureandfunctionofDNAandRNA
Re lategenes,proteinsandtraitsinorganisms
HL Outlinetheconceptofthegeneticcode,includingcodonsand anticodons
Describethestructureofachromosomeandthe ro leofagene Comparegeneticandepigeneticmechanisms Explainwhatismeant by nuclearinheritance
Modelinheritancetothefirstgenerationofasingleunlinkedtraitin crossesin vo lvinghomozygousandheter ozyg ousparents Modelsexdetermination by XandYchromosomesinhumans HL Modeltheinheritanceofsex-linkedtraitsfromknownexamples (colourblindnessandhaemophilia) HL
Modelacrossin vo lvingincompletedominance
HL Re searchoneexampleofepigeneticinheritanceinnature HL IllustrateandstateMendel’slawsofsegregationandindependent assortment
Modelinheritancetothesecondgenerationoftwounlinkedtraitsin crossesin vo lvinghomozygousandheter ozyg ousparents
HL ExplainhowlinkageaffectsMendel’slawofindependent assortment
Strand1OrganisationofLife
LearningIntentions
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment Digital ● End-of- chapter quiz
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment
3DModel Enzyme substrate complex Digitalanimation
In ve stigative Log Digital ●
End-of- chapter quiz
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ChapterLOs
Explainthevariationsthatcomefromsexual re productionand mutations
Understandgeneandchromosomemutations
Distinguishbetweenartificialandnatu ra lselection
Discussthe ra tionale fo r, andthebasisof,thetheoryofevolution by naturalselection
Considerevidence fo revolution by naturalselection
Discusstheimportanceofthetheoryofevolutioninunderstanding biology
Strand2StructuresandProcessesofLife
In ve stigation4a: To in ve stigatea fa ctor (pH)thataffectsthe ra teofanenzyme- catalysed re action
In ve stigation4b: To in ve stigatea fa ctor (temperature)that affectsthe ra teofan enzyme-catalysed re action
In ve stigation4c: To in ve stigate afactor(substrate concentration)that affectsthe ra teofan enzyme-catalysed re action
In ve stigation4d: To in ve stigatea fa ctor (enzymeconcentration) thataffectsthe ra teof anenzyme-catalysed re action
LearningIntentions
Explainhowenzymesfunction
Understandthatenzymesareselectivecatalysts
Understandtheimportanceofenzymesinmetabolism
Re searchtheuseofenzymesinindustries
Re cognisethe ro leofenzymesinindustrialapplications(including immobilisedenzymes) HL Illustrateenzymeactivityusingtheinducedfitmodel To in ve stigate fa ctorsaffectingthe ra teofenzyme-catalysed re actions
In ve stigationsAssessment
Strand2StructuresandProcessesofLife
Mindmap Po we rPoint Flashcards Knowledge Checklist
Digitalanimation
End-of-chapter assessment In ve stigative Log Digital ● End-of- chapter quiz
Mindmap Po we rPoint
End-of-chapter assessment
Flashcards Knowledge Checklist
Digitalanimation
In ve stigative Log Digital ● End-of- chapter quiz
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LearningIntentions
In ve stigation4e: To in ve stigatea fa ctor (enzymedenaturation) thataffectsthe ra teof anenzyme-catalysed re action 14 PHOTOSYNTHESIS
In ve stigation5a: To in ve stigatea fa ctor (lightintensity)that affectsthe ra teof photosynthesis In ve stigation5b: To in ve stigatea fa ctor (temperature)that affectsthe ra teof photosynthesis In ve stigation5c : To in ve stigatea fa ctor (carbondioxidelevel orconcentration)that affectsthe ra teof photosynthesis
In ve stigation6: To in ve stigatethe conditionsnecessary fo r fe rmentation ● Presenceofsugars ● Presenceof microorganisms (yeastorbacteria) ● Anaerobic environment ● Suitable temperature
Outlinetheprocessofphotosynthesis,including: Photosynthesisasananabolic re action
The ro leofphotosynthesisasacarbonsink
Thesourcesofthe re actantsandproducts
Thecellularlocation fo rphotosynthesis
Re presentthe ov erallsequenceofphotosynthesis
Abalancedequation fo rphotosynthesis
Modelthetwo-stageprocessofphotosynthesisand re fe rtothe ro le oftransfermolecules
Re cognisethesignificanceoftheinternalstructureofchloroplasts fo rphotosynthesis
To in ve stigate fa ctorsthataffectthe ra teofphotosynthesis:
Outlinetheprocessesofaerobicandanaerobic re spiration,including: — Re spirationasacatabolic re action The ro leof re spirationincarbon re leaseandenergytransfer Thesourcesofthe re actantsandproducts
Thecellularlocation fo r re spiration
Abalancedequation fo r re spiration
HL Modelthetwo-stageprocessof re spirationand re fe rtothe ro leof transfermolecules
HL Re cognisethesignificanceoftheinternalstructureofmitochondria fo r re spiration To in ve stigatetheconditionsnecessary fo r fe rmentation.
10
Strand2StructuresandProcessesofLife
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment
Digital ●
End-of- chapter quiz
3DModelCancer cells
Digitalanimation
LearningIntentions
Outlinethecellcycle
UnderstandtheprocessofDNA re plication
Understandtheconceptsofhaploidanddiploid
Comparethe ro lesofmitosisandmeiosisintransmittinggenetic information
Explainthe ro leofDNA re plicationandmitosisinthecellcycle
Outlinehowcancersdevelop
Examinethe ro leofdifferent fa ctorsinthedevelopmentofcancers
Evaluateemergingevidence fo rthepreventionand/ortreatmentof cancers
Explaininterphase,nucleardivision(fourstages)andcytokinesis
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment
Digitalanimation
End-of- chapter quiz
Digital ●
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ModelhowDNAis re plicated
ModeltheflowofinformationfromDNA,throughmRNAtoprotein
Modeltheprocessesoftranscriptionandtranslation Re latethe structureoftRNAtothecodonnatureofthegeneticcode
Modelhowgene(orpoint)andchromosomalmutationsoccur
Re fe rtoexamplesofgene(orpoint)andchromosomalmutations
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment
Digital
Digitalanimation
End-of- chapter quiz
●
Strand2StructuresandProcessesofLife
LearningIntentions
Outlinethestructuresandsystems fo r re sponseinhumansandplants
Re latethestructuresofthecomponentpartsoftheaxialand appendicularskeletontotheirfunctions
Modelthefunctionofanantagonisticmusclepair
Re latethefunctionsofcartilage,ligamentandtendonsinsynovial joints
3DModelof backboneand ribcage 3DModelof kneejoint
Mindmap Po we rPoint Flashcards Knowledge Checklist 3DModelof Brain 3DModelof Neurons Digitalanimation
End-of-chapter assessment Digital ●
End-of- chapter quiz
Mindmap Po we rPoint Flashcards Knowledge Checklist Digitalanimation
End-of-chapter assessment Digital ●
End-of- chapter quiz
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18
Re latethestructureofthepartsofthecentralandperipheralnervous systemstotheirfunctions
Re latethestructureofamotorandsensoryneurontotheirfunction
Explainthe ro leofneurotransmittersatasynapse
Discussthe ro lesofdopamineandendorphinsinhumansandthe influenceoflifestylechoicesontheirlevels
The ro le,structureandmechanismsof re flexactions
Modelhowanimpulsetr ave lsacrossasynapticcleft
Considertheimpactsofdisruptionstoimpulsetr avel
Identifythelocationofthemajorglandsintheendocrinesystem
Describethefunctionsofthehormonesassociatedwiththemajor endocrineglands Re cognisetheimpactofhormonalmanipulationonorganismsinterms ofsport,healthandagriculture
Strand2StructuresandProcessesofLife
Re sources
In ve stigationsAssessment
Mindmap Po we rPoint Flashcards Knowledge Checklist Digitalanimation
End-of-chapter assessment
Digital ●
End-of- chapter quiz
Mindmap Po we rPoint Flashcards Knowledge Checklist Digitalanimation
End-of-chapter assessment
Digital ● End-of- chapter quiz
Mindmap Po we rPoint Flashcards Knowledge Checklist 3DModel Fe male Re productive system Digitalanimation
End-of-chapter assessment
End-of- chapter quiz
Digital ●
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ChapterLOs LearningIntentions
Explainhomeostasis
2.4.5
Understandhomeostasisasamodelofstimulus-responsetochange in vo lving re ceptorsandeffectors
Understandthat re sponsesmayoccurduetonegative fe edback
Comparenervousandhormonalcoordination
Distinguishbetweeninnateandadaptive(oracquired)immunity
Distinguishbetweenactiveandpassiveimmunity
Outlinestrategiesappliedtopreventandtreatmicrobialdiseases
Modelhowviruses re plicatewithincells
Explore fa ctorsthatcontributetotheemergenceofinfectiousdiseases
Discusstheimportanceofaknowledgeofemergingdiseasesinsociety
Comparethe ro lesofdifferenttypesofwhitebloodcellsinimmune re sponses
HL
Re latethestructuresofthemaleand fe malehuman re productive systemstotheirfunctions
Outlinethephasesofthemenstrualcycle
Outlinethechangesinhormonallevelsduringthephasesofthe menstrualcycle
HL
Describepregnancyfromthedevelopmentofthe fe rt ilisedzygoteto birth
Modelthe ro leofhormonesinhumanmaleand fe male re productive systems
Appreciatetheimpactofadvancementsinmoderntechnologyon prenatalandpostnatalcare
Discustheuseandbiologicalimplicationsofstrategiestocontrol fe rt ilityandtreatments fo rinfertility
21
HOMEOSTASIS
3x40-minute classes Or 2x1-hourclasses
22
IMMUNITY
10 x40-minute classes Or (6hoursand 40minutes)
23
In ve stigationsAssessment
Strand2StructuresandProcessesofLife
LearningIntentions
Mindmap Po we rPoint Flashcards Knowledge Checklist 3DModel Anatomyof Flo we r
End-of-chapter assessment
In ve stigative Log Digital ●
End-of- chapter quiz
In ve stigation7: To in ve stigateand comparethestructures ofinsectpollinatedand wind-pollinatedplants and re latethemtotheir functionsusingprimary andsecondarydata
Understandthestructuresandfunctionsofthe re productiveparts offlo we ringplantstoinclude: Flo we rs,seeds,fruitsandtheiradaptations fo rinsect-orwindpollination Ro leofflo we rsinpollination Ro leofseedsinplant re productionandtheproductionofgr ow th re gulators Methodsoffruitandseeddispersal To in ve stigateandcomparethestructuresofinsect-pollinatedand wind-pollinatedplants
Mindmap Po we rPoint Flashcards Knowledge Checklist Digitalanimation
End-of-chapter assessment
In ve stigative Log Digital ●
In ve stigation8a: To in ve stigatehow temperatureaffects the ra tesofosmosis acrosssemi-permeable membranes
End-of- chapter quiz
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Distinguishbetweendiffusion,osmosisandactivetransport
Examinethe ro leofosmosisin fo odpreservationandplanthealth To in ve stigatethe fa ctorsthataffectthe ra teofosmosisacross semi-permeablemembrane
In ve stigation8b: To in ve stigatehowthe concentrationgradient affectsthe ra tesof osmosisacrosssemi- permeablemembranes
In ve stigation8c: To in ve stigatehow sur fa ceareaaffects the ra tesofosmosis acrosssemi-permeable membranes
Mindmap Po we rPoint Flashcards Knowledge Checklist 3DModel Structureof Kidney Digitalanimation
End-of-chapter assessment
Strand2StructuresandProcessesofLife
Re latethemacrostructureoftheurinarysystemtoitsfunctionsin filteringand re movingwaste
2.6.3
Digital
End-of- chapter quiz
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Mindmap Po we rPoint Flashcards Knowledge Checklist Digitalanimation
End-of-chapter assessment Digital ●
End-of- chapter quiz
Mindmap Po we rPoint Flashcards Knowledge Checklist Digitalanimation
End-of-chapter assessment Digital ●
End-of- chapter quiz
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HL Outlinethefiltrationofbloodinthenephron,andthe fo rmation ofurine
Outlinethe ro leofADHinosmoregulation
HL
7x40-minute classes or (4hoursand 40minutes)
Modelhowthemacrostructureofthehumandigestivesystem andassociatedorgansandglandscarryoutthedigestionof fa ts, carboh yd ra tesandproteins
Describeingestion,digestion,absorptionandegestion
Describethemechanicalbreakdownof fo odincludingthe ro leofteeth, peristalsis,thestomachandbilesalts
Describethechemicalbreakdownof fo odincludingthe ro lesofan amylase,aproteaseandalipase
Describetheabsorption,transportandstorageoftheproductsof digestion(withspecial re fe re ncetothevilliandhepaticportal ve in)
Re searchthebiologicalimplicationsofdietarychoicesin re lationto health,age,gender,activity,varietyof fo ods,sufficientwaterand ro le ofdietaryfibre
Re latetheanatomyandphysiologyofthebreathingsystemtoits ro le ingasexchangeinthelungs
Explainthemechanismofbreathing
HL Outlinethe ro leofcarbondioxideconcentrationasacontrolling fa ctorinthehumanbreathingsystemandinplantstomata
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SYSTEM
7x40-minute classes or (4hoursand 40minutes)
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Strand2StructuresandProcessesofLife
In ve stigationsAssessment Re
Mindmap Po we rPoint Flashcards Knowledge Checklist
End-of-chapter assessment
3DModel Structureof Heart 3DModel Re d BloodCell Digitalanimation
In ve stigative Log Digital ● End-of- chapter quiz
In ve stigation9: To in ve stigatethe structuresoftheheart and re latethemtotheir functions
LearningIntentions
Distinguishbetweenarteries, ve insandcapillariesbasedontheir macrostructuresand ro le
Knowthestructuresandfunctionsofthepartsoftheheart
Modeltheinteractionbetweenthecirculatoryandotherhuman bodysystemstoinclude:
Thepulmonaryandsystemiccircuits
Aportalsystem
Outlineheartbeatanditscontrol by thepacemaker
Outlinepulse,bloodpressureandthecardiacbloodsupply Re latethecompositionofbloodtoitsfunctions
Appreciatethevalueofknowledgeonbloodgroupings fo r humanhealth
To in ve stigatethestructuresoftheheartand re latethemtotheir functions.
Mindmap Po we rPoint Flashcards Knowledge Checklist Digitalanimation
End-of-chapter assessment
In ve stigative Log Digital ● End-of- chapter quiz
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In ve stigation
10: To in ve stigate fa ctors affectingthe ra teof transpirationinplants
Re latethestructuresofthe ro ot,stemandleafandtheirassociated tissues(dermal,groundandvascular)withtheirfunctions
Explainthetransportofwater,minerals,carbondioxideand photosyntheticproductsintheplant
● Airmo ve ment
Understandthestructuresandprocesses fo rtransportinplantsto includeosmosis,diffusion,transpiration,stomataandcarbondioxide
● Te mperature
● Sur fa cearea
● Presenceor absenceofacuticle
Understandthe ro leof ro otpressure,cohesionandtensionin planttransport
HL
HL Explainthe ro leofCO 2 asacontrolling fa ctorinplantstomata
To in ve stigate fa ctorsaffectingthe ra teoftranspirationinplants
● Lightintensity
● CO 2 concentration.
10 x40-minute classes Or (6hoursand 40minutes)
In ve stigationsAssessment
Strand3InteractionsofLife
LearningIntentions
Mindmap Po we rPoint
End-of-chapter assessment
Flashcards Knowledge Checklist
Digitalanimation
In ve stigative Log Digital ●
In ve stigation11: To evaluateprimaryor secondarydata re lating totheeffectsofhuman activityonspecies diversity
End-of- chapter quiz
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Outlinewhatismeant by thebiosphere,ecosystems,habitatsand biodiversity
Discusstheimpactofbiodiversityloss(environmental,economic,social andculturalimpacts)inlocalecosystems
Discussthe ro leconservationplaysinlimitingbiodiversityloss
Illustratehowlimiting fa ctors(abioticandbiotic)determinethe carryingcapacity fo rspeciesinIrishecosystems
Considerhownutrientsaretransferredfromonetrophicleveltothe nextandthelossofenergyateachtrophiclevel
Outlinetheuseof py ra midsofnumbersinthestudyofecosystems
Modelthemo ve mentofmatterandenergythroughecosystemsto explainandpredicttheimpactofchange
Understand fo odchainsand we bs
Outlinetheconceptofthenicheanduseexamplesasitappliesto adaptationsoforganisms
HL ModelspeciesdiversityinecosystemsusingSimpson’sDiversity Indexequation
HL Consider,usingSandJpopulationcurves,howthecarryingcapacity fo rspeciesinIrishecosystemsvarieswithlimiting fa ctors
HL Comparetheuseof py ra midsofnumbers(andtheirshapesand limitations)and py ra midsofbiomassinthestudyofecosystems
To evaluateprimaryorsecondarydata re latingtotheeffectsof humanactivityonspeciesdiversity
Mindmap Po we rPoint Flashcards Knowledge Checklist Digitalanimation
End-of-chapter assessment In ve stigative Log Digital ● End-of- chapter quiz
In ve stigation12: To useobservationand collectionmethodsto carryoutaqualitative surveyofthespeciesin anecosystem In ve stigation13: To identifyorganismsin anecosystem HLIn ve stigation 14: To in ve stigate quantitativelythe impactofvariation inabiotic fa ctorson thedistributionand abundanceofaspecies
Strand3InteractionsofLife
Useprimarydatafromachosenecosystemto:
Modelahabitatintheecosystemincludingitssize,speciesand re levantbioticandabiotic fa ctors
To explaincompetitionandsymbiosis(mutualism,commensalism, parasitism)as fe eding re lationships
HL
To includethemeasurementofabiotic fa ctors — To explainpredationasa fe eding fa ctor
To useobservationandcollectionmethodstocarryouta qualitativesurveyofthespeciesinanecosystem.
To identifyorganismsinanecosystem
To in ve stigatequantitativelytheimpactofvariationinabiotic fa ctorsonthedistributionandabundanceofaspecies
To includethe measurementof abiotic fa ctors To explain predationasa fe eding fa ctor
Mindmap Po we rPoint
End-of-chapter assessment
Flashcards Knowledge Checklist Digitalanimation
In ve stigative Log Digital ●
End-of- chapter quiz
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In ve stigation15: To in ve stigate fa ctors affectingthegr ow thof microorganisms pH Te mperature Nutrients Wa ter Externalsolute concentrations Presenceofantifungal chemicals.
Distinguishbetweenbacteriaandfungi(Rhizopus)intermsof structure,nutritionandcellularnatureIn ve stigation
Discusstheimportanceofmicroorganismsinindustries
OutlinetheconceptofamicrobiomeuExplorethe ro leofthe microbiomeinpromotinghumanhealth
HL Understandthephasesingr ow thcurvesofmicroorganisms
HL Understandhowaknowledgeofgr ow thcurvesmaybeusedto increasetheyieldofproductsinindustries
To in ve stigate fa ctorsaffectingthegr ow thofmicroorganisms.
In ve stigationsAssessment
Mindmap Po we rPoint
End-of-chapter assessment
Flashcards Knowledge Checklist
Digital
Digitalanimation
End-of- chapter quiz
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Mindmap Po we rPoint
End-of-chapter assessment
Flashcards Knowledge Checklist
Digitalanimation
In ve stigative Log Digital ●
End-of- chapter quiz
In ve stigativeLog
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In ve stigation
16: To in ve stigatepatterns usingaDNAprofile, usingprimaryor secondarydata
Strand3InteractionsofLife ChapterLOs
LearningIntentions
Modelthecarboncyclewith re fe re ncetophotosynthesis, re spiration, decomposers, fo ssilfuelsandcarbonsinks
Modelthenitrogencyclewith re fe re ncetonitrogenfixation, nitrification,decompositionanddenitrification
Explorethe ro leofmicrobiomesinnutrientcyclinginsoils
Outlinehowclimatewarminginfluencesthefunctioningofsoil microbiomes
Evaluateethicalandsustainabilityissuesassociatedwiththecyclingof nutrients
Discussthelinkbetweenatmosphericcarbondioxide,methaneand climatechange
Evaluatebiologicalstrategiesto re duceatmosphericlevelsofcarbon dioxideandmethane
Outlinetheconceptofgeneticengineeringanditsapplications
Outlinewhatismeant by DNAprofilinganditspotentialuses
Useagenomedatabasetosearch fo ralleles re latedtospecificgenetic diseases
Discusstheethicalissuesarisingfromadvancementsingenetic technologies
Modelthestepsin vo lvedingeneratingaDNAprofile(toinclude DNAextraction,polymerasechain re actionandgelelectrophoresis)
OutlinetheprincipleofDNAsequencing To in ve stigatepatternsusingaDNAprofilesusingprimaryor secondarydata
Stage1: Initial re sponsetothein ve stigationbrief
Stage2: Background re search
Stage3: Designingandplanningtheexperiment
Stage4: Conductingtheexperiment
Stage5: Dataanalysisandconclusions
Stage6: FinalisingtheBiologyinPracticeIn ve stigation re port
34 NUTRIENT CYCLING
4x40-minute classes Or (3hoursand 40minutes) 3.2.4
35 GENETIC
BiologyinPractice In ve stigation (20hours)
UNIFYINGSTRAND NATUREOFSCIENCE
CHAPTER1 SCIENTIFICKNOWLEDGE
1
(a) Scienceistheorganisedstudyofthenatural worldbasedonfactslearnedbyobservationand experiment.
(b) Biologyisthescientificstudyoflife.
2
(a) Anobservationmeansthatsomethingisnoticed.
(b) Ahypothesisisasuggestedexplanationforan observationthatallowsforapredictionthatcanbe tested.
(c) Anexperimentisascientifictest,carriedoutunder controlledconditions,asatestforahypothesis.
(d) Data(thesingularisdatum)istheinformation gatheredinanexperiment.
(e) Aconclusionisasummaryofresultsthatincludesa statementastowhetherthehypothesisisaccepted, rejectedoraltered.
(f) Atheoryisahypothesisthathasbeensupportedby manydifferentexperiments.
(g) Aprinciple(orlaw)isbasedonatheorythathas beenvalidwhenfullytestedoveralongperiodof time.
(h) Biasisanunfair,unreasonedorpersonaljudgement.
(i) Areplicateisarepeatedexperiment.
3
(a) Primarydataisinformationcollectedbythe personthemselves(e.g.inexperiments,surveys, questionnaires).
Secondarydataisinformationcollectedby somebodyelse(e.g.researchcarriedoutby someoneelse,somethingyousawonTV,readabout orheardinapodcast).
(b) Ahypothesisisasuggestedexplanationforan observationthatallowsforapredictionthatcanbe tested.
Atheoryisahypothesisthathasbeensupportedby manydifferentexperiments.
(c) Atheoryisahypothesisthathasbeensupportedby manydifferentexperiments.
reviewed,andreproducibility(i.e.theexperiments canbereplicatedbyothers).
(c) Peerreviewistheevaluationofworkbyoneormore peoplewithsimilarexpertisetothosewhoproduced thework.
(d) Peerreviewensuresthatarticlesareofahigh standard,thattheyreportonwell-designed experimentsandthattheyaresupportedbyand builduponotherworkinthesamearea.
5
(a) True (b) True (c) False (d) False (e) True (f) False (g) False
6
(a) Issuited
(b) Notsuited
(c) Notsuited
(d) Issuited
7
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Aprinciple(orlaw)isbasedonatheorythathas beenvalidwhenfullytestedoveralongperiodof time.
4
(a) Scientificstudiesareusuallyfirstreportedin scientificjournals.
(b) Importanceofpublishingresultsincludeclearand accuratecommunicationofresults,adherence tointernationalconventions,studiesarepeer
(e) Notsuited
(f) Notsuited
(g) Issuited
(h) Notsuited
(a) Possiblehypothesis:‘Theseedsatthebackofthe housedidnotgrowbecausetheydidnotreceive enoughsunlight’or‘Ifseedsareplantedinanarea thatreceivesinsufficientsunlight,thentheywillnot growproperlyoratall.’Oranyacceptableanswer.
(b) Possibleprediction:Ifseedsareplantedinalocation withmoresunlight,theywillgrowbetterthanseeds plantedinashadedarea.
(c) Possibleexperiment:Plantidenticalseedsintwo locations:onethatreceivesfullsunlightandonethat isshaded.Keepallotherconditionsthesame(soil type,water,seedtype,etc.).Observeandrecord thegrowthoftheplantsoverafewweeks.
(d) Prediction:Ifseedsareplantedinalocationwith moresunlight,theywillgrowbetterthanseeds plantedinashadedarea.
(e) Rejectorrevise yourhypothesis.Consider other possibleexplanations anddesignanewexperiment totestadifferenthypothesis.
(f) Additionalhypotheses: Thesoilatthebackofthe houselacksnutrientsneededforseedgrowth.The seedsatthebackwereeatenbypestsordisturbed byanimals.
8
(a) Hypothesis:Addingiodinetowaterspeedsupthe developmentoftadpolesintofrogs.
(b) Prediction:Ifiodineisaddedtothewater,thenmore tadpoleswilldevelopintofrogswithintwoweeks comparedtowaterwithoutiodine.
(c) Yes.Thecontainerwithiodinehadfarmorefrogs, whichsupportstheideathatiodineaccelerates development.
(d) Conclusion:Iodinemayplayaroleinspeedingupthe growthoftadpolesintofrogs.
(e) Tadpoleshavetailsandnolegs.
9
(a) Hypothesis:Thetemperatureaffectstherateof seedgermination.
(b) Prediction:Ifseedsarekeptatdifferent temperatures,thenthepercentageofseedsthat germinatewillvary,withanoptimaltemperature givingthehighestgerminationrate.
(c) Reason:Waterisessentialforseedgermination. Acceptableanswer:Itactivatesenzymes,softens theseedcoat,andallowstheembryotogrow. Withoutwater,seedswillnotgerminate.
(d) Possibleconclusion:Thereisanoptimaltemperature (30°C)atwhichthehighestpercentageofseeds germinate.Germinationislowerattemperatures thataretoolowortoohigh.
(e) Thetypeandnumberofseedsused.
10
(a) Observation:Peoplewhohadpreviously caughtcowpoxdidnotgetsmallpox.
(b) Hypothesis:Infectionwithcowpoxprotectsaperson fromgettingsmallpox.
(c) Hetookpusfromacowpoxblisteronamilkmaid. Heinjecteditintoayoungboy(JamesPhipps).After theboyrecoveredfromcowpox,Jennerinjectedhim withsmallpoxpus.Heobservedwhethertheboy developedsmallpox.
(d) Result:Theboydidnotgetsmallpox,evenafter repeatedexposure.
(e) TheresultsupportedJenner’shypothesisthat cowpoxinfectionprovidesprotectionagainst smallpox.
(f) Reason:Itwouldbeconsideredunethicaland unsafetodeliberatelyexposeachildtoapotentially deadlydiseasewithoutinformedconsent,proper safetyprotocols,orethicalapproval.Modern medicalresearchmustfollowstrictethical guidelinestoprotectparticipants.
11
(a) Biasisanunfair,unreasonedorpersonaljudgement.
(b) Examplesofbias:usingmostlymalelabrats,tissues, andcells,andexcludingfemalesduetoassumptions abouthormonalvariability.
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Theideathatscientistsmayunconsciously bring racialorculturalassumptions intotheirwork. Thearticlementionsalargestudythatfound few significantpsychologicaldifferencesbetweenmales andfemales,despitelong-heldbeliefssuggesting otherwise
(c) Reason:Researchersoftenavoidusingfemale animalsduetoconcernsthattheirhormonal cyclesmightintroducevariabilityandcomplicate results.
(d) Yes.Thearticlesupportstheideathat scientistsshouldbeunbiased,butitalsohighlights thatbiasisoftenpresent,evenunintentionally. Itarguesthatscienceisnotalwaysasobjective asitclaimstobeandcallsformorebalancedand inclusiveresearchpractices.
(e) Thearticledoesnotprovidespecificdata,sources, ordetailedmethodologiesfortheclaimsmade. Withoutaccesstotheoriginalstudiesorclear references,itwouldbedifficultforastudentto verifyorbuilduponthefindings.
12
Thisquestionisbasedonstudents’ownresearch.They shouldaddressallaspectsofthequestiononpage11of thetextbook.
CHAPTER2 INVESTIGATINGINSCIENCE
1
(a) Yes.Thisquestioncanbeinvestigatedusingthe correctchemicals,acontrolandproperprocedures.
(b) Yes.Thisquestioncanbeinvestigatedusingradish seeds,thecorrectchemicals,acontrolandproper procedures.
(c) Yes.Thisquestioncanbeinvestigatedusingseeds,a controlandproperprocedures.
(d) No.Itisnotpossibletoscientificallymeasure whetherbehaviourismoralornot.
(e) Yes.Thisquestionallowsforhypothesestobemade andvalidinvestigation(s)tobecarriedout.
(f) No.Thisisamoralquestionandcannotbetested properly.
2
(a)(i) Independentvariable:pH
(ii) Dependentvariable:therateofreaction
(b) Controlledvariablesincludetemperature,substrate concentrationorenzymeconcentration.
(c) Possiblehypothesis:changingpHwillaffecttherate ofenzymereaction.
3
Theansweris (b) Reliable.
4
Theansweris (a) Systematicerror.
5
Theansweris (d) Bothhumanerrorandthelimitationsof themeasuringdevice.
6 Theansweris (c) Neitheraccuratenorprecise.
7
(a) Acontrolisusedasacomparisonwiththe experiment.
(b) Randomselectionisamethodofchoosingasample whereeachmemberofthesamplehasanequal chanceofbeingselectedfromthelargergroup.
(c) Doubleblindtestingmeansthatneitherthetester northetestedknowwhoisreceivingtherealorthe dummy(orplacebo)treatment.
(d) Integritymeansthatalltherulesandvalues governingscientificactivitiesareobeyed.
8
(a) Repeatabilitymeansthatmeasurementsandresults areverysimilarwhenrepeatedbythesamepeople usingthesameequipment.
Reproducibilitymeansthatmeasurementsand resultsareverysimilarwhencarriedoutbydifferent peopleusingdifferentequipmentandmethods.
(b) Quantitativedatarelatestoinformationthatcanbe representednumerically.
Qualitativedatarelatestoinformationthatisnot describednumerically.
(c) Randomerrorsarisebychance(anddonotrecur). Systematicerrorsareconsistentdifferences betweentheobservedandthetruevalueof something.
(d) Correlationmeansthatthereisanassociation betweentwovariables.
Causationmeansthatachangeinonevariableisthe directresultofachangeinanothervariable.
(e) Theindependentvariableisthefactorthatis changedintheexperiment.
Thedependentvariableisthefactorthatisaffected bytheindependentvariableandthatismeasured/ observed.
(d) Constantfactorsincludethewatercontentof thesubstrate,thepHofthesubstrate,thelight intensityandthetimethattheseedsweregivento germinate.
(e) Themeanpercentagegerminationwas60.
(f) Alargesample(suchas100)increasesthereliability oftheresults.
(g) Theinvestigationwasrepeatedfourtimesto increasereliability.
(h) Safetyprecautionscouldincludebeingcarefulof brokenglassware,washinghandsbeforeandafter eachinvestigation,beingcarefulwhenheating solutions,notconsuminganyoftheseeds.
(i) Graphofresults:
9
(a) Thislabel/symbolindicatesasubstancethatis harmfulorirritant.
(b) Thislabel/symbolindicatesasubstancethatis corrosiveandwilldamagelivingtissue.
10
(a) Correlation:thereisacorrelationbetweenthe numberoffireenginescalledtoafireandthe damagedonebythefire.
(b) Causation:thesizeofthefirecausesthedamage andcausesthenumberoffireenginesthatare calledtothefire.
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11
(a) Asuitablehypothesis:temperatureaffectsthe percentagegerminationofgrassseeds.
(b) Theindependentvariable:Thetemperature
(c) Thedependentvariable:thepercentage germinationofthegrassseeds
12
(a) Suggestedhypothesis:atwo-monthexercise programmewouldaffecttherestingheartrateof people.
(b) Suggestedprediction:exercisingfortwomonths wouldlowertheheartrateofpeople.
(c) Thecontrolwastherestingheartratesofthepeople beforetheexerciseprogrammebegan.
(d) Theyshouldhavebeenselectedatrandom(i.e.by givingeachpersonanumberanddrawingnumbers fromadrum).
(e) Thelargerthesamplesize,themorereliablethe results.
(f) Toseeifthehypothesisappliedtobothmalesand females.
(g) Inbeatsperminute
(h) Range:46to66beatsperminute
(i) Themeanheartrateforfemalesfellfrom76to66 beatsperminute.
(j) Theratefellfrom66to56.Thepercentagechange: 15.15% 66–56 × 66 100 1 =15.15%
(k) Possibleconclusion:theexerciseprogramme loweredtheaverageheartrateofbothmales andfemales.
(l) Thehypothesiswassupported(i.e.exerciseeffected therestingheartratesofpeople).
13
(a) pH6isthemostsuitablevalueforthegermination ofgrass.
(b) Ahypothesisisasuggestedexplanationforan observationthatallowsforapredictionthatcanbe tested.
(c) Mainvariable:thepH
(d) Thefunctionofacontrolistoactasacomparison withtheactualinvestigation.
(e) Theresultsmightbepublishedinascientificjournal.
(f) Possiblelimitationsincludetheextentofour knowledge,thebasisofinvestigation,interpreting
14
theresults,changesinthenaturalworldand accidentaldiscoveries.
(a) Purposeofanexperiment:totestahypothesis.
(b) Acontrolisusedasacomparison.
(c) Thegroupgiventheglassesofwaterwerethe controlgroup.
(d) Themethodofselectingtheparticipantswasflawed becauseonlyfriendswereselected,thesamplesize wassmallandtherefore,notveryreliable.Itisalso notclearifthegroupswereselectedatrandom.
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(e) Includepeoplewhowerenotfriendsandselecta largersampleforeachgroup.
CHAPTER3 SCIENCEINSOCIETY
1
(a) Relevancemeansthattheinformationisrelatedto thetopicyouareconsidering.
(b) Accuracyreferstohowcloseameasurementisto thetrueoracceptedvalue.
(c) Biasmeansunfairlyselectingorencouragingone outcomeoveranother.
2
(a) True (b) False (c) False (d) False (e) True (f) False (g) True
3
(a) Examplesofapositiveeffect:newformsoftransport (jetenginesandelectricengines)oranyacceptable answer
(b) Examplesofapositiveeffect:environmentaland healthhazardsfromnewlyformedchemicalsin industry,theatomicbomboranyacceptableanswer.
4
(a) Sustainabilitymeansmeetingourownneedswithout compromisingtheabilityoffuturegenerationsto meettheirneeds.
(b) Thisquestionasksforstudenttodotheirown research.Someusefulinformation:Indiumisarare, silvery-whitemetalthatplaysacrucialroleinmodern technology,especiallyinLCDscreens,touchscreens, solarpanels,andsemiconductors.However,itis consideredunsustainableforseveralkeyreasons: Indiumisnotmineddirectly;itisabyproductofzinc mining,whichmeansitsavailabilityistiedtothe productionofanothermetal.
Onlyabout20%ofindiumpresentinzincoresis currentlyrecovered.
Alargeportionoftheworld’sindiumsupplycomes fromafewcountries,withChinacontrolling43–66%ofglobalreserves.
Thiscreatessupplychainvulnerabilitiesand potentialgeopoliticalrisks.
Demandisrisingduetothegrowthofconsumer electronicsandsolarenergy.
Recyclingindiumfromuseddevicesiscostprohibitivebecauseitexistsinverysmallamountsin eachproduct.
Extractingmoreindiumisnoteconomically viableunlesspricesrisesignificantly.
Theenvironmentalimpactofminingandrefining processesaddstoitsunsustainability.
5
(a) Ethicsmeanswhetheranactionisrightorwrong.
(b) No.Itwasnotethical.
(c) Honesty,dutyofcare,responsibility.
6
Thisquestionasksforstudenttodotheirownresearch. SuggestionsincludeAlbertEinstein,RosalindFranklin, NikolaTesla,RachelCarson,MarieCurie,LouisPasteur andStephenHawking.
7
(a) Yes,thearticledoessuggestGMcropsaresafe. DavidZilberman,arespectedagriculturaleconomist, isquotedsayingthatthehealthrisksofGMcrops remaintheoretical,whilethebenefitsarewelldocumented.Thearticlenotesthatnosignificant riskshavebeenfounddespiteextensiveefforts toidentifythem:“Onecanonlyfailtoturnup significantriskaftertryinghardtofindit–asisthe casewithGMcrops.”
(b) Yes,ScientificAmericanisgenerallyconsidereda reliablesource.Reasons:reputationandlongevity, expertcontributors,credibleauthorandquoted expert,evidence-basedclaims(datafromtheUnited NationsFoodandAgriculturalOrganisationare referenced).
(c) Yes,thisarticleshowsbias.Somereasonsinclude one-sidedargumentation,dismissivetonetoward critics,andlackofbalancedviewpoints.
(d) GMcropsmighthaveaneconomicbenefitasifGM cropsweremorewidelyadoptedaroundtheworld, theprice[offood]wouldgolower,andfewerpeople woulddieofhunger;orGMcropscouldproduce higheryields.
(e) BenefitsofgrowingGMcropsinclude:increased farmersafetybyallowingthemtouselesspesticide. Raisedtheoutputofcorn,cottonandsoyby20to 30percent,allowingsomepeopletosurvivewho wouldnothavewithoutit.GMcropscangrowindry andsaltyland,withstandhighandlowtemperatures, andtolerateinsects,diseaseandherbicides.
(f) ReasonswhyGMcropsshouldbesafeincludeno provenhealthrisksandextensivescientifictestingor anyacceptableanswer
(g) Possiblereasons:resentmentofAmerican agribusiness;precaution,i.e.ifsomethingisnot provencompletelysafe,itshouldberestricted; environmentalconcernsoranyacceptableanswer.
(h) Possiblebenefits:increasedfoodproductionand foodsecurity;reducedneedforchemicalpesticides oranyacceptableanswer.
(i) Theauthorviewsthisasunsustainableasthe UnitedNationsFoodandAgricultureOrganization estimatesthattheworldwillhavetogrow70 percentmorefoodby2050justtokeepupwith populationgrowth.Climatechangewillmakemuch oftheworld’sarablelandmoredifficulttofarm.
(j) Onereasontheauthor’sopinionfrom2011maynot befullyvalidtodayisthatscientificunderstanding, technology,andglobalpoliciesaroundGMcrops haveevolvedsignificantlysincethen.
8
(a) Yes,ScienceDaily.comisgenerallyconsidereda reliablesource.Possiblereasons:sourceofcontent: Itsummarisesstudiespublishedinpeer-reviewed journalsorreleasedbyreputableinstitutions(like universities).Itreferencesthestudy’sfirstauthor. Itcitestheoriginalsource,suchastheuniversity, allowingreaderstoverifytheinformation.
(b) Biasdependedonhowsmokingwasportrayed. Thebrainsofthesmokersinthestudyweremore arousedbyimagesthatshowedsmokinginapositive lightthanbyimagesthatencouragedthemtostop.
(c) 80%arenotsmokers.
(d) Yes,itexplainsthisbehaviourusingfindingsfrom neuroscienceandpsychology.Reasonsinclude: Biasedbrainresponses:Thestudyfound thatsmokers’brainsaremorearousedbypositive imagesofsmokingthanbynegativeones. Alteredemotionalreactions:Smokers showedreducedemotionalimpactwhenexposedto negativeimagesaboutsmoking.
Motivationcentresinthebrain:Thestudyobserved thatbrainregionslinkedtomotivationweremore activewhensmokerssawpositivesmokingimagery. Thisimpliesthatpositivereinforcementfromsmoking mayoverpowernegativehealthinformation.
(e) 5–30%remainasnon-smokers.
(f) Societaleffectsincludesmokershavea3to9times greaterriskofdevelopingcancer,lungdisease orheartproblems.Cigarettesarealsoassociated withfertilityproblems,prematureaging,alackof hygieneandsocialstigmatisation,andtheyhavea negativeimpactonthehealthofotherpeoplewho areexposedtosecond-handsmoke.Overall,1outof 2smokerswilldiefromtobaccouse.
(g) Thearticlesupportstheideathatsmokinginfluences howpeoplethinkandfeelaboutsmokingitself, makingthemmorelikelytoignorerisksandfocuson perceivedbenefits,apsychologicaleffectthatcan makequittingmoredifficult.
(h) InFavour:Adultshavetherighttomakeinformed choicesabouttheirownbodiesandlifestyles, includingthedecisiontosmoke.Aslongastheyare awareoftherisksanddonotharmothers,restricting theirchoicecouldbeseenasaninfringementon personalliberty.
Against:Overall,1outof2smokerswilldiefrom tobaccouse.Ethically,thishighstatisticshouldbe addressed.
CHAPTER4 BIOLOGICALREASONING
1
(a) Aphenomenonissomethingthatisunusual,difficult tounderstandandexplainandcanbeobservedand studied.
(b) Examplesofbiologicalphenomenaincludedamaged skinrepairsitself,butdamagedbraincellsdonot repair,sometimestheseaglowsinthedarkandthat plantsbendtowardslight.
2
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(a) Abiologicalmodelisasimplifiedrepresentationofa complexlivingsystemorphenomenon.
(b) Biologicalmodelschangewhennewinformationor databecomesavailable.
(c) Benefitsofbiologicalmodelsincludethatthey describecomplexlivingsystemsorphenomena,they allowforpredictionstobemade,andtheyhelpto solveproblems.
3
(a) Asystemisagroupofstructures(oftenorgans) thatworktogethertocarryoutaparticulartaskor function.
(b)(i) Proteinformationinvolvestheinteractionof moleculessuchasDNA,RNAandaminoacids.
(ii) Photosynthesisortheplantvascularor transportsystemareplantsystems.
(iii) Systemsinthehumanbodyincludethe digestive,nervousandcirculatorysystems.
(c) Digestivesystem:structuresororgansincludethe
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mouth,oesophagus,stomach,smallintestine,large intestine,appendix,rectumandanus.
Nervoussystem:structuresororgansincludethe brain,spinalcord,nerves,neurons,synapses.
Circulatorysystem:structuresororgansincludethe heart,bloodvessels(arteries,veins,andcapillaries), andblood.
(a) Interdependencemeansthatlivingthingsinteract andrelyoneachotherandtheirsurroundingsin ordertosurvive.
(b) Examplesofinterdependence:grassesdependon thesoil(forsupport,waterandminerals),flowers dependoninsects(forpollination)andfoxesdepend onrabbits(forfood).
(c)(i) Animalsdependonplantsforfood.
(ii) Plantsdependonanimalsforpollinationor forseeddispersal.
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(a) Theunityoflifemeansthatlivingthingssharemany features.
(b) Examplesoftheunityoflife:alllifehasDNAand RNA,manyanimalshavesimilarbonestructures,and thegeneticcodeissharedbyalllivingthings.
(c) ThefirstlivingthingsusedATPanditsusehasbeen passeddownfromgenerationtogenerationby genes.
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(a) BiodiversitymeansthevarietyoflifeonEarth.
(b) Theunityoflifeandbiodiversityareaccountedfor byevolution.
7
(a) False (b) False (c) True (d) True (e) True (f) True
8
(a) Hollowbonesarelight.
(b) Flippersareusefulforswimming.
(c) Lightseedsandaparachuteallowthewindtospread ordispersetheseedsfarther.
(d) Enamelprotectstheteeth.
(e) Plantsgrowtowardslighttoallowformore photosynthesis.
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(a) A=Cell B=Chromosome C=Gene D=DNA
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(b) DNA
(c) Twofunctionsofgenes:inheritance(theypass traitsfromonegenerationtothenext),codingfor proteins(theygiveinstructionsforsynthesizing proteinsbytranscriptionandtranslation).
