Bio Revision Qns Caltec S.4

U.C.EBIOLOGYQUESTIONS 1.(a)Describewhattakesplaceafterthefusionofmaleandfemalereproductivecells inhumansupto whentheplacentaisformed. (b)Stateanyfiverolesofplacentaduringpregnancy. (c)Listanyfoursecondarysexualcharacteristicsinhumanmalesandfemales. (d)Statethefunctionsofthe (i)Placentatotheembryo (ii)Villiontheplacenta (e)(i)Explainwhythemotherandembryo’sblooddon’tmix. (ii)Givethedifferencebetweenbloodintheumbilicalveinandthatinthe umbilical artery. 2.Inanexperimenttoinvestigatethegrowthpatternofaleguminousplant,astudent fromLondonCollegeofSt.Lawrencedecidedtouselengthofleavesasthe parameterforgrowthandcameupwiththefollowingresultsinaperiodof17weeks. Timein weeksLeafbreadth(in mm)Leafinlength(in mm)Leafarea(in mm2) 1 0.4 1.0 0.4 3 0.6 1.0 0.6 5 0.7 1.2 0.84 7 1.0 1.3 1.3 9 1.6 1.4 2.24 11 2.8 2.8 7.84 13 6.8 5.2 35.36 15 7.6 5.8 44.08 17 7.8 7.4 57.72 (a)Plotagraphofleafareaagainsttime. (b)Whatkindofgrowthcurveisexhibitedbytheplant? (c)Usingyourgraphdeterminetheleafareaat (i)12weeks (ii)14weeks (d)Accountfortherateofgrowth (i)Between1st_9thweek (ii)12th_17thweek (e)Namethemeristematictissuesinplants. (f)Listtwodifferencesbetweengrowthinplantsandanimals. (g)Statethreecausesofdormancyinseeds. 3.(a)Describethelifecycleofatapeworm. (08marks) (b)Howisthespreadoftapewormcontrolled? (02 marks) (c)Describehowgutparasitesareabletosurvive. (05 marks) 3.(a)Describethestructureofthedifferenttypesofskeletoninanimals? (09marks) (b)Explainhowthevertebralcolumninmammalsisadaptedtoitsfunction.(06 marks) 4.(a)Aplantwithnormalseedswascrossedwithoneofthesamespecieshaving wrinkled seeds. Theoffspringresultingfromthiscrossinghadnormalseeds.Oneoftheplants ofthisgenerationwasthencrossedwithawrinkledseededonetoproduce anothergenerationofoffsprings. (i)UsingrelevantgeneticsymbolsworkouttheF2generationgenetypes. (Showyourworking) (ii)ShowthegenetypicratiooftheF2generation. (b)Whatisthenamegiventothechromosomenumberin (i)gametes (ii)zygote 5.(a)Describetwowaysinwhichthewhitebloodcellsdefendthebody.(02marks) (b)Describehowredbloodcellsareadaptedtotheirfunctions. (10 marks) (c)Describethechangesthatoccurinanindividual’sbloodifapersonmoves fromalowlandandgoestoliveonahighland.Explainyouranswer. (03marks) 6.Inanexperiment,astudentlookedatthelightsourceofvaryingintensities.The diameterofthepupilwasmeasuredateachintensity.Thedatabelowshowshow thediametervariedwithlightintensity. Lightintensity(Arbitraryunits)0 0246810 Diameterofthepupil(mm) 8.47.24.22.91.81.4 (a)Onthegraphpaperprovided,drawagraphtoshowhowthepupildiameter variedwithlightintensity. (06 marks) (b)(i)Describetheshapeofthecurveplottedin(A)above (2 marks) (ii)Fromthegraph,statetherelationshipbetweenlightintensityandpupil diameter. (01marks) (c)Usingthestructuresofthemammalianeye,explainhowthepupilisableto adjustitsdiameteratvariouslightintensities. (02marks) (d)Statetwocommoneyedefectsinhumansandstatehowtheyarecorrected. (04marks) (e)Describetheeventsthatleadtoonetowithdrawa (i)Handaftertouchingahotobject. (04 marks) (ii)Givetwodifferencesbetweennervouscontrolandcontrolby hormones. (02marks) 7.(a)Fromtheknowledgeofinheritance,whatismeantbythefollowingterms. (i)Phenotype (ii)Genotype (iii)Recessivegene. (iv)Dominantgene (b)(i)Colourblindnessisasexlinkedrecessivecharacterinhumanbeings.Ifa colourblind manmarriesacarrierwoman,illustrateusingwelldefinedsymbolsthepossible genotypesandphenotypesofoffsprings. (09 marks) (ii)Statethebenefitsofstudyinggeneticstohumandaytodaylife. (03 marks) 8.(a)(i)Whatisseeddormancy? (01 marks) (ii)Whatarethecausesofseeddormancy? (03 marks) (b)Describeanexperimenttoshowthatwaterisnecessaryforgeneration.(11 marks) 9.(a)Definethetermhomeostasis. (02marks) (b)Describeanythreecomponentsofahomeostaticprocess. (03 marks) (c)Describethehomeostaticmechanismbywhichbloodglucoseismaintainedat normal levels. (10 marks) 10.(a)Inwhatwaysistheileumadaptedtoitsfunctions? (04 marks) (b)Brieflydescribetheprocessofdigestionoffoodintheduodenum. (05 marks) (c)Outlinethefateofabsorbedsolubleproductsofdigestionafterabsorptioninthe body. (06marks) 11.