Biology must know questions

Must knowquestions<3 1. Describewhat happenstoafertilisedegginitsearlydevelopment.a. Thezygoteundergoesmitosistoformdaughter cellswhicharecalledembryo.b. Theembryoimplantsintheuterinelining.c. Finger-likeprojectionscalledvilli growfromtheembryointotheuterinelining.Theycontainbloodcapillariesof theembryo. Thevilli andtheuterineliningmakeuptheplacenta.d. Amnioticsacwill enclosetheembryo. Amnioticfluidfillstheamnioticsac.e. Theumbilical cordattachesthefetustotheplacenta. Thetwoumbilical arteriestransport deoxygenatedbloodandmetabolicwasteproductsfromthefetustotheplacenta. Theumbilical veinstransport oxygenatedbloodandfoodsubstanceslikeglucosefromtheplacentatothefetus. 2. Describehowmeiosisleadstotheformationof newgeneticcombinations.a. Formationof gametesinvolvesmeiosisi. Crossingover of chromatidsof homologouschromosomesinprophaselof meiosis.ii. Formationof newcombinationsof allelesinprophasel.iii. Independent assortment of chromosomesat metaphasel.b. Randomfertilisation 3. Howdoesagenemutationleadtotheproductionof anewenzyme/hormone/protein?a. ChangesinDNA, basesequenceb. Changeinsequenceof nucleotidesc. Control productionof aspecificpolypeptided. Changeinsequenceof aminoacids 4. Comparebreathingandrespiration.a. Breathingismovingair intoandout of thelungsbut respirationisthereleaseofenergyfromfood.b. Breathingisaphysical processof exchangeof gasesbut respirationisachemical processthat takesplaceinlivingcells. 5. Describetheprocessesafter exercise.a. Continuetobreatheat ahighratetoprovideenoughoxygentopayofftheoxygendebt.

b. Continuetohaveahighpulseratetoprovideenoughoxygentopayofftheoxygendebt.c. Lacticacidistransportedfromthemusclestotheliver wherelacticacidisbrokendown. 6. Differentiatebetweenareflexactionandavoluntaryaction.a. Areflexactionisfaster thanavoluntaryactionb. Areflexactionisanunconsciouscontrol but avoluntaryactionisaconsciouscontrol.c. Reflexactionisautomaticbut voluntaryactionisnot automatic.d. Reflexactionbeginswiththereceptor beingstimulatedhowever voluntaryactionbeginswithadecisionfromthebrain.e. Reflexactionwill alwaysinvolvethesensoryneuronshowever voluntaryactionmayor maynot involvethesensoryneuron.f. Bothinvolvethetransmissionof nerveimpulses.g. Bothinvolvemotor neuronstransmittingnerveimpulsetotheeffector. 7. Suggest what causesthefall inbloodpressurewhenthebloodpassesfromtheaortatothevenacava.a. Aortaandarterieshavethicker muscular wallsascomparedtoveins. Capillarieshavenomuscletissueinthewall. Therewill begreater recoil of thevessel wall inthearterythancomparedtotheveins. Thereisnorecoil of thecapillarywall.b. Aortaandarterieshavesmaller lumenrelativetodiameter ascomparedtocapillariesandveins. Thiscauseslossof bloodpressureasbloodmovesfromsmaller crosssectional areatolarger crosssectional areainthecapillariesandtheveins.c. Thelossof pressureduetofrictionfromarteriestocapillariesthanveins. 8. Explainhowexercisecausesafall inthebloodglucoseconcentration.a. Musclecellsundergoahigher rateof aerobicrespiration. Moreglucoseoxidisedtoreleasemoreenergyfor muscular contractions.b. Hencemoreglucoseneededhencemoreglucoseuptakefromthebloodintomusclecells.c. Hencebloodglucoseconcentrationinbloodfalls.9. Suggest what ismeant bymetabolicwater.a. It isthewater producedfromchemical processesthat takeplaceinlivingcells. 10. ADHisinvolvedinthepreventionof dehydration. ExplainhowADHreduceswaterlossfromthebody.a. Dehydrationmeansthereisalower water potential intheblood.