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(a) Matterisanythingthattakesupspaceandhasmass. Energyistheabilitytodowork(ortomakethings move).
(b)(i) Calciumisreturnedtothesoilwhenlivingthings dieandaredecomposed(orinthewaste productsexcretedbylivingthings).
(ii) Decomposersbreakdowndeadlivingthings(to releasemineralsbackintothesoil).
(iii) Decomposersincludefungiandbacteria.
(iv) Calciumissaidtorecycle.
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(a) Themainsourceofenergyissunlight.
(b) Energyfromthesunpassesintotreesandtheninto squirrelsandisthenreleasedasheat.
(c) Energydoesnotrecycle.Energyflowsfromthesun, intolivingthingsandthenintotheenvironmentas heat.
(d) Asheat
(e) Energyissaidtoflow.
STRAND1 ORGANISATIONOFLIFE
CHAPTER5 THECHARACTERISTICSOFLIFE
1
(a) Eleven
(b) Thecharacteristicsoflivingthings:organisation, response,respiration,nutrition,excretion, reproduction,growth,metabolism,homeostasis, heredityandacellularbasis.
2
(a) Fivelevelsshownbymulticellularorganisms:cells, tissues,organs,organsystems,andorganism.
(b) Levelsnotshownbymulticellularorganisms:tissues ororgansororgansystems
(c) Cellorganellesincludemitochondria,chloroplast, nucleus,ribosomes,endoplasmicreticulum,orany acceptableanswer.
(d) Organisms:humans,frogs,butterflyorany acceptableanswer.
3
(a) Animalsreacttotemperature,pressure,pain,sound orlight.
(b) Plantsreacttolight,gravity,temperature,chemicals andwater.
(c) Organsystems:nervoussystemandmuscular system.
4
(a) Theyneedtorespiretoreleaseenergyfromfood.
(b) Anaerobic:respirationiscarriedoutintheabsence ofoxygen.
Aerobic:respirationiscarriedoutinthepresenceof oxygen.
(c) Glucoseiscommonlybrokendowninrespiration.
5
Theansweris(d)Nutrition.
6
(a) Excretionistheremovalofthewasteproductsof chemicalreactionsfromthebody.
(b) Itisimportantinordertoremovetoxicorpoisonous waste.
(c) Animalshaveahighermetabolicrateandtherefore, producemorewasteproduct.
(d) Substancesexcretedbyanimalsincludecarbon dioxide,urinecontainingwater,saltandurea,sweat containingsaltandwater.
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Feature
Typeof reproduction
(a) ProducesidenticaloffspringAsexual
(b) Involvesgametes Sexual
(c) Involvestwoparents Sexual
(d) Takesplaceinbacteria Asexual
(e) Producesoffspringdissimilarto theirparents Sexual
8
(a) Bacteriagrowbysimplecelldivisioncalledbinary fissionwhilehumanzygotegrowsthroughcomplex celldivision(mitosis)anddifferentiation.
(b) Differentiation:thewayinwhichcellschangeis calleddifferentiation(e.g.growthallowsaseedto changeintoayoungplantwithrootsandshoots).
(c) Growthisimportantasitallowsorganismstochange overtime.
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(a) (iii)Rusting
(b) (ii)Apersonrunning
(c) Inwinter,theirmetabolicratewouldslowdown greatly.Insummer,theywouldhaveahigher metabolicrateduetobeingmuchmoreactive.
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(a) Factorsthatmustbecontrolledtomaintain homeostasisincludetemperature,pH,andthe concentrationofsubstancessuchasoxygen,carbon dioxide,toxinsandglucose.
(b) Thisisanexampleoffailureofhomeostasisbecause theliverplaysanimportantroleinmaintainingthe internalbalanceofthebodybydetoxifyingharmful substances(e.g.alcohol)andbreakingdownwaste products(e.g.urea).
(c) Homeostasisandmetabolism:homeostasisensures thattheconditionsinanorganismarecorrectfor metabolismtooccurefficiently.(e.g.homeostasis ensuresbodytemperatureiscorrect,soenzyme activityisatitsoptimumrateallowingmetabolic reactionstooccur).
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(e) Organsofexcretioninanimals:skinorlungsor kidneys.
(a) Hereditaryfeaturesindogs:earshape,eyecolour, heightoranyacceptableanswer
(b) Hereditaryfeaturesinroses:colouroftheirpetals, theshapeoftheirleavesoranyacceptableanswer
(c) Chromosomes
(d) Proteinisproducedbygenes.
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(a) Reasonswhyrocksarenotliving:theydonotgrow, reproduce,carryoutmetabolism,respondtostimuli oranyacceptableanswer
(b) Aflamegrows.
(c) Reasonswhyaflameisnon-livinginclude:nocells, nometabolism,noreproductionoranyacceptable answer
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(a) PersonA
(b) Similarities:bothresultshaveanincreaseinblood glucoseconcentrationatthestartandbothshow
adecreaseinbloodglucoseconcentrationaftera certainperiodoftime.
(c) PersonA
(d) Ittook60minuteslongerforpersonBbloodglucose concentrationtofall.
(e) PersonB
(f) 115-120minutes
(g) PersonBcouldhavediabetes.Theirbloodglucose levelremainedhighforalongperiodoftimeafter consumingglucose.Thisisanindicationthatthey havediabetesastheyhaven’tproducedenough insulintocontrolbloodglucoselevels.
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(h) Glucoseisafoodforrespirationsoenergycanbe released.
CHAPTER6 VIRUSES,CLASSIFICATIONANDTHE DOMAINSOFLIFE
1
(a) A=Protein
(b) B=Nucleicacid(DNAorRNA)
(c) Thevirusisround.
(d) Thefunctionofvirusesistoreplicate(byenteringa hostandcausingthehosttoproducenewviruses).
2
(a) Virusesaredifficulttoclassifyaslivingornon-living astheyhavefeaturesofboth.
Thenon-livingfeaturesofvirusesinclude:theyare notcellular,cannotreproducebythemselves,have noorganelles,nometabolismandnorespiration. ThelivingfeaturesincludetheyhaveDNAorRNA andaproteincoat,theycanreplicateinalivehost cellandshowheredity.
(b) Insupportofvirusesasliving:theyhaveDNAorRNA, haveaproteincoat;canreplicateinalivehostcell andshowheredity.
(c) Virusesareconsiderednon-livingastheyarenot cellular;cannotreproducebythemselves,containno organelles,thereisnometabolismornorespiration.
3
(a) Economicbenefits:bacteriophagescancontrol infectionsandareusedinthebiologicalcontrolof pests
Medicalbenefits:usedasvectorsingenetherapy andusedtomakevaccines.
(b) Economicproblemscausedbyviruses:causehuman diseasesandcauseplantdiseases.
(c) Medicalproblemscausedbyviruses:causehuman diseases,plantvirusesdiseases,canleadto malnutritionandill-health.
(d) Humanscontractvirusesbytouchandbyinhalation. Precautionstoavoidviruses:regularhandwashing, vaccinations,stayhomewhensickandavoidcontact withsickpeople.
4
(a) Seeanswer2(a).
(b) Bacteriophagesarevirusesthatinfectbacteria.
(c) Virusesaremuchsmallerthanbacteria.
5
(a) Humanvirusdiseasesincludethecommoncold, influenza,polio,rabies,mumps,measlesorany acceptableanswer.
(b) Virusdiseasesofanimalsincludefootandmouth disease,rabies,swinefever,birdfluorany acceptableanswer.
(c) Virusdiseasesofplantsincludepotatomosaic disease,tomatomosaicdiseaseoranyacceptable answer.
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(a) X=Protein
(b) Y=DNAorRNA
(c) Potato(ortomato)mosaicvirus
(d) Virusesaredistinguishedbytheirshape.
(e) Virusesmaybeusedtocontrolbacterialinfections (bacteriophages)orusedinbiologicalcontrol.
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(a) Topreventmicrocephaly.
(b) Precautionsincludeprotectionagainstmosquito bites(e.g.usenetsorrepellentsorclothing),delay conceptionafterexposuretomosquitos,use condomsforsex,don’thavesexoranyacceptable answer.
(c) Zikavirusmayenterthroughtheopeningintheskin madebyamosquitobiteoracrosstheplacentafrom aninfectedmothertoherbaby.
(d) Zikavirushasaproteincoatwhichsurroundsan aminoacid(whichisRNA).
(e) Beneficialvirusesincludethoseusedforgene therapy,bacteriophages,andthoseusedin biologicalcontrol.
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(a) Hypothesis:‘Ifratsweretreatedwithbacteriophage, thentheywouldhavelessbacteria’.
(b) Theratshadthesamecolour,genderandageso thattherewouldonlybeoneindependentvariable (bacteriophageornobacteriophage).
(c) ThecontrolgroupwasgroupA,theratsthatwere notexposedtobacteriophage.
(d) Bacteriophagesarevirusesthatinfectbacteria.
(e) GroupB,theratstreatedwithbacteriophage,had thefewestbacteria.
(f) Theconclusionisthatthebacteriophagereduced thenumberofbacteriainthelungsofmale,twoyearold,whiterats.
(g) Theycouldrepeattheinvestigationusingfemale rats,differentagedrats,differentcolouredratsand largernumbersofrats.
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(a) Classificationisthearrangementoforganismsinto groupsbasedonsimilaritiesanddifferences.
(b) Benefitsofclassificationincludeitsimplifies thestudyoforganisms,ithelpstounderstand theevolutionoforganisms,itshowstheinterrelationshipsoforganisms,itinformsusofthe varietyoflifeonEarthanditallowsmorereliable communication.
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(a) Examplesoftaxa:kingdom,phylum,class,order, family,genusandspecies.
(b) Thetwotaxausedinthebinomialsystemaregenus andspecies.
(c) ThebinomialsystemwasfirstproposedbyLinnaeus.
(d) HorsesareinthegenusEquus.
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(a) Aspeciesisagroupoforganismscapableof naturallyinterbreedingtoproducefertileoffspring.
(b) Horsesanddonkeysareclassifiedasdifferent speciesbecausetheiroffspringarenotfertile.
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(a) Prokaryoticorganismsdonothaveanucleus ormembrane-enclosedorganelles.Eukaryotic organismshaveanucleusandmembrane-enclosed organelles.
(b)(i) Theprokaryotickingdomsare:bacteriaand archaea.
(ii) Theeukaryotickingdomsareprotists,plants, fungiandanimals.
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(a) True (b) False (c) False (d) False (e) False
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(a) Nucleus:prokaryoticcellsdonothaveanucleus. Eukaryoticcellshaveanucleus.
(b) Cellorganelles:prokaryoticcellsdonothave organelles.Eukaryoticcellshaveorganelles.
(c) Size:prokaryoticcellsaresmaller.Eukaryoticcells arelarger.
Examples:prokaryoticcellsincludebacteriaand archaea.Eukaryoticcellsincludeprotists,plants, fungiandanimals.
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(a) Thebinomialsystemmeansthatorganismsare namedusingtwonames–thegenusandthe speciesname.
(b) CatsareinthegenusFelis.
(c) Catsareinthedomaincalledeukaryotes.
(d) Catsareintheanimalkingdom.
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(a) Thethreedomainsare:bacteria,archaeaand eukaryotes.
(b) Thesixkingdomsare:bacteria,archaea,protists, plants,fungiandanimals.
(c) Theprokaryotickingdomsarebacteriaandarchaea. Theeukaryotickingdomsareprotists,plants,fungi andanimals.
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(a) Phylogenyistheclassificationoforganismsbasedon theirevolutionaryhistory.
(b)(i) Thenewbacteriumismostcloselyrelatedto bacterialcandidateB.
(ii) Thereasonisthatthenewbacteriumhasmore basesincommonwithcandidateB(6)thanit haswithcandidateA(2).
19
(a) Thechimpanzeeismostcloselyrelatedtohumans.
(b) Apartfromhumans,themouseandthehorseare mostcloselyrelated.
13
(a) ThethreedomainsareassociatedwithCarlWoese.
(b) Thethreedomainsarebacteria,archaeaand eukaryotes.
(c) Themostrecentlydiscovereddomainoflifeisthe archaea.
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(c) Theflyismorecloselyrelatedtothefrog.There areonlythreeaminodifferencesbetweenthem (comparedto22aminoaciddifferencesbetween theflyandyeast).
(d) Apartfromhumansandchimpanzees,theleast closelyrelatedorganismsarethemouseandthe yeast(theyhavethegreatestnumberofaminoacid differences,i.e.36).
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(a) Thecommonancestorofcrocodilesanddinosaursis pointornodeC.
(b) ThecommonancestoroffrogsandbirdsispointB.
(c) NodeAproducedthemostdescendants.
(d) Themostcloselyrelatedanimalsare(iv)Birdand dinosaur.
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(a) Themostcloselyrelatedspeciesarespecies2and3.
(b) NodeA
(c) Species1ismorecloselyrelatedtospecies3thanit istospecies5.
(d) Point(ornode)B
(e) Species2and3evolvedmostrecently.
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AnimalA=Tribolium
AnimalB=Planarian
AnimalC=Nematode
23
A=Lessercelandine
B=Daffodil
C=Primrose
D=Bluebell
E=Nettle
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CHAPTER7 THEUNITOFLIFE:THECELL
1
(a) Thecell
(b) Unicellularorganisms:single-celledorganisms tendtohaveashortlifespan.Unicellularorganisms aresmall.Thecellmustcarryoutallthereactions neededtomaintainlife.
Multicellularorganisms:multicellularorganismscan becomeverylarge.Multicellularorganismscanhave alongerlife,havetissuesandhaveorgansthatare differentiatedorspecialisedtocarryoutdifferent functions.
(c) Celltheorystatesthat: Alllivingthingsarecomposedofoneormorecells. Thecellisthemostbasicunitoflife.
Allcellsariseonlyfrompre-existingcells(thisis calledcellcontinuity).
(d) Cellcontinuitymeansthatalllivingcellscomefrom pre-existingcells.
2
(a) Unicellularorganisms:amoeba,bacteriaorany acceptableanswer.
(b) Multicellularplants:rosebush,grassorany acceptableanswer.
(c) Multicellularanimal:human,dogoranyacceptable answer.
(d) Unicellularorganismsdonothavetissuesasthey areonlymadeupofonecell.Atissueismanycells workingtogethertocarryoutsamefunction.
3
(a) Atissueisagroupofsimilarcellsthataremodified (oradapted)tocarryoutthesamefunction(s).
Anorganisastructurecomposedofagroupof tissuesthatworktogethertocarryoutoneormore functions.
(b) Correctorder:transmission,electronmicroscope, scanningelectronmicroscope,lightmicroscope.
4
(a) A=Eyepiece
B=Coarsefocus
C=Objectivelens
D=Stage
E=Stageheightadjuster
F=Mirrororlightsource
(b) Functionofamicroscopeistoproduceaclearly visible,magnifiedimageofsmallobjects.
(c) ThefunctionforpartlabelledB:forroughor approximatefocusing.
ThefunctionforpartlabelledF:tosupplylightto slide.
(d) TotalmagnificationisX400.
(e) Actualdiameterofthecellis-0.0015mm
5
(a) Thin:solightcanpassthroughit.
(b) Stained:tomakeitmorevisible.
(c) Coverslip:toprotectlensandstopsampleonslide fromdryingout.
(d) Coverslipangle:topreventairbubbles.
(e) Power:lowpowergivesawiderfieldofviewmaking iteasiertolocatespecimen.Highpowerthen magnifiestheimagetoseegreaterdetail.
(c)
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(a) Cheekcells.
(b) Theinsideofthemouthwasscrapedwithacotton woolbudorawoodenspatula.Thecellsweregently scrapedontoamicroscopeslideandspreadout.
(c) Stain:methyleneblue.
(d) Stainappliedbyusingadropper.
(e) Nucleus:darkblue;cytoplasmlightblue.
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(a) A=Mitochondria
B=Ribosome
C=Chloroplast
(b) RespirationtakesplaceinA,mitochondria.
(c) Chloroplastandmitochondrialbothhavetheirown DNAandbothhaveadoublemembrane.
(d) Somecellshavealargernumberofmitochondria astheyrequiremoreenergy.Exampleofsuchcells: muscles.
(e) Chloroplast(C)
Reason:theyaregreensotheycanabsorblight.
(f) StructureB,ribosomesareusedtoproduceprotein.
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(a) A=Protein
B=Lipid
C=Phospholipid
(b) PorethisanswerseemswrongQuestioniswhatcan passinandoutofapore?
(c) Functionsofmembranes:Theyretainthecellor organellecontents.Theyrecognisemoleculesthat touchthem(theyactasreceptors).Theycontrol whatentersandleavesthecellororganelle.
(d) Mitochondriaorchloroplast
(e) Vacuole,endoplasmicreticulum,orGolgiapparatus
9
(a) Onioncells
(b) Solightcanpassthroughitfromthemicroscope.
(c) Iodine
(d) Red-yellow
(e) Thestainednucleuswasorange.Thestained cytoplasmwasyellow.
(f) Theywerenotgreenastheydonotcontain chloroplast.
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(a) Musclecellsrequirelargeramountsofenergy.
(b) Whitefatcellsrequirelessenergy.
(c) Possiblehypothesis:brownfatcellshavemore mitochondriaandtherefore,increasetheamountof energyreleased,reducingtheneedforstoringfat.
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(a) Inchromosomes
(b) Cellorganelles:nucleus,mitochondria,chloroplast
(c) noanswergivenSuggestedanswer:Vacuole
(d) Thecellmembraneinplantcellsislocated immediatelyinsidethecellwall.
(e) Membrane-enclosedorganellesareassociated withvacuole,ribosome,Golgiapparatus,and/or endoplasmicreticulum.
(f) eukaryotic
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(a) DNAandprotein
(b) Inthenucleus.
(c) DNA
(d) Chromosomesaredifficulttoseeastheyareinthe formofchromatin.
(e) Duringcelldivision(e.g.mitosis).
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(a) Cellwall,chloroplastsorvacuole
(b) Commonstructures:mitochondria,cellmembrane, ribosomes,Golgiapparatus,endoplasmicreticulum.
(c) Prokaryoticcells
(d) Inthevacuole.
(e) Commonstructuralfeatures:DNAanddoubleouter membrane.
(f) Inmitochondriaandchloroplast.
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(a) Plantcell
(b) Reasons:ithasacellwall,chloroplastandlarge vacuole.
(c) A=Vacuole
B=Chloroplast
C=Nucleus
(d) Cellsap
(e) Cellulose
(f) Eukaryotic
Reason:ithasanucleusandhasmembranebound organelles.
(g) Mitochondria,Golgiapparatusorendoplasmic reticulum
15
(a) Mitochondria
(b) Function:siteofrespiration
(c) Differentcellsneeddifferentamountsofenergy.
(d) Mitochondriaaretoosmalltoseeusinganoptical microscope.
(e) InaloopofDNA.
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(d) Asanimalswithmostlywhitefatcellshaveless mitochondria,theycarryoutlessrespiration, thereforeproducinglessheat.
16 HL
(a) Endoplasmicreticulumisasystemofmembrane tubulesincells.TheERiscontinuouswiththeouter membraneofthenuclearmembrane.
(b) SmoothERformsmanyproteins,storescalciumin livercellsandbreaksdownpoisonsinlivercells. RoughERproducesandtransportsproteinsandnew membranes.
(c) SmoothERandroughER
(d) SmoothERformsmanyproteins,storescalcium inlivercellsandbreaksdownpoisonsinlivercells. RoughERproducesandtransportsproteins.
17 HL
(a) Golgiapparatuslookslikeanumberofflattened membranesacks.
(b) Function:tomanufacture,store,sortandtransport molecules.
(c) Foundinbothplantandanimalcells.
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CHAPTER8 BIOMOLECULES:THECHEMICALS
OFLIFE
1
(a) Biomoleculesarechemicalsthataremadebyliving things.
(b) Examplesofbiomoleculesincludecarbohydrates, lipids,proteins,nucleicacids,vitamins,ADPandATP.
(c) Themainfourelementsinbiomoleculesarecarbon, hydrogen,oxygenandnitrogen.
(d) Elementsindissolvedsaltsincludesodium,chlorine, potassium,magnesiumandcalcium.
(e) Traceelementsareelementsthatareonlyrequired byorganismsintinyamounts.
(f) Traceelementsincludeiron,copper,zincandiodine.
2
(a) ThegeneralformulaforcarbohydratesisCx(H2O)y.
(b) Theelementsinequalnumbersarecarbonand oxygen.
(c) Theratioofcarbontohydrogenincarbohydratesis 1:2.
(d)(i) Asugarunitisaringofcarbonatoms.
(ii) Thethreetypesofcarbohydratesare: monosaccharides,disaccharidesand polysaccharides.
(iii) Glucose(orfructoseorribose)isa monosaccharide.
Sucrose(ormaltoseorlactose)isadisaccharide. Starch(orglycogenorcellulose)isa polysaccharide.
(e) Thestatementisnottrue.Mostpolysaccharidesare insoluble(oronlyslightlysoluble)inwater.
3
(a) Sourcesofcarbohydrates:bread,potatoes,rice, pasta,sugarsfruitsoranyacceptableanswer.
(b) Sourcesoflipids:butter,margarine,oils,cream, cheeseoranyacceptableanswer.
(c) Sourcesofproteins:meat,fish,eggs,nuts,peas, beansoranyacceptableanswer.
4
(a) Carbohydratesandlipidsarebothcomposedof carbon,hydrogenandoxygen.
(b) Elementsinproteinbutnotinlipidsincludenitrogen andphosphorus.
(c) Phosphateisinphospholipidsbutnotinlipids.
(d) Phospholipidsarefoundinmembranesinacell.
(e) Carbohydratesaremostlysolubleinwaterwhile lipidsareinsolubleinwater(orcarbohydrateshave carbon,hydrogenandoxygenintheratioof1:2:1 whilelipidshavethesameelementsbutnotinthat ratio).
5
(a) Fatsandoilsbothcontaincarbon,hydrogenand oxygen.Bothareinsolubleinwater.
(b) Fatsaresolidatroomtemperature.Lipidsareliquid atroomtemperature.
(c) Atriglycerideisthebasicunitoflipidsandis composedofaglycerolattachedtothreefattyacids.
(d) Lipidsdifferfromeachotherbyhavingdifferent fattyacids.
(e) Alipidhasglycerolattachedtothreefattyacids.Ina phospholipidoneofthefattyacidsisreplacedwitha phosphate.
6
(a) X=Amino(oramine)group
(b) ThechemicalcompositionofXisNH2.
(c) Thebondbetweenaminoacidsisapeptidebond.
(d) Aminoacid,peptide,polypeptide,protein
(e) Thereare20aminoacidsusedbyorganisms
(f) Goodsourcesofproteinincludemeat,fish,eggs, nuts,peas,beansoranyacceptableanswer.
7
(a) Themetabolicroleisthewayinwhichbiomolecules actinchemicalreactions.
(b) Examplesofmetabolismincludedigestion, respiration,photosynthesis.
(c)(i) Ametabolicroleofglucoseisrespiration(or usedinmembranesormakehormones).
(ii) Ametabolicroleoflipidsisrespiration.
(iii) Ametabolicroleofproteinsistoactasenzymes, hormones,antibodies,transportingmoleculesin andoutofcells.
8
(a) Water-solublevitaminsincludevitaminC.
(b) DietarysourcesofvitaminCinclude:vegetablesand freshfruit.
DietarysourcesofvitaminBinclude:[tobeadded].
(c) ThefunctionsofvitaminCincludeformingcollagen, growthandmaintenanceofbonesandteeth, healingwoundsandhelpingtheimmunesystemto function.
(d) Fat-solublevitaminsincludevitaminD.
(e) DietarysourcesofvitaminDincludeoilyfish,egg yolk,fortifiedfoodsthathavevitaminDadded.
(f) AfunctionofvitaminDistoabsorbcalciumfromour intestines.
9
(a) Thisstatementisnottrue.Failuretoeatother nutrientscanmakeusillalso.However,alackof vitaminCcausesscurvyandalackofvitaminD causesricketsandosteomalacia.
(b) Wemustconsumewater-solublevitaminsmore frequentlybecausetheyareexcretedfromthe bodyinurine,andtheyarenotstoredinthebody. Fat-solublevitaminsarestored(infat)andarenot excretedasmuch.
(c) VitaminCissolubleinwaterandpassesoutof thepotatoeswhentheyareboiled.Alsohigh temperaturesdestroyvitaminC.
10
(a) Plantsneedmineralssuchasmagnesiumand calcium.
(b) Plantsabsorbmineralsfromthesoil.
(c) Magnesiumisessentialtomakechlorophyll. Calciumisessentialtohelpbindcellwallstogether
(d) Humansneedironandcalcium(alongwith phosphorus,sulphur,potassium,sodium,chlorine, fluorineandiodine).
(e) Sourcesofironinclude:meat,eggs,wholegrains, greenvegetablesoranyacceptableanswer. Sourcesofcalciuminclude:dairyproducts(suchas milk,butter,cheese,yogurt),darkgreenvegetables oranyacceptableanswer.
(f) Theroleofironistoformhaemoglobin. Theroleofcalciumistoformbonesandteeth.
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(a) Possibleanswers:Waterisneededtoform cytoplasmandbodyfluids(suchasbloodplasma). Itisagoodsolvent.Itisusedfortransportinthe body.Itallowschemicalreactions.Ithasaneutral pH.Itmoveseasilyacrossmembranes.Itithelpsto regulatetemperature.
(b)(i) Qualitativelymeanstestingforthepresenceor absenceofasubstance.
(ii) Aqualitativetestmeasuresthepresenceor absenceofasubstance.Aquantitativetest measurestheamountofthesubstancethatis present.
(iii) Benedict’s(orFehling’s)solution(orreagent)is usedtotestforreducingsugar.
(iv) Benedict’ssolutionturns(brick)redinthe presenceofreducingsugar.
(v) Benedict’ssolutionstaysblueintheabsence ofreducingsugar.
(vi) Thecontrolistousewater(withBenedict’s solution).
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(a) Carbon,hydrogenandoxygenarepresentinall lipids.
(b) Fatsaresolidatroomtemperature.Oilsareliquidat roomtemperature.
(c) Phospholipidshavetwofattyacidsandaphosphate attachedtoaglycerol.Triglycerideshavethreefatty acidsattachedtoaglycerol.
(d) Lipidscanbeusedinrespiration;usedtoform membranes;usedtoformmanyhormones.
13
(a)(i) Thiswasaqualitativetest.Testingforthe presenceofasubstanceisaqualitativetest.
(ii) Abrickredcolourindicatesapositiveresult.
(iii) Thesolutionswereheatedinaveryhotwater bath.
(iv) Thecontroltuberemainedblue.
(b)(i) Iodinesolutionisared/yellowcolour.
(ii) Iodineisusedtotestforstarch.Itisalsousedas astainforexaminingplantcellsundera microscope.
(c)(i) Thiswasaquantitativetest.Testingforthe amountofasubstanceisaquantitativetest.
(ii) Benedict’ssolution(quantitative)orFehling’s solutionwasused.
(iii) Thefinalcoloursofthesolutionswerecompared withacolourcharttodeterminetheamountof reducingsugarpresent.
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(g) Mineralsarenotbiomoleculesbecausetheyarenot madebylivingthings.
(a) Theinformationshownissecondarydata.Thisis becauseitwasinformationdiscoveredbysomeone else.
(b) Theinformationisquantitativedata.Thisisbecause itisnumericalinformationandrelatetotheamount ofsubstancesthatarepresent.
(c) FoodAhas3.9gofstarch(i.e.25g–(10.4g+10.7g), assumingthecarbohydrateiseitherstarchorsugar). FoodBhas11.1gofstarch(i.e.13g–(0.6g+1.3g)).
(d) FoodAistinnedfruit.FoodBispowderedpotato mash.Thisisbecausefruithasmorefibrethan potatomash.
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(a) Thefoodwiththehighestpercentageofwateristhe apple.
(b) Thefoodwithnolipidistheapple.
(c) Thetwofoodswiththegreatestpercentageof aminoacidsarethemeatandthepeas.
(d) Peascontaincarbohydratewhilemeatdoesnot.
(e) Thepercentageofcarbohydrateinpotatois75%.
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(a) Theconstituentpartsofaproteinareaminoacids.
(b) ‘Formfitsfunction’meansthatthereisarelationship betweenthestructure(orform)ofanobjectandits role(orfunction).
(c) Theshapeofaproteinisdeterminedbythelawsof physics.
(d) Theproblembeingsolvedis“determiningaprotein’s 3-Dshapefromthesequenceofitsconstituent parts”.
(e) Metabolicrolesofproteinsinclude:actasenzymes, hormones,antibodiestransportingmoleculesinand outofcells.
(f) Knowledgeoftheshapeofaproteinmayhelpin quickerandmoreadvanceddrugdiscovery.Itmay explainthefunctionmanyproteins.Itmaymake senseofdisease-causinggenevariationsthatdiffer betweenpeople.
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(a) Thereare3aminoaciddifferencesbetweenWagyu beefandCut1.
(b) Thereare5aminoaciddifferencesbetweenWagyu beefandCut2.
(c) TherearenoaminoaciddifferencesbetweenWagyu beefandCut3.
(d) Cut2isthemostdifferentfromWagyubeef.Ithas themost(5)aminoaciddifferencesfromtheWagyu beef.
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(e) Cut3ismostlikelytobeWagyubeef.Ithasthesame sequenceofaminoacidsastheWagyubeef.
(f) Theaminoacidsequenceinaveganburgerwould beverydifferentfromthesequenceinachicken burger.
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(a) ‘Asustainablefoodsystem’provideshealthyfoodto meetourpresentneedswithoutcompromising(or affecting)theabilityoffuturegenerationstomeet theirownfoodneeds.
(b) Theenvironmentischangingduetoclimatechange, deforestation,desertification,damagetocoastal reefsandmarineecosystems.
(c) About40%ofgloballandisusedforfood production.
(d) 70%offreshwaterisusedtogrowfood.
(e) Thestudyrecommendsthatweeatvegetables,fruit, wholegrains,legumes,nuts,unsaturatedoils,alow amountofseafoodandpoultry.
(f) Weshouldconsumenoorlowquantitiesofred meat,processedmeat,addedsugar,refinedgrains andstarchyvegetables.
(g) Foodproductionresultsinincreasedlanduse, destructionofhabitats,increasedpollution,extra useofwaterandclimatechange,allofwhichmay leadtotheextinctionofspecies.
(h) Sustainablefoodproductionwouldprovidemajor healthbenefitsandalargereductionintotaldeaths.
CHAPTER9 TRANSFERMOLECULES
1
(a) ADP=Adenosinediphosphate
ATP=Adenosinetriphosphate
(b) ADPhastwophosphateswhileATPhasthree phosphates.
(c) ATPisahighenergymoleculethatstoresand providesenergyforcellularprocesses.ADPisalow energymoleculethatcanbeconvertedintoATP.
(d) ATP
(e) Thereleaseofenergyisacatabolicprocess.
Reason:whenmusclescontract,ATPisbrokendown intoADPandaphosphate,releasingenergy.
2
(a) (iii)Ribose
(b) Three
(c) ATPisahighenergymolecule.
(d) Photosynthesis,activetransport,proteinsynthesis ormusclecontractions
3
(a)
Phosphategroups Unstable
(b) Locatedintheextraunstablebond
(c) ADP
(d) ADP+energy+P→ATP+water
4
(a) Metabolismisthesumofallthechemicalreactions inanorganism.
(b) Anabolicreactionsuseenergytoconvertsmaller moleculesintolargermolecules.
Catabolicreactionsreleaseenergywhenlarge moleculesarebrokendowntoformsmaller molecules.
(c)(i) Catabolic (ii) Anabolic
5
(a) X=P(Phosphate)
(b) Y=Water
(c) Release
(d) Catabolic
(e) ATPismorecomplex.
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(a) NADP:nicotinamideadeninedinucleotidephosphate
(b) Photosynthesis
(c) NAD+isalow-energymoleculeusedinrespiration. NADHisahigh-energyelectronandhydrogen carrier.
(d) Bothactaselectroncarriers.
(e) NAD+isinvolvedmainlyincatabolicreactions(e.g. cellularrespiration).
NADP+isinvolvedmainlyinanabolicreactions(e.g., photosynthesis).
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(a) NAD⁺+2e⁻+H⁺→NADH
NAD+ +2e– +H+ NADH (Low energy) (High-energy electrons) (High energy)
(b) NAD+gainstwoelectronsandaproton.Thesecond electroncancelsouttheoriginalpositivechargeon theNAD⁺molecule.
(c) Respiration
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(a) ATPisbrokendownintoADPandaphosphatewhere itcanbereused.
(b) NAD+isreused.NAD+acceptsmoreelectronsand protonstoformNADH.
(c) NADHandOxygen
(d) NADPH
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(a) Nitrogenbase:adenine
(b) Sugar:ribose
(c) Advantages:ATPisahighenergymoleculeorATP iseasilybrokendownorATPcanbereusedorATP easilyreleasesenergy.Oranyacceptableanswer.
(d) TheconcentrationofATPmoleculesremains constantasthecellcanregenerateATPasquicklyas itisusedup.
10 HL Theansweris (d) ATPandNADPH.
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(a) Anabolic
(b) Catabolic
(c) Anabolic
(d) Anabolic
(e) Catabolic
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(a) X=ADP
(b) Y=Energy
(c) Bothactaselectroncarriers.
CHAPTER10 DNA,RNAANDTHEGENETIC CODE
1
(a) DNAstandsfordeoxyribonucleicacid.
(b) ThethreepartsofDNAareaphosphate,a deoxyribosesugarandanitrogen-containingbase.
(c) ThebasesinDNAareadenine,thymine,guanineand cytosine.
2
(a) A=Adenine C=Cytosine
(b)
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(d) Complementarybasesarepairsofbasesthatmatch upi.e.adenineandthyminematchupasdoguanine andcytosine.
(e) DNAismostlyfoundinthenucleus.
(c) X=Phosphate Y=Deoxyribose
(d) LetterYrepresentsacarbohydrate.
(e) Z=Guanine
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(a) Thereare9basesinthediagram. (b)
(c) DNAisadoublehelix.
(d) FourpossiblebasesinDNAareadenine(A),thymine (T),guanine(g)andcytosine.
4
(a) AgeneisasectionofDNAthatcausesthe productionofaprotein.
(b) Mostgenesarelocatedinthenucleus.
(c) GenesaremadeofDNA.
(d) Genesarefoundonchromosomes.
5
(a) RNAstandsforribonucleicacid.
(b) Tableneedstobeformattedwithcoloursetc]
HasthesugardeoxyriboseHasthesugarribose HasthebasethymineHasthebaseuracil
Isadoublestrand
Isasinglestrand
(c) IfDNAhasthebasesequenceATTGGCATTthenthe complementarystrandofRNAwillbeUAACCGUAA.
(d) RNAisnormallyshorterthanDNAbecauseonly someoftheDNAisusedtoformRNAwhenmakinga protein.
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(a) Thereare2strandsinthestructureofDNA.
(b) Thereis1strandinthestructureofRNA.
(c) Proteinsareformedintheribosome.
(d) TheintermediarymoleculeisRNA.
(e) Thesubunitsthatformaproteinareaminoacids.
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(a)(i) X=Adenine
(ii) Y=Guanine
(b) ChromosomesaremadeofDNAandprotein.
Containsdeoxyribose ✔
Formsadoublehelix ✔
Hasphosphategroups ✔
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(c) Thereare46chromosomesinanormalhumancell.
(d) Chromosomesarelocatedinthenucleus.
(e) RNAhasuracil.
(f) Uracilreplacesthymine.
(g) Proteinsaremadeinribosomes.
(h) RNAcarriesinstructionsfromDNAtowhereproteins aremade.
Hasuracilasabase ✔
Containsnucleotides ✔
Hasribosesugar ✔
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(a) CodingDNAhasthegeneticinstructionstoproduce aprotein.Non-codingDNAhasgeneticinstructions thatdonotproduceaprotein.
(b) Itisnowknownthatsomeofthenon-codingDNA hasotherfunctionsbesidesformingproteinse.g.it turnsgenesonandoffandcontrolstheactivityof genes.
(c) 27%oftheDNAwouldbeguanine.(If23%is adenine,thenanother23%isthyminesothe remaining54%ismadeupofguanineandcytosine. Halfofthis(27%)mustbeguanine).
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(a) Acharacteristicisaninheritedfeaturethatvaries amongindividuals.Atraitisonevariant(orversion) ofacharacteristic.
(b) Longstem:trait
Lengthofthestem:characteristic
Shortstem:trait
11
Genesproduceproteinswhichareresponsiblefortraits.
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(a) DNAandRNA
(b) DNAcontainsthesugardeoxyribose.RNAcontains thesugarribose.
(c) Thecommonnitrogenousbasesareadenine, guanineandcytosine.
(d) DNAisdoublestranded.
(e)(i) TheweakbondsinAarehydrogenbonds.
(ii) Adeninehas2hydrogenbonds.
(iii) Adeninehas2hydrogenbondsbutcytosinehas 3hydrogenbonds,sotheydonotcombine.
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(a) Thegeneticcodeisthesetofrulesbywhichthe sequenceofbasesinDNAactingingroupsofthree determinesthesequenceofaminoacidsinaprotein.
(b) Atripletorcodonisasequenceofthreebasesin DNAorRNAthatspecifiesaparticularaminoacid.
(c) Ageneisasequenceofcodons.
(d)(i) 27nitrogenousbasesrepresents27/3= 9codons.
(ii) Thissequencecancodeforamaximumof 9aminoacids.
(e) Astartcodonindicatesthebeginningofagene. Mostcodonscodeforaminoacids. Astopcodonindicatestheendofagene.
(f) AnanticodonisasequenceofthreebasesintRNA thatarecomplementarytoasequenceofthree bases(oracodon)inmRNA.
(g) TheanticodonfortheDNAcodonAAAisAAA(AAA onDNAlinkswithUUUinmRNA.ThismRNAthen linkswithAAAintRNA).
TheanticodonfortheDNAcodonATGisAUG(ATG onDNAlinkswithUACinmRNA.ThismRNAthen linkswithAUGintRNA).
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(a) ThecomplementarystrandtotheDNAsequence ATTGCCTAGisTAACGGATC.
(b) ThecomplementarystrandofRNAwouldbe UAACGGAUC.
(c) Thesequence(ATTGCCTAG)represents3codons.
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(a) 28%ofthebassareadenine(If22%iscytosine,then another22%isguaninesotheremaining56%is madeupofadenineandthymine.Halfofthis(28%) mustbeadenine).
(b) 22%isguanine.
(c)(i) Therewere750adeninebasesinthegene(20% werecytosine,therefore20%wereguanine. Thisleaves60%,halfofwhichwereadenine. 30%of2500=750).
(ii) Therewere500guaninebasesinthisgene.
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(a) Thereare20differentaminoacidsusedbyliving things.
(b) TheRNAcodonformethionineisAUG.
(c) Arginineisrepresentedby6codons(CGU,CGC, CGA,CGG,AGA,AGG).
(d)(i) Astopcodonindicatestheendofthegene. (ii) UAAorUAGarealsostopcodons.
(e)(i) ThesequenceAUUCACGGGcodesfor3amino acids.
(b) X=deoxyriboseY=phosphate
(c) 4
(ii) AUUcodesfortheaminoacidIle(isoleucine). CACcodesfortheaminoacidHis(histidine). GGGcodesfortheaminoacidGly(glycine).
(f) Thisissothateachcodonwillonlyspecifyasingle aminoacid.Iftherewasmorethanoneaminoacid specifiedthentheproteinwouldhavedifferent sequencesofaminoacids,withdifferentshapesand functions.
CHAPTER11 GENETICINHERITANCE
(a) Inthecoolerpartsofthebody.
Reason:atnormalbodytemperature,theenzyme isinactive,sonopigmentisproduced,therefore, kittensarebornwhite.Incoolerareasofthebody (liketheextremities),theenzymebecomesactive, leadingtopigmentproductionanddarkerfur.
(b) Epigenetics
(c) Yes,thegenesforpigmentproductionare thesameinbothkittensandadultcats.
(d) Cellsfromtheextremities
(e) Temperature
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(a) Cytosine
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(a) Genotype=bb (b)
Parentgenotype
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
(c) 50%chance
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1browneye 1blueeye
(a)(i) Homozygousmeansthatthetwoallelesare identical.
Heterozygousmeansthattheallelesare different.
(ii) PPxpp
(b) (i)
(e) Wwandww 1whitesheep 1blacksheep Wwww W w w ww Ww Ww ww
Parentgenotype Genotypes ofgametes
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Offspringgenotype
(ii) 25%
(a) Genotypes=SsandSs
(b) Gametes=Sors
(c) SS,Ss,SsandSs
Parentgenotype
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
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(a) Genotypeofblacksheep=ww
(b) Genotypeofwhitesheep=Ww
(c) Gametes=Worw
(d) Gamete=w
Offspringgenotype
Offspringphenotype
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(a) Genotype=bb
(b) Heterozygousparent(Bb)producesgameteswith genotypeBorb.
Blueeyeparentproducesthegametewithgenotype b.
(c) Bbandbb b B 1browneye 1blueeye Bbbb b bb Bb Bb bb
Parentgenotype Genotypes ofgametes
Offspringgenotype
Offspringphenotype
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(a) DominantalleleB=Blackdog
(b) Recessivealleleb=Whitedog
(c) One
(d) Homozygous
(e) Genotype=Bb Phenotype=Blackdog
(f) Sexchromosomesofmaleblackdog=XY Sexchromosomesoffemalewhitedog=XX
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(a) BenefitsofMendeliangenetics: AnunderstandingofMendeliangeneticsallowsfor thepredictionofhowtraitsmaybeinherited. Itallowsustopredicttheprobabilityofpassingon certaingeneticconditionstothenextgeneration (i.e.itisthebasisforgeneticcounselling). Inagriculture,itisthebasisforselectivebreedingof plantsandanimals(whichallowsfortheinheritance ofdesiredtraits,suchasimprovedyieldsorimproved resistancetodisease).
Mendeliangeneticsareusedingeneticresearch toproducenewdiscoveriesingeneticdisorders, andtostudytheeffectsofnewdrugsondifferent individuals.
Ithashelpedinourunderstandingofhowevolution worksandhownewspeciesdevelop(species diversity).
(b) LimitationsofMendeliangenetics: Mendeliangeneticsappliestotraitscontrolled bysinglegenes.However,manytraits(suchas intelligenceandhaircolour)arecontrolledbymany genesandMendeliangeneticsdoesnotfullyexplain theinheritanceofthesetraits.
Itdoesnotaccountforthewaysinwhichthe environment(andepigenetics)interactswithhow geneswork.
Mendeliangeneticsdoesnotrelatetothe inheritanceoftraitscontrolledbygeneswhichare closetoeachotheronachromosome(linkedgenes).
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(a) Fathergenotype=XNY Mothergenotype=XNXn Son’sgenotype=XnXn
(b) Fromhismother
(c) 0%
Parentgenotype
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
Explanationusingamodel: AllFemalesnormal 1Malenormal 1Malecolourblind
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(a) 5children
(b) 3femalechildren
(c) 2werehaemophiliacs
(d) Parent1genotype=XNXn
Parent2genotype=XNY
(e) Daughter’sfatherphenotype=Haemophilia
Daughter’sfathergenotype=XnY
(f) 100%chance
Parentgenotype
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
Explanationusingamodel: 1Femalenormal(carrier) 1Malenormal
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(a) Roanbullgenotype=RW Whitecoatedcow=WW
(b) Genotypeofgametesfromroanbull=RorW Genotypeofgametesfromwhitecoatedcow=W
(c) Possibleoffspringgenotype=RWandWW
(d) Thematchingphenotypeofoffspring=1roancalf and1whitecoatedcalf
(e) 0%
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
Explanationofanswersforc,dandeusingamodel: 1roancalf 1whitecoatedcalf RWWW Parentgenotype
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(a) Allelesaredifferentformsofthesamegene. Incompletedominancemeansthatneitherallele isdominantorrecessivewithrespecttotheother, andbothallelesareexpressedintheheterozygous condition.