(a)Describetheprocessthatoccurafterpollinationinaflowerleadingtothe formationofa fruit. (b)Howareplantsadaptedtopromote; (i)Self-pollination? (ii)Crosspollination? (c)Statehowinsectflowersaredifferentfromwindpollinatedflowersfora successful pollination. (d)Explainthevariousmethodsofseedandfruitdispersal? 12.(a)Differentiatebetween; (i)Growthanddevelopment, (ii)Primarygrowthandsecondarygrowth (iii)Dormancyandgermination (b)Stateanytwoimportanceof; (i)Seeddormancy (ii)Secondarygrowth (c)Explainthecausesofseeddormancyandstatehoweachisbroken. 13.Theinformationbelowwascollectedbyageneticistthenumberofindividualswith their correspondingheightsinagivenpopulation. Numberof individualsof(‘000)1.52.05.09.016.022.014.04.03.0 Height(cm) 155160167170173176185191195 (i)Usingtheinformationprovided,plotasuitablegraphtorepresentthe data.(09marks) (ii)Fromthegraph,determinethenumberofindividualsmeasuring180cm inheight. (01mark) (b)(i)Describehowthenumberofindividualsvariedwithheight. (03 marks) (ii)Whichtypeofvariationisexhibitedbytheindividualsregardingthe character inquestion? (01mark) (iii)Apartfromheight,outlinethreeothercharactersthatshowsimilarbehavior inman. (03marks) (iv)Statethreepropertiesofthecharactersyouhavejustmentionedin(b) above. (03marks) 14.(a)Whatismeantbytropism? (b)Thediagrambelowshowstheeffectofauxinsondifferentseedlingsgrowingin thesame condition.Theeffectthepartsofthegrowingseedlingwereshowninthegraph. Concentrationofauxins(partspermillion) (i)Suggestwhateachsurverepresentsonthepartoftheseedlings. (ii)Givetworeasonsforeachofyouranswer. (iii)Stateany3differencesandsimilaritiesbetweencurveXandY. (c)(i)Namethetypeofgrowthresponseunderinvestigation. (ii)Stateany2importanceofthegrowthresponse. (d)Explainhowauxinscanbeofimportancetoplants. 15.(a)Describethestructureofthetaprootsystem. (b)Describetheinternalstructureofamonocotyledonousroot. (c)Statehow; (i)Theinternalstructureofamonocotrootissimilartoadicotroot. (ii)Theinternalstructureofamonocotisdifferentfromadicotroot. (d)Explainhowtherootsaremodifiedtoperformdifferentfunctions. 16.(a)Whatismetamorphosis? (b)Describehowthelifecycleofahouseflydiffersfromacockroach. (c)Explainhow; (i)Thespreadofmalariabymosquitocanbecontrolled. (ii)Thespreadofcholerabyahouseflycanbeminimized. 17.Thetablebelowshowstheamountofsoilremovedannuallyper1000m2and numberofyears neededtoerode18cmoftopsoilinsouthernpiedmontondifferentfieldshaving5 different typesofgroundcover. Typeofground coverKgofsoilremovedannuallyper 100m2Numberofyearsneededto erode18cmoftopsoilatthis rate. Virginforest 5 500000 Grass 775 3225 Rotation 35800 70 Cotton 79000 32 Bareground 166000 15 (a)Formthetable,whichgroundcover(s)sho (i)Thehighestrateoferosion. (ii)Thelowestrateoferosion (b)Explainwhythegroundcoverstatedin(a)abovehas. (i)Thehighestrateoferosion. (ii)Thelowestrateoferosion. (c)Outline2waysinwhichthetopsoilcouldbelostinthefollowingfields. (i)Virginforest (ii)Rotationfield (iii)Bareground (d)Suggestwayshowerosioncanbereducedinthefieldwiththehighestrateof erosionstatedina(ia0above. (e)Ifthefiguresfromsouthernpiedmontwhichisagenerallyflatlandwere comparedtothoseobtainedfromthesteepslopesofmountainElgonwith similargroundcover.Explainthedifferenceinthetimeneededtoerode18cmof topsoil. 18.(a)Whatismeantbytherateofphotosynthesis? (b)Explainthefactorslimitingtherateofphotosynthesisineachofthefollowing conditions. (i)Aquatichabitat (ii)Atnight (iii)Thickforest (c)Describeanexperimenttoshowthatcarbondioxideisnecessaryfor photosynthesis. 19.Whatistranspiration? (b)Explainhowthefollowingfactorsaffecttherateoftranspiration. (i)Humidity (ii)Temperature (iii)Stomatasizeanddistribution (iv)Leafsurfacearea (c)Statehowthefollowingplantsovercomethechallengeofwater. (i)Xerophytes (ii)Mesophytes (iii)Hydrophytes 41.Differentiatebetweenosmoregulationandexcretion. (b)Describetheroleofvasopressininregulatingwaterinman. (c)Explainhow; (i)Kidneynephronisrelatedtoitsfunctionofurineformation. (ii)Ureaisformedandeliminatedinman. (iii)Thebodyregulatesaminoacids. 20.(a)Whatismeantbycellularrespiration? …