b. Thepituitaryglandwill releasemoreADHc. ADHmakesthewallsof thecollectingduct morepermeabletowaterd. Morewater isreabsorbedfromthecollectingduct intothesurroundingbloodcapillariese. Thiswill returnthewater potential of bloodtonormal. 11. Apersonisonlyabletoproducelowlevelsof carbonicanhydrase. Suggest andexplaintheeffect of thisdeficiencyongasexchangeinthisperson.a. Intherespiringtissues, thereislesscarbonicanhydraseintheredbloodcellsandthisleadstolessconversionof carbondioxideandwater toformcarbonicacids.b. At thelungs, lesser carbonicanhydraseintheredbloodcell leadstolesserconversionof carbonicacidtoformcarbondioxideandwater.c. Morecarbondioxideaccumulatesinthebodytissues.d. Lesser carbondioxidewill diffuseout of thebloodintothealveolar cavitytobeexhaled. 12. Suggest apossiblenutritional advantagetotheyoungcowof theactionof rennin.a. Ayoungcow’sstomachissmall. Rennincausesmilktocurdleandformlumps.b. Milkisretainedinthestomachfor alonger timec. For proteasetodigest theproteininmilk. 13. Withreferencetothemovement of substancesinaneuron, describehowsaltsarereabsorbedinthekidney.a. At theproximal convolutedtubule, most mineral saltsandglucosearereabsorbedintothesurroundingbloodcapillaries.b. If theconcentrationof mineral saltsandglucoseishigher thantheblood,diffusionof mineral saltsandglucoseoccurs.c. If theconcentrationof mineral saltsandglucosearelower intheblood, activetransport occurs.d. Energyfromrespirationisused.14. Compareandcontrast themovement of air andfoodinregionQ. Air: inhaleandexhalethroughthetrachea, bonchi,bronchiolesandintothealveoli. Pressurechanges. Food: peristalsisandoesophagus

Rhythmiccontractionof thecircular musclesandlongitudinal muscles. Circularmusclescontract andlongitudinal musclesrelax→foodispushedforward. 15. Describethecauseof Down’ssyndrome.● Chromosomemutation● Childhasonemorecopyof chromosome21 16. Describethecauseof sickle-cell anemia.● Geneticmutation● Recessiveallele● Inherited2recessivealleles/ homozygousrecessive. 17. Explainhowthe‘lub’ and‘dub’ soundsaregeneratedintheheart.● “Lub”: closingof AVvalves/ bicuspidandtricuspidvalves○ Whenpressureintheventriclesrise● “Dub”: closingof semi-lunar valves○ Whenthepressureintheaortarise 18. Explainhowanamedhormonecancausetheriseinheart rate.● Adrenal glandsecretesadrenalineintothebloodstream● Adrenalinecarriedtothetarget organsinthebloodstream.● Stimulatesliver cellstoconvert glycogentoglucose● Moreglucoseinbloodstream● Moreglucoseandoxygenbrought torespiringcells● Higher rateof aerobicrespiration● Moreenergyreleased19. Explain, withreferencetohumanbloodgroups, what ismeant bycodominanceandmultiplealleles.● Codominanceresultswhen2allelescontrollingthesametrait bothexpressedthemselvesintheorganism.● Multipleallelesisatermusedfor thesamegenethat existsinmorethantwoalleles.● Thereare3allelescontrollingthebloodgroup. IA, IB, IO.● IAandIBaredominant over IO● IAandIBexhibit codominance● GenotypeIAIOandIAIAwill bebloodgroupA● GenotypeIBIOandIBIBwill bebloodgroupB● GenotypeIOIOwill bebloodgroupO● GenotypeIAIBwill bebloodgroupAB.

20. Definediscontinuousvariation.Discontinuousvariationdealswithafewclear cut phenotypes. It iscontrolledbyoneorafewgenes. 21. Defineagene.Ageneisaunit of inheritance, asequenceof nucleotides, andisapart of DNA. It codesfor theproductionof aspecificpolypeptide. 22. Definealleles.Analleleisadifferent formof thesamegene. Theyoccupythesamerelativepositiononapair of chromosomes. 23. Smokingtobaccocancausetheocclusionof coronaryarteries.Suggest theeffectsof occludingcoronaryarteries. ● Decreasedflowof bloodwithoxygenandglucosetotheheart muscles.● Reducedrateof aerobicrespirationinheart musclecellsandhencelessenergyreleased.● Heart ratedecreases● Lessbloodwithoxygenandglucosepumpedtothebodytissues.● Reducedrateof aerobicrespirationinbodytissues● Fatigue!24. Suggest arolefor themusclefibresinsmall arteries.● Larger proportionof musclefibresinthesmall arterywall● Musclescontract andrelaxtobringabout constrictionanddilationof theartery.● Small arterieshelptoregulatethetemperature. Arteriolesintheskindilatetoallowmorebloodtoflowtotheskinsurfacetolosemorelatent heat ofvapourisation. 25. Explainwhyarterieshaveathickelasticlayer.● Arterieswithstandhighbloodpressurethat isforcedout of theheart● Thickelasticarteriesallowthearterywall tostretchandrecoil, helpingtopushbloodalongtheartery. 26. Inonepart of theworld, eucalyptustreeshaveevolvedtoresist fires.Explainhowthesetreeshaveevolvedtoresist fires.

● Fireistheforceof natural selection,● Natureselectsthetreesthat areresistant tothefiretosurviveandreproducetheir ownkind