Homozygousmeansthatthetwoallelesare identical.
Thephenotypemeansthephysicalexpressionofa geneorthephysicalmake-uporappearanceofthe organism.
(b) Offspringgenotype=BBBbBbbb Offspringphenotype=1blackfeather,2blue feathers,1whitefeather
(c) Ratio:1blackfeather:2bluefeathers:1white feathers
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(d) 3blackfeathers:1whitefeathers
Explanationofanswers:
Parentgenotype
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
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(a) Non-nuclearinheritanceisthetransmissionof geneticmaterialthatisnotlocatedinthenucleusof thecell.ItreferstoloopsofDNAinmitochondria andchloroplast.
(b) OrganellesthathaveDNA:nucleus,mitochondriaor chloroplast
(c) Nucleus
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(a) Faultymitochondriawouldaffectthecellsabilityto produceenergy.
(b) Thedonoregghashealthymitochondria,but itsnucleuscontainsthedonor’sgeneticmaterial. Toensurethechildinheritstheintendedmother’s DNAthedonor’snucleusisremovedtoeliminate hergeneticcontribution.Thisallowsthemother’s nucleus(withherDNA)tobeinsertedinstead.
(c) Thetransplantednucleuscontainsthemother’s nuclearDNA,whichdoesnotaffectmitochondrial functiondirectly.Mitochondrialdiseasesarecaused bymutationsinmitochondrialDNA,notnuclear DNA.Sincethemitochondriaremainfromthedonor egg,andtheyarehealthy,thechilddoesnotinherit thefaultymitochondrialDNA.
(d) Childrenbornthroughthistechniquearesaid tohavethreegeneticcontributorsas:the motherprovidesthenuclearDNA(mostofthe child’sgenetictraits),thefatherprovidessperm andnuclearDNA,andthedonorwoman,provides thehealthymitochondria(mitochondrialDNA).
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Thegeneticconstitutionofthegametesandthe genotypesandphenotypesoftheprodigyaredescribed inthefollowingdiagram.
1blackeyesootybody
1pearleyebrownbody
1pearleyesootybody
Explanationofanswers:
Parentgenotype
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Parentgenotype=PpBbandppbb
GenotypeofgametesfromparentPpBb-PB,Pb,pB,pb
Genotypeofgametesfromparentppbb-pb
Offspringgenotype=PpBb,Ppbb,ppBbandppbb
OffspringPhenotype=1Blackeyebrownbody
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
1blackeye,brownbody 1blackeye,sootybody 1pearleye,brownbody 1pearleye,sootybody
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(a) Allpossiblegenotypesandphenotypes:
G=grey,g=ebony,L=longwings,l=vestigialwing
Parentgenotype
GgLlggll
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
Greybody,longwing
Greybody,vestigialwing
Ebonybody,longwing Ebonybody,vestigialwing
(b) Theyassortindependently(i.e.theyobeythelaw ofindependentassortment).Thisallowsformore variation.
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(a) Genotype=RrYy
(b) Genotypeofgametes=RYRyrYandry
(c) RorrcancombinewitheitherYory,andviceversa oreitherallele(member)ofapaircancombinewith eitheralleleofanotherpair(atgameteformation).
(d) PunnettSquareshowinghowresultswereobtained:
Parentgenotype
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
(e) RryyandrrYy
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1roundyellowseed 1roundgreenseed 1wrinkledyellowseed 1wrinkledgreenseed
(a)(i) Agreen-seededplant=gg (ii) Homozygousdominantforroundseed=RR (iii) Heterozygousforflowercolour=Pp (iv) Homozygousrecessiveforplantheight=tt
(b) Geneticcrossshowingpossiblegenotypesand phenotypes:
Y=yellow,y=green,T=tall,t=dwarf
Parentgenotype
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
1tallyellow 1tallgreen 1dwarfyellow 1dwarfgreen
(c) Possibledifferences:theywouldbemostly(orall) parentalphenotypesormostly(orall)tall,yellow anddwarf,greenorno(orfew)recombinants,orno (orfew)tall,greenanddwarf,yellow,ortheywould nothavethesame(1:1:1:1)ratio,ortherewouldbe lessvariation.
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(a) 4chromosomes
(b) Heterozygous
(c) No.Thegeneisnotlinkedtothesexchromosomes.
(e) Possiblegametes: Parent Rr XY R Y
(f) Diagramshowingnon-tonguerollerprodigy:
(a) Linkageorlinkedgenesmeansthatgenesare locatedonthesamechromosome.
(b) Sexlinkagemeansthatacharacteristiciscontrolled byageneonasexchromosome.
(c)
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(a) Mendel’slawofsegregationstatesthat: Inheritedcharacteristicsarecontrolledbypairsof alleles. Theseallelessegregate(orseparate)fromeach otheratgameteformation,withonlyoneallelefrom eachpairbeingfoundineachgamete.
(b) Aplantthatisheterozygousfortallstemhasthe genotypeTt.Accordingtothelawofsegregation, duringgameteformationhalfthegameteswillcarry theTallele(tall)andhalfwillcarrythetallele(short).
(c) Mendel’slawofindependentassortmentstatesthat whengametesareformedeitherofapairofallelesis equallylikelytocombinewitheitherofasecondpair ofalleles.
(d) Yes,astonguerollingisthedominantallele.
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(d) AplantwithgenotypeTtYyisheterozygousfor bothtraits.Accordingtothelawofindependent assortment,theallelesforstemheight(T/t)andseed colour(Y/y)areinheritedindependently.This plantcanproducefourtypesofgametesinequal proportions:TY,Ty,tYandty.
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(a) Theyassortindependently(i.e.theyobeythelaw ofindependentassortment).Itallowsformore variation.
(b) Parentgenotype=RrTtandrrtt
(c) Modelshowingpossibleoffspring:
Parentgenotype
Genotypes ofgametes
Offspringgenotype
Offspringphenotype
1pinkandtall
1pinkandshort
1whiteandtall
1whiteandshort
(d) Youwouldexpectlessvariationamongtheoffspring genotypesandphenotypeswhengenesarelinked.
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(a) Lawofsegregationstatesthataplantthat isheterozygousfortallstemhasthegenotypeTt. Accordingtothelawofsegregation,duringgamete formationhalfthegameteswillcarrytheTallele (tall)andhalfwillcarrythetallele(short).
Mendel’slawofindependentassortmentstatesthat whengametesareformedeitherofapairofallelesis equallylikelytocombinewitheitherofasecondpair ofalleles.
(b)(i) SSYyorssYy
(ii) SSYy=Smoothandyellow
ssYy=wrinkledandyellow
(c) Smoothandyellow
Anothergenotype=SSYY
(d) Genotypeoftwogametes=SyorsY
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Answerdependsonstudents’exampleinrelationto researchofepigeneticinheritance.Studentsshould ensuretheyaddressallpartsofthequestionintheir answer.
CHAPTER12 EVOLUTION:THEORIGINSOFLIFE
1
(a) Variationmeansdifferencesbetweenthemembers ofthesamespecies.
(b) Variationsmaybeacquiredorinherited.
(c) Acquiredvariationsarelearnedordevelopedduring life(theyarenotinherited).Inheritedvariationsare controlledbygenes(andarepassedontothenext generation).
2
(a) ChangesinDNAleadtoinheritedvariation.
(b)(i) Agoodinheritedvariation:anygeneticvariation thatallowstheorganismtolivelongerand reproducee.g.abetterenzyme,agenefor darkerskiniflivinginasunnierclimate,the prolongedabilityofthelactosedigestinggene towork(ratherthanstoppinginchildhood),a betterformofhaemoglobin.Oranysuitable answer.
(ii) Abadorharmfulinheritedvariation:anygenetic variationthatreduceslifespanortheability toreproducee.g.agenethatcausesdisease (suchascancerorsicklecellorcysticfibrosis),or theinabilitytoproducespermoreggs,apoor immunesystem.Oranysuitableanswer.
3
(a) Variationsmaybeacquiredorinherited.
(b) Thecausesofinheritedvariationsaresexual reproductionandmutations.
(c) Examplesofgeneticvariationsincludeeyecolour, thenumberoffingers,theabilitytoproducean enzyme,ahormoneorATPoranyrelevantanswer.
4
(a) Amutationisasuddenchangeintheamountor structureofDNA.
(b) Mutationsmaybepoint(orgene)mutationsor chromosomemutations.
(c) Apointmutationisachangeinasinglegene.A chromosomemutationisalargechangeinthe structureornumberofoneormorechromosomes (andinvolvesmanygenes).
5
(a) Artificialselectionmeanshumanschoosingwhich organismstobreed.Naturalselectionmeansthat natureselectsthoseorganismsthatarewelladapted totheirenvironmentsothattheysurviveand reproducetopassontheirgenes.
(b) Practicalapplicationsofartificialselectioninclude breedingchosentypesofanimals,breedingchosen typesofplants,breedingchosentypesofpets,or breedingchosentypesoforganismsinlaboratories.
(c) Benefitsofartificialselectionincludecattlethat producemoremeatormilk,sheepthatproduce morewooloroffspring,petsthataremoredesirable oranyrelevantanswer.
Disadvantagesofartificialselectioninclude organismswithreducedgeneticvariation(leadingto diseaseandillhealth),unwantedsideeffects(such asdogswithbreathingdifficulties),unintendedside effects(suchaspetswithreducedlifespans),ethical concerns(suchasanimalwelfareinpuppybreeding farms)oranysuitableanswer.
(c) Rabbitsoverbreedandtheenvironmentcanonly supportalimitednumberofrabbits.
(d) Rabbitsmightstruggletogetfood,water,shelter andmates(orpartners).
(e) Thebrownrabbitsaremostlikelybetteradaptedto theirenvironment.Thisisbecausebrownrabbitsare bettercamouflagedandarelesslikelytobekilled bypredators.(However,inasnowyenvironment thewhiterabbitsarebetteradaptedduetotheir camouflage).
(f) Natureselectsthebrownrabbits(i.e.theysurvive longerandcanproducemoreoffspring).Thewhite rabbitsaremorelikelytobekilledsothattheirgenes arenotpassedontothenextgeneration.
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6
(a) Variationingeneticsmeansdifferencesbetweenthe membersofthesamespecies.
(b) Anothercauseofvariationissexualreproduction.
(c) Mutationsmaybepoint(orgene)mutationsor chromosomemutations.
(d) Mutationsresultinvariation.Beneficialvariationsare selectedbynaturetoliveonandreproduce.Harmful variationsarenotselectedanddieout.Without mutations,naturalselectionwouldhavefewernew traitstoselect,andevolutionwouldslowdown.
7
(a) Amutationisasuddenchangeintheamountor structureofDNA.
(b) DiseasescausedbymutationsincludeHuntington’s disease,cancer,cysticfibrosis,haemophilia,Down syndrome…
(c) Huntington’sdiseaseresultsinrestlessness, difficultywalking,thinkingorremembering. Acceptanycorrectsymptomsfortheother mutations.
(d) Amutagenisanagentthatcauses(orspeedsupthe rateof)mutation.
(e) Examplesofmutagens:gammarays,asbestos, X-rays,ultra-violetraysandpesticides
8
(a) Artificialselectionmeanshumanschoosingwhich organismstobreed.Naturalselectionmeansthat natureselectsthoseorganismsthatarewelladapted totheirenvironmentsothattheysurviveand reproducetopassontheirgenes.
(b) Examplesoftheuseofartificialselectioninclude breedingchosentypesofanimals,breedingchosen typesofplants,breedingchosentypesofpetsor breedingchosentypesoforganismsinlaboratories.
9
(a) Largenumbersofoffspringisproduced.However, theenvironmentcanonlysupportalimitednumber oforganisms.Natureallowsthewelladapted organismstosurvive(andreproduce)whilethose organismsthatarenotsowelladaptedtotheir environmentdieanddonotreproduce.
(b) Theorganismsthatarebestadaptedtotheir environmentsurvive,reproduceandpassontheir genes.
11
(a) Thismeansthatthereisastruggleforexistence(i.e. notalltheorganismscansurvive).
(b) Geneticvariationsmeanthatnaturewillselectthose variationsthatarebestadaptedtotheenvironment. Theywillsurvive,reproduceandpassontheirgenes.
(c) Iftheorganismdoesnotreproducethenthe variationwillnotpassontothenextgeneration.
(d) Longlifeofitselfisofnoevolutionaryvalueif theorganismsdonotalsoreproduce.Ifthelong lifeleadstomorereproduction,thenitwillbeof evolutionaryadvantage.
12
(a) Sourcesofevidenceinsupportofevolutioninclude embryology,fossilrecords,phylogeny,comparative anatomy,antibioticresistance,speciation.
(b) Thestudyofembryosshowsthatmanyorganisms showsimilaritiesintheirembryosastheydevelop. Thisindicatesthattheyhavearisenfromacommon origin.
(c) ThefirstlivingthingshadDNA.Theyhavepassedit downthegenerationstoalmostalloftoday’sliving things.
(d) Humans,whalesandbatsallhavepentadactyllimbs becausetheyhaveallevolvedfromacommon ancestorthathadthesamelimbstructure.
13
(a) Evolutionisthewayinwhichlivingthingschange geneticallytoproducenewformsoflifeoverlong periodsoftime.
(b) EvolutionwasfirstproposedbyCharlesDarwinand AlfredRusselWallace.
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(a) Antibioticresistancemeansthatbacteriaarenot killedbysome(orany)antibiotics.
(b) Theproblemwithantibioticresistanceisthatthe bacteriaarenotkilledbyantibiotics.Thismakes itverydifficulttotreatandcontrolbacterial infections.
(c) Bacterialresistanceisincreasedbyoveruse(orover prescription)ofantibiotics,notcompletingthe courseoftheantibioticortheoveruseofantibiotics inagriculture.
14
(a) Thezinc-tolerantdandelionsmayhavearisenby mutationsorasaresultofsexualreproduction.
(b) Dandelionsproduceahugenumberofseeds.Those seedsthatwereintolerantofhighconcentrationsof zincfailedtogrow.However,ifevenoneseedthat wastolerantofhighzincconcentrationslandedin thegrasslanditcouldhavegrown.Inturnitwould haveproducedseedsthatwerealsotolerantofhigh zincconcentrations.
(c) Thetwotypesofdandelionswouldnotbeable toreproducetogetherastheirflowersbloomed atdifferenttimes.Thiswouldmeantheywereno longeronespecies.
15
(a) Thetermusedisvariation.
(b) Thedifferencescouldbeduetoage,diet,genetics…
(c) Theanswermaybeeitheryesorno,butitmustbe supportedbyavalidreason.Forexample: Yes,weightisalsodependentonage,diet, genetics…or
No,themenmighthaveallbeenathletes(low weights),weightlifters(heavierweights),mayhave beendietingoranysuitableanswer.
(d) Amutationisasuddenchangeintheamountor structureofDNA.
(e) Mutationsarecausedbyradiationorchemicals orvirusesorcarcinogensoranycorrectnamed exampleofthese.
(f) Conditionscausedbymutationsincludecancer, cysticfibrosis,haemophilia,sicklecellanaemiaor anysuitableanswer.
16
(a) ThetheoryofevolutionwasproposedbyCharles DarwinandAlfredRusselWallace.
(b) Evolutionisthewayinwhichlivingthingschange geneticallytoproducenewformsoflifeoverlong periodsoftime.
Inheritedvariationsariseasaresultofsexual reproductionandmutations.Theyarecontrolledby genes.
Variations:Thistermmeansthedifferencesbetween membersofthesamespecies.
(e) Sourcesofevidenceinsupportofevolutioninclude embryology,fossilrecords,phylogeny,comparative anatomy,antibioticresistance,speciation.
17
(a) Antibioticsarechemicalsproducedby microorganismstokillbacteriaandfungi.
(b) Penicillinisanantibiotic.
(c) Antibioticresistancemeansthatbacteriaarenot killedbytheantibiotic.
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(c) Sexualreproductionrearrangesgenesandproduces sexcellsthatarenon-identical.Bothofthesefactors contributetogeneticvariation.
(d) Otherpointsinclude:organismsoverbreed; thenumbersinapopulationremainconstant; thereisastruggleforexistence;natureselects thoseorganismsthatarebetteradaptedtotheir environment.
(d) Antibioticresistantbacteriaarisebymutation.
(e) Thisstatementisfalse.Peoplearenotresistantto antibiotics;bacteria,however,mayberesistantto antibiotics.
(f) Antibioticresistancesupportsthetheoryof evolutionbecausebacteriashowgeneticvariation (duetomutations),somebacteriaarekilledbythe antibiotic,somebacteriacanresisttheantibiotic, theresistantbacteriasurvive,reproduceandpasson theirantibioticresistancegenes.
18
(a) Priortothe1850streeswerecoveredinpalecolouredlichens.Thepale-colouredmothswere camouflagedwhileonthelichenandsurvived predation.Dark-colouredmothsweremorevisible onthepalelichenandweremoreoftenkilledby predators.
(b) PriortotheIndustrialRevolutiontherewasless pollutionandthereforethetreeswerecoveredby pale-colouredlichens.Thedarkmothsweremore visibleonthelichenandwereoftenkilled.
(c) Thedark-colouredmothsmayhavearisendueto sexualreproductionorduetomutation.
(d) AftertheIndustrialRevolution:
(i) Theblackmothssurvivedbecausethelichens diedoffduetopollution.Thedarkbarks camouflagedtheblackmoths.
(ii) Thepale-colouredmothsdecreasedbecause theyweremorevisibleonthedarkbarkand werekilled.
(e) Therapidpaceofthisevolutionarychangewasdue tothesuddenchangeofthetreecoveringsfrom pale(lichens)todark(bark)causedbypollution.
(f) Lesspollutionresultedinmorepale-coloured lichens.Thisresultedinanincreaseinpale-coloured moths.
19
(a) Reasonsfortheimportanceofthetheoryof evolution:itexplainsthediversityoflife,itexplains theunityoflife,itexplainshownewspeciesemerge, itprovidesanoverallexplanationofmanybiological phenomena,itprovidesaframeworkforresearchin areassuchasmedicine,agriculture,conservation, diseasecontrol,biotechnologyandhumanoriginsor anysuitableanswer.
(b) Thisstatementisnottrue.Thetheoryofevolution hasbeensupportedbyavastnumberofstudies carriedoutoverahugerangeofbiological disciplinessinceitwasfirstproposed(in1858).Itis supportedbyavastrangeofevidence.
(c) Thetheoryofevolutionshowsthatlivingthings sharesomanyfeaturesbecausetheyhave descendedfromacommonancestor(i.e.itshows theunityoflife).
Thetheoryofevolutionalsoshowshowdistinct speciescandevelopfromacommonancestor(i.e.it showsthediversityoflife).
(iii) Completedphylogenetictree:
20
(a) Aminoacidsalwayshavecarbon,oxygen,hydrogen andnitrogen.
(b) Thebondbetweenaminoacidsisapeptidebond.
(c) Ashortsequenceofaminoacidsiscalledapeptide.
(d)(i) SpeciesAandEaremostcloselyrelated.This isbecausetheyhavethefewestnumberof aminoaciddifferences(3).
(ii) SpeciesBismostlikelytheleastrelatedtothe otherfour.SpeciesBshowsatotalof 154differences(i.e.43+37+33+41); speciesAshows94differences(i.e.43+21+ 27+3);speciesCshows84differences(i.e. 21+37+7+19);speciesDshows79differences (27+33+7+12)andspeciesEshows 75differences(3+41+19+12).
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CHAPTER13 ENZYMES
1
(a) Bothcatalystsandenzymesspeedupachemical reactionwithoutbeingusedupintheprocess.
(b) Allenzymesarecatalysts,butnotallcatalystsare enzymes.
2
(a) Enzyme=K
(b) Substrate=ABC
(c) A+B+C
3
(a) Proteins
(b) Aminoacids
(c) Theshapeoftheenzymeisimportantasit determinestheenzymesspecificityandfunction.
4
Column AColumnB
Anexampleofanenzyme Amylase
Thegroupofbiomoleculestowhich enzymesbelong Proteins
Enzymeactivityisaffected by thisTemperature Enzymes workbecauseofthisCorrectshape Thesubstancewithwhichanenzyme reacts Substrate
AnenzymeisanexampleofthisCatalysts
5
(a) True
(b) False
Reason:enzymesaremadefromproteins.
(c) False
Reason:enzymesarecatalysts(theyspeedup areaction,withoutitselfbeingusedupinthe reaction).
(d) False
Reason:enzymesarespecific,theshapeofan enzymeallowsittoreactwithonlyoneparticular substrate.
(e) True
6
(a) Thetemperatureisunsuitable(toolow).
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(f) False
Reason:thesubstancewithwhichanenzymereacts isthesubstrate.
(b) Therateofreactionincreasesbecausethe temperatureisincreasingtowardstheoptimum temperature.
(c) Therateofreactiondeclinesasthetemperatureis toohighandbecomesunsuitable,movingawayfrom itsoptimumtemperature.
(d) 37°C
(e) Enzymesbecomedenatured.
7
(a) Abioreactorisavesselinwhichlivingcellsor enzymesareusedtomakeaproduct.
(b) Biofuelsareliquidfuelsproducedfromrenewable biologicalsources.
(c) Biofuels:ethanol,biodieselorbiogas
(d) Advantageofbiofuels:renewableenergysource Disadvantageofbiofuels:producespollutinggases whenburned
(e) Acceptayesornoanswerifthereasongivenis acceptable.
Sampleanswer:Yes
Reason:Thesustainabilityofbiofuelsisacomplex issuewithargumentsonbothsides.Whilebiofuels canreducegreenhousegasemissionscomparedto fossilfuels,theirproductioncanleadtounintended environmentalconsequences,suchasdeforestation, lossofbiodiversity,andwaterresourcedepletion. Additionally,usingfoodcropsforbiofuelproduction canimpactfoodsecurity.
Sampleanswer:No
Reason:However,advancementsinsecondgenerationbiofuels,whichusenon-foodfeedstocks, showpromiseformoresustainableproduction methods.
(f) Pharmaceuticalsarecompoundsmanufacturedfor useasmedicinaltreatments.
(g) Advantageofpharmaceuticals:fightcancers,lower cholesterollevels,lowerbloodpressureandtreat depression,diabetes,breathingdisorders,painand manyotherconditions.
8
(a) Industry:biofuelsorothersuitableanswers.
(b) Advantage:Itisarenewableenergysource.
(c) Problem:Itproducespollutinggaseswhenburned.
9
(a) Freeenzymesareenzymesthatarenotattachedto anysubstance.
(b) Disadvantage:Thisprocessisverywasteful,asthe enzymesareonlyusedonce.
(c) Immobilisedenzymesareenzymesthatareattached toeachotherortoaninertmaterial.
(d) Advantages: Immobilisedenzymescanbereused. Theproductispureanddoesnotneedtobe separatedfromtheenzyme.
Theproductionprocessischeaperthaniffree enzymesareused.
10
Thefollowingfactorswereinvestigated:temperature, pH,heatdenaturation,substrateconcentrationand/or enzymeconcentration.
11
(a) Catalase
(b) Hydrogenperoxide
(c) Bykeepingwaterbathatconstanttemperature.
(d) ByusingdifferentpHbuffers
(e) Waterandoxygen
(f) Bymeasuringthevolumeoffoam(bubbles) producedin2minutes.
(g) Control:bynotaddingtheenzymecatalase.
(h)(i) Nofoamproducedbythecontrol.
(ii) pH2
12
(a) Enzyme:catalase
Substrate:hydrogenperoxide
(b) Washing-upliquidisusedasittrapsoxygentoform foam(bubbles).
(c) Tovarythetemperature.
(d) pHwaskeptconstant.
(e) ByusingapHbuffer.
(f) Control:bynotaddingtheenzymecatalase.
(g) Bymeasuringthevolumeoffoam(bubbles) producedin2minutes.
(h)(i) Thetemperaturewaslesssuitable(10°C),so enzymeshapewasaltered.
(ii) Itstoppedproducingfoam.
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(a)(i) Temperature
(v) GraphtoshowtheeffectofpHontherateofan enzymereaction:
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(ii) Acatalystisasubstancethatspeedsupa reaction,withoutitselfbeingusedupinthe reaction.
(b)(i) Catalase
(ii) Source:celeryorliver
Substrate:hydrogenperoxide
(iii) Theshapeoftheenzymewouldbealtered.
(iv) Bymeasuringthevolumeoffoam(bubbles) producedin2minutes.
(a) Hypothesis:‘Asthesubstrateconcentration increases,therateofenzymeactivityincreases,up toapoint’.
(b) Prediction:asthesubstrateconcentrationincreases, therateofenzymeactivitywillinitiallyrise.However, onceallenzymeactivesitesareoccupied(saturation point),furtherincreasesinsubstrateconcentration willnotleadtoahigherreactionrate.
(c) Precaution:usinggloves,gogglesorlabcoats
(d) Independentvariable:substrateconcentration
(e) Dependentvariable:measuredvolumeoffoam (bubbles)producedin2minutes
(f) Fixedvariables:temperature,pHorenzyme concentration
(g) Conclusion:therateofenzymeactivityincreasesas thesubstrateconcentrationincreases,uptoapoint.
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(a) A=Substrate
B=Enzymesubstatecomplex
(b) Activesitetheory(alsoknownasinducedfitmodel orlockandkeytheory)
(c) Catabolicreaction
(d) Reason:alarger(complex)moleculeisbrokendown intoasmallermolecule(simpler).
(e) Specificity:theenzymeonlyreactswithonlyone particular(type)substrate.
(f) Ribosomes
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(a) Anenzymeisabiological(orprotein)catalyst.
(b) Proteins
(c) pH,temperature,enzymeconcentration,and substrateconcentration.
(d) Theenzymeonlyreactswithonlyoneparticular (type)substrate.
(e) Activesite
(f) Theactivesiteisinducedorcausedtochangeshape slightlybythesubstrate.
Thesubstrateandenzymeformanenzyme–substratecomplex.
Thesubstrateischangedintotheproduct(s). Theactivesitereturnstoitsoriginalshapeandthe enzymecanbereused.
(a) Graphofresults:
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(b) Slowestat0.5moldm⁻3
(c) pHortemperature
(d) ByusingapHbufferorawaterbath.
(e) Introduceagreatervolumeofenzymesolution.
CHAPTER14 PHOTOSYNTHESIS
1
(a) Ananabolicprocessusesenergytoconvertsmaller moleculesintolargermolecules.
(b) Photosynthesisisananabolicprocess.Thisis becausephotosynthesisuseslightenergytoconvert carbondioxideandwatermoleculesintoglucose (whichisalargermolecule).
(c) Wordequationtorepresentphotosynthesis: Carbondioxide+Water+Light Chlorophyll Glucose+Oxygen
(d) Chemicalequationtorepresentphotosynthesis: Chlorophyll 6CO2 +6H2O+Light
2
(a) Reactantsarethesubstancesthatarepresentatthe startofachemicalreaction.
(b) Thereactantsinphotosynthesisarecarbondioxide andwater.
(c) Thesourceofcarbondioxideiscarbondioxideinthe airorthatisreleasedduetorespirationintheleaf. Thesourceofwateriswaterthatisabsorbedbythe rootsandcarrieduptothephotosyntheticparts.
3
(a) Theproductsarethesubstancesthatareformedina chemicalreaction.
(b) Theproductsinphotosynthesisareglucoseand oxygen.
(c) Thesourceofglucoseiscarbondioxideandwater (withthecarbonandoxygencomingfromthe carbondioxideandthehydrogencomingfrom water).
4
(a) Acarbonsinkisanythingthatabsorbsmorecarbon fromtheatmospherethanitreleases.
(b) Examplesofcarbonsinksareforests,oceans,soil andfossilfuels.
(c) Photosynthesisactsasacarbonsinkbecauseittakes carbon(dioxide)fromtheenvironmentandconverts ittoglucose.
5
(a) Thecellularlocationforphotosynthesisisinthe chloroplast.
(b) Chlorophyllisachemical.Achloroplastisacell organellethatcontainschlorophyll.
(c) Photosynthesistakesplaceinanygreenpartofthe plante.g.theleaf,stem,sepalsand/orgreenfruit.
6
(a) X=Carbondioxide
(b) Y=Glucose
(c) Light
(d) Green
(e) Mostoftheoxygenisreleasedintotheatmosphere. Someoftheoxygenmaybeusedintheplantfor respiration.
(f) Environmentalfactorsaffectingphotosynthesis includelightintensity,carbondioxideconcentration andtemperature.
(g) GasX(carbondioxide)entersthroughthestomata andthroughthelenticels.
7
(a)(i) ChemicalA=Carbondioxide
(ii) ChemicalB=Glucose
(b) Photosynthesisisvitaltoanimalsbecauseitprovides foodandoxygen.
(c) Plantsabsorbcarbondioxideandreducecarbon dioxideintheenvironment.Bygrowingmoreplants (especiallyreforestation),wecandecreasethe amountofcarbondioxideintheenvironment.
(d) Plantshelptoformcarbonsinksbyabsorbingcarbon dioxideandstoringitinplantstructuresandtissues. Evenwhentheplantsdie,theystillstorecarbonwhich maygoontoformcarbonsinkssuchasfossilfuels.
(e) Chloroplast
(f) Chlorophyll
(g) Thefunctionofchlorophyllistoabsorblight.
8
(a) Inthechloroplast.
(b) Glucose
(c)(i) Anyofthefollowingthreefactorsisacceptable: lightintensity,temperatureorcarbondioxide concentration.Thefollowinganswersarebased onlightintensity.
(ii) Apparatususedinexperiment:
9
(iii) Thelightintensitywasvariedbyalteringthe distanceofthelampfromtheapparatus.
(iv) Thefactorkeptconstantwastemperature(or carbondioxideconcentration).
(v) Thetemperaturewaskeptconstantbyusinga waterbathatthesametemperature.
(vi) Therateofphotosynthesiswasmeasuredby countingthenumberofbubblesperminute releasedbytheunderwaterplant.
(vii) Errorsmayarisebymiscountingthebubbles (orotheracceptableanswerssuchastaking wrongmeasurementsofthedistanceor miscalculatingorthelightintensityintheroom changingetc.).
(a) Anyofthefollowingfactorsareacceptable: lightintensity,temperatureorcarbondioxide concentration.Thefollowinganswersarebasedon temperature.
(b) Thetemperatureisvariedbyusingwaterbathsat differenttemperatures.
(f) Thebenefitofpondweedisthatitgrows underwater.Thisallowsthebubbles(ofoxygen)to beseenandcounted.Thenumberofbubblesper minuteindicatestherateofphotosynthesis.
10
(a) Suitableplantsinclude:hornwortormyriophyllumor anynon-invasiveunderwaterplant.
(b) Oxygen
(c) Thenormaltestforoxygenisthatitrelightsa glowingsplint.
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(c) Therateofphotosynthesiswasmeasuredby countingthenumberofbubblesperminutereleased bytheunderwaterplant.
(d) Anotherfactorkeptconstantwaslightintensity(or carbondioxideconcentration).
(e) Lightintensitywaskeptconstantbykeepingthe lampatthesamedistancefromtheapparatus(orby usingthesameconcentrationofsodiumhydrogen carbonate).
(d) Thecarbondioxideconcentrationiskeptconstantby addingexcesssodiumhydrogencarbonatetowater. Thissaturatesthewaterwithcarbondioxide.
(e) Placetheapparatusinawaterbathataconstant temperature.
(f) Thelightintensitycouldbevariedbyalteringthe distancebetweenthelampandtheapparatus(orby usingalampwithadimmerswitch).
(g) Therateofphotosynthesiscouldbemeasuredby measuringthevolumeofgasproducedinagiven time(orbycountingthenumberofbubblesreleased perminute).
11
(a) Suitableplantsinclude:hornwortormyriophyllumor anynon-invasiveunderwaterplant.
(b) Thebenefitofunderwaterplantsisthatthe bubbles(ofoxygen)canbeseenandcounted.The numberofbubblesperminuteindicatestherateof photosynthesis.
(c) Anyofthefollowingthreefactorsisacceptable: lightintensity,temperatureorcarbondioxide concentration.Thefollowinganswersarebasedon carbondioxideconcentration.
(d) Carbondioxideconcentrationwasvariedbyusing waterwithdifferentconcentrationsofsodium hydrogencarbonate.
(e) Itwasimportanttokeepotherfactorsconstant becauseineachinvestigationthereshouldbeonly onevariablefactor.
(f) Factorskeptconstantweretemperatureandlight intensity.
(g) Temperaturewaskeptconstantbyusingawater bathatthesametemperature. Lightintensitywaskeptconstantbykeepingthe lampatthesamedistancefromtheapparatus.
(h) Therateofphotosynthesiswasmeasuredby countingthenumberofbubblesreleasedper minute.
12
(a) Suitableplantsinclude:hornwortormyriophyllumor anynon-invasiveunderwaterplant.
(b) Therateofphotosynthesiscouldbecalculated bycountingthenumberofbubblesreleasedper minute.Thisshouldbedonethreetimesandthe averagerateperminuteobtained.
(c) Thefactortheycouldvaryiscarbondioxide concentration.
(d) Carbondioxideconcentrationcouldbevariedby usingwaterwithdifferentconcentrationsofsodium hydrogencarbonate.
(e) Temperatureandlightintensity.
(f) Temperature:byusingawaterbathatthesame temperature.
Lightintensity:bykeepingthelampatthesame distancefromtheapparatus.
(g) Globalwarmingmeansthatthetemperature isincreasing.Thismayincreasetherateof photosynthesisandincreasefoodproduction.
Foodcropsmayalsobeabletogrowinregionsthat werepreviouslytoocold.
Anotherpotentialbenefitisthatthegrowingseason maybelonger.
13 HL
(a) Light-dependentreactions
(b) Light-independentreactions
(c) Light-dependentreactions
(d) Light-dependentreactions
(e) Light-dependentreactions
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(a)(i) Anabolicmeansthatenergyisusedtoconvert smallermoleculesintolargermolecules.
(ii) Photosynthesistakesplaceinchloroplasts.
(iii) Chlorophyll
(b) Carbohydrates
(c)(i) HydrogenionsorH+andelectronsore(ii) Possiblefatesforoxygenarethatitisreleased outoftheplantoritisusedintheplantfor respiration.
(d)(i) Sourcesofcarbondioxide:theatmosphereor respirationwithintheplant.
(ii) Carbondioxidemayenterplantsthrough stomataorthroughlenticels.
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(a) Thelight-dependentreactionscanonlytakeplacein thepresenceoflight.
Thelight-independentreactionsdonotneedlight.
(b) Diagramoforganellewherephotosynthesistakes place:
Chloroplastmembranes
Asinglethylakoid()
Stackofthylakoids(granum) –Lightdependentstage LoopofDNA Stroma–Lightindependentstage
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(a) Chlorophyll
(b) Thesourceoftheenergyis(sun)light.
(c)(i) Inthenon-cyclicpathwaytheelectronsleave chlorophyllandpassalongaseriesofelectron acceptorsandeventuallycombinewithNADP+ toformNADPH.
Inthecyclicpathwaytheelectronsleave chlorophyllandpassalongaseriesofelectron acceptorsandeventuallypassbacktothe chlorophyllmolecule.
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(c) Seediagramabove.
(ii) Theend-productsofthenon-cyclicpathwayare ATP,NADPHandoxygen.
Theend-productsofthecyclicpathwayareADP, NADP+andglucose.
(d)(i) Electrontransportchains:boththenon-cyclic andthecyclicpathways
(ii) Thesplittingofwater:non-cyclicpathway.
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(a) Thefunctionofthepigmentsistocollectlight.
(b) Thereasonforhavingarangeofpigmentsisto collectarangeofwavelengthsorcoloursoflight andpasstheenergyontothereactioncentre chlorophyll.
(c) Inthechlorophyll.
(d) Electronsfirstbecomeenergisedinchlorophyll.
18
(a) Athylakoidisaflattenedmembraneenclosed structurefoundinchloroplasts.
(b) Chlorophyll
(c) ATPsynthase
(d)(i) X=ADP
(ii) Y=ATP
(iii) Theenergyissuppliedbytheflowofhydrogen ionsacrossthemembrane.
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(a) Stomataallowforgasexchangeinphotosynthesis (i.e.theyallowcarbondioxidetopassinandoxygen andwatertopassout).
(b) Thereactioncentrechlorophyllallows(light)energy totransfertoelectrons.Inthiswaytheelectrons becomeenergised.
(c) Theparticlesreleasedfromchlorophyllare energisedelectrons.
(d) TheelectronsformNADPH.
(e) Theeventsinthelight-independentreaction: Carbondioxideisconvertedtoglucose.
NADPHreleaseshydrogenionsandenergised electrons.
NADPHisconvertedtoNADP+ ATPreleasesenergy. ATPisconvertedtoADP. Glucoseisformed.
(f) Thelight-independentreactionssupplyADPand NADP+tothelight-dependentreactions.
20
(a) Themaineventsinthelight-independentreactions are:
Carbondioxideisconvertedtoglucose.
NADPHreleaseshydrogenionsandenergised electrons.
NADPHisconvertedtoNADP+ ATPreleasesenergy.
ATPisconvertedtoADP. Glucoseisformed.
(b) Thelight-independentreactionsaremainlyanabolic reactions.Thisisbecauseenergyisusedtoconvert carbondioxidetoglucose. However,thebreakdownofNADPHandATPare bothcatabolicreactions.
(c) ADPandNADP+areusedinthelight-dependent reactions.
(d) NADPHtransfersbothhydrogenions(H+)and electronstocarbondioxide.
(e) Labelleddiagramofachloroplast:
Chloroplastmembranes
Asinglethylakoid()
Stackofthylakoids(granum) LoopofDNA Stroma
Theinternalstructureisadaptedtofacilitate photosynthesisasfollows:Theycontainflat membranediscscalledthylakoids.
Thylakoidscontainpigmentstotrapsunlight. Themembranesofthethylakoidscontainelectron transportchainsandtheenzymeATPsynthase. Stromacontainsallthemoleculesneededforthe light-independentreactions
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(a) Thesplittingofwateriscalledphotolysis.
(b) X=Oxygen
(c) Y=NADPH
(d) MoleculeYisproducedwhenNADP+gainselectrons andhydrogenionsorprotons.
(e) Stage2isthelight-independentstage.
(f) ATP=Adenosinetriphosphate.
(g) TheroleofATPistotransferenergy.
(h) Z=Glucose
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(a)(i) ThemostabsorbedcolourbychlorophyllAis violet.
(ii) ThemostabsorbedcolourbychlorophyllBis blue.
(iii) Greenandyellowlightisreflected.
(b) Theenergisedelectronsmayreturntochlorophyllor enteracyclicpathwayorpasstoelectroncarriers(or acceptors).
TheenergisedelectronsmaytransfertoNADP+ (acceptNADP)orformNADPHorenteranon-cyclic pathwayorjoinwithCO2 toformglucose.
(c) Electronsarealsoprovidedbywaterwhenitsplits.
(d) Themainsourceofwaterforplantsisfromthesoil.
CHAPTER15 RESPIRATION
1
(a) Respirationisthecontrolledreleaseofenergyfrom food.
(b) Livingthingsgettheirenergyfromrespirationto allowotherprocessestooccurinthebody.
(c) Glucose
2
(a) Similaritiesbetweenaerobicandanaerobic respiration:
BothproduceATP. Bothbeginwithglycolysis. Bothinvolvethebreakdownofglucose.
(b) Differencesbetweenaerobicandanaerobic respiration:
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Oxygenisrequiredforaerobicrespirationandisnot neededforanaerobicrespiration. AerobicrespirationproduceslargeramountofATP. Aerobicrespirationoccursinmitochondriawhile anaerobicrespirationoccursincytosol.
3
(a) Carbondioxide,ATP,andwater.
(b) Lacticacid,andasmallamountofATP.
(c) Ethanol,carbondioxide,andasmallamountofATP.
4
(a) Balancedchemicalequationforaerobicrespiration:
(b) (i) Aerobicrespiration:
(ii) Anaerobicrespirationinamusclecell:
Glucose 2lacticacid+asmallamountofenergy
(iii) Anaerobicrespirationinyeast:
Glucose Ethanol+2carbondioxide+asmallamountofenergy
5
(a) Reactantsarethesubstancesthatarepresentatthe startofachemicalreaction.
(b) Sourceofglucose:foodweeatsuchasbreadand fruits.
Sourceofoxygen:takenfromtheairthroughthe lungs.
(c) CarbondioxidewhichisproducedduringtheCitric acidcycle(orKrebsCycle).
Waterwhichisformedattheendoftheelectron transportchainwhenoxygencombines withelectronsandhydrogenions.
ATPwhichisformedthroughstage1andstage2 (butmostATPismadeduringtheelectrontransport chain).
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(a)(i) Doesnotrequireoxygen.
(ii) Carbondioxide
(b)(i) Apparatususedtocarryoutafermentation experiment:
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6
(a) Carbondioxidewhichisagas.
(b) Advantage:plantsabsorbcarbondioxideduring photosynthesistomakeglucose.
(c) Problem:itisagreenhousegaswhichcanleadto globaltemperaturesrising.
(d) ATP
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(a) X=OxygenandY=Glucose.
(b) Benefit:providesalargeamountofenergy(ATP)for prolongedactivity.
(c) Anathletegetsoxygenfromtheatmosphereandit entersthebloodthroughthelungsbydiffusion.
(d) Lacticacid
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(a) Yeast
(b) Bakingindustryandbrewingindustry
(c) Inthebakingindustry,CO₂,carbondioxide.
Inthebrewingindustry,ethanol(alcohol)isthemain product.
(d) Carbondioxide(CO₂):inthebakingindustry,CO₂ causesdoughtorise,givingbreaditslightandairy texture.
Ethanol(alcohol):inthebrewingindustry,ethanolis themainproduct,formingthealcoholiccontentin beverageslikebeerandwine.
Waterbath (30°C) Oil
Boiledglucose solution+yeast
Waterbath (30°C)
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(a) Aerobicrespirationisthecontrolledreleaseof energyfromfoodusingoxygen.
(b) Products:water,carbondioxideandATP.
(c) Oxygen
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Boiledglucose solution+yeast
(ii) Woreprotectivegear(labcoats,goggles,gloves) andhandledglasswarecarefully.
(iii) 30°C
(iv) Nomorecarbondioxidebubblesformed.
(v) Controls:noyeastwasaddedtoglucose solution.
Yeastandglucosewereputinawaterbathat 30°C(soenzymesinyeastbecomedenatured).
(a)(i) Oxygenmustbeabsent.
(ii) Lessenergyisreleasedfromanaerobic respiration.
(b)(i) FlaskA
(ii) Yeastproduceslargeramountsofcarbon dioxideduringanaerobicconditionsandthatis whyyouseecarbondioxidebubbles.
(iii) FlaskBisthecontrol.
(iv) Yeastandglucose
(v) Tokeeptemperatureconstantat30°C.
(vi) Thefermentationlockletsthisgasescapefrom thecontainerwithoutlettingoxygen,bacteria, enter.Thishelpsmaintainasterileenvironment, preventingspoilageorunwantedmicrobial growth.
Conicalflask
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(a) Wordequationforglycolysis:
2ADP+2 P2 ATP+water
Glucose (C6)
(C3)
2NAD+ 2NADH
(b) Pyruvicacid(pyruvate),ATPandNADH.
(c) Cytosol(orcytoplasm)
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(a) Presenceofoxygen:pyruvicacidentersstage2of aerobicrespiration.
NADHtransferselectronstotheelectrontransport chain
ATPreleasesenergyforcellularprocessesormuscle contractionofactivetransport.
(b) Absenceofoxygen:pyruvicacidturnsintolacticacid inmusclesorethanolandcarbondioxideinyeast whenoxygenisabsent.
