UNIT6:CellMembraneTransport
EssentialIdea(s):
Name:_____________________
Membranescontrolthecompositionofcellsbyactiveandpassivetransport
IBAssessmentStatements
1.1.U3
CellSurfacetovolumeisanimportantlimitationtocellsize.
• Outlinetheactivitiesoccurringinthevolumeandatthesurfaceofthecell.
• Calculatethesurfacearea,volumeandSA:Vratioofacube.
• Explainthebenefitsandlimitationsofusingcubestomodelthesurfaceareaandvolumeofacell.
• DescribetherelationshipbetweencellsizeandtheSA:Vratioofthecell.
• ExplainwhycellsareoftenlimitedinsizebytheSA:Vratio.
• ListthreeadaptationsofcellsthatmaximizetheSA:volumeratio.
1.4.U1
Particlesmoveacrossmembranesbysimplediffusion,facilitateddiffusion,osmosisandactivetransport.
• Describesimplediffusion.
• Explaintwoexamplesofsimplediffusionofmoleculesintoandoutofcells.
• Outlinefactorsthatregulatetherateofdiffusion.
• Describefacilitateddiffusion.
• Describeoneexampleoffacilitateddiffusionthroughaproteinchannel.
• Defineosmosis.
• Predictthedirectionofwatermovementbasedupondifferencesinsoluteconcentration.
• Compareactivetransportandpassivetransport.
• Explainoneexampleofactivetransportofmoleculesintoandoutofcellsthroughproteinpumps
1.4.S1
Estimationofosmolarityintissuesbybathingsamplesinhypotonicandhypertonicsolutions.
• Defineosmolarity,isotonic,hypotonicandhypertonic.
• Calculatethepercentagechangebetweenmeasurementvalues.
• Calculatethemeanvalueofadataset.
• Calculatethestandarddeviationvalueofadataset.
• Statethatthetermstandarddeviationisusedtosummarizethespreadofvaluesaroundthemean,and
that68%ofthevaluesfallwithinonestandarddeviationofthemean.
• Explainhowthestandarddeviationisusefulforcomparingthemeansandthespreadofdatabetweentwo
ormoresamples.
• Determinethecorrecttypeofgraphtorepresentexperimentalresults.
• Statethaterrorbarsareagraphicalrepresentationofthevariabilityofdata.
• Accuratelygraphmeanandstandarddeviationofdatasets.
• Determineosmolarityofasamplegivenchangesinmasswhenplacedinsolutionsofvarioustonicities.
1.4.NOS
Experimentaldesign-accuratequantitativemeasurementinosmosisexperimentsisessential.
• Definequantitativeandqualitative.
• Determinemeasurementuncertaintyofameasurementtool.
• Explaintheneedforrepeatedmeasurements(multipletrials)inexperimentaldesign.
• Explaintheneedtocontrolledvariablesinexperimentaldesign.
1.4.A2
Tissuesororganstobeusedinmedicalproceduresmustbebathedinasolutionwiththesameosmolarityasthe
cytoplasmtopreventosmosis.
• Explainwhathappenstocellswhenplacedinsolutionsofthesameosmolarity,higherosmolarityandlower
osmolarity.
• Outlinetheuseofnormalsalineinmedicalprocedures
1.4.U2
Thefluidityofmembranesallowsmaterialstobetakenintocellsbyendocytosisorreleasedbyexocytosis.
• Describethefluidpropertiesofthecellmembraneandvesicles.
• Explainvesicleformationviaendocytosis.
• Outlinetwoexamplesofmaterialsbroughtintothecellviaendocytosis.
• Explainreleaseofmaterialsfromcellsviaexocytosis.
• Outlinetwoexamplesofmaterialsreleasedfromacellviaexocytosis
SURFACEAREA:VOLUME(…whycellsaresmall…)
SURFACEAREA
Cellsurfaceareadictates…
Themoresurfacearea,themore…
VOLUME
Cellvolumedictates…
Themorevolume,themore….
Asacellbecomestoolarge….
Somecellsincreasesurfaceareatovolumeratiobyhaving…
sketchanddescribe
SIMPLEDIFFUSION
CAPTION:
Ratesofdiffusiondependon:
DIFFUSIONIS:
PHOSPHOLIPIDBILAYERMUSTBE:
EXAMPLES:
DiffusionofCO2andO2intoandoutoflungalveoli
DiffusionofCO2andO2intoandoutofeyecorneacells
FACILITATEDDIFFUSION
FACILTATEDDIFFUSIONIS:
PHOSPHOLIPIDBILAYERMUSTBE…
EXAMPLE:
CAPTION:
CAPTION:
OSMOSIS
OSMOSISIS:
OSMOSISDEPENDSON…
HYPOTONIC
Whathappenstocellsplacedin
HYPOTOMICSOLUTION
ISOTONIC
HYPERTONIC
Whathappenstocellsplacedin
ISOTONICSOLUTION
Whathappenstocellsplacedin
HYPERTONICSOLUTION
ACTIVETRANSPORT
CAPTION:
ACTIVETRANSPORTIS:
PROTEINPUMPS:
EXAMPLES:
SodiumPotassiumPumpinNeurons
ProtonPumpinCellularRespirationandPhotosynthesis