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(a) Inthemitochondria.
(b) End-products:carbondioxide,NADHandATP.
(c) AcetylCoA(AcetylCoenzymeA)
(d) NADH
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(a) ItproducesalargeamountofATP.
(b) Theelectronsaretransferredtooxygen(thefinal electronacceptor)toformwater.
(c) Intheinnermembraneofmitochondria(cristae).
(d) Theparticlesarehydrogenions(H⁺),alsoknown asprotons.(Thesearepumpedacrosstheinner mitochondrialmembrane,creatingaprotongradient thatdrivesATPsynthesisthroughATPsynthase).
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(a) Glycolysis
(b) Pyruvicacid(orpyruvate)
(c)(i) Yeast:convertedtoethanolandcarbondioxide.
(ii) Muscles:convertedtolacticacid.
(d) Carbondioxide
(e) Criticacidcycle(orKrebscycle)
(f) Inthemitochondria.
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(a) DifferencesbetweenStage1andStage2: Oxygenrequiredforaerobicrespirationandisnot neededforanaerobicrespiration.
AerobicrespirationproduceslargeramountofATP thananaerobicrespiration.
(b) Inthecytosol(orcytoplasm).
(c) Anaerobic
(d) Ethanolandcarbondioxideinyeastandlacticacidin muscles.
(e) ATP
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(a)(i) Glycolysis
(ii) ATP
(iii) ADPcombineswithanotherphosphate(p)and energytoformATP.
(iv) Pyruvicacid(orpyruvate)
(v) W=Mitochondria
(vi) X=AcetylCoA(AcetylCoenzymeA)
(vii) Y=Citricacidcycle(orKrebscycle)
(viii) Z=Lacticacid
(ix) Whenoxygenisused,alargeramountofenergy isreleased.
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(a) Cellorganelleassociatedwithrespiration:
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(b) Theinnermembranecontainsinfoldingswhich increasethesurfacearea(forelectrontransport chains).
Mitochondriaareenclosedinadoublemembrane (whichretainallthebiomoleculesneededfor respiration).
MitochondriahavetheirownloopofDNA(which makessomeofthebiomoleculesneededfor respiration)oranyacceptableanswer.
(c) Pyruvicacid(pyruvate)
(d) AcetylCoA(AcetylCoenzymeA)
(e) NADHreleaseshigh-energyelectrons.Theelectrons arepassedfromelectroncarriertoelectroncarrier alongthechain.Theelectronsreleaseenergyto pumpprotonsintothespacebetweenthetwo membranes.Protonspassbackacrosstheinner membranethroughATPsynthase,formingATP.
2Pyruvicacid
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(a)(i) No
(ii) Cytosol(orcytoplasm)
(b) (i) Labelleddiagramoftheapparatusused:
(v) Boilingglucosesolution,addingalayerofoil, usingafermentationlock.
(vi) Nomorecarbondioxidebubblesformed.
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(a) From08.00amtherateofphotosynthesisbegins toincreaseaslightisnowavailable.Itcontinuesto increaseupto14:00whenlightintensityfromthe sunisatitshighest.Thentherateofphotosynthesis decreasesuntil18:00aslesslightisnowavailable untilphotosynthesisstopstakingplace.
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Boiledglucose solution+yeast
Waterbath (30°C)
Boiledglucose solution+yeast Waterbath (30°C)
(ii) Glucose
(iii) 30°C
(iv) Byusingawaterbath.
(b) Glucose
(c) At11amand17:00(5pm).
(d)(i) Glucoseusedinrespiration=Glucose producedinphotosynthesis.Theplantisnot gainingorlosingglucoseoverall.
(ii) RateofCO₂uptakebyphotosynthesis=Rateof CO₂releasebyrespiration.
ThereisnonetgainorlossofCO₂inthe environment.
(iii) O₂producedbyphotosynthesis=O₂consumed byrespiration.
Thereisnonetgainorlossofoxygen.
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(a) Stage2
(b) Stage1
(c) Stage2
(d) Stage2
(e) Stage2
(f) Stage1
(g) Stage1
CHAPTER16 CELLDIVISIONANDCANCER
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(a) Thecellcycleisaseriesofeventsthattakeplaceina cellduringtheperiodbetweenonecelldivisionand thenext.
(b)(i) Inthelongestphasesofthecellcyclethecellis growinginsize,carryingoutmetabolism,making neworganellesandformingcopiesofitsDNA.
(ii) Intheshortestphaseofthecellcyclecell divisiontakesplace.
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(a) DNAreplicationmeansthatanoriginalDNA moleculemakestwoidenticalcopiesofitself.
(b) Inthenucleus.
(c) TheroleofDNAreplicationistomakeexactcopies ofDNAwhichcanthenseparateduringcelldivision.
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(a) DNA=Deoxyribonucleicacid
(b) Acomplementarypairistwonucleotidesthatmatch eachother(seechapter10).
(c) ComplementarypairsinDNAareadenineand thymine(AandT)andguanineandcytosine(G andC).
4
(a) BeforeDNAreplicationbeginstheDNAdoublehelix unwindsandthebasepairsseparate.
(b) ThecomplementarystrandisCTAAGCATT.
5
(a) X=Deoxyribose
(b) Y=Phosphate
(c) 1=Thymine 2=Cytosine
(d) DiagramofnewsectionsofDNAformed:
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(a) Haploidmeansthecellornucleushasonlyonesetof chromosomes.
(b) Diagramofahaploidcell:
(c) Theroleofmeiosisistohalvethechromosome numberandallowforsexualreproductionandto formcellswithnewcombinationsofgeneswhich causesgeneticvariation.
(c) Diploidmeansthecellornucleushastwosetsof chromosomes.
(d) Diagramofadiploidcell:
Pairsof chromosomes
2n=4
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(a)(i) Meiosishalvesthechromosomenumber.
(ii) Mitosiskeepsthechromosomenumberthesame.
(b) DNAreplication
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(a) Mitosistakesplaceinskincells(orinthebone marroworinanynamedbodyorgan).
(b)(i) Ahaploidhumancellhas23chromosomes.
(ii) Humancellsresultingfrommitosishave 46chromosomes.
(iii) Cellsthatresultfrommitosisshouldhave identicalgenes(unlessamutationtakesplace).
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(a) Atumourisamassofcells.
(b) Abenigntumourstopsgrowing,doesnotspread toinvadeothertissuesandisnotcancerous.A malignanttumourcontinuestogrow,spreadsto invadeothertissuesandiscancerous.
(c) Malignanttumoursarecancer.
(d) Cancerisagroupofdisordersinwhichcertaincells losetheirabilitytocontroltherateofmitosis,and thenumberoftimesmitosistakesplace.
(e) Earlydetectionofcancerissignificantbecausethe cancercellsmaynothavespread.
(f) Vaccinesstimulatethebodytoproduceantibodies againstspecificdisease-causingorganisms(such asviruses).Forexample,avaccinecanactagainst theHPVvirusandpreventitfromcausingcervical cancer.
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(a) Environmentalfactorsthatincreasetheriskof cancerincludesmokingcigarettes,exposureto ultra-violetradiationandinhalingasbestosfibres.
(b) Therisksat(a)canbereducedbynotsmokingandby avoidingexcessiveultra-violetradiationorbywearing sunscreenwithhighsunprotectionfactor(SPF).
(c) Cancercanspreadinthebloodstreamorinasystem ofcolourlessfluidthatcirculatesallaroundthebody (calledthelymphaticsystem).
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(a)(i) 800000
(ii) 2million
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(a) Mitosisandmeiosis
(b)(i) Thechromosomenumberismaintainedin mitosis.
(ii) Mitosisformsidenticaldaughtercells.
(iii) Meiosishalvesthechromosomenumber.
(iv) Meiosisproducescellswithdifferent combinationsofgenes.
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(a) Thecellshows6chromosomes.
(b) Thecellisdiploid.Therearetwoofeach chromosome(ortwosetsofchromosomes).
(c) Aftermitosiseachcellwillhave6chromosomes.
(d) Thereare6centromeres. HL
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(e) Thereare12chromatids. HL
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(a) Inunicellularorganismstheroleofmitosisis reproduction.
(b) Inmulticellularorganismstheroleofmitosisis growthandrepair.
(b) Thenumberofpeoplewithmalignantmelanoma increasedsteadilyfrom2000to2020.
(c) Thenumberofmelanomasmayhaveincreaseddue togreaterexposuretosun(asthenumberofsun holidaysincreasedinthesametimespan).
(d) Eitherofthefollowinganswersisacceptable(once theexplanationmatchesthestatement).
Yes,thehypothesisissupported.
Reason:thisisbecausefrom2000to2020the numberofpeoplewearingsunscreenandgetting melanomaislowerthanthenumberofpeoplenot usingsunscreen.
No,thehypothesisisnotsupported.
Reason:thisbecausethereasonforthedifference shownmightnotbesunscreenbeingappliedornot. Itmightbethatthosewearingsunscreenonlywent intothesunforshorterperiodsoftime(orthatthe sunwasnotastrongorsomeotherreason).
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(a) GenesaremadeDNA.
(b) Atumoursuppressorgenepreventscancer(by controllingcelldivisionandbyensuringDNAis repaired).
(c) Theinactivationofageneinthiswayiscalled epigenetics.
(d) Theinactivationofthep53geneincreasestheriskof cancerdeveloping.
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(a) ThestagerepresentedbyXiscellgrowth.
(b) DNAreplicationtakesplaceinstageY.
(c) Prophase,metaphase,anaphase,telophase.
(d) Spindlefibrescontractinanaphase.
(e) Diploidnumbermeansthecellornucleushastwo setsofchromosomes.
(f) Cancer
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(a) Interphase
(b) Interphaseisnotarestingphasebecausethecellis growing,carryingoutmetabolism,producingnew organellesandmakingcopiesofitsDNA.
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(a) Prophase,metaphase,anaphase,andtelophase.
(b)(i) Telophase
(ii) Metaphase
(iii) Prophase
(iv) Anaphase
(v) Telophase
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(a) Thenuclearmembranemustbreakdowntoallow thechromosomestobepulledtooppositeendsof thecell.
(b) Spindlefibresformtopullthechromosomesto oppositeendsofthecell.
(c) Allofthechromosomesarepulledapart.
(d) Eachresultingnucleuswillhavethesamenumberof chromosomesaswerepresentintheoriginalcell.
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(a) Meiosishalvesthenumberofchromosomes.
(b) Mitosistakesplaceinskincells(orinthebone marroworinanynamedbodyorgan).
(c) Fertilisationdoublesthenumberofchromosomes.
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(a) Theeggofachimpanzeehas24chromosomes.
(b) Thespermofachimpanzeehas24chromosomes.
(c) Achimpanzeezygotehas48chromosomes.
(d) Achimpanzeemouthcellhas48chromosomes.
(d) Thefunctionsofmeiosisaretohalvethe chromosomenumberandallowforsexual reproductionortoformcellswithnewcombinations ofgeneswhichcausesgeneticvariation.
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(a) B,A,D,C.
(b) Interphase
(c) Mitosisandmeiosis.
(d) Cytokinesisisthedividingofthecytoplasmtoform twoseparatecellsimmediatelyaftermitosis.
(e) Cancer
(f) Environmentalcausesofcancerincludesmoking cigarettes,exposuretohighenergyradiationsuch asultra-violetradiationorX-rays,asbestosfibres, pesticides,exhaustfumesandradongas.
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(a) Thestageofnon-divisioninthecellcycleiscalled interphase.
(b) Cellactivitiesduringinterphaseincludecellgrowth, respiration,photosynthesis,digestion,excretionand DNAreplication.
(c)(i) Anaphase.
(ii) Thechromosomesarebeingpulledtoopposite endsofthecell.
(d) Thestageimmediatelybeforeanaphaseis metaphase.
(e) Sketchofacellwithadiploidnumberof4:
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(a) A=Chromosome(orchromatid)
B=Centromere
C=Spindlefibre
(b) Thestageshownismetaphase.
(c) Thediploidnumberis4.
(f) Inmulticellularorganismsthefunctionofmitosisis growthandrepair.
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(a) Thecontrolgroupshouldhavebeenselectedat random.
(b) Thecontrolgroupshouldbetreatedthesameasthe groupthatwasgettingtheTaxolinjectionsexcept thattheywouldnotgetTaxolinjections(i.e.the samecageconditions,thesametemperature,the samefoodbutinjectedwithasolutionthatdidnot containanyTaxol).
(c) Comparedtothelength,thevolumeisamore accuratemeasureofthetotalnumberofcellsin eachtumour.
(d) Thetumoursgrewslowerandweresmallerinthe ratsthatweretreatedwithTaxol.
(e) TheresultsdonotindicatethatTaxolpreventsall tumours.Thetumoursgrewinbothsetsofrats. However,after40daysthetumoursweresmallerin theratsthatweretreatedwithTaxol.
(f) TheratstreatedwithTaxolhaddisturbedspindles. Thismeantthattheircellscouldnotdivideasfastas cellswhichwerenotexposedtoTaxol.Thiscaused thetumourstobesmaller.
CHAPTER17 DNAREPLICATION,PROTEIN SYNTHESISANDMUTATIONS
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(a) DNAreplicationtakesplaceinthenucleus.
(b) DNApolymerase
(c)(i) 3basepairs
(ii) 2triplets(AGXandXYA)
(iii) DiagramtoshownewDNAproduced:
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(a) MessengerRNAormRNA.
(b) ThecomplementarystrandtoATTGGCATTis TAACCGTAA.
(c) Ribosomes
(d) Aminoacids
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(a) DNA
(b) ThefourbasesinDNAareadenine,thymine,guanine andcytosine.
(c) X=Thymine Y=Cytosine
(d) MostDNAisfoundinthenucleus.
(e) mRNA(ormessengerRNA)
(f) TheRNAbasescomplementarytoATTGCAare UAACGU.
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(a) Thereare2strandsinaDNAmolecule.
(b) ThebasepairsinDNAareeitheradenine/thymineor guanine/cytosine.
(c) BeforereplicationtheDNAdoublehelixunwindsand thenanenzymebreaksapartthehydrogenbonds betweenthebasepairs.
(e)
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(d) mRNAormessengerRNA
Containsthesugar deoxyribose Containsthesugar ribose
HasthebasethymineHasthebaseuracil
(f) Aminoacids
(g) Tobecomefunctionalproteinsthesmaller moleculesjointogetherandthentheproteinfolds tohavethecorrectshape.
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(a) TranscriptionistheconversionofDNAto complementarystrandofmRNA.Translationisthe conversionofasequenceofbasesonmRNAintoa protein.
(b) Thenucleus
(c) mRNA
(d) Ribosome
(e) Protein
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(a) RNAisribonucleicacid.
(b) The3typesofRNAare:messengerRNA(mRNA), transferRNA(tRNA)andribosomalRNA(rRNA).
(c) MessengerRNA(mRNA)carriesacode(ormessage) fromDNAtotheribosome.
TransferRNA(tRNA)carriesaspecificaminoacidto theribosome.
RibosomalRNA(rRNA)formsthestructureofthe ribosome.
(d) RNAisfoundinthenucleus,inthecytoplasmandin aribosome.
(e) ThesequenceofbasesonDNAisconvertedintoa complementarysequenceofbasesonRNA(orthe codecarriedbyDNAisconvertedtoacodeonRNA).
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(a)(i) Atripletisasequenceof3basesonDNAorRNA.
(ii) Acodonisasequenceof3bases(atriplet)on DNAorRNAthatspecifiesaparticularamino acid.
(iii) Ananticodonisasequenceof3basesintRNA thatarecomplementarytoasequenceof3 bases(acodon)inmRNA.
(b) Astartcodonindicatesthebeginningofagene. Mostcodonscodeforaparticularaminoacid. Astopcodonindicatestheendofagene.
(c) Ananticodonisassociatedwithaparticularamino acid.
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(a) Ribosomesaremadeofribosomalribonucleicacid (rRNA).
(b) MessengerRNA(mRNA)andtransferRNA(tRNA) (c)(i) mRNAisformedintranscription. (ii) tRNAisassociatedwithaminoacids.
(iii) tRNAcontainsanaminoacid.
(d) Whentheproteinleavestheribosome,itfoldsto makeitfunctional.
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(a) TranscriptionistheconversionofDNAto complementarystrandofmRNA.Translationisthe conversionofasequenceofbasesonmRNAintoa protein.
(b) Translationoccursintheribosome.
(c) 3basesinsequenceformacodon.
(d) mRNAcodonscanspecifythestartofagene,an aminoacidandtheendofagene.
(e) The“t”inTRNAstandsfortransfer.
(f) Anaminoacid.
(g) Inribosomesorinthecytosol(orcytoplasm)
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(a) ProcessK:transcription.
(b) MoleculeL:messengerormRNA.
(c) Thebasesequence:UGCACGACU.
(d) MoleculeLleavesthroughanuclearpore.
(e)(i) StructureM:ribosome.
(ii) StructureMismainlymadeofribosomalorrRNA.
(f) tRNAbringsaminoacidstotheribosome.tRNAbinds tomRNAwiththecodon(ortriplet)matchingthe anticodon.Asequenceofaminoacidsassembles orpeptidebondsform.Theproteinfolds.(Students shouldmentionastartorastopcodon.Any3or4of theabovepointsproperlyexplainedwouldsuffice).
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(a) Amutationisasuddenchangeintheamountor structureofDNA.
(b) Mutagensareagentsthatcause(orspeedupthe rateof)mutations.
(c) Agentsthatincreasetherateofmutations include:x-rays,gammarays,cosmicrays,UVrays, formaldehyde,smoke,dioxins,pesticidesandsome viruses.
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(a) Point(orgene)mutationsandchromosomal mutations.
(b) Anexampleofapointmutationiscysticfibrosis. Cysticfibrosiscausestheproductionofathick, stickymucus.Thismucusclogsthelungsleading toinfectionsandblocksthepancreasleadingto digestiveproblems.
AnexampleofachromosomemutationisDown syndrome.Thisiscausedbyanextrachromosome whichcausesarangeofphysicalandintellectual features.
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(d) PrecautionsincludeleadshieldwhenbeingX-rayed, highsunprotectionfactorsunscreens,avoidinhaling smokeandavoidothermutagens.
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(a) Mutationscausegeneticvariations.Natureselects thosevariationsthatallowtheorganismtolive longerandreproducemoreoften.
(b) Withoutmutations,evolutionwouldstilltakeplace becausesexualreproductionalsocausesgenetic variations.
(c)(i) Albinismiscausedbyalackofthechemical calledmelanin.
(ii) Melaninprotectsagainstultra-violetradiation. Withoutmelaninpeoplearemorelikelytosuffer frommutations.Peoplewithalbinismshould avoidprolongedexposuretosunlightand protecttheirskinwithhigh-factorsunscreen.
(d) MessengerormRNA
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(a) Apointmutationisachangeinasinglebaseorgene. Achromosomalmutationisachangeinmanygenes orinalargersectionofDNA.
(b) Examplesofpointmutationsinclude:cysticfibrosis, haemophilia,albinismandsickle-cellanaemia.
(c) Examplesofchromosomalmutationsinclude: deletions,duplications,inversions,translocations andDownsyndrome.
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(a) Chromosomalmutations:deletions,duplications, inversionsandtranslocations.
(b)(i) Inversion
(ii) Deletion
(iii) Duplication
(iv) Translocation
CHAPTER18 THEMUSCULOSKELETALSYSTEM
1
(a)(i) Astimulusisanythingthatcausesareactionin anorganismorinanyofitsparts.
(ii) Aresponseistheactivityofanorganismorany ofitspartsasaresultofastimulus.
(b) Examplesofanimalstimuliincludenoise,sight,smell, pain,hungeretc.
(c) Examplesofplantstimuliincludelight,gravity,water andchemicals.
(d) Animalresponsesincludemovement,productionof enzymesorhormonesandfeeding.
(e) Plantresponsesincludegrowth,flowering,fruit formationandproductionofenzymes.
2
(a) Muscularsystem,skeletalsystem,nervoussystem
(b) Chemical(orhormonal)system,defencesystem, reproductivesystem,celldivision.
3
(a) Adaptationisanalterationthatimprovesan organism’schanceofsurvivalandreproduction.
(b) Anatomicaladaptationisastructuralalteration.
(c) Anatomicaladaptationsinplantsincludeneedle shapedleaves,achangeinthenumberofstomata, achangeinthethicknessofthecuticle,thornsor spikes.
(d) Chemicaladaptationsinplantsincludeplant hormones(orgrowthregulators)ortoxicchemicals inleaves.
4
(a) Thefunctionsoftheskeletonincludesupport, protection,movement,shapeandmanufactureof bloodcomponents.
(b) Support:boneskeepthebodyupright.
Protection:skullprotectsthebrain,vertebrae protectthespinalcord,ribsprotecttheheartand lungs.
Movement:bonesactasrigidleversagainstwhich musclescanpull.
Shape:theskeletongivesabasicshapetothebody. Manufactureofbloodcomponents:redandwhite bloodcellsandplateletsareformedinbonemarrow.
D=Humerus
E=Femur
F=Patella
(b) B(rib)protectsthelungsandheartorallowsfor inhalation/exhalationorgivesshapetothechest.
(c) X,YandZareallsynovialjoints.
(d) Bonesinthepectoralgirdle:Clavicleandscapula.
(e) Eispartoftheappendicularskeleton.
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(a) A=Neuralspine
B=Transverseprocess
C=Neuralcanal
D=Centrum
E=Facet
(b) AandBbothfunctioninmuscularattachment.
(c) ThespinalcordisfoundinC.
(d) ThefunctionofEistoallowthenextvertebrato rotateslightly.
8
(a) Astimuluscausesareaction(orresponse).A responseistheactioncarriedoutduetoastimulus.
(b) Thepectoralgirdleistheshoulder.Thepelvicgirdle isthehip.
(c) Ligamentsconnectbonetobone.Tendonsconnect muscletobone.
9
(a) Vertebraearethebonesofthebackbone.
(b) Thestructuresbetweenthevertebraearethe (intervertebral)discs.
(c) Thediscsprotectthevertebraeandactasshock absorbers.
10
(a) A=Scapula
B=Humerus
C=Radius
D=Carpal(s)
(b) Xisasynovialjointorafreelymovablejoint.
(c) Eisthebiceps.Itiscontracted.
11
5
(a) Theaxialskeletonparts:skull,sternum,ribsand vertebrae(orbackbone).
(b) Theappendicularskeletonparts:clavicle,scapula, bonesofthearmsandlegs(maybenamed individually),pelvis.
6
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(a) A=Synovialmembrane(acceptligament)
B=Cartilage
(b) C=Synovialfluid
(c) TissueC(synovialfluid)lubricatesthejointand reducesfriction.
(d) Tendonconnectsbonetomuscle.
(a) A=Skull
B=Rib(s)
C=Pelvis(orpelvicgirdle)
(e) TissueB(cartilage)protectsthebones,actsasa shockabsorberandreducesfriction.
(f) Themainbiomoleculeincartilageiscollagen.
12
(a) A=Tendon
B=Patellaorkneecap
C=Femur
D=Synovialfluid
E=Cartilage
(b) Thekneeisasynovialjoint.
(c) Misaflexor(straightenstheleg).
(d) ThepartnerofMisatpositionX.
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(a) Cartilageprotectsbones,actsasashockabsorber andreducesfriction.
(b) Ligamentconnectsbonetobone.
(c) Tendonconnectsbonetomuscle.
(d) Synovialfluidlubricatesthejointandreduces friction.
14
(a) Aslippeddiscpressesonanerve.Thepainisfelt wherethenerveends(e.g.intheleg).
(b) Ligamentsandtendonshaveapoorbloodsupply andsoareslowtoheal.
(c) Whenwerest(orsleep)theintervertebraldiscs expandslightly.Thismakesusslightlytallerinthe mornings.Whenweareactivebydaythediscs compressandmakeusslightlysmaller.
(d) Flexormusclesclosethejawwhenwebiteonfood (sotheymustbestrong).Theextensormusclesonly havetoopenthejawandsoareweaker.
(e) Ifthejointsbetweendiscswerefreelymovable,they woulddamagethenervesinthespinalcord.
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(a) Anantagonisticpairistwomusclesthathave oppositeeffects.
(b) Thebicepsandtricepsformanantagonisticpair.
(c) Musclescanonlycontract.Theycannotelongate themselves.Inanantagonisticpair,thefirstmuscle contractsandelongatesthesecond.Later,the secondmusclecontractsandelongatesthefirst.
(d) Aflexorclosesajoint.Anextensoropensajoint.
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(a) Functionsincludesupport,protection,movement, shapeandbloodcomponentmanufacture.
(b)(i) Thecervicalvertebraearefoundintheneck.
(ii) Thelumbarvertebraearefoundinthesmall(or lowerpart)oftheback.
17
(a) Diagramofthestructureofasynovialjoint: Labels=Anythreeof:muscle,tendon,ligament, cartilage,synovialmembrane,synovialfluid.
Muscle Tendon
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(c) Thespinalcordrunsthroughthevertebrae.
(d) Humerus,radiusandulna.
Ligament
Synovial fluid
Ligament
Cartilage
Muscle
(b) Functionsofanythreelabelledparts: Musclecontractstomovethejoint. Tendonconnectsmuscletobone. Ligamentconnectsbonetobone.
Cartilageprotectsbones,actsasashockabsorber andreducesfriction.
Synovialmembranesecretesandretainssynovial fluid.
Synovialfluidlubricatesjointsandreducesfriction.
18
(a) A=Scapula
B=Humerus
C=Ulna(theradiusisnearesttothethumb)
(b) Tendonsattachmuscletobone.
(c) Thebicepscontractstoraisethelowerarm.
(d) Anantagonisticpairistwomusclesthathave oppositeeffects.
(e) Functionsincludesupport,protection,shapeand bloodcomponentmanufacture.
19
(a) Functionsinclude:support,protection,movement, shapeandbloodcomponentmanufacture.
(b) Thepectoralgirdleandthepelvicgirdle(acceptthe scapulaandthepelvis).
(c) Longbonesinlegarefemur,tibiaandfibula.
(d) Anantagonisticpairistwomusclesthathave oppositeeffects.
(e) Thebicepsandtricepsareanantagonisticmuscle pair.
(f) Thebicepscontracttoraisethelowerarm,the tricepscontracttostraightenthelowerarm.
(g) Intervertebraldiscsarediscsofcartilagelocated betweenthevertebraeinthebackbone.
(h) Intervertebraldiscsaremadeofcartilage.Their functionistoprotectthevertebraeandactasshock absorbers.
Patella Tendon
Synovial membrane
CHAPTER19 THENERVOUSSYSTEM
1
(a) Thecentralnervoussystem(CNS)consistsofthe brainandthespinalcord.
Theperipheralnervoussystem(PNS)consistsofthe nervefibresandcellbodiesoutsidetheCNS.
(b) Brainandspinalcord.
(c) Nervefibresandcellbodies.
2
(a) A=Cerebrum
B=Hypothalamus
C=Pituitary
D=Cerebellum
E=Medullaoblongata
F=Spinalcord
(b) Cerebrum:controlsmuscles(andvoluntary movements),thesenses,learning,emotions, memoryandunderstanding.
Hypothalamus:regulatestheinternalenvironment ofthebody(homeostasis).
Pituitary:produceshormonesTSH,LH,FSH,prolactin oroxytocin.
Cerebellum:controlsmuscularcoordinationand balance.
Medullaoblongata:controlsinvoluntaryactions(e.g. breathing).
Spinalcord:carrieselectricalimpulsestoandfrom thebrain.
(c) E,D,thecerebellum
(d) Theouterlayerofthecerebrumiscalledthe cerebralcortex.Itisheavilyfolded,toincrease surfacearea.Thecerebralcortexisgreybecause itcontainsthecellbodies(whicharegrey)of nervecells.Theinnerpartofthecerebrumiswhite becauseitcontainsmanynerves.
3
(a) Meninges
Location:outermembraneofbrain Function:protectsbrainandspinalcord
(b) Cerebrospinalfluid
Location:betweenthemembranesofthemeninges Function:protectiveshockabsorberforbrain
(c) Corpuscallosum
(e) Hypothalamus
Location:belowthethalamusatthecentreofthe brain
Function:regulatestheinternalenvironmentofthe body(homeostasis).
(f) Medullaoblongata
Location:Topofspinalcord
Function:controlsinvoluntaryactions(e.g. breathing).
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Location:inbothsidesofthecerebrum Function:bundleofnervefibresthatallowsthetwo sidesofthecerebrumtocommunicatewitheach other.
(d) Thalamus
Location:belowthecerebrumatthebaseofbrain
Function:endsallincomingimpulsestothecorrect partofthebrain.
4
(a) Aneuronisanervecell.
(b) Typesofneurons:sensory,motorandinterneuron
(c) Sensoryneuronscarryimpulsestothecentral nervoussystem.
Interneuronscarryimpulsesbetweensensoryand motorneurons.
Motorneuronscarryimpulsesawayfromthecentral nervoussystem.
5
(a) Typeofneuron:motorneuron
(b) A=Cellbody,producesneurotransmitters.
B=Dendrite,carriesimpulsestowardsthecellbody. C=Axon,tocarryimpulsesawayfromcellbodies.
D=Myelinsheath,insulatestheelectricalimpulses.
E=Neurotransmitterswelling,releases neurotransmittersthatcarrytheimpulsefromone nervecelltoanother.
(c) Electrical
(d) Travelsawayfromcellbodytowards neurotransmitterswelling
(e) Diagramofasensoryneuron: DiagramofaInterneuron
Neurotransmitterswelling orsynapticknob
(b) Examplesincludethegraspreflexinchildren, blinkingtheeyesforprotection,breathing,control ofbloodpressure,andtheprotectiveactionswe takewhenfalling.
(c) Benefits:arefastandhelpprotectthebody.
(d) (i) A=Sensoryneuron B=Interneuron C=Motorneuron
(ii) Impulseisgoingtowardsinterneuroninspinal cord
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6
(a) Adendritecarriesimpulsestowardsthecellbody. Axonscarryimpulsesawayfromcellbodies.
(b) Tomakethemyelinsheath.
(c) Themyelinsheathallowsanimpulsetospeedup.
7
(a) Asynapseisaregionwheretwoneuronscomeinto closecontact.
(b) Synapsesallowselectricalimpulsestopassfromone neurontoanother.
Synapsescontrolthedirectionoftheimpulse. Synapsespreventoverstimulationofeffectors.
(c) Asynapticcleftisthetinygapbetweenthetwo neuronsatasynapse.
8
(a)(i) Neurotransmittersarechemicalsmessengers.
(ii) Neurotransmittersubstancesarechemicalsthat allowthetransmissionofanimpulseacrossthe synapticcleft.
(iii) Dopamine,acetylcholineandendorphins.
(b) Schwanncells:theymakethemyelinsheath. Myelinsheath:insulatestheelectricalimpulse.
(c) Synapticcleft
9
(a) Neurotransmittersarechemicalsthatallowthe transmissionofanimpulseacrossthesynapticcleft.
(b) Causes:exercise,carryoutpleasurableactivities (suchaslaughing,dancing,eatingorsex)orwhenwe feelpainorstress.
(c) Benefits:blockspain,decreasesinflammation, reducesstress,anxietyanddepressionandtriggers thereleaseofdopamine.
(d) Pleasurableactivityproducesdopamine.
(e) Benefit:playsaroleinmemory,mood,sleep, learning,concentrationandmovement.
(f) Ittriggersustorepeattheactivity.
10
(a) Lifestylechoices:laughing,exercise,and/oreating.
(b)(i) Laughingcausesanincreaseinlevels. (ii) Consequence:improvesmood.
11
(a) Areflexactionisanautomatic,involuntary, unthinkingresponsetoastimulus.
12
(iii) Centralnervoussystem
Reason:itcontainsthespinalcord.
(a) Motorneuron
(b) A=Dendrite
B=Axon
C=Cellbody
(c) A,dendrite
(d) Myelinsheath
(e) Brainandspinalcord
13
(a) Synapse
(b) Synapticcleft
(c) Neurotransmitters
(d) Invesiclesintheneurotransmitterswellings.
(e) Onthearrivalofanelectricalimpulsethe neurotransmitterswellingsarestimulatedtorelease aneurotransmitter(chemical)inthepresynaptic neuron.
Theneurotransmitterdiffusesquicklyacrossthe synapticclefttothenextneuron(postsynaptic neuron).
Theyjoinwithreceptorsonthemotorneuron. Thisallowstheelectricalimpulsetoberegenerated inthenextneuron.
Theneurotransmitterisfinallybrokendown byenzymesandrecycledbackintothe neurotransmitterswellings.
(f) Sensoryneuronandmotorneuron
14 HL
(a) Pre-synapticneuroncarrieselectricalimpulse towardsthesynapse.
Post-synapticneuronreceiveselectricalimpulse.
(b) Onthearrivalofanelectricalimpulsethe neurotransmitterswellingsarestimulatedtorelease a neurotransmitter(chemical)inthepresynapticneuron. Theneurotransmitterdiffusesquicklyacrossthe synapticclefttothenextneuron(postsynapticneuron). Theyjoinwithreceptorsonthemotorneuron. Thisallowstheelectricalimpulsetoberegeneratedin thenextneuron.
Theneurotransmitterisfinallybrokendownby enzymesandrecycledbackintotheneurotransmitter swellings.
(c)(i) Theneurotransmittersareinactivatedby enzymes.
(ii) Inactivatedneurotransmitterspassbackacross thesynapticcleftandarereabsorbedback intotheneurotransmitterswellingsinthepresynapticneuron.
15 HL
(a) A=Cerebralcortex
B=Hypothalamus
C=Pituitary
D=Cerebellum
E=Spinalcord
(b)(i) Medullaoblongatacontrolsinvoluntaryactions (e.g.breathing).
(ii) Thecerebellumcontrolsmuscularcoordination andbalance.
(c)(i) Greymatter:cellbodies,astheyaregrey.
(ii) Whitematter:manynervesoraxons,whichare white.
(d)(i) Meninges
(ii) 3layers
(iii) Meningitis
(iv) Spinalcord
16 HL
(a) Ions
(b) Onthearrivalofanelectricalimpulsethe neurotransmitterswellingsarestimulatedtorelease aneurotransmitter(chemical)inthepresynaptic neuron.
CHAPTER20
1
Theneurotransmitterdiffusesquicklyacrossthe synapticclefttothenextneuron(postsynaptic neuron).
Theyjoinwithreceptorsonthemotorneuron. Thisallowstheelectricalimpulsetoberegenerated inthenextneuron.
Theneurotransmitterisfinallybrokendown byenzymesandrecycledbackintothe neurotransmitterswellings.
(c) Endorphinsacttoblockpain,decreaseinflammation, reducestress,anxietyanddepression.
Dopaminegivesfeelingsofpleasure,satisfaction andmotivationandisinvolvedinaddictions.
(d) Toimprovemood.
17 HL
(a) Degenerativeillnessisaprogressivedeteriorationof cells.
(b) Manygenes.
(c) Abuild-upofprotein-basedplaquesinthebrain.
(d) Possiblesymptom:memorylossordifficulty completingtasks.
(e) Bydevelopingnewwaystoscanthebrainanddetect thefirstsignsoftrouble.
(f) Possiblereason:Peoplearelivinglonger.
18 HL
(a) Ithasasimilarmolecularstructureorshapethat allowsittofitintothedopaminereceptor.
(b) Itblocksthereceptorswithoutactivatingit.
(c) Togivefeelingsofpleasure,satisfactionand motivation.
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(a)(i) Ahormoneisachemicalmessengerproduced byanendocrineglandandcarriedbythe bloodstreamtoanotherpartofthebody.
(ii) Endocrineglandsareductlessglandsthat producehormones,whicharereleasedintothe bloodstream.
(b) Pancreas
Pancreasproduceenzymesamylaseandlipase. IsletsofLangerhansinthepancreasproducesa hormonecalledinsulin.
2
(a) A=Pituitary
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B=Thyroid
C=Adrenal
(b) A=PituitaryproducesTSH,LH,FSH,Prolactin, OxytocinorADH.
B=Thyroidproducesthyroxine.
C=Adrenalproducesadrenaline.
(c) Functionsofhormonesproducedbypituitarygland: Thyroidstimulatinghormone(TSH)stimulatesthe productionofthyroxineinthethyroidgland.
Luteinisinghormone(LH)triggersovulation (releasingofaneggintheovary).
Folliclestimulatinghormone(FSH)stimulatesthe developmentofthegraafianfollicleintheovary.
Prolactin:stimulatesmilkproductioninthe mammaryglandsofbreast.
Oxytocinstimulatesuterinecontractionsduring childbirth.
SecreteshormonesADHcontrolsthewater/salt concentrationoftheblood.
Functionofhormonesproducedbythyroidgland: thyroxinecontrolsyourmetabolism.
Functionofhormonesproducedbyadrenalgland: allowsapersontorespondtostressorincreases mentalawareness.
(d) Positionsofparathyroidsandthepancreas:
(b) Diagramindicatinghormone-producingglands:
W(Pituitary)
X(Thyroid)
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3
(a) Thyroidsecretesthyroxine.
(b) Itcontrolsmetabolism.
4
(a) Insulin
(b) IsletsofLangerhans
(c) Diabetes
5
(a)(i) Head=Pituitary
(ii) Neck=Thyroid
(iii) Abdomen=Adrenal
(b) Males=Testes
Females=Ovaries
6
(a) Tohelpformmorethyroxine.
(b) Toseeifthethyroidisunderoroveractive.
(c) Highglucoselevelsinurineindicatesdiabetes.
(d) Insulinisahormonewhichismadefromaprotein. Therefore,insulinwouldbedigestedinthedigestive systemifswallowed.
(e) Astheysecretehormonesintothebloodstream.
(f) Toincreasesugarlevels(glucoselevels)quickly.
(g) Ifahormoneismadefromaprotein,itwouldbe digestedinthedigestivesystemifswallowed.
(h) Theyarechemicallystableandresiststomachacid.
7
(a) (iii)Theadrenals
(b) (iv)Pancreas
(c) (iv)Chemicalmessengers
(d) (ii)Iodine
(e) (i)Pituitary
8
(a) Ahormoneisachemicalmessengerproducedbyan endocrineglandandcarriedbythebloodstreamto anotherpartofthebody.
(c)(i) Thyroid(oranyotheracceptableanswer) producesthyroxine.
(ii) Function:thyroxinecontrolsmetabolism.
(iii) Transportedinthebloodstream.
9
(a) Itissometimesreferredtoasadual-functiongland asitproducesenzymesandhormones(orboth endocrineandexocrine).
(b)
glucose levels
metabolism Adrenal gland KidneyAdrenaline‘fightor flight’
10
(a) Hormonalmanipulationreferstothealterationor regulationofhormonelevelsinanorganism.
(b)(i) Sports:anabolicsteroids,humangrowth hormonesorerythropoietin.
(ii) Health:contraceptivepills,hormone replacementtherapy(HRT)orinsulinisinjected.
(iii) Agriculture:anabolicsteroids.
(c) Sports:anabolicsteroids(tobuildupmuscle,speed upmusclerecovery,andhelptostrengthenbones). Humangrowthhormonetobuildmoremuscle. Erythropoietintoincreasethenumberofredblood cells.
11
Health:contraceptivepillspreventpregnancy. Hormonereplacementtherapy(HRT)replaces femalehormones(oestrogenandprogesterone)at themenopause.
Insulinisinjectedtocontrol(mostlytype1)diabetes. Agriculture:anabolicsteroidsareusedinsome countriestoproducemoremeatandmilk.
(a) Ahormoneisachemicalmessengerproducedbyan endocrineglandandcarriedbythebloodstreamto anotherpartofthebody.
(b) A=Pancreas
B=Thyroid
C=Testes
(c)(i) InsulinandPancreas(a)
(ii) ThyroxineandThyroid(B)
(iii) TestosteroneandTestes(C)
(d) Examplesofhormonalmanipulationinsport: anabolicsteroids,humangrowthhormoneand/or erythropoietin.
Examplesofhormonalmanipulationinhealth: contraceptivepills,Hormonereplacementtherapy (HRT)and/orinsulinisinjected.
Exampleofhormonalmanipulationinagriculture: anabolicsteroids.
12
(a)(i) Endocrine (ii) Blood/inthebloodstream.
(iii) ThePancreasproducesenzymesandhormones (orbothendocrineandexocrine).
(b)(i) Proteins
(ii) Namedhormone:thyroxine (1)Location:trachea (2)Function:controlsmetabolism. Namedhormone:adrenaline (1)Location:topofkidneys. (2)Function:increasesmentalalertness.
13
(a) Endocrineglandsareductlessglandsthatproduce hormones,whicharereleasedintothebloodstream.
(b)(i) Insulin
(ii) IsletsofLangerhans
(iii) Cellsorliver
(iv) Controlsglucoselevelsinblood.
(c) Examplesofhormonalmanipulation: Sports:anabolicsteroids,Humangrowthhormone, and/orerythropoietin.
Health:contraceptivepills,Hormonereplacement therapy(HRT)and/orinsulinisinjected.
Agriculture:anabolicsteroids
14
(a) Anincreaseinbloodglucoselevels.
(b) Excessglucoseisconvertedtoglycogen.
(c) Bloodglucoselevelshavedecreased.
(d) Pancreas
(e) Ifinsulinlevelsorlow,glucoselevelsaremuch higherinblood.Thekidneyscan’tthenreabsorb alltheglucose.Therefore,theurineoftencontains higherconcentrationsofglucose.
CHAPTER21 HOMEOSTASIS
1
(a) Homeostasisistheabilityofanorganismtomaintain aconstantinternalenvironment.
(b) Thetermexternalchangereferstoachangein thesurroundingsinwhichanorganismlives.The terminternalchangereferstoachangeinthe surroundingsofthecellsinamulticellularorganism.
(c) Theinternalsurroundingofhumancellsistissue fluid.
2
(a) Kidney,pancreas,liver,lungsorskin.
(b) ThekidneyscontrolbloodpHandwateri.e.thesalt concentrationofblood.
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Theliverbreaksdowntoxicchemicalsintheblood. Thelungstakeinoxygenandexcretecarbondioxide. Temperatureiscontrolledbytheskinandblood vessels.
(c) Ifkidneystopfunctioning,atoxicbuild-upinthe bloodwouldoccur.
Ifliverstopfunctioning,atoxinaccumulationoccurs. Ifskinstopfunctioning,thereisaninabilityto regulatetemperature. Iflungsstopfunctioning,thereisaninabilityto removecarbondioxide.
Ifpancreasstopfunctioning,thereisaninabilityto produceinsulincausingdiabetes.
3
PartsofhomeostaticsystemFunctions
Effector Response
Receptor Stimulus ControlcentreDecision
4
(a) Negativefeedbackmeansthatthecorrectlevelof onefactorinhibitsapreviousstepinthecycle.
(b) Theproductionofthyroxinebythethyroidgland inhibitstheproductionofTSHbythepituitary.
(c) Ifourtemperatureisnormal(37°C)orbelownormal, thebraindoesnotsendnerveimpulsessothatwe donotsweat.Thisallowsustoretainmoreheat.
Ifourtemperatureistoohigh,receptorsinthebrain detectthisandsendnerveimpulsestoourskin, causingustosweat.Whensweatevaporates,we cooldown.
5
(a) Functionmostefficiently:maintainingoptimalbody temperature(around37°Cinhumans)ensuresthat enzymesfunctionattheirpeakefficiency.
(b) Workindependently:regulationofbloodglucose levelsallowshumanstofunctionnormallyeven whentheyhaven’teatenforhours.
Humanscancontinuetofunctionwhentheexternal temperaturedropsinwinterbecausetheycan controltheirinternaltemperature.
(c) Slightchanges:Humanbodytemperaturefalls(by about1°C)atnightwhenwesleep.
Humanbodytemperatureriseswhenwegetan infection(thisiscalledafeverandisanattempt bythebodytodestroywhateveriscausingthe infection).
6
(a) Homeostasisistheabilityofanorganismtomaintain aconstantinternalenvironment.
(b) Rolesoflungsincludetheexcretionofwater, excretionofCO2,and/orreleaseofheat.
(c) Homeostasisisimportanttocontrolsuitable temperaturesoenzymereactionscanoccurat optimumrate.
7
(a) Xrelatestothedog.
Reason:maintainsaconstantbodytemperature evenifexternaltemperatureisnotthesame.
(b) Throughmetabolicreactioncalledrespiration.Heat isreleasedasaby-product.
(c) Relationshipbetweenbodytemperatureand externalenvironment:Stayingactiveinvarying temperaturessupportsmetabolicefficiencyallowing enzymeactivitytooccuratoptimumtemperature.
(d) Externalenvironment
(e) Problemsincludetheirmetabolicrateslows,their movementbecomessluggishandtheirreproductive processisinterrupted.
(f)(i) Liver:absorptionofglucoseorreleaseof glucoseorheatgeneration.
(ii) Lungs:excretionofwaterorexcretionofCO2 or releaseofheat.
8
(a) Negativefeedbackmeansthatthecorrectlevelof onefactorinhibitsapreviousstepinthecycle.
(b) Thyroxineoranyacceptableanswer.
(c) Controlsmetabolism.
(d) Theproductionofthyroxinebythethyroidgland inhibitstheproductionofTSHbythepituitary. However,theproductionofTSH(thyroidstimulating hormone)bythepituitaryglandstimulatesthe thyroidglandtoproducethyroxine.
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(iii) Insulin:regulatesbloodglucoselevels.
9
(a) TSH
(b) Thyroxine
(c) TSHreleasedbypituitarygland. Thyroxineisproducedinthyroid.
(d) Itiscallednegativefeedbackbecausewhenthe levelofthyroxineinthebloodbecomestoohigh, itinhibitsthereleaseofTSHfromthepituitarygland. Theproductionofonehormonecaninhibitthe productionofanotherhormone.
10
Hormones
(a) Rateofresponseisslow.
(b) Durationofeffectsislonglasting.
(c) Transmissionischemical.
(d) Locationtheyeffectmaybewidespreadaroundthe body.
Nervoussystem
(a) Rateofresponseisfast.
(b) Durationofeffectsisshortlived.
(c) Transmissioniselectrical.
(d) Locationtheyeffectislocalised.
11
(a) Theendocrinesystemisslowerbecauseitrelies onhormonestravelingthroughthebloodstreamto reachtargetorgans.Thisprocesstakesmore timecomparedtothenervoussystem,which useselectricalimpulsesthattravelrapidlyalong neurons.
(b) Thenervoussystemproducesimmediatebutshortlivedresponsesbecausenerveimpulsesstoponce thestimulusisremoved.Incontrast,hormonescan remaininthebloodstreamforlongerperiods, causinglonger-lastingeffects.
(c) Nervoussystem:usesneurotransmitters(for example:dopamine,acetylcholine).
Endocrinesystem:useshormones(forexample: insulin,adrenaline,thyroxine).
(d) Nervoussystem:transmitsmessagesviaelectrical impulses.
Endocrinesystem:transmitsmessagesby releasinghormonesintothebloodstream.
CHAPTER22 IMMUNITY
1
(a) Apathogenisanorganismoragentthatcauses disease.
(b) Pathogensincludeviruses,bacteria,fungi,protists, parasiticanimalsandprions.
(c) Prionsaremisfoldedproteinsthatarecapableof beingtransmittedandthatcanincreaseinnumber byconvertingrelatedproteinsintomoreprions.
(d) Prionsreplicatebyconvertingnormalshaped proteinsintothemisfoldedprionshape.
2
(a) Immunitymeanstheabilitytoresistdisease.
(b) Innateimmunityisadefencesystemthatweare bornwith,andwhichdoesnotdependonprevious exposuretopathogens.
Acquired(oradaptive)immunityisalong-lasting protectionagainstreinfectionfollowinginfection with(orimmunisationagainst)aspecificpathogen.
(b) Antibodiesaremadebywhitebloodcellscalled lymphocytes.
(c) Adultshavebeenexposedtoagreatervarietyof antigensthanchildren.
5
(a) Theantibody-antigenreactionisspecificbecause eachantigenwillstimulatetheproductionofonly oneparticular-shapedantibody.
Pathogen
Antigen
3
(a) Theskinhelpstodefendthebodybybeingabarrier totheentryofpathogens.
(b) Bloodclottinghelpstodefendthebodyby sealingoverawoundandpreventingtheentryof pathogens.
(c) Mucousmembraneshelptodefendthebodyby trappingpathogensandpreventingthemfrom enteringfartherintothebody.
(d) Ciliahelptodefendthebodybybeatingandcreating acurrentwhichmovesmucusoutofthebody.
(e) Acidinthestomachkillsmanypathogens.
(f) Phagocytesarewhitebloodcellsthatsurround, engulfanddestroymanyofthepathogensthatthey meet.
(g) Complementisasetofproteinsinthebloodthat destroysvirusesandotherpathogens.
(h) Interferonsareproteinsproducedbyvirus-infected cellsthatpreventvirusesfrommultiplying.
(i) Inflammationisalocalisedswellingwhichincreases theflowofbloodcells,antibodiesandclotting proteinstothesitetospeeduprepair.
(j) Lacticacidpreventsthegrowthofpathogensin areassuchastheskin,intestinesandreproductive tract(especiallythevagina).
4
(a)(i) Anantigenisaforeignmoleculethatstimulates theproductionofantibodies.
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Anantibodyisaproteinproducedbywhite bloodcellsinresponsetoaspecificantigen.
(ii) Anantigenisaforeignmoleculethatstimulates theproductionofantibodies.
Apathogenisanorganismoragentthatcauses disease.
Antibody
The antigen ’fits‘the antibody
(b) Memorycellsremaininthebodyforalongtime (manyyears).
Thesememorycellsbecomeactiveifthesame antigenisdetectedagain.
Theycausetheproductionofthecorrectantibody muchfaster,inmuchlargeramountsandmuch longerlived.
Memorycellspreventusfrombeingreinfectedby thesamepathogen.
6
(a) Activeimmunityistheproductionofaperson’sown antibodies.
Passiveimmunityiswhenwegetantibodiesmadeby anotherindividual.
(b) Foreignantigensinthebody.
(c) Activeimmunitylastslongerbecauseinactive immunitymemorycellsareformedwhichsurvive formanyyears.Memorycellsdonotforminpassive immunity.
7
(a) Naturalactiveimmunityoccurswhenapathogen entersthebodyinthenormalway,andweproduce antibodiesagainstit.
(b) Naturalpassiveimmunityoccurswhenachildgets antibodiesfromitsmotheracrosstheplacentaorin breastmilk.
(c) Artificialactiveimmunityoccurswhenapathogen ismedicallyintroducedintothebody,asina vaccination.
(d) Artificialpassiveimmunityoccurswhenaperson getsaninjectionofantibodiesmadebyanother organism.
8
(a) Avaccineisanon-disease-causingdoseofa pathogenwhichstimulatestheproductionof antibodies.
(b) Vaccinationisanexampleofactiveimmunity. Vaccinationisactivebecausethepersonproduces theirownantibodies.
(c) Vaccinationprovideslong-termresistanceto infection.Thisisbecauseweproduceourown antibodies,andthememorycellssurvivealongtime.
9
(a) Youngchildrenarebornwithantibodiesfromtheir motheragainstmostofthecommonpathogens.
(b) Breast-fedbabiesgetantibodiesfromtheirmother whichareactivefor6monthsaftertheystopbreast feeding.
(c) Apersonmayfeelillastheyhavebeeninjectedwith asmalldoseofnon-reproductivepathogen.
(d) Thestingcontainsforeignsubstanceswhichtrigger thereleaseofhistamines.Inflammationisalocalised swellingwhichincreasestheflowofbloodcells, antibodiesandclottingproteinstothesitetospeed uprepair.
(e) Thesalivaofthedogcontainslysozyme(andother substances)whichbreakdownbacterialcellwalls.
(f) Activeimmunitylastslongerthanpassiveimmunity becauseinactiveimmunityweproduceourown antibodies,andthememorycellssurvivealongtime. Inpassiveimmunitytheforeignantibodiesonlylasta fewmonths.
(g) Boosterinjectionsaregiventostrengthenour immunityastheyincreasethenumberofantibodies.
(h) Aseriesofvaccineswereproducedbecausethe virus(SARS-CoV-2)mutatesconstantlyproducing slightlydifferentantigens.Theserequiredslightly differentandmoreactiveantibodies.
(i) Allergicreactionsoccurwhenthebodyreacts inappropriatelytoarelativelyharmlessantigen.
(j) Thedrugsinhibittheimmunesystemsothatthey willnotattackthenewtransplantedstructure (whichcontainsantigens).Thedangerthenisthat thepersoncannotfightoffnormalinfections.
(k) Somepathogensmutatetoproducenewand differentantigens.Ouroldantibodieswillnotbe activeagainstthesenewantigens.
(l) Somepeopleareathighriskbecausetheyare notvaccinated,haveweakenedimmunesystems (immunocompromised)orarebabiesinthewomb.
10
(a) Immunityistheabilitytoresistdisease.
(c) Vaccinationistheintroductionofanon-diseasecausingdoseofapathogenwhichstimulatesthe productionofantibodies.
11
(a) Smallpox
(b) Avaccineisanon-disease-causingdoseofa pathogenwhichstimulatestheproductionof antibodies.Theantibodiesactagainstantigenson thepathogenandneutraliseandkillthepathogen.
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(b) Theskinisaphysicalbarriertotheentryofpathogens. Theskiniscoatedwithsebumwhichactstokill bacteria.
Theskinisalsocoatedwithlysozymewhichkills bacteria.
Theskinmicrobiotapreventspathogensfrom growing.
(c) Immunityistheabilitytoresistdisease.
(d) Activeimmunityistheproductionofaperson’sown antibodies.
Passiveimmunityiswhenwegetantibodiesmadeby anotherindividual.
(e) Apathogenisanorganismoragentthatcauses disease.
(f) Colostrum(seechapter23)containslargeamounts ofthemother’santibodies.Theseantibodiesprotect thebabyagainstanypathogensthatthemotherhad encountered.
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(a) Microbialdiseasesmaybepreventedbyfrequent handwashing,correcthandling/storage/cooking offood,usingcleanwater,usinghygienictoilets, reducingthenumberofdiseasevectors,isolating whenweareinfected,wearingfacemasks,and/or beingvaccinated.
(b) Microbialdiseasesmaybetreatedbyusing antibioticsforbacterialinfections,antiviraldrugsfor virusinfections,orantifungalsforfungusinfections.
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(a) Replication
(b) Viruseslandonahost,theyinjecttheirnucleicacid (DNAorRNA)intothehost,thehostmakesnew virusnucleicacidandnewviruscoats,thenew virusesforminthehost,andthehostburststoexpel thenewviruses.
(c) Virusescanonlyreproduceinlivehosts,andthey usuallycauseharm.
(d) Differencesbetweenviruses:
DNAviruses
RNAviruses
HaveDNA HaveRNA
ReplicateinhostnucleusReplicateinhostcytoplasm Havelowerrateof mutation Havehigherrateof mutation
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(a) Factorsincludemutationsproducingnewtypesof pathogens,themisuseandoveruseofantibioticshas givenrisetomulti-resistantbacteria,andincreased exposuretoanimalsleadingtodiseasesspreading fromanimalstohumans.
(b) Factorsincludehowlongthepathogencansurvive inahost,apopulationthatislessimmunetothe infection,increasedmovementoftheinfected population,andthemorecontagiousthediseaseis (theR0 number).
(c) Infectiousdiseasesspreadbytinyparticlesintheair, largerparticles(droplets)intheair,physicalcontact, fromfaecestothemouth,and/orbyvectors.
(d) Knowledgeofemergingdiseasesisimportant becausetheycauseeconomicproblems,theycause healthproblems,theyspreadrapidly,theycause socialdisorder,theycauseautoimmunediseases, andtheytriggerresearchintotreatmentsforthe newdiseases.
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(a) Thereproductionnumber(R0)isamathematical representationofhowcontagiousadiseaseis.
(b) TheR0 valueof0.4fordiseaseXmeansthaton averageeachinfectedpersonwillpassonthe diseaseto0.4people(orlessthanoneperson)ina completelysusceptiblepopulation.
TheR0 valueof1.8fordiseaseYmeansthaton averageeachinfectedpersonwillpassonthe diseaseto1.8peopleinacompletelysusceptible population.
DiseaseXisnotverycontagious(doesnoteasily spread)andwilldieout.
DiseaseYiscontagiousandwillspreadoutand causeanoutbreak(orevenapandemic).
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(a) Monocytes(whichcanbecomemacrophages) recogniseantigensonthesurfaceofpathogens, engulfanddestroypathogens,anddisplayantigens ontheirsurfacetostimulateotherwhitebloodcells toformantibodies.
Naturalkillercellsreleasechemicalswhichdestroy bodycellsthatdisplayantigens(whichmaybefrom pathogensorcancercells).
(b) Blymphocytesmatureinthebonemarrow. Tlymphocytesmatureinthethymusgland.
(c) TherearetwotypesofBcells.
PlasmaBcellsmakeantibodies.
MemoryBcellssurviveforyearsandcanmakethe specificantibodiesifthesamepathogenentersthe bodyagain.
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(a) ThetwotypesofBcellsareplasmaBcellsand memoryBcells.
(b) PlasmaBcellsmakeantibodies.
MemoryBcellssurviveforyearsandcanmakethe specificantibodiesifthesamepathogenentersthe bodyagain.
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(a) ThefourtypesofTlymphocytesare:helperTcells, killerTcells,suppressorTcellsandmemoryTcells.
MemoryTcellssurviveforyearsafteraninfection andstimulateBcellsandkillerTcellsifthesame infectionentersthebody.
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(a) HelperTcellsarestimulatedbyantigensonthe surfaceofmonocytes(ormacrophages).
(b) HelperTcellsareinhibitedbysuppressorTcells.
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(a) NaturalkillercellsandkillerTcells.
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(b) HelperTcellsstimulateBcellsandkillerTcells. KillerTcellsdestroyabnormalhumanbodycells(i.e. thosethatareinfectedwithavirusorarecancer cells).
SuppressorTcellsinhibittheimmuneresponse.
(b) Thesecellsattackcancercellsbecausethecancer cellshaveantigensontheirsurface(normalbody cellsdonothavetheseantigenspresent).
(c) Memorycellslivealongtimeandcanbecomeactive ifthesamepathogenre-entersthebody.
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(a)(i) Immunitymeanstheabilitytoresistdisease. (ii) Activeimmunityistheproductionofaperson’s ownantibodies.
Passiveimmunityiswhenwegetantibodies madebyanotherindividual.
(b) Theskinprovidesastructuralbarriertoinfection. Itpreventspathogensfromenteringthebody.It isfast-acting.Ifskinisbrokenbloodclottingalso preventstheentryoffurtherpathogens,
(c)(i) Whitebloodcells
(ii) BcellsandTcells
Bcellsmakeantibodies.
TcellsstimulateBcells,destroybodycellsthat arevirusinfectedorcancerous,turnoffthe immuneresponse,livealongtimeandbecome activeifwearere-infectedwiththesame pathogen.
(d) Vaccinationexposesthebodytoaharmlessform ofapathogensothattheimmunesystemcan recognisethepathogen,makeantibodiesagainstit andproducememorycells.
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(a) Apollengrainisanexampleof(ii)Anantigen.
(b) Lysozymeisfoundin(iv)Tears.
(c) Antigens(iii)Stimulateantibodies.
(d) Bcellsmaturein(iv)Bonemarrow.
(e) KillerTcellsproduce(i)Perforin.
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(a)(i) Anantigenisaforeignmoleculethatstimulates theproductionofantibodies.
(ii) Anantibodyisaproteinproducedbywhite bloodcellsinresponsetoaspecificantigen.
(b) Bcells(orBlymphocytes)
(c)(i) Anyanswerbetween1and2weeks(e.g.9or 10days).
(ii) Oneortwodays.
(d)(i) MoreantibodieswereproducedafterinjectionY thanafterinjectionX.
(ii) Antibodieswereproducedmuchsoonerafter reactionYthanafterreactionX.
(e) Theantibodyconcentrationdeclinedbecausethe pathogensweredestroyed.
(f) GraphshowingdifferentantigenattimeY:
Beneficialbacteria:bacteriainthevaginaproduce lacticacid.Thisacidpreventsthegrowthof pathogens.
Phagocyticwhilebloodcells:thesecellssurround, engulfanddestroymanyofthepathogensthatthey meet.
Complement:isasetofproteinsinthebloodthat destroysvirusesandotherpathogens.
Interferons:proteinsproducedbyvirus-infected cellsthatpreventvirusesfrommultiplying.
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24 HL
(a) BcellsandTcells.
Bcellsmakeantibodiesandremainasmemorycells.
Tcells:helperTcellsstimulateBcells.
KillerTcellsdestroybodycellsthatarevirusinfected orcancerous.
SuppressorTcellsturnofftheimmuneresponse.
MemoryTcellslivealongtimeandbecomeactiveif wearere-infectedwiththesamepathogen.
(b) Thisstatementistrue.
Reason:bothformsofimmunityproduceantibodies.
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(a) Passiveimmunity
(b) Anantibody,ratherthanavaccination,isgivenif theinfectionmayalreadyhaveoccurredorthere isapossibilityofadangerousinfectionorwhenno vaccineisavailableorthevaccineistooexpensive.
(c) Givingantibodiesproducesshorttermimmunity(as nomemorycellsareformed).
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(a) Anyoneofthefollowing:skin,clotting,lysozyme, sebaceousglands,mucus,cilia,acid,beneficial bacteria,phagocyticwhitebloodcells,complement, interferonsorinflammation.
Skin:Theskinhelpstodefendthebodybybeinga barriertotheentryofpathogens.
Clotting:helpstodefendthebodybysealingovera woundandpreventingtheentryofpathogens
Lysozyme:anenzymefoundinsweat,tearsand salivathatattacksanddissolvesthecellwallsof manybacteria.
Sebaceousglands:theseglandsproducesebum(oil). Sebumcontainschemicalsthatkillbacteria.Italso helpslubricatetheskinandpreventitfromcracking open.
Mucus:mucousmembraneshelptodefendthebody bytrappingpathogensandpreventingthemfrom enteringfartherintothebody.
Cilia:helptodefendthebodybybeatingandcreating acurrentwhichmovesmucusoutofthebody.
Acid:acidinthestomachkillsmanypathogens.
Inflammation:alocalisedswellingwhichincreases theflowofbloodcells,antibodiesandclotting proteinstothesitetospeeduprepair.
(b) Organsspecifictotheimmunesystemincludethe thymus,spleen,tonsils,adenoidsorlymphnodes.
(c) Anantigenisaforeignmoleculethatstimulatesthe productionofantibodies.
Anantibodyisaproteinproducedbywhiteblood cellsinresponsetoaspecificantigen.
(d)(i) KillerTcellsdestroyabnormal(virusinfectedor cancerous)bodycells.
HelperTcellsstimulatethecorrectBcellsto multiply,andtheyalsostimulatekillerTcells.
(ii) SuppressorTcells
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(a) Mucousmembranesarefoundintherespiratory tract(ornamedpart)orthedigestivetract(or namedpart)orthereproductivetract(ornamed part).
(b) Inthebonemarrow.
(c) Bcells(orBlymphocytes)
(d) Apartfromlymphocytes,whitebloodcellsinclude monocytes,macrophagesandphagocytes.
(e)(i) TheantibodyresponseisslowaftervaccineA andfastafterinfection(orB).
Thenumberofantibodiesproducedislowafter vaccineAandhighafterinfection(orB).
(ii) Reasons:AfterA,itisthefirsttimeinfected, therearenomemorycellspresentorafterB therearememorycellspresent.
(f) Thepartofthevirusrecognisedbyantibodiesisthe proteincoatortheantigen.
(g) AntibioticsarenotprescribedforCovid-19because itisavirusandantibioticshavenoeffectagainst viruses(ortheyonlykillbacteria).
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(a) Anytwoofthefollowing:skin,clotting,lysozyme, sebaceousglands,mucus,cilia,acid,beneficial bacteria,phagocyticwhitebloodcells,complement, interferonsorinflammation.
(b) Acquiredimmunitydefendsagainstviruseswhen BcellsproduceantibodiesandwhenkillerTcells destroyvirusinfectedcells.
(c)(i) Cell-mediatedresponsesinvolveTcellskilling infectedbodycells.
(ii) HumoralresponsesinvolveBcellsproducing antibodiestofightofftheinfection.
CHAPTER23 HUMANREPRODUCTION
1
(a) A=Scrotum
B=Testes
C=Epididymis
D=Spermduct
E=Prostategland
F=Seminalvesicle
G=Urethra
H=Penis
I=Glans
(b)(i) 35°C
(ii) Thetemperatureislowerasmeiosisdoes nottakeplaceproperlyinmalesatnormalbody temperature,i.e.37°C.
(c) Seminalvesicle,prostateglandandtestes.
(d) Urineandsemen.
(e) X=bladder.Function:storesurine.
Y=Ureter.Function:carriesurinefromkidneyto bladder.
2
(a) Spermonlyhave23chromosomesandanormal bodycellhas46chromosomes.
Spermhaveaflagellumandanormalbodycellhas noflagellum.
Spermareinvolvedinreproduction.Anormalbody cellisnotinvolvedinreproductionoranyother acceptableanswer.
(b)(i) Acrosome:aregioncontainingenzymesthatcan digestthemembraneoftheegg.
(ii) Prostategland:producesseminalfluid.
(iii) Testes:producespermandtestosterone.
(iv) Epididymis:spermmatureintheepididymisand arestoredthere.
(v) Seminalfluid:providesamediumforthesperm toswimin.Italsonourishesthesperm.
(b) Anacrosomeisaregioncontainingenzymesthat candigestthemembraneoftheegg. Anucleuscontains23chromosomes. Amidpieceorcollarcontainsmanymitochondria whichprovideenergyforthespermtoswim. Atailorflagellumallowsthespermtoswim.
5
(a) Primarysexualmalecharacteristicsarethe reproductivesexorgansthataredirectlyinvolvedin reproduction.Theseincludethepenisandtestes Secondarysexualmalecharacteristicsarethose featuresthatdistinguishmalesfromfemales,apart fromthesexorgansthemselves.Formalesthis includesgrowthofpubic,underarm,facialandbody hair,enlargementofthelarynx/voicedeepensand breaks,increasedmuscularandbonedevelopment, wideningoftheshoulders,growthspurtand increasedsecretionofsebumintheskin.
(b) Testosterone
(c) Theseincludegrowthofpubic,underarm,facial andbodyhair,enlargementofthelarynx,causing thevoicetobreakanddeepen,increasedmuscular andbonedevelopment,wideningoftheshoulders, growthspurt(bodyweightmaydouble),and increasedsecretionofsebumintheskin.
6
(a) A=Ovary
B=Funnel
C=Fallopiantube
D=Uterus
E=Endometrium
F=Cervix
G=Vagina
(b)(i) Meiosisoccursintheovary(A).
(ii) Egg
(iii) Oestrogenandprogesterone
3
(a) Agonadisanorganthatproducessexcellsin animals.
(b) Themalegonadsarecalledtestes.
(c) Pubertyisthebeginningofsexualmaturity.
4
(a) Diagramofasperm:
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(c) X=Bladder.Function:storesurine.
Y=Urethra.Function:carriesurinefromthebladder outofthebody.
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(a) Themenstrualcycleisaseriesofeventsthat occursevery28daysonaverageinthefemale,if fertilisationhasnottakenplace.
(b) Fourphasesaremenstruation,thefollicularphase, ovulationandthelutealphase.
(c)(i) Menstruation
(ii) Ovulation
(d)(i) FSH
(ii) Progesterone(andsomeoestrogen)
8
(a) Bothhormonesprevent(inhibit)eggsfrom developing.Bothhormonescausetheendometrium tothickenatdifferentstagesofmenstrualcycle.
(b) Combinationofoestrogenandprogesterone atpubertycausesthesecondaryfemale characteristics.
(c) Femalesecondarycharacteristicsincludematuring andenlargementofthebreasts,wideningofthe pelvis(toallowforbirth),increasedbodyfat,growth ofpubicandunderarmhairandgrowthspurt.
9
(a) Menstrualcycle
(b) Menstruationoraperiod
(c) Intheovaries.
(d) Ovulation
(e) Theliningofuterusbreaksdownastheuterus musclebeginstocontract.
(f) No,pregnancyhasn’toccurred.
Reason:Thelevelofprogesteroneisdecreasingat theendofcycle.
10
(a)(i) Fertilisationiswhenthenucleusofaspermfuses withthenucleusofanegg,formingadiploid zygote.
(ii) Implantationistheembeddingoftheembryo intotheliningoftheuterus.
(b) Diagramshowingthelocationoffertilisationand implantationinthefemalereproductivesystem:
Aneggcellusuallylivesfor24hourswhilespermcan liveupto6days.
(c) Testes,spermduct,urethra,vagina,uterusand fallopiantube.
(d) Ovary,fallopiantubeanduterus.
(e)(i) Spermcansurviveinfemalefor3to6days.
(ii) Aneggcansurvivefrom12to24hours.
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(a) Fallopiantube
(b) Acrosomesatthefrontendofthespermcontain enzymesthatareusedtodigestanopeningthrough themembraneoftheegg.
Oncespermlosesitstail,theheadofthesperm enterstheegg.
Oncethespermhasenteredtheegg,themembrane oftheeggundergoesarapidchemicalchange, formingafertilisationmembrane.
Thispreventsfurtherspermfromentering.
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(a) Similarities: Botheggandspermarehaploidcontaining23 chromosomes.
Bothareinvolvedinsexualreproduction. Bothareformedbymeiosis(oranyacceptable answer).
(b) Differences:
Aneggcellislargerthansperm.
Spermhaveaflagellumtomovewhileeggshaveno flagellum.
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(a) Placentaisformedfromtheendometrialtissueof themotherandfromtissueintheembryo.
(b)(i) Carbondioxideandurea.Oranyacceptable answer.
(ii) Oxygen,glucose,antibodies,hormonesorany acceptableanswer.
(c) Alcohol,nicotine.Oranyacceptableanswer.
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(a) A=Amnion
B=Endometrium
C=Placenta
D=Umbilicalcord
E=Amnioticfluid
F=Foetus
G=Cervix
(b) Theplacenta(C)ismadebyboththemotherand developingembryo.
(c) Theamnioticfluid(E)surroundsandprotectthe embryo(byactingasashockabsorber).
(d) Atthenavel.
(e) Blood
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(a) Thebloodofthemotherandfoetusmayhave differentbloodtypesanddifferentbloodpressure.
(b) Theplacentacouldbeanendocrineglandas itisaductlessglandthatsecreteshormones (progesterone).
(c) Hormonalchangesincludethattheplacentastops producingprogesteroneand/orthepituitarygland ofthemotherproducesahormonecalledoxytocin.
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(a) Colostrumisathick,yellowfluidcalledcolostrumfor thefirstfewdaysafterbirthinthebreasts.
(b) Prolactin
(c) Progesteronelevelsfallaroundthetimeofbirth stimulatingtheproductionofprolactin.
(d) Prolactin(andthereforemilk)continuestobe producedaslongasthebabybreastfeeds.
(e) Breastfeedingprovidesacontinuingsupplyof antibodiesinthemilkproducedbythemother.This meansthebabyhasextraresistancetothemost commoninfections.
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(a) Beforepregnancy:
FSHstimulatesthedevelopmentofgraafianfollicle. Oestrogenstimulatesthegrowthoftheuterine lining(endometrium).
LH(luteinisinghormone)causesovulation.
Progesteronemaintainsthethickeneduterinelining toallowimplantationtooccur.
(b) Duringpregnancy:
Progesteronemaintainsthethickeneduterinelining tosupportthedevelopingembryoandprevents contractionsinearlypregnancy.
(c) Afterpregnancy:
Prolactinstimulatestheproductionofbreastmilkin themammaryglands.
(b)(i) Naturalcontraception:involvesnothaving intercourseatthosetimesinthemenstrualcycle whenpregnancyismostlikely.
(ii) Mechanicalcontraception:involvesusinga physicalbarriertopreventspermfromreaching theegg.
Examples: Condoms(malecondomscoverthepenis, femalecondomsareplacedinthevagina).
Diaphragms(dome-shapedrubberdevicesfitted intothevaginabeforeintercourse).
Caps(smallrigidrubberdevicesthatcoverthe cervix).
Intra-uterinedevices(IUDsaredevicesplaced intheuterustointerferewithfertilisationand implantation).
(iii) Surgicalcontraception:sterilisationforfemales andvasectomyformales.
Femalesterilisationinvolvescuttingortyingthe Fallopiantubes(calledtuballigation)sothat spermcannotreachanegg.
Inavasectomy,eachvasdeferens(spermduct) inthemaleiscutandsealedshut.Themalewill continuetoejaculatebuttherearenosperm presentinthesemen.
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(a) Prenatal(orantenatal)careismedicalattention givenduringpregnancy(i.e.beforethebabyisborn).
Postnatalcareorscreeninginvolvestestingthe motherandbabyforhealthproblemsafterthebirth.
(b) Example:Prenatalcareinvolvesregularvisitsto ageneralpractitioner(GPordoctor),midwifeor obstetrician.
Advantage:Allowsthemothertogetvaccinated (especiallyagainstwhoopingcough,influenzaand Covid-19etc.)
(c)(i) GeneticscreeningmeanstestingDNAfor specificmutationsthatareknowntocause(or increasetheriskof)disease.
(ii) Thisprocedurecarriesaslightrisk(suchas infectionormiscarriage).
(d) Postnatalscreeningexample:Thenewbornblood spottestinvolvestakingasmallsampleofblood fromthebaby’sheel.
Advantage:Ittestsforninerare(butserious) conditions.TheseincludePKUandcysticfibrosis.
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(a) Fertilityistheabilitytohaveoffspring.
(b) Thefertileperiodisthattimeduringthemenstrual cyclewhenpregnancyismostlikelytooccur followingintercourse.
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(c) Thefertileperiodgenerallylastsabout7days.It startsfivedaysbeforeovulationandendsontheday afterovulation.
20
(a) Contraceptionisthedeliberatepreventionof fertilisationorpregnancy.
21
(iv) Chemicalcontraception:spermicides (substancesthatkillsperm)arenormallyused alongwiththemechanicalmethodsof contraception.
Examples:hormonessuchasprogesteroneand oestrogenpreventovulation.
(a) Infertilityistheinabilitytoproduceoffspring.
(b) Causes:lownumbersofsperm,problemswiththe spermswimmingand/orblockagesinthepathof sperm.
(c) Treatments:hormonaltreatment,surgeryorassisted reproductivetechnology(ART).
(d) IntracytoplasmicsperminjectionisaformofIVF.It involvesinjectingspermdirectlyintoanegg.
22
(a) Causes:failuretoovulateduetoendocrinegland failureand/orblockageoftheFallopiantubes.
(b) Treatments:injectionsofhormonesupplementsto stimulateovulation.
Artificialinsemination,whichistheplacingofsperm directlyintothecervixoruterustoincreasethe chanceoffertilisation
Invitrofertilisation.
(c) Invitrofertilisation(IVF)involvesfusinganegganda spermoutsidethebody.
23
(a) Thesedrugsstimulateseveraleggstodevelop.The eggsarelatersurgicallyremovedfromtheovaries.
(b) Toincreasethechancesofimplantation.
(c) Toallowthefertilisedeggstoimplantnaturally.
(d) Sometimesanumberofembryosareplacedintothe femaletoincreasechancesofimplantation.Thiscan resultinthebirthofmorethanonebaby.
24
(a) A=Oestrogen
B=Progesterone
(b) Day14:ovulation
(c) GraphB
(d) Graphrepresentingchangesinthethicknessofthe endometrium:
26
(a) Secondarysexualcharacteristicsarethosefeatures thatdistinguishmalesfromfemales,apartfromthe sexorgansthemselves.
Secondaryfemalecharacteristicsincludethe enlargementofthebreasts,wideningofthe pelvis,increasedbodyfatandgrowthofpubicand underarmhair.
Secondarymalecharacteristicsincludegrowthof pubic,underarm,facialandbodyhair,enlargement ofthelarynx,causingthevoicetobreakand deepen,increasedmuscularandbonedevelopment, wideningoftheshoulders,growthspurt(body weightmaydouble)andincreasedsecretionof sebumintheskin.
(b)(i) A=Urethra
B=Scrotum
C=Epididymis
D=Testes
E=Spermduct
(ii) Inthetestes.
(iii) Toproduceseminalfluid.
(iv) Differences:eggcell(orovum)islargerthan sperm.
Spermhaveaflagellumtomove.Eggshaveno flagellum.
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(a) A=Ovary
B=Fallopiantube
C=Uterus
(b) Diagramindicatingendometrium(X),fertilisation site(Y)andmeiosissite(Z).
(c) Advantagesofbreastfeeding: Milkcontainstheidealbalanceofnutrients. Breastmilkcontainsantibodiesforextraresistance tomostcommoninfections.
Breastfeedingishygienic,asbreastmilkissterile. Breastfeedinghelpsthemother’sbodytorecover fromtheeffectsofpregnancyandbirth.
Breastfeedinghelpsreducetheriskofsomecancers inthemother.
Aneggcellusuallylivesfor24hours.Spermcan liveupto6days,oranyacceptableanswer.
(c)(i) Infertilityistheinabilitytoproduceoffspring. Causes:lownumbersofsperm,problemswith thespermswimmingand/orblockagesinthe pathofsperm.
(ii) Typesofcontraception:mechanical,Natural, Chemicalandsurgicalcontraception.
(1) Naturalcontraception:involvesnothaving intercourseatthosetimesinthemenstrualcycle whenpregnancyismostlikely.
(2) Mechanicalcontraception:involvesusinga physicalbarriertopreventspermfromreaching theegg.
Examples:
Condoms(malecondomscoverthepenis, femalecondomsareplacedinthevagina).
Diaphragms(dome-shapedrubberdevicesfitted intothevaginabeforeintercourse).
Caps(smallrigidrubberdevicesthatcoverthe cervix).
Intra-uterinedevices(IUDsaredevicesplaced intheuterustointerferewithfertilisationand implantation).
(3) Surgicalcontraception:sterilisationfor femalesandvasectomyformales.
Femalesterilisationinvolvescuttingortyingthe Fallopiantubes(calledtuballigation)sothat spermcannotreachanegg.
Inavasectomy,eachvasdeferens(spermduct) inthemaleiscutandsealedshut.Themalewill
27
continuetoejaculatebuttherearenosperm presentinthesemen.
(4) Chemicalcontraception:spermicides (substancesthatkillsperm)arenormally usedalongwiththemechanicalmethodsof contraception.
Examples:hormonessuchasprogesteroneand oestrogenpreventovulation.
(a) Diagramofmalereproductivesystem:
Prostategland
(ii) DetectionofPKU:Bloodspottestisusedto detectPKU.Itinvolvestakingasmallsampleof bloodfromthebaby’sheelandtestingit.
(iii) ThereisnocureforPKU,butitcanbecontrolled byfollowingahighlyrestricted,low-proteindiet, takingdietarysupplementsandhavingregular bloodtests.
29
(a)(i) Diagramoffemalereproductivesystem:
Fallopiantube(fertilisation)
(b) Xondiagramshowswheremeiosisoccurs.
(c) Yondiagramshowswherespermarestored.
(d) Testosteronecausestheprimarymalesex characteristicsearlyinlife,i.e.thegrowthof thepenisandothermalereproductiveparts. Testosteronealsocausesthesecondarymale characteristics.
(e) Treatmentsformaleinfertility:hormonaltreatment, surgeryorassistedreproductivetechnology(ART).
28
(a)(i) Prenatalcare:
Ultrasoundscansusesoundwavestoproduce imagesofthefoetusintheuterus.Ultrasound scanshelptoidentifyissuessuchasthe developmentofthefoetus,thepresenceof morethanonefoetus,somebirthdefects, thesexofthefoetusandthepositionofthe placenta.
(ii) Postnatalcare:
Thenewbornbloodspottestinvolvestakinga smallsampleofbloodfromthebaby’sheeland testingitforninerare(butserious)conditions.
(b)(i) PKU(phenylketonuria)isararebutpotentially seriousinheriteddisorder.PKUcausesanamino acid(phenylalanine)tobuildupinthebloodand brain.Thiscanleadtobraindamage.
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(ii) Oestrogencausestheendometriumtothicken inthefirsthalfofthecycle.
Progesteronecontinuesthisprocessinthe second14days.
Bothhormonesprevent(inhibit)eggsfrom developing.
(b)(i) Theplacentaallowsexchange(bydiffusion) betweenthebloodofthemotherandofthe embryo.
Itpreventsthebloodofthemotherandembryo frommixing
Itactsasanendocrineglandwhenitproduces thehormoneprogesterone.
(ii) Fromuterinetissueandembryonictissue.
(iii) Contractionsoftheuteruspushthefoetusdown towardsthecervix.
Amucousplugthatblocksthecervixisexpelled, alongwithsomeblood.
Themembranesaroundthefoetusbreakto allowthelossofamnioticfluidfromthevagina (the‘waters’aresaidtobreak).
Thecervixdilates(opens)enoughtoallowthe babytobeborn.
Thefoetusispushedoutthroughthecervixand vaginaofthemother,usuallyheadfirst.The umbilicalcordisstillattachedtothebaby.
Thecordisclampedortied(nearthebaby’s body)andthencut.
Continuinguteruscontractionsexpelthe placentaandfoetalmembranes(calledthe afterbirth)fromthemother.
Scrotum Urethra
Uterus
Endometrium (implantation)
Funnel
Vagina
Ovary (meiosis)
Vulva Cervix
(iv) Invitrofertilisation(IVF)involvesfusinganegg andaspermoutsidethebody.
(c) Anumberoftheseembryosareputintotheuterus toallowthemtoimplantnaturally.
30
(a) 266days(38weeks)
(b) Stage1:
Contractionsoftheuteruspushthefoetusdown towardsthecervix.
Amucousplugthatblocksthecervixisexpelled, alongwithsomeblood.
Themembranesaroundthefoetusbreaktoallow thelossofamnioticfluidfromthevagina(the ‘waters’aresaidtobreak).
Stage2:
Thecervixdilates(opens)enoughtoallowthebaby tobeborn.
Thefoetusispushedoutthroughthecervixand vaginaofthemother,usuallyheadfirst.The umbilicalcordisstillattachedtothebaby. Thecordisclampedortied(nearthebaby’sbody) andthencut.
Stage3:
Continuinguteruscontractionsexpeltheplacenta andfoetalmembranes(calledtheafterbirth)from themother.
(c)(i) Progesteronelevelsdecreaseatbirth.
(ii) Oxytocinincreasesthelevelofcontractions.
(d)(i) Prolactin
(ii) Colostrumhashigherlevelsofminerals,proteins andantibodies.
31 HL
(a) FSHandLH.
(b) FSH(follicle-stimulatinghormone)causesthe diploidsperm-producingcellsinthetestestodivide bymeiosisandproducehaploidsperm.
LH(luteinisinghormone)stimulatesthetestesto producetestosterone.
32 HL
(a) Inorder:FSH,Oestrogen,LHandProgesterone.
(b) FSHproducedinDays1to5.
OestrogenproducedmainlyfromDays5to14. LHproducedonDay14. ProgesteroneproducedfromDays14to28.
(c) FSH:stimulatesafewpotentialeggstodevelop, surroundedbyGraafianfollicle. Stimulatestheproductionofoestrogen.
Progesterone:maintainsthestructureofthe endometrium.
Itinhibits(bynegativefeedback)theproductionof FSH,whichpreventsfurthereggsfromdeveloping. ItalsoinhibitsLHsothatfurtherovulationand pregnanciesareprevented.
Progesteronealsopreventscontractionsofthe uterus.
33 HL
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Oestrogen:causestheendometriumtodevelopand stimulatesthereleaseofthenexthormone,LH.
LH:causesovulation.
ItthencausestheremainsoftheGraafianfollicleto developintothecorpusluteum.
LHstimulatestheproductionofprogesterone.
(a) Gameteisasexcellcapableoffusion.
(b) Azygoteisthesinglecellformedwhena spermfertilisesanegg.Itcontainsafullsetof chromosomes(diploid).
(c) Zygotedividesbymitosistoproduceasolidclumpof cellscalledthemorula.
(d) Themorulaformsahollowballofcellscalledthe blastocyst.
(e) Theoutercellsoftheblastocystformalayercalled thetrophoblast.Thiswilllaterformthemembranes aroundtheembryo.
(f) Theinnercellsoftheblastocyst(calledtheinnercell mass)willlaterformtheembryo.
(g) Amnionisamembranethatsurroundstheembryo.
(h) Germlayersarebasiclayersofcellsintheblastocyst fromwhichalladulttissuesandorganswillform.
34 HL
(a) Ectoderm,mesoderm,endoderm
(b) Ectoderm:skin,nails,hair,andnervoussystem. Mesoderm:muscles,skeleton,excretorysystem, respiratorysystem,circulatorysystemand reproductivesystem.
Endoderm:liverandpancreas,andtheinnerliningof digestive,respiratoryandexcretorysystems.
35 HL
(a) Ectoderm,mesoderm,endoderm.
(b) Ectoderm:skin,nails,hair,andnervoussystem. Mesoderm:muscles,skeleton,excretorysystem, respiratorysystem,circulatorysystemand reproductivesystem.
Endoderm:liverandpancreas,andtheinnerliningof digestive,respiratoryandexcretorysystems.
(c) Fromuterinetissueandembryonictissue.
(d) Amnionisamembranethatsurroundstheembryo.
(e) Amnionprotectstheembryoandfoetus.
36 HL
(a)(i) IntheEndometrium:
Change:thickeningoftheendometriallining.
ApproximateDay(s):Days6–14
(ii) IntheOvary:
Change:ovulation(releaseofaneggfromthe ovary).
ApproximateDay(s):Day14
(b) Inthepituitarygland.
(c) FSH:stimulatesafewpotentialeggstodevelop, surroundedbyGraafianfollicle. stimulatestheproductionofoestrogen. LH:causesovulation.
ItthencausestheremainsoftheGraafianfollicleto developintothecorpusluteum LHstimulatestheproductionofprogesterone.
(d) Oestrogenandprogesterone
(e) Oestrogen:causestheendometriumtodevelop. Stimulatesthereleaseofthenexthormone,LH. Progesterone:maintainsthestructureofthe endometrium.
Itinhibits(bynegativefeedback)theproductionof FSH,whichpreventsfurthereggsfromdeveloping. ItalsoinhibitsLHsothatfurtherovulationand pregnanciesareprevented.
Progesteronealsopreventscontractionsofthe uterus.
37 HL
(a)(i) Relativenumbers:eggislow,spermishigh.
(ii) Frequency:eggismonthly,spermis continuously.
(iii) Relativesize:eggislarger,spermissmaller.
Differencesbetweeneggandsperm
EggSperm
Relativenumbers LownumberHighnumber
Frequencyofproduction MonthlyContinuously
Relativesize LargerSmaller
CHAPTER24
1
(a) Stamen=Male
(b) Style=Female
(c) Ovary=Female
(b) Secondarysexualcharacteristicsarethosefeatures thatdistinguishmalesfromfemales,apartfromthe sexorgansthemselves.
(c) Testosterone
(d) Hormonaltreatment,surgeryand/orassisted reproductivetechnology(ART).
38 HL
(a)(i) Prostateglandproducesseminalfluid.
(ii) Epididymisstoresspermandallowsthemto mature.
(b)(i) 23
(ii) Diagramofspermshowingmitochondria:
(iii) Possiblecausesofmaleinfertilityincludelow numbersofsperm,problemswiththesperm swimmingandblockagesinthepathofsperm.
(c)(i) 28days
(ii) A=Oestrogen
B=Progesterone
(iii) Menstruation(oraperiod),theendometrium breaksdown.
(iv) GraafianfolliclesmakehormoneA(oestrogen).
(v) Ovulation
(vi) LH
(vii) CorpusLuteummakeshormoneB (progesterone).
PLANTREPRODUCTION
(d) Filament=Male (e) Ovule=Female (f) Stigma=Female (g) Carpel=Female (h) Anther=Male
2
(a) Reproduction
(b) A=Filament
B=Anther
C=Stigma
D=Ovary
E=Stamen
(c) Thisfloweriswindpollinated. Reasons: Thepetalsarenotbrightlycoloured(ortheyare green),
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Theanthersareoutsidethepetals. Thestigmasareoutsidethepetals. Theanthersandstigmasarelarge.
(d) Meiosisoccursintheanthers(b)andovulesinthe ovary(D).
3
(a) Agameteisasexcell.
(b) Themalegametesinaflowerarethespermnuclei.
(c) Thefemalegametesinafloweraretheeggcells.
4
(a) Apetalisvisiblewhenthefloweropens(orisusually brightlycolouredorisinsidethesepalsbeforethe floweropens.
Asepalisvisiblebeforethefloweropens(oris usuallygreenorisoutsidethepetalsbeforethe floweropens).
(b) Anovaryisfemalestructure(orcontainstheegg(s)). Anantherismale(orcontainsthepollen).
(c) Theovarysurroundstheovule(s).
(d) Thecarpelisfemale. Thestamenismale.
(e) Theantherismaleandproducesandreleasespollen. Thestigmaisfemaleandreceivesthepollen.
Collar
5
(a) DiagramX:
A=Anther
B=Filament
C=Ovary
D=Stigma
DiagramY: E=Stigma F=Anther G=Sepal
(b) Theantherproducesthepollen(bymeiosis). Thefilamentsupportstheanther.
Theovarycontainsoneormoreovules(orcarries outmeiosistoproduceeggs).
Thestigmaiswherethepollenland. Theantherproducesthepollen(bymeiosis). Thesepalprotectstheflowerwhenitisabud.
(c) Xiswindpollinated.
Reasons: Itdoesnothavebrightlycolouredpetals(orithas greenpetals).
Theanthersareoutsidethepetals. Theanthersarelarge, Thestigmaisoutsidethepetals. Thestigmaislarge.
(d) Yisanimalpollinated.
Reasons: Ithasbrightlycolouredpetals. Theanthersareinsidethepetals. Thestigmasareinsidethepetals. Theanthersaresmall. Thestigmasaresmallandrounded.
6
(a) Pollinationisthetransferofpollenfromanantherto astigma.
(b) Pollinationmaybecarriedoutbythewind,by animalsorbyself-pollination.
(c) Pollinationiscompletewhenthepollenlandsonthe stigma.
(d) Self-pollinationmeansthatthepollenistransferred fromananthertoastigmaonthesameplant.
Cross-pollinationmeansthatthepollenis transferredfromananthertoastigmaonadifferent plant.
9
(a) Acotyledonisaseedleaf.
(b) Monocotshaveonecotyledon.Dicotshavetwo cotyledons.
10
(a) Seedsdevelopfromfertilisedovules.
(b) Thetestadevelopsfromtheoutercoatoftheovule (calledtheintegument).
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7
(a) Fertilisationtakesplaceintheovule.
(b) Apollentubegrowsthroughthestyle.
(c) Fertilisationresultsinazygote.
8
(a) Pollennucleus=10
(b) Aneggnucleus=10
(c) Astigmacell=20
(d) Thezygote=20
(e) Anembryocell=20
(f) Acotyledoncell=20
(g) Afruitcell=20
(c) Theembryodevelopsfromthezygote.
(d) Thecotyledon(s)developfromtheembryo.
(e) Thefruitdevelopsfromtheovary.
11
(a) Growthregulatorsarechemicalsthatcontrolthe growthofplants.
(b) Growthpromotersincreasethegrowthofplants. Growthinhibitorsreducethegrowthofplants.
(c)(i) Auxins,cytokininsandgibberellinsincreasethe growthofplants.
(ii) Etheneandabscisicacidpreventgrowthin plants.
12
(a) Seeddispersalisthetransferofseeds(orfruits) awayfromtheparentplant.
(b) Advantagesinclude:avoidingcompetition, increasingthechanceofsurvival,itallowsplantsto growinnewareas,anditincreasesthenumberof thespecies.
(c) Methodsandexamples: Winddispersal:dandelion,sycamore,ash Waterdispersal:alder,waterlilies Animaldispersal:burdock,strawberries,tomatoes Self-dispersal:peas,beans
13
(a) Afruitisadevelopedormatureovary.
(b) Functions:seedprotectionandseeddispersal.
14
(a) Germinationisthegrowthofaseedifthe environmentalconditionsaresuitable.
(b) Theconditionsforgerminationinclude:water, oxygen,andasuitabletemperature.
(c) Waterisnecessarytoallowenzymereactionstotake place.
Oxygenisnecessaryforrespiration. Asuitabletemperatureisnecessarytoallowenzyme action.
15
(a) A=Anther B=Filament
(b) PollenisproducedinA.
(c) Polleniscarriedtothestigma.
(d) Cross-pollinationmeansthatthepollenis transferredfromananthertoastigmaonadifferent plant.
(e) Methodsofcross-pollinationinclude:windand animalpollination.
16
(a) X=Style
Y=Ovary
Z=Ovule
(b) Bywind.
(c) Thespermnucleus
(d) Thenucleusinthepollentravelsdownthrougha pollentubetogettotheeggcell.
(e) StructureYdevelopsintoafruit. StructureZdevelopsintoaseed.
(f) PartZ(i.e.theseed)willproducegrowthregulators.
17
(a) Fromtheovule.
(b) Inthecotyledonsorintheendosperm.
(c) Theembryocontains:theplumule(whichdevelops intotheaerialparts)andtheradicle(whichdevelops intotheroots).
18
(a)(i) Thepetalprotectstheflowerandmayattract insects(oranimals).
(ii) Theantherproducesthepollen.
(iii) Thestigmaisalandingplatformforthepollen.
(b) Throughthestyle.
19
(a) Blackberriesdispersetheirseedsbybeingswallowed byanimals(withtheseedsexpelledasfaeces). Sycamoreseedsaredispersedbythewind. Peaseedsareself-dispersed(whenthefruit explodesopen).
(b)(i) Dispersalisthetransferofseeds(orfruits)away fromtheparentplant.
(ii) Thebenefitsoffruitsinclude:protectingthe seedsanddispersalofseeds.
(iii) Benefitsofseeddispersalinclude:avoiding competition,increasingthechanceofsurvival, allowingplantstogrowinnewareas,and increasingthenumberofthespecies.
20
(a) X=Stigma(orstamen)
Y=Ovule
Z=Sepal
(e) Pollinationiscompletewhenthepollenlandsonthe stigma.
(f) Thebrightlycolouredpetalsattractinsects.
(g) TheseeddevelopsinpartY(theovule).
(h) Functionsoffruitsinclude:protectingtheseedsand thedispersalofseeds.
21
(a) Fromtheovule.
(b) Biomoleculesstoredintheendospermorcotyledons includestarch,fats,andproteins.
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(b) Thesepals(Z)protecttheflowerwhenitisinbud.
(c) PollenisreceivedontopartX(stigmaorstamen).
(d) Thisflowerisanimalpollinated. Adaptationsinclude:largepetals,brightlycoloured petals,anthersareinsidethepetals,anthersare small,stigmasareinsidethepetals,andstigmasare smallandrounded.
(c)(i) A=(2)Stigma
B=(3)Anther
C=(1)Petal
(ii) Petal=(2)Attractspollinators
Stigma=(1)Trapspollen
Anther=(3)Producespollen
(iii) Pollinationisthetransferofpollenfroman anthertoastigma.
(iv) Typesofpollination:crossorself-pollination.
(v) PartBisthemalepartoftheflower.
22
(a)(i) A=Anther
B=Filament
C=Stigma
(ii) Visiblewind-pollinatedadaptationsinclude:no (orsmall)petals,greenpetals,anthersoutside petals,largeanthers,stigmasoutsidepetals, and/orlargefeatherystigmas.
(iii) Pollenisformedintheanther(partA).
(iv) Pollenmaybecarriedbyanimalsorbythewind.
(v) Haploid
(b)(i) Acotyledonisaseedleaf.
(ii) Themainfunctionofthecotyledonistostore food.
(iii) Themainfunctionofthetestaistoprotectthe seed.
Theplumuledevelopsintotheaerialpartsofthe plant.
Theradicledevelopsintotheundergroundparts oftheplant.
(iv) 1.Methodsoffruitandseeddispersalinclude: wind,water,animalandself-dispersal.
2.Benefitsoffruitandseeddispersalinclude: avoidingcompetition,increasingthechanceof survival,allowingplantstogrowinnewareas andincreasingthenumberofthespecies.
CHAPTER25 TRANSPORTACROSSMEMBRANES
1
(a) Permeablemembranes:allowallsubstancestopass throughfreely.
(b) Impermeablemembranes:substancescannotpass through.
(c) Aselectivelypermeable(orsemipermeable) membraneallowssomebutnotallmoleculestopass through.
2
(a) Examplesofdiffusioninplants:(i)carbondioxide(ii) diffusingintoaleafand(iii)oxygendiffusingoutofa leaf.
(b) Examplesofdiffusioninanimals:(i)oxygendiffusing (ii)fromtheblood(iii)intoamusclecellor(i)carbon dioxidediffusing(ii)outofacell(iii)intotheblood.
(c) See (b) above.
3
(a) Asoluteisasubstancethathasbeendissolved. Saltdissolvedinwaterisanexampleofasolute.
(b) Asolventisaliquidthatdissolvesothersubstances. Wateristhemostcommonbiologicalsolvent.
(c) Asolutionisamixtureofasoluteandsolvent. Saltwaterisanexampleofasolution.
4
(a) Diffusionisthespreadingoutofmoleculesfrom aregionofhighconcentrationtoaregionoflow concentration.
(b) Osmosisisthemovementofwatermoleculesacross aselectivelypermeablemembranefromaregionof high-waterconcentrationtoaregionoflow-water concentration.
(c) Bothprocessesinvolvethemovementofmolecules fromahighconcentrationtoalowconcentration andbotharepassive.
(d) Diffusiondoesnotrequireaselectivelypermeable membrane,butosmosisdoes.
(e) Factorsinclude:temperature,surfaceareaand concentrationgradient.
5
(a) Bloodplasmashouldhavethesameconcentration asbloodcellsbecauseiftheydon’t,waterwould eitherenterorleavethecellscausingthemtoswell andburstorshrivel.
(b) Thekidneys.
6
(a) Flaccid
(b) Thesolutionoutsidethecellismoreconcentrated.
(c) Thecellwallisfullypermeable.
7
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(c) Ifbloodplasmabecamelessconcentratedthan bloodcells,waterwouldenterbloodcellsbyosmosis causingthemtoburst.
(a) Turgor,orturgorpressure,istheoutwardpressure ofthecytoplasmandvacuoleagainstthecellwallof aplant.
(b) Itprovidesstrengthtothecell.
(c) Asanimalcellshavenocellwall,theywouldburst.
8
(a) Waterwouldenterredbloodcellsindistilledwater, causingittoswellandburst.
(b) Plantcellshaveacellwall(whileanimalcellsdonot).
9
(a) Osmosis
(b) Possiblereasonsincludefairtesting,averagesfor accuracy,andreplicationforreliability.
(c) Thepotatoeshave1%saltconcentrationasthe potatoesinthe1%saltsolutionhadthesamemass asthefreshpotatoes.
10
(a) Waterenteredbyosmosisasthesolutioninthe Viskingtubingwasmoreconcentrated.
(b) Iodinemoleculesaresmallenoughtodiffuseinto thetubingthroughthemembrane.Wheniodine comesintocontactwithstarchinsidethetubing,it reactstoformablue-blackcolour.
(c) Thecolourofthedistilledwaterandiodineoutside thetubingchangedbecauseiodinediffusesintothe tubing,reducingitsconcentrationinthesurrounding solution.
(d) Theblue-blackcolourchangeonlyhappens wheniodinecomesintocontactwithstarch.
11
(a) Saltingfishhelpspreserveitashighlevelsofsalt meanthatbacteriawouldlosewaterduetoosmosis andshrivelanddie.
(b) Jamhasahighsugarconcentration.Therefore,this dehydratesmicroorganismsandpreventsthemfrom growingeasilyonthesurfaceofjam.
12
(a) Cellophaneisusedasitactsasasemipermeable membrane.
(b) ThelevelofliquidatXwillincreaseinheight.
(c) Tapwaterislessconcentrated.
(d) Thesolutionwouldriseevenhigherinthetube.
(e) Osmosisallowsthewatertoenterthroughthe cellophane.
13
(a)(i) Moreconcentrated:solutionC
(ii) Lessconcentrated:distilledwaterinbeakerA
(iii) SolutionB
(b) BeakerA:waterwillentertheViskingtubingdueto osmosisassolutioninthecellophanebagismore concentrated.Masswillincrease.
BeakerB:nochangeinmassassameamountof waterwillenterorleavetheViskingtubingasboth solutionshavethesameconcentration.
BeakerC:waterwillleavetheViskingtubingdue toosmosisassolutioninthecellophanebagisless concentrated.Masswilldecrease.
14
(a)(i) Osmosisisthemovementofwatermolecules acrossaselectivelypermeablemembranefrom aregionofhigh-waterconcentrationtoaregion oflowwaterconcentration.
(ii) Aselectivelypermeable(orsemipermeable) membraneallowssomebutnotallmoleculesto passthrough.
(b)(i) Possiblefactorstobeinvestigatedcould includetemperature,surfaceareaor concentrationgradient.
Note:Thefollowingisbasedontemperature.
(ii) Diagramofapparatusused:
Ascontrols,repeattheprocedureateach temperatureusingViskingtubing‘bags’ containingdistilledwater.
(iv) MeasuredthemassoftheViskingtubingbefore andafteryouaddedtothebeakerofdistilled water.
(v) Viskingtubing‘bags’containingdistilledwater (vi) Surfaceareaandconcentrationgradientwere keptconstant.
(vii) Temperature
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(iii) Note:Theinvestigationshouldincludethe followingstepsinthedescription.
Soakthree40cmstripsofViskingtubingin water(thissoftensthem).
Tieaknotinoneendofeachofthestrips. Usingasyringe,addthesamevolumeofthe sucrosesolutiontothethreepiecesofVisking tubing,tyingsecondknotsineachonetoseal thecontents.
Gentlypateachtubedryusingtissuepaper. Notethe‘fullness’(orturgidity)ofeachtubeand recorditsmass.
PlaceeachtubeofViskingtubinginabeakerof distilledwaterandplacethebeakersinwater bathsat0°C,20°Cand40°C.
Thewaterbathsmaintainthetemperaturesat thechosenlevelsthroughouttheinvestigation. Leavetheapparatusfor20minutes(toallow timeforosmosis).
Removethebags,drythemasbeforeandnote andrecordthe‘fullness’andmassofeachbag. (Thechangeinmassisameasureoftherateof osmosis.)
(viii) Results:asthetemperatureincreased,the rateofosmosisincreased,andthemassofthe bagsincreased.
15
(a) Thecellsapismoreconcentratedallowingwaterto enterbyosmosis.
(b) Bothprocesses(osmosisanddiffusion)involvethe movementofmoleculesfromahighconcentration toalowconcentrationandbotharepassive.
(c)(i) Viskingtubingactsastheselectivelypermeable membrane.
(ii) Variablescouldincludetemperature,surface areaorconcentrationgradient.
(iii) Dependentvariablescouldincludemeasuring theincreaseordecreaseinmassoftheVisking tubing.
16
(a)(i) Aselectivelypermeable(orsemipermeable) membraneallowssomebutnotallmoleculesto passthrough.
(ii) Nucleus,mitochondria,chloroplastorcell membrane.
(b)(i) Diffusionisthespreadingoutofmolecules fromaregionofhighconcentrationtoaregion oflowconcentration.
(ii) Oxygendiffusesintothebloodfromthealveoli ofthelungs.
(c)(i) Water
(ii) Watermoleculesmovefromanareaof higherwaterconcentrationtoanareaof lowerwaterconcentrationthroughasemipermeablemembrane.
(iii) Highsugarorsaltconcentrationswouldmean thatbacteriawouldlosewaterduetoosmosis andshrivelanddie.
17
(a) Activetransportistheuseofenergytomove moleculesacrossbiologicalmembranesagainsta concentrationgradient.
(b) Diffusioninvolvesmoleculesmovingfroma regionofhighconcentrationtoaregionoflow concentration.Energyisnotrequired. Activetransportinvolvesmoleculesmovingfrom aregionoflowconcentrationtoaregionofhigh concentration.Energyisrequired.
(c) AlowenergymoleculeisADP.
18
(a) Nucleus,mitochondria,chloroplastorcell membrane.
(b)(i) LetterA
(ii) Osmosis
(c)(i) Topreservethefoodforlonger.
(ii) Bacteriawouldlosewaterduetoosmosisand shrivelanddie.
19
(a) Osmosis
(b)(i) Turgor,orturgorpressure,istheoutward pressureofthecytoplasmandvacuoleagainst thecellwallofaplant.
(ii) CellA
(iii) Cellwall
(iv) Thevacuole
(v) CellBhaslostwaterbyosmosisandhas shrivelled.Ithaslostwaterduetothecellbeing exposedtoamoreconcentratedsolution.
20
(a) Turgid
(b) Shapemaintainedduetoturgorpressureoroutward pressureofthecytoplasmandvacuoleagainstthe cellwallofaplant.
(c) SolutionBismoreconcentratedthanSolutionA.
(d) Osmosis.Osmosisisthemovementofwater moleculesacrossaselectivelypermeablemembrane fromaregionofhigh-waterconcentrationtoa regionoflowwaterconcentration.
(e) Byaddingdistilledwater.
(f) Saltingmeatoraddingsugartojamwouldmeanthat bacteriawouldlosewaterduetoosmosisandshrivel anddie.
21
(a) Water
(b) Osmosis
(c) 4g/100cm3
(d) Becausetheplanttissueandthesugarsolutionhad thesameconcentration,therewasnochangein mass.
(e)(i) Turgid
(ii) Theymaintainitduetothe(presenceof)cell wall,or(presenceof)thevacuole,orbytakingin asmuchwaterastheylose.
(f) Possiblereasonswhythemassreduces: Waterhasmovedoutofthecells(byosmosis) (Watermoves)fromaregionofhigh-water concentration(insidethecell)toaregionoflowwaterconcentration(outsidethecell).
Duetothehighsugarconcentrationoutsidethe cellswhencomparedtoinsidethecells.
(g) Ananimalcellwouldincreaseinsizeorswellor burst.
CHAPTER26 THEURINARYSYSTEM
1
(a) A=Aorta
B=Renalartery
C=Kidney
D=Renalvein
E=Ureters
(b)(i) Kidney(C).
(ii) Inthebladder(F).
(iii) Intherenalarteries(B).
(iv) Intherenalvein(D).
(v) Thesphinctermuscle(G).
(vi) Bytheurethra(H).
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F=Bladder
G=Sphinctermuscle
H=Urethra
I=Venacava
2
(a) Thekidneysareosmoregulatorybecausethey controlthewaterandsaltbalanceoftheblood(or body).
(b) Thebodygainswaterbydrinking,food,reabsorption anddigestion.
(c) Waterislostfromthebodyasurine,sweat,tears, faeces,bleeding,breathing,spitting,vomitingand/ orbreastfeeding.
3
(a) Fromprotein.
(b) Intheliver.
(c) Intheliver.
(d) Inthekidneys.
(e) Asurine.
4
(a) Urineismadeinthekidneys.
(b) Urineisstoredinthebladder.
(c) Urineisexcretedintheurethra.
5
(a) Filtrationmeansthatwaterandsmallmoleculespass fromthebloodintothekidneys.
(b) Filtrationtakesplaceinthecortexofthekidney.
(c) Substancesfilteredinthekidneysinclude:water, glucose,aminoacids,vitamins,smallhormones,urea andsalts.
6
(a) Reabsorptionmeansthatsubstancespassfromthe kidneysbackintotheblood.
(b) Reabsorptiontakesplaceinthecortex,medullaand pelvisofthekidneys.
(c) Urea
7
(a) (i) Excretionisremovaloftheproductsofchemical reactionsfromthebody.
(ii) Productsexcretedincludeurea,salts,water, carbondioxide,toxinsand/ordrugs.
(iii) Organsofexcretioninclude:kidneys,lungsand skin.
(iv) Osmoregulationisthecontrolofthewaterand saltbalanceofthebody.
(b)(i) A=Renalartery
B=Renalvein
(ii) C=Ureter
(iii) Urine
(iv) X=Cortex
Y=Medulla
Z=Pelvis
(v) Inthecortex(X).
(vi) Clinksthekidneytothebladder.
(vii) Totheaorta.
8
(a) Excretionisremovaloftheproductsofchemical reactionsfromthebody.
(b) Substancesexcretedbythekidneysinclude:water, urea,andsalts.
(c)(i) A=Kidney
B=Ureter
C=Bladder
(ii) Inthecortex.
(iii) Otherfunctionsofthekidneyare osmoregulationandpHcontrol.
9
(a) Thevolumesofsweatandurinearethesameat 25°C.
(b) Asthetemperaturerisesthevolumeofurine produceddecreases.
(c) Asthetemperaturerisesmorewaterislostassweat. Toreducewaterlosslessurineisproducedasthe temperaturerises.
10
(a) Anephronisatubethatformsurine.
(b) Nephronsareinthekidneys.
(c) Bowman’scapsuleisinthecortexofthekidney.
(d)(i) Filtrationmeansthatwaterandsmallmolecules passfromthebloodintothekidneys.
(a) Diagramshowinglocationofnephroninkidney: Nephron
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(ii) Substancesthatleavethebloodinthekidneys include:water,glucose,aminoacids,vitamins, smallhormones,urea,andsalts.
(iii) Substancesnotfilteredinclude:redbloodcells, whitebloodcells,platelets,antibodies,clotting proteinsandsomehormones.
(c) A=Renalarteriole
B=Afferentarteriole
C=Glomerulus
D=Efferentarteriole
E=Capillary
F=Renalvein
G=Bowman’scapsule
H=Proximalconvolutedtubule
I=LoopofHenle
J=Distalconvolutedtubule
K=Collectingduct
(d) Functions:
Renalarteriolecarriesbloodtothekidney. Afferentarteriolecarriesbloodtotheglomerulus. Glomerulusfilterstheblood.
Efferentarteriolecarriesbloodawayfromthe glomerulus.
Capillaryreabsorbssubstancesfromnephron. Renalveincarriesbloodawayfromkidney. Bowman’scapsulecollectsthefiltratefromthe glomerulus.
Proximalconvolutedtubulereabsorbsuseful substances.
LoopofHenlereabsorbswater.
Distalconvolutedtubulereabsorbssaltsandwater andcontrolspHvaluesoftheblood.
Collectingductreabsorbswaterandtransfersurine toureter.
11 HL
Cortex
Medulla
12 HL
(a) Bloodpressureintheglomerulusishighbecause theincomingbloodisinanarteriolewithhigh pressure,theincomingafferentarterioleiswider, theoutgoingefferentarterioleisnarrowerandthe differenceinsizesincreasesthebloodpressure.
(b) Themitochondriaprovidetheenergyneededfor activetransport.
13 HL
(a) Thereisnoproteinintheglomerularfiltrateas proteinistoolargetobefilteredintheglomerulus.
(b) Urinehasnoglucosebecauseglucoseisreabsorbed intheproximalconvolutedtubule.
(c) Thedifferenceinconcentrationsisduetothe reabsorptionofwaterindifferentpartsofthe nephron(i.e.thereisthesameamountofurea,butit iscontainedinalowervolumeofwater).
(d) Somesaltisreabsorbedinthenephron,butnourea isreabsorbed.
14 HL
(a) Filtrationmeansthatwaterandsmallmoleculespass fromthebloodintothekidneys.
Reabsorptionmeansthatsubstancespassfromthe kidneysbackintotheblood.
(b) Intheglomerulus,waterandglucosearefiltered fromthebloodintoanephron.
Intheproximalconvolutedtubule,waterand glucosearereabsorbed.
15 HL
(a) Excretionisremovaloftheproductsofchemical reactionsfromthebody.
Glomerularfiltrateisadilutesolutionofsubstances filteredfromtheglomerulusintoBowman’scapsule.
(b) Redbloodcellsaretoobigtopassthroughthe glomerulus.
(c) Theconcentrationsarethesamebecausewater andglucosecanbothpassfreelyfromtheblood, throughtheglomerulusandintotheglomerular filtrate.
(d) Glucoseisnormallyabsentfromurinebecauseit isreabsorbedbackintothebloodintheproximal convolutedtubule.
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(a)(i) Therenalartery.
(ii) Ureaisderivedfromthebreakdown (deamination)ofexcessaminoacids. Carbondioxideisderivedfromthebreakdown (inrespiration)ofglucose.
(iii) Bislocatedinthecortexofthekidney.
(iv) 1.Filtrationtakesplaceintheglomerulus 2.Reabsorptionofaminoacidstakesplaceinthe proximalconvolutedtubule.
(v) Featuresthataidfiltrationinclude: Bloodpressureintheglomerulusisgreaterthan normalbloodpressure.
Theglomerulushasmanycapillaries.
Thecapillarieshavealargesurfacearefor filtration.
Thecapillariesintheglomerulusaremore porousthannormalcapillaries.
(vi) Toolargebiomoleculesnephroninclude antibodies,clottingproteins,andsome hormones.
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(a)(i) Ureaismadeintheliver.
(ii) Ureaismadefromprotein(oraminoacids).
(b)(i) Bowman’scapsuleislocatedinthecortexofthe kidney.
(ii) TheLoopofHenleisinthemedullaofthe kidney.
(iii) A=Ureter
(iv) Diagramofanephron:
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(b)(i) A=Afferentarteriole
B=Bowman’scapsule
C=Proximalconvolutedtubule
D=LoopofHenle
E=Collectingduct
F=Distalconvolutedtubule.
(ii) Aisderivedfromtherenalartery.
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(a) Thekidneysarelocatedintheabdomen.
(b) A=Cortex
B=Medulla
C=Pelvis
(c) Filtrationoccursinthecortex(orpartA).
(d) Theincominghighpressureisincreasedsothat moleculesareforcedoutofthebloodundervery highpressure.
(e) Thelargenumberofcapillariesallowsforahigh amountofreabsorption.
(f) Urinetravelstothebladderthroughtheureter.
(g) ADHisreleasedwhenaperson’sbloodplasmaistoo concentrated(i.e.personareshortofwater).ADH makesthewallsofthecollectingductsandthedistal convolutedtubulesmorepermeabletowaterso thatmorewaterisreabsorbed.
Ifthebloodconcentrationisnormal,thenADHisnot releasedandlesswaterisabsorbedinthenephrons.
Bowman’s capsule
Proximal convoluted tubule
LoopofHenle
Distalconvoluted tubule
Collecting ducts
Glomerulus
CHAPTER27 THEDIGESTIVESYSTEM
1
(a) Nutritionisthewayinwhichorganismsget chemicalsandenergy(intheformoffood)from theirenvironment.
(b) Ingestionisthetakingoffoodintothedigestive system.
Digestionisthebreakdownoffood(both mechanicallyandchemically).
Absorptiontakesplacewhenthedigestedfood passesfromtheintestineintotheblood.
Egestionistheremovalofunabsorbedwastefrom thedigestivesystem.
(b) Ingestion:inthemouth.
Digestion:mostdigestionoccursinsmallintestine (butoccursthroughoutthealimentarycanal).
Absorption:intheileumofsmallintestine.
Egestion:anus
2
(a) Makesfoodeasiertobeabsorbed,makesfoodmore solubleandeasiertotransport.
(b) Mechanicaldigestionisthephysicalbreakdownof food.
Chemicaldigestionisthebreakdownoffoodusing enzymes.
(c) Examplesofmechanicaldigestioninclude:chewing orgrindingfood,churningfoodinthestomach,and peristalsisinoesophagus.
(d) Exampleofchemicaldigestionincludes:theenzyme amylasebreakingdownstarchintomaltoseinthe mouth.
(e) Benefit:increasesthesurfaceareaofthefood particles,whichallowsenzymestoworkbetter.
3
(a) Correctorder:mouth,oesophagus,stomach, duodenum,ileum,colon,rectumandanus.
(b)(i) Salivarygland:mylase
(ii) Pancreas:mylase,lipase,andsodiumhydrogen carbonate
(iii) Liver:bile
(iv) Gallbladder:bile
(c) Functionsofsubstances: Amylasebreaksdownstarchintomaltose. Lipasebreaksdownlipidsintofattyacidsandglycerol. Bileemulsifiesfatsandneutralisesfoodcomingfrom stomach.
D=Pancreas
E=Colon(orlargeintestine)
F=Oesophagus
G=Appendix
H=Ileum(orsmallintestine)
I=Rectum
J=Anus
K=Gallbladder
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Sodiumhydrogencarbonateneutralisesfoodcoming fromstomach.
(b)(i) Stomach
(ii) Liver
(iii) Ileum
(iv) Oesophagus
(v) Rectum
(vi) Largeintestine(colon) (vii) Gallbladder
(c) Peristalsis
5
(a) Fourtypesofteeth:incisors,canines,premolarsand molars.
(b) Incisorscutandslicefood. Caninesgripandtearfood.
Premolarscrush,grindandchewfood. Molarscrush,grindandchewfood.
(c) Premolarsandmolars
6
(a) Bile(ii)
Reason:bileisnotanenzyme.Theotherthreeare enzymes.
7
(a) Starch(iii)
(b) Theotherthree(aminoacid,fattyacidandglycerol) arefullydigestedandcanbeabsorbed.Starch cannotbeabsorbedbutneedstobedigested.
8
Statement
4
(a) A=Duodenum(orsmallintestine)
B=Liver
C=Stomach
Trueor false?
‘Proteinsarechemicalsdigestedinthemouth.’ False ‘HydrochloricacidhasapHof9.’ False ‘Bilesaltsbreakdownfats.’ True ‘Sodiumhydrogencarbonateisalkaline.’ True ‘Twomajorbloodvesselsflowintotheliver.’ True
‘Thebileductconnectsthepancreasandthe illum.’ False
‘Allthebacteriainthecolonarebadforus.’ False ‘Waterisessential forabalanceddiet.’ True
9
(a) Inthemouth,oesophagus,stomachorduodenum.
(b) Inthemouthorstomachorduodenum.
10
(a) Amylase,lipaseorprotease(pepsin).
(b) Amylaseismadeinsalivaryglandorpancreas.
Lipaseismadeinpancreas.
Protease(pepsin)ismadeinstomachwall.
(c) Amylaseisactiveinmouthandduodenum.
Lipaseisactiveinduodenum.
Protease(pepsin)isactiveinstomach.
(d) Amylase=pH7to8
Lipase=pH7to8
Protease(pepsin)=pH2
(e) Amylaseactsonstarch.
Lipaseactsonlipids.
Protease(pepsin)actsonproteins.
(f) Amylasebreaksdownstarchintoaproductcalled maltose.
Lipasebreaksdownlipidsintoproductscalledfatty acidsandglycerol.
Protease(pepsin)breaksdownproteinsintoa productcalledpeptides(endproductisaminoacids).
(e)(i) Hepaticportalvein
(ii) Liver
(iii) Functionsoftheliverinclude: Breakingdownredbloodcells. Formingbile.
Detoxifyingchemicalsinthebody. Breakingdownunwantedaminoacidstoform urea.
Convertingglucosetoglycogenforstorage. Convertingexcesscarbohydratestofat. Storingvitamins(e.g.vitaminD). Storingmineralssuchasiron,copperandzinc. Makingproteinsthatareinvolvedinblood clotting.
Makingcholesterol,whichisusedtoformmany hormones.
(f) X=Lacteal.Function:toabsorbfattyacidsand glycerol.
(g) Y=Muscle.Function:peristalsis
14
(a) Increasingsurfaceareaforenzymestoacton.
(b) Thisispossibleduetoperistalsis.
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11
(a) A=Liver
B=Stomach
C=Pancreas
D=Oesophagus
E=Gallbladder
F=Duodenum
(b) PartDconsistsofmusculartube.
(c) LiquidstoredinpartEisbile.
(d) NormalpHofBispH2.
(e) Hydrochloricacidcancauseheartburn.
12
(a) Aminoacidsorfattyacidsandglycerolorglucose.
(b)(i) Water-soluble:glucose,aminoacids,vitamins andminerals.
(ii) Water-insoluble:fattyacidsandglycerol.
(c)(i) Watersolubleglucose,aminoacids,vitaminsand mineralspassfromtheileumintoblood capillariesbydiffusion.
(ii) Waterinsolublefattyacidsandglycerolpassinto thelacteal.
(c) Thegallbladderstoresandreleasesbiletohelp digestfats.Withoutit,bileenterstheintestinein smalleramounts,makingithardertodigestlarge amountsoffat
(d) Toneutralizeexcessstomachacidinconditions likeacidrefluxorheartburn.
(e) Antibioticscandisruptthebalanceofgutbacteria, killingbothharmfulandbeneficialmicrobes.
(f) Fibrehelpsregulatebowelmovements(stimulates peristalsis).
15
(a) Intheliver.
(b) Inthegallbladder.
(c) Intheduodenum(orsmallintestine)
(d) Onlipids.
(e) Emulsifiedfats.
16
(a) Peristalsisisaninvoluntarywaveofmuscular contractionthatmovesfoodthroughthealimentary.
(b) Inthesmallintestine(orileum).
(c) Diffusion
(d) Hepaticportalvein
13
(a) Intheileum(orsmallintestine).
(b) Toincreasesurfaceareaforabsorptionofnutrients.
(c) Featuresincludehavingthinwallsandarichblood supply.Eachvilluscontainsalacteal.Theyincrease surfacearea.
(d) Glucose,aminoacids,vitaminsandminerals.
17
(a) Diagramshowingtherelationshipbetweenthe duodenum,liver,gallbladderandpancreas.
Gallbladder Liver
Bileduct
Duodenum
(b) Pancreasreleaseenzymes(amylaseandlipase)into duodenumorpancreasreleasessodiumhydrogen carbonatetoneutralisefoodinduodenum.
(c) Functionsoftheliverinclude: Breakingdownredbloodcells. Detoxifyingchemicalsinthebody. Breakingdownunwantedaminoacidstoformurea. Convertingglucosetoglycogenforstorage. Convertingexcesscarbohydratestofat. Storingvitamins(e.g.vitaminD). Storingmineralssuchasiron,copperandzinc. Makingproteinsthatareinvolvedinbloodclotting. Makingcholesterol,whichisusedtoformmany hormones.
(d) Toabsorbwateroregestion.
18
(a) Abalanceddietcontainsallthefoodtypes,in thecorrectproportions,necessarytosupplythe nutrientsneededtomaintaingoodhealth.
(b) Benefitsofabalanceddiet: Itprovidestheenergyneededfordailyactivities. Itsuppliesallthenutrientsneededforgrowthand repair. Itpreventsdiet-relatedillnesses. Ithelpstomaintainahealthyweight Ithelpstomaintainourabilitytofightinfections.Or anyacceptableanswer.
19
(a) Foodsustainabilityinvolveseatingfoodsthatare healthyforourbodiesandfortheenvironment.
(b) Ithelpsreducetheriskofextinctions.
(c) Examplesoffoodsustainability:Weshouldeatlower downthefoodchain.
Weshouldeatorganicallygrownorgrass-fedanimal produce.
Wemustavoidoverfishing.
Weshouldconsumelocallygrownproduce(both plantandanimal)toreducetheneedfortransport. Weshouldreducefoodwaste.
(d) Example:palmOilandtheOrangutan. IncountrieslikeIndonesiaandMalaysia,vastareas ofrainforestareclearedtomakewayforpalmoil plantations.
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1
(a) Thenoseinhalesandexhalesair. Therearetwonostrils(oropenings)ineachnose.
(b) Thepharynxisthethroat. Thelarynxisthevoicebox.
(c) Theoesophagusisthefoodpipe. Thetracheaisthewindpipe.
20
Thisdestroysthenaturalhabitatofendangered speciesliketheorangutan,Sumatrantiger, andpygmyelephant.
Astheirhabitatsshrink,thesespecies facestarvation,increasedhumanconflict,and ultimately,extinction.
Thisisjustoneofmanyexampleswherethedemand forfood,especiallycashcropsorlivestockgrazing land,leadstobiodiversityloss.
(a) 3milliontonnes
(b) From1970to2010themassoffishcaught increased.From2010–2020themassoffishcaught decreased.
(c) Fishstockswouldhavebeendepleted,andsome speciesmayhavefacedextinction.Itwouldhave upsetthebalanceinnature.
(d) Theintroductionofquotas.
21
(a) Pesticidesarechemicalsubstancesusedtokillor controlpeststhatcandamagecrops,spreaddisease, orharmlivestockandhumans.
(b) Oneadverseeffectofpesticidesisharmtobeneficial insects,suchasbeeswhichactaspollinatorsor pesticidescanbeharmfultohumanhealthorany acceptableanswer.
(c) Advantages:organiccropsarebetterfornatureand thebiosphereandorganiccropsreducetheharmful effectstoagriculturalworkers.
(d) Suggestions:carbonemissionswouldincrease,there wouldbeanincreaseinpackagingoranincreasein energyuse.
(d) Abronchusisoneofthetwosubdivisionsofthe trachea. Bronchiolesaresubdivisionsofthebronchus.
(e) Thethoraxisthechest. Theabdomenistheareabelowthethoraxbutabove thepelvis.
2
(a)(i) Anatomyisthestudyofthestructureofan organismoritsparts.
(ii) Physiologyisthestudyofthefunctionsand processesofanorganismoritsparts.
(b) Therespiratorysystemislinedwithmucuswhich trapspathogensfrompassingtoofardown,hascilia whichbeattosweepmucus(andpathogens)up sowecanswallowit(allowingstomachacidtokill pathogens),andthelungscontainmanywhiteblood cells(macrophages)whichdestroypathogensthat getintothelungs.
3
(a)(i) Thefunctionoftheepiglottisistopreventfood anddrinkfromenteringthetrachea.
(ii) Thefunctionofthealveoliistoexchangegases.
(iii) Thefunctionoftheintercostalmusclesisto changethevolumeofthechestcavitysothat wecanmoveairinandoutofourlungs.
(iv) Thefunctionofthenasalpassagesistofilter, warmandmoistentheairpassingintoourlungs.
(b) Thelargenumberofalveoliresultinalargesurface areaforgasexchangeinthelungs.
4
Oxygenpassesfromthealveoliintoourblood.Oxygen passesfromourbloodintoourmusclecells.
Carbondioxidepassesfromourmusclecellsintoour blood.Carbondioxidepassesfromourbloodintothe alveoli.
5
(a) A=Larynx
B=Trachea
C=Bronchus
D=Bronchiole
E=Ribs
F=Diaphragm
G=Lung
(b) ThefunctionofA(larynx)istoproducesound(or speech).
ThefunctionofG(lung)isgasexchange.
(c) ThepositionofFsuggestsitisnotcontracted(it isrelaxed).Thisisbecausewhenitcontractsit curvesdownwards,butthediagramshowsitcurves upwards(relaxed).
(d) ThemusclesfoundbetweenE(theribs)arethe intercostalmuscles.
6
(a) Adaptationsinclude:theyareverynumerous,they havealargesurfacearea,theyhavethinwalls,they havemoistsurfaces,andtheyaresurroundedby bloodcapillaries.
7
(a) Exhalationispassivebecausethemusclesrelax(and donotuseenergy)duringthisprocess.
Inhalationisactivebecausethemusclescontract (usingenergy)duringthisprocess.
(b) Therightlungisbiggerbecausetheheartoccupies spaceontheleft-handsideofthethorax,reducing thesizeoftheleftlung.
8
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(b)(i) Pulmonaryarteriolestakebloodtothealveoli.
(ii) Capillariestakebloodaroundthealveoli.
(iii) Pulmonaryvenulestakebloodawayfromthe alveoli.
(a)(i) Theballoonrepresentsthelung(s).
(ii) Thebelljarrepresentsthethorax,thoraciccavity orchest.
(b) Whenairiswithdrawn,theballoonexpandsor inflates.
(c) Whenairiswithdrawn,thepressureinthebelljar reduces.Theexternalairpressureisnowhigherthan thepressureinthebelljar.So,airisforcedintothe ballooncausingittoexpand.
(d) Thisrepresentsinhalation.
9
(a) Thevoiceboxisthe(i)larynx.
(b) The%ofcarbondioxideexhaledatrestis(iii)4.4%.
(c) Therateofbreathingiscontrolledby(iii)thebrain.
(d) Theflapoftissueiscalled(iii)theepiglottis.
10
(a)(i) Thediaphragmislocatedatthebaseofthe thorax(orthoracicorchestcavity)separatingit fromtheabdomenbelow.
(ii) Theintercostalmusclesarelocatedbetweenthe ribsinthethorax(orthoracicorchestcavity).
(b)(i) Thepulmonaryvein(s)returnbloodfromthe lungstotheheart.
(ii) Themaingastransportedinthepulmonary vein(s)isoxygen.
(iii) Oxygenistransportedasoxyhaemoglobininthe pulmonaryvein(s).
11
(a) Diagramofthehumanbreathingsystem:
Trachea
Bronchus
Diaphragm Lung
(b)(i) Thefunctionoftheepiglottisistopreventfood anddrinkfromenteringthetrachea.
(ii) Thefunctionofthelarynxistoproducesound (orspeech).
(c) Thediaphragmcontractsandmovesdown.This increasesthevolumeofthethoraciccavitywhich reducesthethoracicairpressure.
Theintercostalmusclescontractcausingtheribsto moveupandout.Thisalsoincreasesthevolumeof thethoraciccavitywhichreducesthethoracicair pressure.
Asaresult,airisforcedintothelungs.
Whenthediaphragmandintercostalmusclesrelax thediaphragmmovesupandtheribsmoveinand down.Thisdecreasesthevolumeofthethoracic cavitywhichincreasesthethoracicairpressure.
Asaresult,airisforcedoutofthelungs.
(d)(i) Adaptationsofthealveoliforgasexchange includetherearehugenumbersofalveoli,they havealargesurfacearea,theyhavethinwalls, theyhavemoistsurfaces,andtheyarecovered bynumerousbloodcapillaries.
(ii) Diffusion
12
(a) A=Bronchiole
B=Alveolus
C=Pulmonaryarteriole
(b) Featuresofthealveoliincludehugenumbers,large surfacearea,thinwallsandmoistsurfaces.
Featuresofthecapillariesincludethinwalls,huge numbers,largesurfaceareaandclosetocells.
(c) X=Bloodcapillaries
13
(a) A=Bronchus
B=Trachea
C=Rib
(b) Gasexchangetakesplaceinalveoli.
(c) Featuresofthealveoliincludehugenumbers,large surfacearea,thinwallsandmoistsurfaces.
(d) Thefunctionofthelarynxistoproducesound(or speech).
(e) Inhalationinvolvesthefollowingsteps:the diaphragmcontracts,intercostalmusclescontract, thevolumeofthoraxincreases,pressureinthorax decreases,andairisforcedintolungs.
14
(a) A=Larynx
B=Trachea
(d) Duringinhalationtheairpressureinsidethechest decreases.
(e) Activeprocessmeansthatenergyisused. Passiveprocessmeansthatenergyisnotused.
(f)(i) A=Villus
B=Alveolus
(ii) Thevilliarelocatedintheileum(orsmall intestine).
Alveoliarelocatedinthelungs.
(iii) Featuresforefficientgasexchangecommonto bothincludethinwalls,manycapillaries,moist surfaces,andlargenumbers.
15
(a) Diagramshowingthestructureofanalveolusandits bloodsupply:
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C=Bronchus
D=Bronchiole
E=Alveolus
(b) StructureBiscomposedofrigidringsofcartilageto preventitfromcollapsing.
(c) Thediaphragmandtheintercostalmuscles.
(b)(i) DiagramX=Inhalation
(ii) Inhalationisoccurringbecausetheribsare movingupandout,thediaphragmismoving down,andthevolumeofthechestisincreasing.
16 HL
(a) Thestructuresarealveoli.
(b) Adaptationsincludelargesurfaceareaorlarge numbers,rich(blood)capillarysupply,moistsurface, membranes(orwalls)arethin,orwallsareonecell thick.
(c) Carbondioxide
(d) Theregionofthebrainthatdetectscarbondioxideis themedullaoblongata.
(e) Ahighlevelofcarbondioxidecausesanincreased rateofbreathing,andanincreaseddepthof breathing.
(f) Exhalationinvolvesthefollowingsteps:the intercostalmusclesanddiaphragmrelax,theribs movedownandin,thediaphragmmovesup,the volumeofthechest(orthoraxorthoraciccavity) decreases,thepressureofthechest(orthoraxor thoraciccavity)increases,andairmovesoutoris forcedout.
Capillary
To heart
Bronchiole
From heart
Alveolus
Carbon dioxide
Oxygen
17
(a) Carbondioxide
(b)(i) Respirationincreasestheconcentrationof carbondioxideintheblood.
(ii) Exhalationdecreasestheconcentrationof carbondioxideintheblood.
(c) CarbondioxidelowersthepHoftheblood.
(d) Inthemedullaoblongata.
(e) HighlevelsofcarbondioxidecauseourbloodpHto fallwhichresultsinanincreaseintherateanddepth ofbreathing.
CHAPTER29 THECIRCULATORYSYSTEMAND BLOOD
1
(a) Structuraldifferences:
Arteryhasathickwall,smalllumen,andvalvesare absent.
Veinhasathinwall,largelumenandvalvesare present.
(b) Otherdifferences:
Arterycarriesbloodawayfromheartandhasahigh bloodpressure.
Veincarriesbloodtotheheartandhasalowblood pressure.
(c) Capillarywallsareonlyonecellthickandcapillaries carrybloodbetweenarteryandvein.
2
(a) Collagen
(b) Layerofmuscleandelasticfibresallowarteriesand veinstochangesize.
(c) Endotheliumlinesallbloodvessels.
3
(a) Theirwallsarenotthinenoughwhencomparedwith capillarywalls.
(b) Theyhaveextremelythinwalls,andthelarge numbersofcapillariesincreasethesurfaceareafor exchangeofsubstances.
4
(a) Thevalvesintheheartpreventbackflowofbloodor allowbloodtoflowinonedirectiononly.
(b) Arterieshavehighbloodpressure.
(c) Topreventdamage.
5
A=Aorta
B=Pulmonaryvein
C=Bicuspidvalve
D=Septum
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E=Rightventricle
F=Rightatrium
G=Semilunarvalve
H=Pulmonaryartery
(b) X=SAnode(orpacemaker)
(c) FunctionC:bicuspidvalvepreventsbloodflowing backintoleftatrium.
FunctionE:rightventriclecontractstoforceblood intothepulmonaryarteryandtothelungs.
FunctionG:semilunarvalvespreventbloodflowing backintotheheart.
FunctionX:SAnodesendsoutelectricalimpulses causingtheleftandrightatriumtocontract.
6
(a) Theyarethinnerbecausetheyonlyhavetopumpa shortdistancetotheventricles.
(b) Theleftventricleisthickerasithastopumpblood alongerdistancethroughoutthebody.Theright ventricleonlyhastopumpbloodtothelungs.
(c) Theseptumkeepsoxygenatedanddeoxygenated bloodseparate.
7
(a) Diagramoftheheart:
(b) Diagramshowingbloodflowinheart:
8
(a) Bloodtakesthefollowingpath→venacava→right atrium→rightventricle→pulmonaryartery→lungs →pulmonaryvein→leftartium→leftventricle→ aorta.
(b) Pulmonarycircuit:
Therightventriclepumpsdeoxygenatedblood aroundthepulmonarycircuit.
Bloodgainsoxygen(andlosescarbondioxide)inthe lungs.
Thiscircuitisrelativelyshort,sothewallsoftheright ventriclearefairlythin.
Systemiccircuit:
Theleftventriclepumpsoxygenatedbloodtothe head,arms,bodyandlegs.
Bloodlosesoxygen(andgainscarbondioxide)toand fromallthebodycells.
Thisisamuchlongerroutethanthepulmonary circuit,sothewallsoftheleftventriclearethicker andstrongerthanthoseoftherightventricle.
(c) Advantages:
Itallowsoxygen-richandoxygen-poorbloodtobe keptseparate.
Italsoensuresthatthebloodpressureishigh enoughtoreachallpartsofthebody.
9
(a) TheSAnode(pacemaker).
(b) Onwallintopofrightatrium.
(c) Youcanfeelthepulse(whichistherhythmicbulging ofthearterywallswitheachheartbeat)atpoints whereanarteryisclosetotheskin,suchasthewrist orneck.Measured:bycountingthenumberofbeats in60seconds(orfor30secondsandmultiplyby2) togettheheartrateinbeatsperminute(bpm).
10
(a) Intheheart.
(b) Themuscleoftheheartissuppliedwithbloodby twocoronaryarteries.
Bloodisdrainedfromthemuscleoftheheartbya numberofcoronary(orcardiac)veins.
11
(a) A=Lungs
B=Pulmonaryvein
C=Aorta
D=Hepaticportalvein
(b)(i) Oxygen:aorta
(ii) Carbondioxide:venacava
E=Renalartery
F=Hepaticvein
G=Venacava
H=Pulmonaryartery
(iii) Glucose:hepaticportalvein
(c) BtoLeftatrium
CtoLeftventricle
GtoRightatrium
HtoRightventricle
12
(a) Aportalsystemisabloodpathwaythatbeginsand endsincapillaries.
(b) Thehepaticportalveinisanexampleofaportal systeminhumans.
(c) Coronaryarteriesdonotformaportalsystemasthey donotbeginwithcapillaries.Itarisesfromaorta.
13
(a) Apulseistherhythmicbulgingofthearterywalls witheachheartbeat.
(b) Becauseanarteryisclosertothesurfaceoftheskin.
(c) Regularexercisestrengthenstheheart,especially theleftventricle,whichpumpsoxygenatedbloodto thebody.
Astrongerheartcanpumpmorebloodwitheach beat,soitdoesn’tneedtobeatasoftentosupply thebodywithenoughoxygen.
(d) Reasonswhyahighrestingpulserateincreases strainontheheartinclude:
Thehearthastoworkharderandfaster,which canweakentheheartmuscleovertime.Thiscan leadtoconditionslikeheartfailure,wheretheheart can’tpumpbloodeffectively.
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14
(a)
Differencesbetweenarteriesand veins
Arteries Veins
Carrybloodawayfromthe heart
Carrybloodtotheheart
BloodisunderhighpressureBloodisunderlowpressure
Have thick,strongwallsHave thin, weakerwalls
Have asmalllumenHave alargelumen
BloodflowsinpulsesBloodflowssmoothly(no pulse)
Normallydeepintissue(to preventdamage)exceptin theneckandwrist
Valvesabsent
Bloodishighin oxygen (exceptpulmonaryartery)
Oftenclosetothesurface
Valvespresent
Bloodislowin oxygen (exceptpulmonary vein)
(b) Bloodpressureistheforceexertedbytheblood againstthewallsofthebloodvessels(mainlythe arteries).
(c) Bloodpressurereadingsaregivenastwovalues. Theupperorhighervaluerecordsthepressureof bloodasapulsepassesthroughtheartery(i.e.when theventriclescontract).
Thelowervaluerecordsthepressurewhen thereisnopulse(i.e.whentheventriclesarenot contracting).
15
(a) Bloodhasfourparts:plasma,redbloodcells (corpuscles),whitebloodcellsandplatelets.
(b) Plasmatransportsglucose,aminoacids,minerals, vitamins,salts,carbondioxide,urea,hormonesand heat.
Redbloodcellscontainhaemoglobinthattransports oxygen.
Whitebloodcellsfightinfection.
(c) Plasma
16
(a) Plateletsclottheblood.
(b) Plateletsareonlyactivatedwhenthereisdamageto abloodvessel,ensuringclottinghappensonlywhen needed.
(c) Advantages: Theyreducethelossofblood. Theypreventtheentryofmicroorganisms.
17
(a) Inbonemarrow.
(b) Haemoglobin
(c) Iron
18
(a) Platelets
(b) Plasma
(c) Redbloodcell
(d) Whitebloodcell
(e) Whitebloodcellcalledlymphocytes.
(f) Plasma
(g) Plasma
19
(a) Bloodgroups:A,B,ABandO.
(b) Itdependsonthetypesofchemicalscalledantigens (ifany)attachedtotheircellmembranes.
(c) Peoplewhohavetherhesusfactorhaveachemical aresaidtobeRhesuspositive(Rh+).
(d) TheRhesusfactor,forexample,isimportantforsafe bloodtransfusions.
ItmayalsoleadtoproblemsforaRhesus-negative motherwhoispregnantwithaRhesus-positivechild.
(d) Veinshavevalvestopreventthebackflowofblood, sincebloodismovingagainstgravityandunderlow pressure.
Arteriesdonotneedvalvesbecausebloodispushed throughthembythehighpressuregeneratedbythe heart.
22
(a) Bloodinthepulmonaryarteryhashighlevelsof carbondioxideandlowlevelsofoxygen.
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20
(a) Biconcave
(b) Theshapegivesthemalargersurfaceareaover whichtheycanexchangeoxygen.
(c) Reasons:Theylackanucleusandmitochondria.
(d) Intheliver.
(e) Bile
21
(a) Whenstandingstillforalongtime,bloodcangather inthelegsduetogravity.Bystandingstill,muscles arenotcontractingtosqueezethevein.Thisreduces theamountofbloodreturningtotheheartand brain,leadingtolowbloodpressureandreduce oxygensupplytothebrain,whichcancausefainting.
(b) Aholeintheseptumallowsoxygen-richandoxygenpoorbloodtomix.Thisreducestheefficiencyof oxygendeliverytothebody,solessoxygenreaches themusclesandorgans,leadingtofatigueandlow energy.
(c) Arteriescarrybloodunderhighpressurefromthe heart,creatingarhythmicpulsewitheachheartbeat. Veinscarrybloodunderlowpressure,andtheflowis steady,notpulsing,sonopulseisfeltinveins.
(b) Bloodinthepulmonaryveinhashighlevelsof oxygenandlowlevelsofcarbondioxide.
23
(a) Aorta
(b) Oxygenated
(c) B=Leftventricle
(d) Wallisthickerastheleftventricle(chamberB) pumpsbloodamuchlongerdistancearoundthe bodyinthesystemiccircuit.
(e) Preventsbloodflowingbackintotheleftatrium.
24
(a)(i) Cardiacmuscleisacontractiletissue,which meansthatitisshortening.
(ii) Theleftventricle
(b)(i) Diagramshowinglocationofvalves:
(ii) Procedure:usingascalpelashallowcutwas madeatthebaseoftheaortaorthebaseof pulmonaryartery.
(iii) Itpreventsbloodflowingbackwardsintothe heart.
(iv) Atthebaseoftheaorta.
25
(a)(i) Thoraciccavity
(ii) Cardiacmuscleisaspecialtypeofmusclethatis slowtofatigue.
(b)(i) PulmonarycircuitandtheSystemiccircuit
(ii) TheSystemiccircuit
(c) Differences:
Redbloodcellshavenomitochondriaandno nucleus,buttypicalbodycellsdo.
Redbloodcellsarebiconcaveinshape,buttypical bodycellsarenot.
Redbloodcellscontainhaemoglobinandaresmaller whiletypicalbodycellshavenohaemoglobinand arelarger.
Bicuspid valve
Tricuspid valve
(d) TheSAnode(pacemakerorsino–atrial)releases electricalimpulsescausingtheatriatocontract. TheAVnodesendsanelectricalimpulsedown muscleoftheseptumcausingtheventriclesto contract.
(e) TheSAnodeislocatedontopofwallofrightatrium. TheAVnodeislocatedonseptumbetweenright atriumandrightventricle.
26
(a) A=Artery
B=Vein
C=Capillary
(b)(i) B,Vein
(ii) B,Vein
(iii) A,Artery
(iv) A,Artery
(v) C,Capillary
27
RedbloodcellsWhitebloodcell
(a) ShapeBiconcaveNodefinite shape
(b) SizeSmallerLarger
(c) FunctionTransport oxygen Fightinfection
(d) Ratio700 1
(e) ContentContain haemoglobin (hasnonucleus) Containnucleus
(f) Site(s)of production BonemarrowBonemarrow
28
(a)(i) Plasma
(ii) Whitebloodcells
(iii) Haemoglobin
(b)(i) A=Rightatrium
B=Septum
C=Leftventricle
D=Leftatrium
(ii) SAnode(pacemaker)
(iii) Leftventricle(chamberC)pumpsbloodamuch longerdistancearoundthebodyinthesystemic circuit.
(iv) X=Semilunarvalveanditpreventsblood flowingbackwardsintoheart.
29
(a) Primarydataisdatacollectedfirst-handbythe researcherforaspecificpurpose.Examplesinclude: surveys,interviews,experiments,andobservations. Oranyacceptableanswer.
(b)(i) Scalpel
(ii) Descriptionofexperimentshouldincludethe following:
Safetyprocedure:weardisposablegloves,lab coat,tiebackhair,washhandswellafterwards, sterilisetheboardanddissectinginstruments. Rinsetheheartincoldwatertowashoutthe jelly-likeclumpsofblood.
Placetheheartonadissectingboardortraywith theventralsurfacefacingup.
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Secondarydataisdatathathasalready beencollectedbysomeoneelseandisusedfora differentpurpose.Examplesinclude:books,articles, governmentreports,onlinedatabases,andcensus data.Oranyacceptableanswer.
Placetheheartonthedissectingboardwiththe frontsidefacingupwards.
Distinguishbetweenthefront(ventral)andback (dorsal)surfaceoftheheartinthefollowingway:
● Thefrontismore rounded.
● Coronaryarteryisonfrontsurface(a groove runsdiagonallyfromthetoprightto thebottomleft).
Giveonedifferencebetweenwallsofright ventricleandleftventricle:
● Theleft ventriclehave thickwallsofmuscle andfirmer,right ventriclehasthinnerwalls ofmuscle.
● Theleft ventriclepumpsbloodalonger distanceinthesystemiccircuit.
Howdoyouexposethetricuspidvalve?
● Usingascalpelandadissectingboard, createashallowcutontherightsideof heart.
● Cutbetweentherightatriumandright ventricle.
● Weargloves.
Howdoyouexposethebicuspidvalve?
● Usingascalpelandadissectingboard, createashallowcutontheleftsideof heart.
● Cutbetweentheleftatriumandleft ventricle.
● Weargloves.
● Usingascalpelandadissectingboard, createashallowcutatthebaseoftheaorta orbaseofpulmonaryartery.
Describethedissectiontolocatetheoriginof coronaryartery.
● Usingascalpelandadissectingboard, createashallowcutonthebaseofthe aorta.
Howwouldyouidentifytheseptumintheheart?
● Itisathickmuscularwallthatseparatesthe leftandrightsideofheart.
(iii) Diagramofheart:
Semilunarvalve
Pericardium
30
(a) A=Aorta
B=Leftatrium
C=Bicuspidvalve
Leftatrium
Bicuspidvalve
D=Septum
E=Pulmonaryartery
F=Venacava
(b) Tokeepoxygenatedanddeoxygenatedblood separate.
(c)(i) Cardiac
(ii) Itisslowtofatigue.
(d)(i) TheSAnodeislocatedontopofwallofright atrium.
TheAVnodeislocatedonseptumbetweenright atriumandrightventricle.
(ii) TheSAnode(pacemakerorsino–atrial)releases electricalimpulsescausingtheatriatocontract. TheAVnodesendsanelectricalimpulsedown muscleoftheseptumcausingtheventriclesto contract.
(e)(i) Pulmonarycircuit
(ii) Systemiccircuit
(f) Soundsarecausedbyvalvesclosing.
(g) Coronaryarterysuppliesoxygenatedbloodto muscleofheart.
CHAPTER30 TRANSPORTINPLANTS
1
(a) Correctorder:cell,tissue,organ,organsystem, organism.
(b) Planttissuesinrootsandshootsinclude:dermal tissue,vasculartissue,groundtissue,xylem,phloem, epidermis,andcortex.Oranyacceptableanswer.
(c) Dermaltissue:protection
Vasculartissue:transport
Groundtissue:foodstorage(orchemicalreactions).
Xylem:transportswater(orgivesstrengthtoplant).
Phloem:transportsfood.
Epidermis:protection
Cortex:foodstorage(orsupport).
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2
(a) Xylemisadeadtissue.Phloemisalivetissue.
(b) Xylemtransportswater.Phloemtransportsfood.
(c) Xylemhaslignin.Phloemdoesnothavelignin.
(d) Xylemhaspits.Phloemdoesnothavepits.
(e) Xylemprovidesstrength.Phloemdoesnotprovide strength.
3
(a) Xylem
(b) A=Xylemvessel
B=Xylemtracheid
(c) Lignin
(d) Invascularbundles.
(e) Phloem
4
(a)(i) DiagramX=Stem
(ii) DiagramY=Root
(b) A=Cortex(orgroundtissue)
B=Vasculartissue(oravascularbundleinX,a vascularcylinderinY)
C=Epidermis(ordermaltissue)
(c) Z=Roothair
(d) Functionsoftheroothairincludewaterabsorption andmineralabsorption.
5
(a) Wateristransportedinxylem.
(b) Adaptationsofxyleminclude:narrowtubes,hollow tubes,noendwalls(orformacontinuoustube),have pits,andarestrengthenedwithlignin.
(c)(i) Thetissueisphloem.
(ii) Phloemtransportsfood(orsucrose).
(iii) Phloemisalivebecauseeachcompanioncellhas anucleus.
6
(a) A=Zoneofprotection
B=Zoneofcellproduction
C=Zoneofelongation
D=Zoneofdifferentiation
(b) Inthezoneofcellproduction(B).
(c) X=Roothairs
(d)(i) Osmosis
(ii) Mineralsareabsorbedbydiffusionandactive transport.
(iii) Osmosis(anddiffusion)donotrequireenergy. Activetransportrequiresenergy.
7
(a) Diagramshowingtheexternalstructureofaleaf: Leaf
Petiole
(b)(i) Thediagramrepresentsaroot.
(ii) A=Dermaltissue(orepidermis)
B=Groundtissue(orcortex)
C=Roothair
(iii) Vasculartissueisusedfortransport.
(iv) Vasculartissueincludesxylemandphloem.
(v) Xylemhelpstosupporttheplant.
(vi) Diagramoflongitudinalsectionofvascular tissue:
8
(a) Chloroplastsaremostlyconcentratednearthe uppersurfaceofaleafbecausethereismorelight ontheuppersurface.
(b) Ifstomatawereontheuppersurfaceofaleafthe plantwouldlosetoomuchwater.
(c) Stomataopenbydaytoallowgasexchangefor photosynthesis(whichneedslight).
(d) Stomatacloseatnighttoreducewaterloss.
(e) Airspacesoverthestomataallowforbettergas exchange.
(f) Leaveshaveacuticletoreducewaterloss.Root hairshavenocuticlesothattheycanabsorbwater.
(g) Theguardcellscanopenandclosethestomata. Stomataopentoallowgasexchange;theycloseto reducewaterloss.
(h) Veinstransportwaterandmineralsintotheleaves. Theyalsotransportfoodoutoftheleaves.
(i) Leavesarethintoreducethedistancethatgases havetodiffusefromtheundersideoftheleaftothe chloroplastsnearthetopoftheleaf. 9
(a) Thedyemakesthewatermorevisible.
(b) Theoillayerpreventswaterlossbyevaporationfrom thesurfaceofthewater.
(c) Thelevelofthewaterwillfall.Thisisduetowater beinglostfromtheplantbytranspiration.
(d)(i) DiagramofTSofroot:
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(ii) DiagramofTSofthestem:
Water(dye) appearshere
Water(dye) appearshere
10
(a) Osmosis
(b) A=Roothair
(c) Minerals
(d) B=Xylem
(e) ThevesselslabelledBareadaptedtocarrywater because: Theyarenarrowtubes. Theyarehollowtubes(orhavenocellcontents). Theyhavenoendwalls(orformacontinuoustube) Theyhavepits.
Theyareadaptedtogivesupportbecausetheyare strengthenedwithlignin.
(f) Thetranspirationstream
(g) C=Phloem
(h) Phloemisadaptedtotransportfoodbecause: Ithasporesintheendwalls(orinthesieveplates). Thereisnocytoplasmororganellestoblocktheflow offood
Thecompanioncellsarealivetocontroleachsieve tubeelement.
Thesievetubeelementsarelocatedontopofeach othertoformacontinuoustube.
blade
Vein Midrib
Xylemvessel (LS) Pit
Lignin Wall Sieve tube element
Companion cell
Phloem(LS)
Sieveplate
11
(a) DiagramofTSofyoungstem:
(i)Dermaltissue
(ii)Vasculartissue
(iii)Groundtissue
(b)(i) Tissue(iii)orvasculartissuehasadifferent locationinayoungroot.
(ii) Tissue(iii)orvasculartissueislocatedasa centralcylinderinayoungroot.
(c) DiagramStructureoftwovasculartissuesofplans:
(d) Byhavingstomataontheundersideoftheleaves theplantsloselesswaterbytranspiration(orby evaporation).
(e) Lenticelsonstemshavethesamefunctionas stomata.
(f) Disadvantageofhighrate:plantswilllosetoomuch waterandwillwilt.
(g) Topreventwiltingplantsclose(orreducethesizeof) theirstomata.
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(d) Phloemiscomposedoflivingcells.
(e) Thefunctionofmeristematictissueistoproduce newcellsbydividingbymitosis.
12
(a) Waterentersroothairsbyosmosis.Thishappens becausethewaterinthesoilismoredilute(orthe contentsoftheroothairsismoreconcentrated).
Waterthenpassesfromcelltocellacrossthecortex byosmosis.
(b) Inthexylem.
(c) Xylemareadaptedfortheupwardmovementof waterbecause: Theyarenarrowtubes. Theyarehollowtubes(orhavenocellcontents). Theyhavenoendwalls(orformacontinuoustube). Theyhavepits.
13
(a) Whenwateruptakeincreasessodoestranspiration (orwhenwateruptakedecreasessodoes transpirationorwateruptakeandtranspirationboth increaseanddecreaseatthesametime).
Reason:increasingratesoftranspirationallowmore watertobetakenup(orincreasingthewateruptake makesmorewateravailablefortranspiration).
(b) Thehighestrateoftranspirationoccursatthe hottest(orwarmestorhighesttemperature)and brightest(orsunniestorgreatestlightintensity).
(c) Theguardcells.
14
(a) Theplantusedwasabeech(orbirchoranysuitable plant).
(b) Therateoftranspirationwasmeasuredbyrecording thedistancetravelledbytheairbubbleinagiventime.
(c) Factorsinvestigatedincludedairmovement, temperature,thesurfaceareaoftheleaves,the presenceorabsenceofacuticle,lightintensity,or carbondioxideconcentration.
(d) Thefactorswerevariedasfollows:
Airmovement:blewairacrosstheleavesusingafan. Temperature:placedtheapparatusinlocationswith differenttemperatures(orusedahotairfan).
Thesurfaceareaoftheleaves:removedleavesfrom theplantandrepeatedtheinvestigation.
Thepresenceorabsenceofacuticle:usedplants withandwithoutacuticle.
Lightintensity:movedalampcloserorfartherfrom theapparatus.
Carbondioxideconcentration:placedtransparent plasticbagsovertheleave(s)containingwateror sodiumhydroxidesolution.
(e) Diagramofapparatususedinexperiment:
(f) Airmovement:Increasedtherateoftranspiration. Temperature:increasedtherateoftranspiration. Thesurfaceareaoftheleaves:thegreaterthe surfaceareathegreatertherateoftranspiration.
Thepresenceorabsenceofacuticle:acuticle reducedtherateoftranspiration.
Lightintensity:increasinglightintensityincreased therateoftranspiration.
Xylemvessel (LS) Pit
Lignin Wall Sieve tube element Companion cell Phloem(LS)
Sieveplate
Rubberstopper
Glasstube(clampedtostand)
Plantshoot
Airbubble
Rubbertubing
15
Carbondioxideconcentration:intheabsenceof carbondioxide,transpirationincreased.
(a) Theoilontopofthewaterstopstheevaporationof waterdirectlyfromthegraduatedcylinder.
(b) Prediction:thevolumeofwaterinthegraduated cylinderwillreduce.
(c) Thelossofmassisduetothelossofwaterby transpiration.
(d) Thelossofwaterwouldnotbethesameasindim light.Thereasonisthatthebrighterthelight,the morethestomataopen.Openingthestomatamore meansthatmorewaterislostastranspiration.
(e) Constantvariablesinclude:temperature,air movement,thesurfaceareaoftheleaves,and/or thecarbondioxideconcentration.
16 HL
(a) Waterentersroothairsbyosmosis.Thishappens becausethewaterinthesoilismoredilute(orthe contentsoftheroothairsismoreconcentrated)and thereisnocuticlepresent.
(b) Mineralsdonotentertheplantbyosmosis.Thisis becauseonlywatermovesbyosmosis(orminerals enterbyeitherdiffusionoractivetransport).
(c) Xylemisadaptedforitsroleasithasnarrowtubes,it hashollowtubes(ortubeshavenocellcontents),its cellshavenoendwalls(orformacontinuoustube), ithaspits,anditisstrengthenedbylignin.
(d) Theforcesofattractionarecalledcohesion.As waterisevaporatedfromtheleaf,itpullsonthenext watermolecules.Thiscreatesanupwardpull.The columnofwateriscontinuous.Thewatermolecules arenotstronglyattachedtothexylemwalls.The upwardpullcausesatranspirationstream.
17
(a) Waterrisesthroughxylem.
(b) Xylemisadaptedforthetransportofwaterbecause ithasnarrowtubes,ithashollowtubes(ortubes havenocellcontents),itscellshavenoendwalls (orformacontinuoustube),ithaspits,anditis strengthenedbylignin.
(c) Ontheinsideofvascularbundles.
(d) Additionalfunction:togivestrengthorsupportto theplant.
(e) Watermovesupaplantagainsttheforceofgravity.
(f) Theprincipalfeaturesofthecohesion-tension modelare:
Watermoleculestendtosticktogether,dueto cohesion.
(a) DiagramoftheTSofaleaf:
Dermal tissue Ground tissue
Vascular tissue
Dermal tissue
(b) Xondiagramabove.
Cuticle
Upper epidermis
Palisade
Vascular bundle Airspace
Spongy mesophyll
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Acontinuouschainofwaterformsinxylem. Transpirationpullswateroutoftheplant. Thispullcreatesatensioninthewatercolumn. Thispullistransmitteddownthecolumnofwater causingittorise.
Lower epidermis
Reason:Mostphotosynthesisoccursinthepalisade layerbecausethesecellshavethegreatest concentrationofchloroplastsandcanabsorbthe mostlightbybeingattheuppersurfaceoftheleaf.
(c) Otheradaptationsinclude:
Leavesarebroad(toabsorbmorelight).
Leavesarethin(foreasierdiffusionofcarbon dioxide).
Theupperepidermisistransparent(toallowlightto passthrough).
Numerousstomata(forgasexchange).
Airspacesarepresent(toallowmaximumsurface areaforgasexchange).
Xylemandphloemarepresent(totransportwaterin andfoodout).
(d) Carbondioxide,oxygen,andwater.
(e) Carbondioxide
19 HL
(a) Gasexchange
(b) X=Guardcell
(c) Carbondioxide
(d) PartAcontainsthemostchloroplasts.Thisis becausethispartoftheleafreceivesthehighest lightintensity.
(e) Thevasculartissuesinplantsarexylemandphloem. Functions:Xylemtransportswater.Phloem transportsfood(orsucrose).
20 HL
(a) PlantBwouldshowthelowestrateoftranspiration. Reason:Thisisbecauseithasthelowest concentrationofstomata.
(b) Apartfromthenumberofstomata,plantscontrol transpirationbythefollowingmethods:The presenceorthicknessorabsenceofacuticle. Stomatabeinglocatedontheundersideofleaves.
HL
18 HL
Havingleaveswithdifferentsurfaceareas(e.g. needleshapedleaves).
Havinghairyleaves(toreducewaterloss).
Havingleavescurledup(e.g.marramgrassinsandy ordrysoil).
(c) Structuraldifferencesinclude:
Xylemhavelignin,phloemdoesnothavelignin, Xylemhavepits,phloemdoesnothavepits; Xylemhavenonucleus,phloemhaveanucleus(in thecompanioncells)
Xylemhavethickerwalls(duetolignin),phloemhave thinnerwalls.
(d) DiagramofLSofaxylemvessel:
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Xylemvessel (LS) Pit
Lignin Wall
STRAND3 INTERACTIONSOFLIFE
CHAPTER31 ECOLOGY,ECOSYSTEMSAND BIODIVERSITY
1
(a) Ecologyisthestudyoftheinteractionsbetween livingthings(organisms)andbetweenlivingthings andtheirenvironment.
(b) Thebiosphereisthatpartoftheplanetwherelife canexist.
(c) Anecosystemisagroupofclearlydistinguished organismsthatinteractwiththeirenvironmentasa unit.
(d) Apopulationisallthemembersofthesamespecies livinginanarea.
(e) Acommunityisallthedifferentpopulationsinan area.
(f) Ahabitatistheplacewhereanorganismlives.
2
(a) Ecosystems:temperatewoodlands,grasslands, lakes,sanddunesystems,rockyseashoresand tropicalrainforests.
(b)(i)and(ii)
Examplesofecosystems
EcosystemFeaturesSamplelocations
Temperate deciduous forest Warmsummer, rainplentiful WesternEurope (includesIreland), EasternUSA
DesertLow rainfallSaharaDesert,Gobi Desert
Tropical rainforest High temperatures andhigh rainfall
GrasslandMild temperatures, low rainfall
Brazil, WestAfrica,parts ofSouth-EastAsia
SteppesofAsia,pampas inSouthAmerica, prairiesinNorthAmerica
FreshwaterNon-saltywaterRivers,lakes, wetlands
MarineSaltwaterSeashoresandoceans
3
(a)(i) Apopulationisallthemembersofthesame specieslivinginanarea.
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(ii) Acommunityisallthedifferentpopulationsin anarea.
(b) Exampleofpopulation:populationoffrogs. Exampleofcommunity:alltheplants,animals,fungi andmicroorganismslivinginafield.
4
(a) Biodiversity(fromthewords‘biologicaldiversity’)is thevarietyoflifethatexistsinaspecifiedarea.
(b) Reasonsfordecreasingbiodiversityincludechanges inlanduse,overexploitation,pollution,climateand invasivespecies.
(c) Environmentalimpactsinclude: Disruptiontoecosystems(e.g.soilqualityandwater purificationisreduced).
Anincreasedriskofextinctions. Areducedabilityoftheecosystemtorecover fromdisturbancessuchasclimatechange,disease outbreaksandinvasivespecies.
Economicimpactsinclude: Alossofcropproduction(duetoalackofpollinators andreducedsoilquality). Lossofnutrientrecyclinginsoil. Reducedfishstocks. Reducedtourismandhospitalityincome(biodiversity attractsvisitors). Lossoffreshair,cleanwaterandfloodcontrol. Increasedriskofdiseasespreadingtohumans. Reducedpossibilitiesofdiscoveringnewmedicines.
Socialimpactsinclude: Areductioninoursenseofconnectiontonature. Thefearthatwearepassingonadepletednatural worldtoourchildren.
Reducedaccesstonaturalwildplaces. Increasedhealthrisks.
Ageneralreductioninthequalityoflife.
Culturalimpactsinclude: Thereductioninourconnectiontoourhistory, folklore,mythologyandlocaltraditions. Thelossoftraditionalfarmingmethods. Lossofknowledgeregardingtraditionalorherbal treatmentsandcures.
Agenerallossofconnectionwiththelandand nature.
5
(a) Thereasonsfortheirreducednumbersincludealack offood,destructionoftheirnestingsites,andtheir consumptionofanimalsthathaveeatenpesticides.
(b) Theyfeedonmiceandratsandhuntonlyatnight. Theyarenocturnal.
(c) Toallowforanewhousingschemesopeoplecan haveahometolivein.
(d) ThebarnowlpopulationinIrelandhasgreatly decreasedinrecentyears.
(e) Theirconsumptionofanimalsthathaveeaten pesticides.
6
(a) Conservationisthewisemanagement(or preservationorprotection)oftheenvironmentin ordertomaintainbiodiversity.
(b) Reasonsinsupportinclude: Itlimitsthelossofbiodiversity. Itpreventsorganismsfrombecomingextinct. Itmaintainsthebalanceofnature.
Organismsmaybefoundtobeusefulinthefuture. Organismsandhabitatsareenjoyabletoseeand visit.
Wehavenorighttowipeoutotherlifeforms.
7
(a) Positiveinfluencesonbiodiversity:
Conservationareas(suchasnationalparks)help preservehabitatsandenrichbiodiversity.
Interventions(suchasreforestationand reintroducingnativespecies)improvesbiodiversity.
Sustainablefarmingmethods(suchasorganic farmingandreducingpesticideuse)helptoincrease biodiversityinagriculturalland.
Sustainablefishing(usinglargemeshnetsandnot overfishing)increasesthenumberoffish.
Breedingprogrammes(followedbyreintroduction tothewild)canimprovebiodiversity.
Rewilding(returninghabitatstoamorenatural statebyfencing,plantingandprotection)increases biodiversity.
Deforestationforgrazing,cropproductionornew roadsandbuildingshugelyreducesbiodiversity.
(b) Negativeinfluencesonbiodiversity:
Overpopulationincreasesthedemandsonnatural habitats,leadingtotheirdestructionandareduction inbiodiversity.
Climatechangemeansthatsomespeciescannot adapttoincreasedtemperatureandchanging weather,resultinginalossofbiodiversity.
Pollution(suchastheoveruseofpesticidesand fertilisersanddumpingofwastes)leadstodisease, deathandalossofbiodiversity.
Overexploitation(suchasoverfishingorexcessive hunting)leadstopopulationdeclinesandpossible extinctions.
(c) Bioticfactors:food,disease,competitionand predationoranyacceptableanswer.
9
(a)(i) Producersareorganismsthatmaketheirown foodbycarryingoutphotosynthesis.
(ii) Consumersareorganismsthattakeinfoodfrom anotherorganism.
(iii) Floraisalltheplantsinanecosystem.
(iv) Faunaisalltheanimalsinanecosystem.
(v) Herbivoresareanimalsthatfeedonplantsonly
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8
Invasivespecies(introducingnon-nativespeciestoa habitat)oftenresultsinadeclineinnativespecies.
(a) Thecarryingcapacityofanecosystemisthe maximumpopulationsizethatcanbesupportedby theavailableresourcesintheecosystem.
(b) Abioticfactors:water,oxygen,space,temperature andsoiloranyacceptableanswer.
(vi) Carnivoresareanimalsthatfeedonanimalsonly.
(vii) Omnivoresareanimalsthatfeedonbothplants andanimals.
(b) Afoodchainisasequenceoforganismsshowingthe transferofenergyfromoneorganismtothenext. (c)(i) Thesun.
(ii) Four (iii) Fromproducertoconsumers(from1sttrophic leveltothefinaltrophiclevel).
(iv) Fromproducertoconsumers(from1sttrophic leveltothefinaltrophiclevel).
10
(a) Theamountofenergy(food)passingalongafood chaindecreasesfromonetrophicleveltothenext.
(b) Animalscannotmaketheirownfood.
(c) Decomposersfeedondeadorganicmatterallowing fornutrientstoberecycled.
11
(a) Thebluetitpopulationwouldincrease.
(b)(i) Thebuttercuppopulationwouldincrease.
(ii) Bluetitpopulationwoulddecrease.
(c) Caterpillarpopulationwouldincrease.
12
(a) Herbivore:Hare,insect,orsnail.
(b) Carnivore:Fox,kestrel,thrushormouse.
(c) Grass→Snail→Thrush→Kestrel
Grass→Insect→Mouse→Kestrel
Grass→Insect→Thrush→Kestrel
Grass→Insect→Mouse→Fox
Grass→Hare→Fox
(d) Fox
(e) Omnivore
(f) Snailpopulationshouldincrease.
13
(a) Ahabitatistheplacewhereanorganismlives.
(b) 15%remain.
(c) Bykillingoffspeciesthroughoverhunting.
(d) Theyaredrivenbytheexpansionofhuman agricultureintowildhabitats.
(e) Reducinghuntingandpoachingandcuttingthe amountoflandthatweuseforfarming.
(f) Reasonsinclude:
Habitatdestructionduetourbanisationand industrialisation.
Widespreaduseofadvancedhuntingtoolsand technology.
14
(a)(i) Biodiversity(fromthewords‘biological diversity’)isthevarietyoflifethatexistsina specifiedarea.
(ii) Conservationisthewisemanagement(or preservationorprotection)theenvironmentin ordertomaintainbiodiversity.
(b) Theminkhaseasyaccesstonests.
(c) Theycaneatbothplantsandanimals.
(d) Minkmayfrequentlyentergullnestingareas, evenwhennothunting.Thiscausesstressand disturbance,leadinggullstoabandontheir nestsorfailtoincubateeggsproperly.
Repeateddisturbancescanresultinlowerbreeding successandfewerchickssurvivingtoadulthood.
(e) Competitionwithnativepredators: Minkmaycompetewithnativepredators(likeotters orbirdsofprey)forthesamefoodsources,suchas fish,smallmammals,orbirdeggs. Thiscompetitioncanleadtoadeclineinnative predatorpopulations,disruptingthenaturalbalance ofthefoodchain.
Asaresult,preyspeciesthatwereoncecontrolled bynativepredatorsmightincreaseordecrease unnaturally,affectingtheentireecosystem.
15
(a) Ashtree→moths→Robin
(b) Biodiversitywilldecreaseduetoashdieback.Itis likelytocausethedeathofmostoftheashtrees overthenexttwodecades.Thiswillalsoaffect organismsthatfeedonash.
(c) Establishagenebankofresistant(ortolerant)trees, and/orthinningordiversifyingspeciesorother correctway.
(d) Possibleeffects:
Moth(orotherconsumersofash)populationfalls. Robin(orotherconsumerofmoths)populationfalls. Otherplantpopulationsincrease. Soilerosionoranycorrectenvironmentaleffect.
Theyhelptoevaluatethebiodiversityofan ecosystemanditsabilitytoresistchanges. Theyhelptoidentifythreatstotrophiclevelsandto guideconservationefforts.
Theyhelptopredictfuturechangesinthe ecosystem.
Theycanbeusedtoevaluatetheimpactofhuman activitiesonecosystems.
17
(a) Anecologicalnicheisthefunctionalroleofan organisminanecosystem.
(b) Advantage:Theyavoidcompetitionwitheachother astheyeatdifferentfood.
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(a)(i) Aspeciesdiversityindexisamathematical measureofthediversityofspeciesina community.
(ii) Thespeciesrichnessreferstothenumberof differentspeciesinthecommunity.
(iii) Therelativeabundanceofthedifferentspecies referstotheproportionofalloftheorganismsin thecommunitythateachspeciesrepresents.
(b) Habitat:0.661
(c)(i) Woodland:0.523
(ii) Park:0.582
(iii) Thenearbyparkhasagreaterdiversityof species.
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(a) Aspeciesdiversityindexisamathematicalmeasure ofthediversityofspeciesinacommunity.
(b) Field:0.845
(c) Thespeciesrichnesswoulddecrease.
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(a) Apopulationcurvesrepresenthowthenumbersina populationvaryoveragivenperiodoftime.
(b)(i) AJ-shapedpopulationcurveisassociatedwith organismsgrowinginanenvironmentwith unlimitedresources.
(ii) AnS-shapedpopulationcurveisassociatedwith environmentswhereresourcesarescarce.
16
(a) Pyramidofnumbers
(b) Atypicalecologicalpyramidiswideatthebaseand narrowatthetopbecause: Energyislostateachtrophiclevel(mostlyasheat throughrespiration).
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Onlyabout10%oftheenergyispassedontothe nextlevel.
(c) Theyindicatethehealthofanecosystem. Theyprovideaclearpictureoftheflowofenergy throughdifferenttrophiclevels.
(c)(i) DiagramshowingaJ-populationcurve: Populationsize
(ii) DiagramshowinganS-populationcurve:
Populationsize
(d) Asthepopulationgrows,resourcessuchasfood, water,space,andshelterbecomescarce.This leadstoincreasedcompetition,whichslowsdown thegrowthrateuntilthepopulationreaches thecarryingcapacityoftheenvironment,i.e. themaximumnumberofindividualsthatthe environmentcansustainablysupport.
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(a)(i) Biomassisthetotalmassofalltheorganismsin anarea.
(ii) Apyramidofbiomassrepresentsthe(bio)mass oforganismsateachtrophiclevelinafood chain.
(iii) Thecarryingcapacityofanecosystemisthe maximumpopulationsizethatcanbesupported bytheavailableresources.
(b) Pyramidofbiomass:
(c) No,asnormallybiomassismeasuredasdryweight, totakeaccountofthevaryingamountsofwaterin livingtissues.
(d) Biomassispassedbetweeneachtrophiclevelina foodchainthroughtheprocessoffeedingwhenone organismconsumesanother.
(e) Normallybiomassdecreasesasyoumoveupthe trophiclevelsduetotheenergylossesasyoumove upafoodchain.
(f) Pyramidsofbiomassaremoreaccurate,astheytake accountofthesizeoftheorganisms.
(g) Pyramidsofnumbersareeasierasitiseasierto countnumbersthantomeasurebiomass.
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(a) Photosynthesis
(b) Frog
(c) Grasshopper
(d) Biomassdecreasesasyouascendthepyramid becauseofenergylossateachtrophiclevel.
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(a) Invertedpyramidofbiomass
(b) Thiscanhappenwhentheproducershavehighrates ofphotosynthesisandareabletoreproduceorgrow rapidlyoveraveryshortperiodoftime.
(c) Phytoplanktonareshortlived.
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CHAPTER32 INVESTIGATINGANECOSYSTEM
1
(a) Theecosystemstudiedwasagrassland(orany appropriateecosystem).
(b) Inagrasslandecosystem:
(i) Producersinclude:grass,clover,buttercups, dandelions,daisies,nettles.Poppies,thistles, dockleaves,primroses,andbluebells.Orany acceptableanswer.
(ii) Consumersinclude:earthworms,snails,slugs, spiders,beetles,aphids,ladybirds,caterpillars, bees,wasps,butterflies,moths,rabbits,badgers, foxes,hedgehogs,thrushes,blackbirds,and hawks.Oranyacceptableanswer.
(iii) Herbivoresinclude:snails,slugs,beetles,aphids, caterpillars,bees,wasps,butterflies,moths,and rabbits.Oranyacceptableanswer.
(iv) Carnivoresinclude:spiders,beetles,ladybirds, wasps,foxes,thrushes,andhawks.Orany acceptableanswer.
(v) Omnivoresinclude:beetles,badgers, hedgehogs,andblackbirds.Oranyacceptable answer.
Clover
Snail
Thrush Hawk
(c) Diagramofafoodweb:
2
(a) Producersinclude:grass,clover,buttercups, dandelions,daisies,nettles.Poppies,thistles,dock leaves,primroses,andbluebells.Oranyacceptable answer.
(b) Herbivoresinclude:snails,slugs,beetles,aphids, caterpillars,bees,wasps,butterflies,moths,and rabbits.Oranyacceptableanswer.
(c) Carnivoresinclude:spiders,beetles,ladybirds, wasps,foxes,thrushes,andhawks.Orany acceptableanswer.
(d) Scavengersinclude:foxes,crows,seagulls,foxes, badgers,pinemartens,maggots,beetles,andants. Oranyacceptableanswer.
(e) Detritusfeedersinclude:earthworms,woodlice, millipedes,slugs,snails,andmaggots.Orany acceptableanswer.
(f) Topconsumersinclude:ladybirds,hawks,badgers, foxes,pinemarten,andowls.Oranyacceptable answer.
3
(a) Buttercup→caterpillar→blackbird→foxor Dockleaf→slug→thrush→hawk
(b)(i) Producers=buttercupordockleaf.
(ii) Consumers=anyoftheanimalsshownonthe foodchainsabove.
(iii) Herbivore=caterpillarorslug.
(iv) Carnivore=blackbirdorfoxorthrushorhawk.
(v) Thethirdtrophiclevel=blackbirdorthrush.
4
(a) Ahabitatistheplacewhereanorganismlives.
(b) Diagramofequipmentusedtocollectanimals:
Flexible tube Insect Suckair inhere
Gauze ormesh Jar
5
Beatingtray
Pitfalltrap
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Captured insect
Organisms
(c) Pooter:placetheflexibletubeovertheorganism andsuckinontheothertube.Apootermaybeused tocollectspiders,ants,beetles,aphidsetc.
Abeatingtrayisplacedunderalargeplantandthe plantisshakentodislodgeorganisms.Abeatingtray maycollectspiders,caterpillars,beetles,aphids, slugs,snailsetc.
Apitfalltrapisplacedinthegroundsothat organismscancrawluptoitandfallin.Apitfall trapcancollectsnails,slugs,beetles,ants,spiders, woodlice,earwigs,centipedes,millipedesetc.
(a) Anyvisiblestructure(s)fromanamedanimale.g. onacentipede:thenumberoflegs,thepresence orabsenceofwings,presenceorabsenceofashell, thenumberofbodysegments.Oranyacceptable answer.
(b) Anyvisiblestructure(s)fromanamedplante.g.on adandelion:thecolourofthepetals,thenumberof petals,theshapeoftheleaves,thepositionofthe leavesonthestem(i.e.oppositeoralternate).Orany acceptableanswer.
(c) Apitfalltraporabeatingtraycouldbeusedto collectacentipede.
(d) Seeanswer4(c)above.
Snail Rock (toprevent drowning) Stone
6
(a) Diagramshowingequipmentused:
(b) Animal=freshwaterlimpet
(c) Aroundworm’sbodyisnotdividedintosegments. Thebodyofaleechisdividedintosegments.
9
Flexible tube Insect Suckair inhere Pooter tu I r mesh J in here
7
8
Pitfalltrap Snail Rock (toprevent drowning) Stone
Sweepnet
Butterfly Net Stronghandle
Gauze ormesh Jar Captured insect
(a) Throwaball(oranysuitableobject)overthe shoulderandplacethequadratwheretheball(or object)lands.
(b) Quadratsarethrownatrandomtoensuretheareais studiedinafairandunbiasedmanner.
(c)(i) Thefrequencyofthebluebellsis (6/10)x100=60%.
(ii) 20bluebellsintotal=2bluebells/quadrat. Eachquadratis0.5x0.5=0.25m2
Areaofwoodland=20x30=600m2
Numberofquadratstocovertheentire woodland=600x4=2400.
Totalnumberofbluebells=2400x2=4800.
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Pooter:placetheflexibletubeovertheorganism andsuckinontheothertube.
Apitfalltrapisplacedinthegroundsothat organismscancrawluptoitandfallin.
Sweepnet:Sweptthroughlonggrassorattheside ofahedge.
(b) Toidentifytheanimalsfoundthestudentscoulduse akey.
(c) Abioticfactorsincludetemperature,pHofsoil,light intensity,rainfalletc.
(a) A=Nematode
B=Musca
C=Planarian
D=Chilopod
E=Helix
(a)(i) Leechfeaturesare:suckerspresent,body dividedintosegments,notentaclesonwormlike body,soft-bodied
(ii) Roundwormfeatures:theirbodyisroundedlike athread,bodynotdividedintosegments,no tentaclesonwormlikebody,andsoft-bodied.
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(a) Abioticfactorsarenon-livingfeatures.
(b) Inagrasslandtheabioticfactorsinclude temperature,lightintensity,soilpH,soilmoisture content,andsoiltype.Oranyacceptableanswer.
(c) Temperatureismeasuredusingathermometer. Lightintensityismeasuredusingalightmeter.
(d) Grassespreferahigherlightintensitysograssesdo notgrowsowellintheshadeofahedgerow.
(Or:Ivyprefersalowerlightintensityandsothey growintheshadeofahedgerow).
11
(a) Bioticfactorsmeanlivingfeatures.
(b) Bioticfactorsinclude:thenumberofplants,the numberofherbivores,thenumberofcarnivores,the numberofdecomposers,competition,predationor anyacceptableanswer.
12
(a) Aqualitativesurveyexaminesthepresence(or absence)ofspecies.Aquantitativestudymeasures thenumbersoforganismsthatarepresent.
(b)(i) Abioticfeature=pHofthesoil.
(ii) ThesoilpHwasmeasuredusingapHmeter.
(iii) Thespeciesinvestigatedwasdandelions(or grassorbuttercupsoranysuitablespecies)
(iv) Aquadratwasusedtomeasuretheabundance.
(v) Aball(oranysuitableobject)wasthrownover theshoulder.Thequadratwasplacedwhere theball(orobject)landed.Thepercentagecover ofthedandelions(orothernamedplant)was estimatedforeachoftenquadrats.The frequencyofdandelionswascalculated.
(vi) Dandelionsgrewbestinneutralorslightly alkalinesoil(i.e.atpHvaluesof6or7).Theydid notgrowatpHvaluesbelow6.
13
(a) Edaphicmeansrelatedtosoil.
(b) Edaphicfactorsinclude:soilpH,soiltype,spoil mineralcontent,soilhumuscontent,soilwaterand aircontentoranyacceptableanswer.
14
(a) Thebadgersshouldbemarkedsothattheyare notendangerede.g.useeartagsordyeontheir undersides(ormicrochips).
(b) Totalpopulationbadgers=(180x150)/40=675.
(c) Theanimalsarereleasedwheretheywerecaughtso thatthemarkedanimalscanmixrandomlywiththe restofthepopulation.
15
(a) Thenumberofmice=(40x40)/5=320.
(b) Populationdensity=320/2.5=128fieldmiceper hectare.
(c) Onemonthwasallowedtoensurethemarked animalswouldmixthoroughlywiththerestofthe population.
16
(a) Animalthatkillsandeatsanotheranimal=predator.
(b) Animalkilledandeaten=prey.
(c) Ifthepreydeclinesthepredatorsmay:declinein number,switchtoanotherprey,movetoanew location.
17
(a)(i) Predationreferstothehunting,killingand eatingofanotheranimal,e.g.thepredationof rabbitsbyfoxes.
(ii) Predatoristheanimalthathunts,killsandeats anotheranimal,e.g.thefoxisapredator.
(iii) Preyistheanimalthatishunted,killedand eaten,e.g.therabbitistheprey.
(b)(i) Thepreycontrolsthenumberofpredators becausethepreyprovidefoodforthepredators.
(ii) Thepredatorscontrolthenumberofpreyby killingandeatingtheprey.
(iii) Preyspecieshaveadaptionstoescapesuchas camouflage.
Predatorsdependonpreyforsurvival. Whenpreynumbersdrop,thepredators’ numbersalsodeclineduetothelackoffood.
(iv) Predatorssurvivewhenthenumberofpreyis smallbecausetheymayswitchtoanotherprey ormovetoanewlocation.
18
(a) Graphshowingvariationofpopulationovertime: PreyPredator
(b) Asthenumberofpreydecline,thenumberof predatorsdeclinessometimelater. Asthenumberofpreyincreases,thenumberof predatorsincreasessometimelater. Thenumberofpredatorsisalwayslowerthanthe numberofprey.
(c) Ifadiseaseaffectedthepredator,youwouldexpect thepreynumberstoincrease.Thisisbecausethere wouldbefewerpredatorsandsothepreywould haveagreaterchanceofsurvival.
(d) Themainroleofpredationistocontrolthenumber ofpreyorganisms.
19
(a) Examplesofpredator-preyrelationshipsinclude: rabbitsandfoxes,owlandmouse,hawkandrat, spiderandflyoranyacceptableanswer.
(b) Graphshowingfluctuationofnumbersinapredatorpreyrelationship:
Predator(e.g.fox)
Prey(e.g.rabbits)
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(c) Asthenumberofpreyincreases,thenumberof predatorsincreasessometimelater.
Asthenumberofpreydecline,thenumberof predatorsdeclinessometimelater.
Thenumberofpredatorsisalwayslowerthanthe numberofprey.
(d) Theroleofpredationistocontrolthenumberof preyorganisms.
20
(a) Fauna:animals
Predators:ananimalthatkillsandeatsanother animal.
Carnivorous:feedingonanimalsonly.
(b) Declineofredsquirrel:thearrivaloflargergrey squirrelsorgreysquirrelsoutcompetedredsquirrels forfoodorgreysquirrelscarriedadiseasecalled squirrelpoxvirusthatwasfataltoredsquirrels.
(c) Predator:pinemarten
(d) Activitiesaffectingpinemartens:huntingorhabitat loss.
(e) Populationofgreysquirrelsdeclinedduetopreyfor oreatenbythepinemartenorshoweda“predator naivety’’tothepinemarten.
(f) Foodchain=pinenuts→squirrel→pinemarten
Numberoforganisms
(g) Graphshowingpredator-preyrelationship:
24
(a) Aball(oranysuitableobject)wasthrownoverthe shoulder.Aquadratwasplacedwheretheball(or object)landed.Thepercentagecoveroftheplants ineachquadratwasestimated.Theprocesswas repeatedtentimes.
(b) Thepercentagefrequencyofgrass=(8/10)x100= 80%.
Thepercentagefrequencyofdandelions=(5/10)x 100=50%.
(c) Barchartillustratingpercentagefrequencyofgrass anddandelion:
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21
(a) Aqualitativesurveyexaminesthepresence(or absence)ofspecies.Aquantitativestudymeasures thenumbersoforganismsthatarepresent.
(b) Aquadratisasquareframeusedinecologytostudy andsampleplantandanimalpopulationsinahabitat study.
(c) Aball(oranysuitableobject)isthrownoverthe shoulder.Aquadratisplacedwheretheball(or object)landed.Thepercentagecoveroftheplants isestimated.Theprocessisrepeated.Thefrequency ofplantsiscalculated.
(d) Anumberofquadratsarethrowntoincreasethe reliabilityofthesamplingtechniqueused.The largerthenumberofquadratsused,themore representativeandreliableisthedatacollected.
(e) Thepresenceorabsenceisqualitative.The percentagecoverisquantitative.
22
(a) Thespeciesinvestigatedwasdandelions(orany suitablespecies).
(b) Abioticfeaturesinvestigatedinclude:soilpHorlight intensity(oranyothersuitableabioticfactor).
(c) SoilpHwasmeasuredusingapHmeter.Light intensitywasmeasuredusingalightmeter.
(d) Dandelionsgrewbestinneutralorslightlyalkaline soil(i.e.atpHvaluesof6or7).Theydidnotgrowat pHvaluesbelow6.
Grassespreferahigherlightintensitysograssesdo notgrowsowellintheshadeofahedgerow.
(Or:Ivyprefersalowerlightintensityandsothey growintheshadeofahedgerow).
23
(a) Quadratswerethrownatrandominbrightlightand indimlight.Thepresenceorabsenceofeachplant wasnotedforeachquadratthrown.
(b) Thepercentagefrequencyofgrassinbrightlight was:(5/5)x100=100%.
Thepercentagefrequencyofcloverinbrightlight was:(2/5)x100=40%.
(c) Grassgrowsbetterinbrightlightthanindimlight.
(d) Yes.Quadratscanbeusedforslowmovingor stationaryanimals.
25
(a) Theapparatusontheleftisapooter.Youplacetube BovertheorganismandyousuckinthroughtubeA. TheapparatusontherightisaTullgrenfunnel. Soil(containingorganisms)isplacedonthegauze. Theheatofthelampcausestheorganismsto movedownandtofallthroughthegauzeintothe collectingjar.
(b)(i) Theecosystemstudiedwasagrassland(or anothersuitableecosystem).
(ii) Thespeciesinvestigatedwasdandelion(orother suitablespecies).
(iii) Factorsinvestigatedincludelightintensity,soil pH,soiltemperatureetc.
(iv) Aball(oranysuitableobject)wasthrownover theshoulder.Aquadratwasplacedwherethe ball(orobject)landed.Thefactorbeing investigated(e.g.lightintensity,soilpH,soil temperatureetc.)wasmeasured.The percentagecoveroftheplantsineachquadrat wasestimated.Theprocesswasrepeatedten times.
26
(a) Exoticspeciesmaybeintroducedasafoodsource orforbiologicalcontrolorforaestheticreasons(i.e. theylooknice).
(b) Themajorityofexoticintroductionsareunsuccessful becausetheyfailtoadapt,ortheyarepreyedupon, ortheirnumbersareinsufficient,ortheysufferdue tocompetition.
Grey squirrel Pine marten
(c) Exoticplantsmayescapeduetoseedorfruit dispersal.
(d)(i) Exoticintroductionsmaybenegativedueto increasedcompetitionorincreasedpredationor anexampleofeitherofthesereasons.
(ii) Exoticintroductionsmaybepositiveduetothe controlofanuisancespecies,ortheyprovide foodorshelter.
(e)(i) Yesorno(providedtheexplanationbelow matchestheanswer).
(ii) Yes,becausetheintroducedexoticisadapted (orsuited)totheecosystemorhabitat.
OR No,becausetheintroducedexoticisnot adapted(orisnotsuited)totheecosystemor habitat.
27
(a)(i) Abioticfactor:watertemperature
(ii) Bioticfactor:foodlevels
(b) Troutdemonstratecarnivorousnutrition.
(c) Troutandottersrepresentapreyandpredator relationship.
(d) Diagramshowingrelationshipbetweentroutand otternumbers:
Numberoforganisms
Time(years)
(e) Fewertroutmightresultinfewerotters(orinthe ottersswitchingtoadifferentpreyorintheotters movingtoanewhabitat).
(f) Foodchain=algae→mayflies→trout→otter
(g) Troutadaptationsinclude:migratetotheseatofeed moreandgrowortheyreturntoriversandlakesto reproduce.
28
(a) Dragonfliesaresuccessfulpredatorsbecause: theyhavehugeeyesorcompoundeyesordazzling aerobaticsorareopportunisticorambushpredators.
(b) Benefitsoffreshwatervegetationinclude: protectionorlayingeggs.
(c) Benefitsoftheadultandthenymphhavingdifferent foodsourcesinclude:theyarenotincompetition (forthesameresource)orthereisagreaterchance ofsurvival.
(d) Swallowsanddragonflieshaveapredator-prey relationship.
(e)(i) Adiseaseaffectingswallowscausesanincrease indragonflies
(ii) Cuttingofvegetationonriverbankcausesa decreaseindragonflies.
(f) Reasonswhyvolunteersarebeingaskedtoidentify dragonfliesinclude:conservationortomonitor numbersorforbiodiversityortoprotectthemfrom extinctionortomonitortheeffectofclimatechange ortomonitorwaterquality.
(g) Avolunteermightuseakeyorcomparepicturesor charts.
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(a) Competitionisanactivestrugglebetween organismsforaresourcethatisinshortsupply.
(b) Contestcompetitioninvolvesanactivephysical strugglewhereoneorganismgetsalloftheresource andtheothergetsnoneoftheresource. Scramblecompetitionmeansthatallofthe competingorganismsgetsomeoftheresource.
(c) Apartfromcompetition,factorsthatcontrolwild populationsinclude:food,predation,disease,and abioticfactors.
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(a) Symbiosisiswheretwoorganismsofdifferent speciesliveincloseassociationandatleastoneof thembenefits.
(b) Inmutualismbothorganismsbenefit.In commensalismoneorganismbenefitsandtheother organismisnotaffected.
(c) Commensalismisaformofsymbiosisbecausetwo organismsliveincloseassociationandoneofthem benefits.
(d) Examplesofcommensalisminclude:bacterialiving onourskinorbirdsmakinganestinatree.
(e)(i) Yes,lichensareaformofsymbiosis.Thisis becausetherearetwoorganisms(analgaand afungus)livingincloseassociationandatleast oneofthembenefits.
(ii) Lichensareanexampleofmutualism.Thisis becausebothorganismsbenefit.
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TroutOtter
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CHAPTER33 MICROORGANISMS
1
(a) Microorganismsaresmalllivingthings.
(b) Examplesincludebacteria,somefungi,archaeaand protists.
2
(a) A=Flagella
B=LoopofDNA
C=Capsule
D=Cytoplasm
E=Plasmid
(b) Flagella (a) allowsbacteriatomove.
LoopofDNA (b) containsgenesthatareresponsible forproteinproduction.
Capsule (c) offersprotection.
Cytoplasm (d) isthesiteofchemicalreactions(like respirationandproteinsynthesis).
Plasmid (e) includesgenesforantibioticresistance.
(c) Enzymesinmicroorganismsaredesignedtowork atspecifictemperatures.Enzymesthatareinan unsuitabletemperaturearedenatured.
6
(a) DiagramshowingbasicstructureofRhizopus:
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3
(a) Autotrophic:maketheirownfood.
Heterotrophic:takeinfoodfromotherorganisms.
(b) Photosynthetic:uselightasanenergysourceto makefood.
Chemosynthetic:usechemicalreactionsasan energysourcetomakefood.
(c) Saprophytes:feedondeadorganicmatter.
Parasitic:feedonalivehostandcausesharm.
(d) Prokaryotic:hasnonucleusandnomembrane enclosedorganelles.
Eukaryotic:hasanucleusandhasmembrane enclosedorganelles.
4
(a) Rhizopus
(b) Fungi
(c) A=Sporangiophore
B=Sporangium
C=Spores
D=Stolon
(d)(i) Digestionandabsorption
(ii) Increasessurfacearea
(e) Saprophytes
(f) Breadorfruit
(g) Eukaryoticcellshaveanucleusandmembrane boundorganelles.
(h) Prokaryotic
5
(a) Enzymesinmicroorganismsaredesignedtoworkat specificpHvalues.Enzymesthatareinanunsuitable pHaredenatured.
(b) Iftheexternalsolutionhasahighersolute(e.g. saltorsugar)concentrationthanthecytoplasm ofthemicroorganism,waterwillmoveoutofthe microorganism.Thisdehydratesthemicroorganism andstopsitsenzymesfromworking.
(b) Stolon(i)areaerialhyphaethatallowthefungusto spreadmorerapidly.
Rhizoids(ii)arehyphaethatgrowintothesubstrate andprovideextrasurfaceareafordigestionand absorptionofthesubstrate.
Sporangium(iii)producesporesallowingforasexual reproduction.
(c) Saprophytes
(d) Fungi
7
(a) Yeast
(b) Themoreyeastcellsthatwereinaculture,themore turbid(orcloudy)theculturebecame.Thismeans thatthemoreturbidacultureis,thelesslightcan passthroughit.
(c) VariedfactorsincludepH,nutrients,water,external soluteconcentration,temperatureorantibacterial orantifungalchemicals.
(d) Answersvarydependingonvariedfactors: pH:pHisvariedusingdifferentpHbuffers.
Nutrients:differentnutrientssuchassucrose, fructose,starchorartificialsweetenersusedinstead ofglucose.
Water:thesameamountofglucosedissolvedin differentvolumesofwater
Externalsoluteconcentration:thesamevolumeof waterwithincreasingamountsofglucose.
Temperature:waterbathsatdifferenttemperatures (0°C,40°Cand60°C).
(e) Twofactorskeptconstant:temperatureand nutrientsused.
(iii) Sporangium
(ii) Rhizoids
(i) Stolon
(f) Temperaturekeptconstantusingwaterbathat sametemperature.
Nutrientkeptconstantusingtheequalamountof samenutrient.
(g) Diagramofapparatususedinexperiment:
Glucosesolution Baker’s yeast pHbuffer4
Glucosesolution
yeast pHbuffer7 Glucosesolution
yeast pHbuffer 10
(h) Conclusion:feweryeastgrewathigherorlowerpH values.MostyeastgrewatpH7atthisisthemost suitabletemperatureforyeastactivity.
8
(a) Byusingawaterbathatthesametemperature.
(b) Byusingawaterbathatdifferenttemperatures.
(c) ByusingthesamepHbuffer.
(d) ByusingdifferentpHbuffers.
(e) Themoreyeastcellsthatareinaculture,themore turbid(orcloudy)theculturebecomes.Thismeans thatthemoreturbidacultureis,thelesslightcan passthroughit.
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(a) Theballoninflatesduetothecarbondioxide producedbytheyeast.
(b) Noyeastwaspresentsonocarbondioxidewas produced.
(c) Byusingaflexiblemeasuringtapetomeasure aroundthewidestpartoftheballoonorplacethe balloonagainstaflatsurfaceandusearulerto measureitsdiameter.
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(a) Inproducingdrugsformedicinalpurposes, microorganismsareusedto: Makeantibiotics.
Makevaccines.
Makeenzymes,hormones,steroids,statins(to reducecholesterol).
Makeanti-cancerdrugs.
Causemanyplantandanimaldiseases
Causedecayofcropsandfood.
(c) Themedicalimportanceofmicroorganismsinclude: Microorganisms(seeMicrobiomebelow)inour intestineshelptodigestfood,preventthegrowthof pathogenicorganismsandproducevitamins. Causemanydiseasessuchaspneumonia, tuberculosis(TB),sorethroats,typhoidandcholera (bacterial)andringwormandthrush(fungal). Probioticsarelivemicroorganismstakeninthediet toimprovehealth
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Makedrugstosupresstheimmunesystem.
(b) Inagriculture,microorganisms: Controlpestssuchasinsectsandparasites. Increasethesupplyofnutrientssuchasnitratesand phosphatesinthesoil.
Improvesoilstructureanditsabilitytoretainwater, oxygenandnutrients.
(d) Infoodproduction,microorganismsareimportant forthefollowingreasons:
Usedtomakebutter,cheese,yoghurt,vinegar,silage, alcoholandmanyotherfermentedfoodproducts.
Geneticallymodifiedmicroorganismsmakeproducts suchasvitamins,aminoacids,flavourings,colourings andtasteenhancers.
Causefooddecay.
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(a) Amicrobiomeisallthemicroorganismsthatexistina particularenvironment.
(b) Skin,mouthorinourgastrointestinaltract.
(c) Gastrointestinaltractisourdigestivesystemorgut.
(d) Microbiomehelptobreakdowncomplex carbohydratesanddietaryfibrethathumanscannot breakdownbythemselves.
Microbiomecausescellsinourimmunesystem tosendoutsignalssothatwecandistinguish betweenbeneficialmicroorganismsandharmfulor pathogenicmicroorganisms.
Microbiomehelpstoreduceinflammation,allows insulintoworkproperly,decreasesfatstorage, allowshormonescontrollingappetiteandfullness toworkproperly,andallowsthelivertofunction properly.
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(a) Microbiomeproducesbrainchemicals,suchas serotonin.
(b) Inflammationmayincreasetheriskofvarious diseases,includingtype2diabetes,heartdisease andcertaincancers.
(c) Peoplewhoconsumedagreaterdiversityofplantbasedfoods.
(d) Weshouldconsumelotsofgreentea,extravirgin oliveoil,brightlycolouredfruitandvegetables, herbsandspicesandthefourfermentedKs(kefir, kombucha,kimchiandkraut)alongwithcheeseand yoghurt,whichallservetofeedourresidentgut bacteria.
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(a) Organism=Rhizopus Kingdom=Fungi
(b) A=Sporangiophore
(c) Nutrition:Saprophytes
Conical flask
Cotton wool
(d) Theyactasdecomposersorhelpsrecyclenutrients.
(e) B=Stolon.Theseareaerialhyphaethatallowthe fungustospreadmorerapidly.
(f) Rhizoidsarehyphaethatgrowintothesubstrate andprovideextrasurfaceareafordigestionand absorptionofthesubstrate.
Sporesallowforasexualreproduction.
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(a) A=Lag
B=Log
C=Stationary
D=Decline
E=Survival
(b) Lag:numbersremainlowandconstant.
Log:numbersincreaseveryrapidly.
Stationary:numbersareatahighlevelbutnow remainconstant.
Decline:numbersfallveryrapidly.
Survival:numbersarelow.
(c) Reasons:
Lag:microorganismsareadaptingtoenvironment.
Log:plentyofresources(plentyoffood,moisture, spaceoroxygen).
Stationary:lackoffood,lackofspace,lackof moisture,lackofoxygen,unsuitablepH,and/orthe build-upoftoxicwasteproducts.
Decline:lackoffood,lackofspace,lackofmoisture, lackofoxygen,unsuitablepH,and/orthebuild-upof toxicwasteproducts.
Survival:somemicroorganismssurviveas endospores.
(d) No
(e) AsinstageE,numbersarelowbutarenotatzero. Theycanformanendosporetosurvive.
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(a) Completeddiagram:
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(b) X=Stationary Y=Decline Z=Survival
(c) Theycomefromendospores.
(d) Adverseconditions:hightemperaturesorunsuitable pHvaluesoranyacceptableanswer.
(e) Externalsoluteconcentrationsandthenutrients available.
CHAPTER34 NUTRIENTCYCLING
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(a) Organismsrequirecarbonbecauseitistheelement thatlifeisbasedon.Forexample,allbiomolecules suchascarbohydrates,proteins,lipids,vitaminsand nucleicacidsarebasedoncarbon.
(b) Plantsgettheircarbonbyabsorbingcarbondioxide.
(c) Animalsgettheircarbonbyconsumingother organisms(suchasplantsandanimals).
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(a) Photosynthesisdecreasescarbondioxide concentrations.
(b) Respirationincreasescarbondioxideconcentrations.
(c) Decompositionincreasescarbondioxide concentrations.
(d) Combustionoffossilfuelsincreasescarbondioxide concentrations.
(e) Carbonsinksdecreasecarbondioxide concentrations.
(f) Carbonsourcesincreasecarbondioxide concentrations.
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(a) A=Photosynthesis
(b) B=Respiration
C=Consumed
D=Death
E=Death
F=Respiration
G=Decompositionorrespiration
H=Combustionorburning
(c) AriseinCO2 concentrationsresultsinclimate change,globalwarming,increasedacidificationof oceans(andotherbodiesofwater).
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(a) Organismswitharoleinthecarboncycleinclude: plants,animals,decomposers(fungiandbacteria).
(b) Plantsreducetheconcentrationofcarbon dioxidebyabsorbingitandconvertingittoplant biomolecules.
Animalsincreasetheconcentrationofcarbon dioxidebyreleasingitinrespiration.
Decomposerssuchasfungiandbacteriaincrease theconcentrationofcarbondioxidebyreleasingitin respiration.
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(a) Abiogeochemicalcycleistherecyclingofessential nutrientsandelementsbetweentheliving(biotic) andnon-living(abiotic)partsoftheEarth.
(b) Thecarbonandnitrogencyclesareexamplesof biogeochemicalcycles.
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(a) Gasesresponsibleforclimatechangeincludecarbon dioxide,methaneandnitrousoxide.
(b) Thegasesaboveallowheatradiationtopassintothe Earth,buttheypreventreflectedheatradiationfrom leavingtheEarth.
(c) Climatewarmingcausesthefollowingeffects: increasedicemelting,sealevelstoincrease,more extremeweather,reversaloftheGulfStream, ecosystemdisruption,threatstoagricultureand watersupplies,newhealthchallenges.
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(a) Carbonrecyclingisimportantbecauseitreturns carbon,thatwasabsorbedinphotosynthesis,to theatmosphere.Thishelpstomaintainaconstant concentrationofcarbondioxideintheatmosphere.
(b) A=Combustionorburning B=Respiration
(c) Microorganismsactasdecomposers.Theybreak downdeadanddecayingmaterialandreleasecarbo andothernutrientsintotheenvironment.
(d) Irelandcandirectlyreducecarbondioxideemissions by:burninglessfossilfuels,increasingourcarbon sinks(e.g.forestsandpeatlands),increaseouruseof renewableenergysources(e.g.wind,solarandtidal energy).
(e) Apartfromthecarboncycle,theothercycleisthe nitrogencycle.
(f) Amicrobiomeisallthemicroorganismsthatexistina particularenvironment.
(g) Thesoilmicrobiomebreaksdownorganicmatterand releasescarbondioxidebackintotheatmosphere.It alsoformscarbonsinksbyallowingcarbontoremain inpartiallydecomposedmaterialinthesoil.
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(a) Climatewarmingwill:increasetheactivityofsoil microbiomes(causingmoreCO2 tobereleased) anditwillalterthediversityoforganismsinthesoil microbiome.
(b) Biologycanbeusedtoreducetheconcentrations ofcarbondioxideandmethaneby:theuseof reforestation,theuseofnewplantspecieswhich canabsorbmoreCO2,increasingthegrowthof algae,alteringthegutmicrobiomesofcattlesothey producelessmethane,improvewastetreatmentso itreleaseslessmethane.
(c) Plantsrequirenitrogenintheformofnitratesand ammonium.
(d) Processesthatconvertnitrogengasintousable plantcompoundsinclude:nitrogenfixationby bacteria,nitrogenfixationbylightningandindustrial conversionofnitrogengastoammoniumnitrate.
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(a) Bacteriainvolvedinthenitrogencycleinclude: nitrogen-fixingbacteria,bacteriaofdecay,nitrifying bacteria,denitrifyingbacteria.
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(a) Plantsandanimalsrequirenitrogentoform biomoleculessuchasproteins,nucleicacids,ADP, ATP.
(b) Plantscannotuseatmosphericnitrogenbecauseitis aninert(orunreactive)gas.
(b) Nitrogen-fixingbacteria
(i) Foundfreeinthesoilandinnodulesontheroots oflegumes
(ii) Actonnitrogengas
(iii) Producenitrates
Bacteriaofdecay
(i) Foundfreeinthesoil
(ii) Deadorganismsoranimalwastes
(iii) Produceammonia
Nitrifyingbacteria
(i) Foundfreeinthesoil
(ii) Actonammonia,ammonium,nitrites
(iii) Producenitrates
Denitrifyingbacteria
(i) Foundinthesoil
(ii) Actonnitrates
(iii) Producenitrogengas
(c) Nitrogenfixingbacteria,bacteriaofdecayand nitrifyingbacteriaarebeneficialforplantsastheyall helptoproducenitrates.
Denitrifyingbacteriaareharmfultoplantsasthey breakdownnitrates.
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(a) Organismsneednitrogentoformbiomoleculessuch asproteins,nucleicacids,ADP,ATP.
(b) A=Nitrogenfixation
B=Denitrification
(c) ThebacteriainvolvedinC(nitrification)arenitrifying bacteria.
(d) Possibleoutcomesoftheapplicationoffertilisers are:morenitrificationormorenitrogenabsorbed byplantsormoreplantgrowthormorefoodfor animalsormoredenitrificationormoreatmospheric nitrogenorwaterpollution(oreutrophicationor algalbloomsoradescriptionofthisprocess.
(e) TheletterDshouldbeplacedononeofthearrows fromanimalsorfrompeaplantstosoilammonia.
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(a) Nitrogenfixationistheconversionofatmospheric nitrogen(orN2)toausableform.
(b) Nitrificationistheconversionofammoniaand ammoniumtonitritesandthentonitrates.
(c) Denitrificationistheconversionofnitratesto nitrogengas.
(a) DiagramsshowingtheCarbonCycle:
(c) Similaritiesbetweenthenitrogenandcarboncycles include:theybothinvolvefixation(orbothinvolve theconversionofinorganicorgaseousformsof theelementsintomoreusableororganicforms)or bothinvolvebacteria(ormicro-organisms)orboth involvedeathanddecayorbothinvolvenutritionor bothinvolveexcretion.
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(a) Ethicalissuesrefertowhetheratopicisrightor wrong.
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(b) Sustainabilityissuesrefertotheabilitytomaintainor supportprocessescontinuouslyoveralongperiodof time.
(c) Ethicalissuesregardingtheuseoffertilisersinclude: willitharmthesoil(andorthesoilmicrobiome), willitcausewaterpollution(eutrophicationor explained),willitcauseairpollution(theproduction offertilisersleadstotheformationofgreenhouse gases),willitcausehealthproblems,isitaffordable.
Sustainabilityissuesregarding theuseoffertilisersinclude: willthecontinualuseleadto waterpollution,willitleadto excessgreenhousegases,will itharmthesoilquality/acidity/ microbiome/organisms(such asearthworms),willtherebea shortageofnaturalfertilisers.
CHAPTER35 GENETICENGINEERING
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(a) Geneticengineeringistheartificialmanipulationor alterationofgenes.
(b) AtargetgeneisasmallsectionofDNAcutfromone organismandinsertingitintotheDNAofasecond organism.
(c) ThealteredDNAiscalledrecombinantDNAandis placedbackintoanorganism.
(d) Geneticallymodifiedorganismisan organismwhosegeneticmaterialhasbeen alteredusingbiotechnology.
(e) Biotechnologyistheindustrialmanipulationof organismsortheircomponentstoperformpractical tasksortocreateusefulproducts.
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(a) No
(b) Geneticengineeringistheartificialmanipulationor alterationofgenes.
(c) Geneticengineeringinvolvescuttingasmallsection ofDNA(usuallycontainingasinglegenecalledthe targetgene)fromoneorganismandinsertingitinto theDNAofasecondorganism.Inthisrespect,itis reallya‘cut-and-paste’process.
ThealteredDNAiscalledrecombinantDNAbecause itrecombinesafterthesmallsectionofDNAis insertedintoit.TherecombinantDNAisplacedback intoanorganism.
Diagramofgeneticengineering:
Chromosome fromspecies1
Geneofinterest
fromspecies2
3
(a) DNAisolationistheremovalofDNAcontainingthe geneofinterest(calledthetargetgene)fromacell oraplasmidfromabacterium.
(b) RestrictionenzymeswillonlycutDNAatparticular sites.
(c) Cuttingmeansthatthetargetgeneiscutoutand theplasmidiscutopen.Botharecutusingthesame restrictionenzyme.
(d) LigationisthejoiningoftwosectionsofDNAtoform asinglestrand.
(e) TransformationistheuptakeofDNAintoacell.
(f) Expressionistheformationofaproductbythe organismwiththerecombinantDNA.
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Column AColumnB
(a) Manipulationofgenes Genetic Engineering
(b) UsedtocuttheDNA Enzyme
(c) Removingthe requiredDNA fromthecell Isolation
(d) AringofDNA foundin bacterialcells Plasmid
(e) Asubstanceproduced by bacteriausinggenetic engineering Insulin
(f) Anapplicationofgenetic engineeringinplants Weedkiller resistance
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(a) Correctorder:Isolation,Cutting,Ligation, Transformation.
(b) Restrictionenzymes
(c) TheremovalofDNAcontainingthegeneofinterest.
(d) Applicationsofgeneticengineeringinclude: Intheproductionofpharmaceuticals,organisms havebeengeneticallyengineeredtoproduceuseful medicinalproductssuchasinsulin,humangrowth hormone,antibiotics,antibodies,vaccinesand cancer-inhibitingchemicals.
Inagriculture,plantscanbegeneticallyengineered toproducegeneticallymodified(GM)plantsthatcan resistweedkillers.Oranyotheracceptableanswer.
6
(a) Geneticengineeringistheartificialmanipulationor alterationofgenes.
(b) ProcessA=Cutting ProcessB=Ligation
(c) StructureX=Plasmid
(d) EnzymeY=Restrictionenzyme
(e) Eachrestrictionenzymeisspecifictoaparticular sequenceofDNAbasesandwillonlyrecognisethat specificsequence,cuttingtheDNAatthosebases only.
(f) AfterProcessBtransformationoccurswhichisthe uptakeofthealteredDNAintoacell.
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(a) DNAprofilingisamethodofmakingaunique patternofbandsfromtheDNAofoneindividualand usingittocomparewiththeDNAprofileofanother individual.
(b) OnaDNAprofile,eachbandrepresentsafragment ofDNAthathasbeenseparatedbasedonitssize.
(c)(i) Forensicsisthewayinwhichscientific knowledgeisusedinlegalsituations.
(ii) Blood,hair,salivaorsemenoranyacceptable answer.
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(a) Bioinformaticsistheuseofcomputerscienceand statisticstocollect,store,organiseandanalyselarge amountsofbiologicalinformation.
(b) Answerindividualtostudent.Anyacceptable answer.
(c) Answerindividualtostudent.Thiswouldbebasedon youranswerfrom(b).
(d) Thegenomeisthecompletesetofallthegenetic materialofanorganism.
(e) GenBankdatabaseoranyacceptableanswer.
12
(a) Ethicsreferstowhethersomethingisrightorwrong.
(b) Reasonsagainst: Whoisallowedaccesstogeneticdata? Arethemethodssafe?
Shoulditbeallowedinembryos?
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(a) Potentialusesinclude: Forensics,solvingacrime.
Establishingfamilyrelationships. Identifyinghumanremains.
Identifyingfoodsources.
(b)(i) TheDNAprofilefromthebloodstainsobtained fromtheclothingofthedefendantmatchesthe DNAprofileofthevictim’sblood.
(ii) Theguilt.Thisisagoodindicationthatthe defendantwasinvolvedinthecrimeasblood stainsobtainedfromtheclothingofdefendant matchestheDNAfromvictim’sblood.
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9
(a) Suspect3
(b) Thisisagoodindicationthatthedefendantwas involvedinthecrime.ThepatternoftheDNAprofile fromthecrimescenematchesthatofthesuspect.
10
(a) Protein
(b) Inribosomes.
(c) mRNA
(d) Procedure: DNAisreleased. DNAiscutintofragmentsusingrestrictionenzymes. FragmentsofDNAareseparated. Theyareseparatedbasedontheirsize. Theyareseparatedbyaprocesscalledgel electrophoresis.
Patternsarecomparedandanalysed.
(e) Accepteitheranswer: No,aspigDNAisdifferenttobeefDNA. Yes,asbeefDNAisfoundinbothsamples.
DoesDNAtestinginvolveproperconsent,privacy andstorageofdata? Shouldembryonicstemcellsbeused?
Shouldatechniquebeallowedifitdoesnothappen innature?
(c) Stemcellsareundifferentiatedcellsthatcangive risetomanydifferenttypesoftissues.
(d)(i) Somepeoplesupporttheuseofadultstemcells andumbilicalcordstemcells,becausethese sources:
Donotinvolvethedestructionofembryos. Areoftencollectedwithinformedconsent.
(ii) Embryonicstemcells
(iii) Extractingembryonicstemcellsdestroysthe embryo,whichsomepeoplebelieveis thebeginningofhumanlife.
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(a) DNAtestingisamedicaltestusedtoidentify mutations(orchanges)ingenesorchromosomes.
(b) DNAtestingcanindicateifyoudoordonothavea geneticcondition.
Thesetestscanalsoidentifyyourriskofdeveloping someconditionsorpassingongeneticdisorders.
(c) Questionsraisedinclude:
Istheconsentfullyinformed(i.e.isthepersonfully awareoftheimplicationsofthetesting)?
Aretheresultsprivateandsecurelystored?
Willthetestresultsbeexplainedclearlyand sensitively?
Whoisentitledtoknowtheresults?
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(a) PreparingaDNAprofileinvolvesthefollowingsteps: Getasampleofcells(i.e.obtaincellsfromaperson oranotherorganism).
Release(orextract)theDNAfromthecells. IncreasetheamountofDNAusingthepolymerase chainreaction(PCR).
CuttheDNAintofragmentsofdifferentlengths. SeparatetheDNAfragmentsaccordingtotheir lengths.
Comparethepatternsproducedfromdifferentcells.
(b) IftheamountofDNAavailableistoosmalltowork with,itcanbeincreasedoramplified.
(c) ThemainstepsinthePCRprocessare:
Denaturation:Thereactionmixtureisheatedabove 94°C.Thisbreaksthehydrogenbondsandallowsthe doublestrandofDNAtoseparateintosinglestrands.
Annealing:Thetemperatureisloweredto50°Cto allowtheprimerstobind(oranneal)tothesinglestrandedDNA.
Extension:Thetemperatureisraisedto72°Cto allowTaqpolymerasetoaddnewnucleotidestothe primerstoformnewdoublestrandsofDNA.
(d) Restrictionenzymes
(e) Gelelectrophoresis
(f) Anelectriccurrentisappliedalongthegel.The currentdrawsthenegativelychargedDNAtothe positiveendofthegel.SmallDNAfragmentsmove fasterthroughtheporousgelthandothelarger fragments.
(g) InaDNAprofile,eachbandrepresentsafragmentof DNAthathasbeenseparatedbasedonitssize.
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(a) DNAprofilingisamethodofmakingaunique patternofbandsfromtheDNAofoneindividualand usingittocomparewiththeDNAprofileofanother individual.
Geneticengineeringistheartificialmanipulationor alterationofgenes.
(b) DNAisreleased.
DNAiscutintofragmentsusingrestrictionenzymes FragmentsofDNAareseparated. Separatedbasedontheirsize. Theyareseparatedbyaprocesscalledgel electrophoresis.
Patternsarecomparedandanalysed.
(c) UsesofDNAprofilinginclude: Forensics,solvingacrime. Establishingfamilyrelationships. Identifyinghumanremains. Identifyingfoodsources.
(d) Identicaltwins(both)havesamegenotype(orsame genes)or(both)comefromsamezygote(fertilised egg).
(a) DNAsequencingistheprocessofdeterminingthe completenucleotidesequenceofageneoraDNA segment.
(b) MainstepsofTheSangermethodofDNA sequencing:
Amplify(usingPCR)andseparatetheDNAsample. AddnucleotidestogenerateacollectionofDNA fragmentsofrandomlengths.
SeparatetheDNAfragmentsbygelelectrophoresis, witheachfragmentbeingonebaseshorterthanthe next.
(c) Endresult:thecompletenucleotidesequenceofa geneoraDNAsegment.
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(a) ItisnecessarytoamplifyDNAbeforesequencing because:
DNAsamplesareoftenverysmall.
TheamountofDNAextractedfromcellsortissuesis usuallytoolittletobedirectlysequenced.
Amplificationimprovesaccuracy.
(b) Nomorenucleotidescanbeattached.This createsDNAfragmentsofdifferentlengths,each endingataknownbase(A,T,C,orG),whichcan thenbeanalysedtodeterminetheDNAsequence.
(c) Whenanelectriccurrentisapplied,DNAfragments arepulledtowardthepositiveelectrode.Thecurrent drawsthenegativelychargedDNAtothepositive endofthegel.
(d) DNAfragmentsseparatebasedonsize.
Smallerfragmentsmovefasterandfartherthrough thegel.
Largerfragmentsmovemoreslowly.
(e)(i) 13nucleotides
(ii) ACGGGTCAGTCCA
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(a) Geneticengineeringistheartificialmanipulationor alterationofgenes.
(b) X=Cutting
Y=Transformationorintroductionofbasesequence changes.
Z=Expression
(c) APlasmidisacircularpieceofDNAinabacteriacell.
(d) Withbacteria.
(e) RestrictionenzymeswillonlycutDNAatparticular sites.
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