Unit 4 ~ LearningGuideName:

INSTRUCTIONS

Completethe followingnotesandquestionsasyouworkthrough therelatedlessons. Youarerequired to havethispackagecompleted BEFOREyouwriteyour unit test. Do your best and ask questions about anythingthatyou don't understand BEFORE you writetheunittest.

U4L1NOTES:INTRODUCTION(webnotesandvideo)

YOU SHOULD WATCH THEOSMOSISLAB VIDEOBEFOREPROCEEDINGANYFURTHER!

CellMembrane Structure

•Early Theory: Proteins were sandwiched between 2 layers of phospholipid molecules.

•Problem:Sincethephospholipidtailsarehydrophobic(hatewater)thistheory didnot explainhowwater cantravel freelythroughmembranes.

Fluid Mosaic Model:

•AcceptedTheory:Thereisadoublelayerofphospholipidsbutthe

•Watertravels throughtheporesformed bythe proteins

YOU SHOULD WATCH THEFLUID MOSAIC MODEL VIDEO BEFORE PROCEEDINGANYFURTHER!

•Theproteinshave,which accountsfor their placementamongthe .

Someoftheproteinsandphospholipidshavecarbohydratechainsattached tothem.

Protein + Carbohydratechain =

Phospholipid + Carbohydratechain =

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Thesecarbohydratechainsfunctionas

.Abodywill cells withthewrongmarkers.

Example: Organrejections intransplants

YOU SHOULD WATCH THECELL MEMBRANEAND STRUCTURE VIDEOBEFOREPROCEEDINGANYFURTHER!

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U4L1PRACTICE:INTRODUCTION

1. Describethefluid mosaic model.

2. Whatprefixisusedtoindicateaproteinorlipidthathasacarbohydratechain attached?

3. Please label the following cell membrane diagram with as much detail as possible.

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U4L2NOTES:CELLMEMBRANEFUNCTION(webnotesand video)

Followingaresomedefinitions youshouldunderstand:

•Impermeable- .

•Permeable- .

•Semi-permeable-

.

**SELECTIVELY PERMEABLE** -

.

•Certainsmaller andcertainlargemolecules canpass through.

CellMembranesareselectivelypermeable(alsocalleddifferentially permeable).

YOU SHOULD WATCH THEMOVEMENT ACROSSTHECELL MEMBRANE VIDEOBEFOREPROCEEDINGANYFURTHER!

MovementAcrossMembranes:

4mainways:

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1. DIFFUSION:

from an area of

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highconcentrationtoanareaoflowconcentrationuntilevenlydistributed.No membrane,carrier, orATPrequired.

*ASoluteismadeupof solid particlesor molecules suspended in airorliquid.*

•DiffusionExample:Afoulodourinthecornerofaroomwillspreadout until itis evenlydistributed

•DiffusionExample:Creamincoffeewilldiffuseuntilconcentrationare balanced

•Diffusionreferstotheprocessbywhichmoleculesintermingleasaresult oftheir ofrandommotion.Considertwo containersofgasAandBseparatedby apartition.Themolecules ofboth gasesareinconstant motionand makenumerouscollisionswiththe partition.

•Ifthepartitionisremovedasintheillustration,thebaseswillmixbecause of the random velocities of their molecules. In time a

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ofAandBmoleculeswillbe producedinthecontainer.

2.OSMOSIS:

.

•Pressurecausedbythe

betweentwodifferentsolutionsiscalled

. Hydrostatic pressure offsets osmotic pressure.(Gravity)

•The solute cannot spread out because it is

themembrane.Therefore, water moves across the membrane from [high water] to [low water]. Recall:squarebracketsrepresenttheterm"concentration"asin[high salt]= highsaltconcentration

•Watermoves throughthe protein-linedporesofthecellmembrane.

Hypertonic,Hypotonic and Isotonic Solutions

Hypertonic Solutions:

HypotonicSolutions:

Isotonic Solutions:

Water will always movefroma solutiontoa

solution.Thereisnonetmovement ofwater between solutions.

Tonicity:

.

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You should watchtheOSMOSISvideos and animationsand identifythe hypertonic and hypotonic solutionsin thevideobeforeproceedinganyfurther!

3.FACILITATED TRANSPORT:()

•Solutes move across a membrane from an area of [ ]toandareaof[ ]with the help of a carrier molecule (protein).

.

•Exampleof Solute:Glucose

Moleculesneededbythecellsuchasglucose,enterthrough

fromtheblood.

4. ACTIVETRANSPORT:Solutesmovefromanareaof

across amembranewiththe aidof

.

•Exampleof Solute:Ions suchas Na+

Sincethemovementisagainsttheconcentration gradient, isrequired.

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oExample:

isremovedfromtheurine,

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byactivetransport,intotheblood. Sincethereis alreadyalotofglucosein theblood,itis traveling theconcentrationgradient.

oExample: . Found in nerve and muscle cells.

Samecarrier,butchanges shapeto fit Na+and K+.

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TransportAcrosstheMembraneSummary

Therearealwaysfourpointstoconsiderwhencomparingthetypesofmovement acrossamembrane. Is amembrane,carrier, orenergy intheformofATPrequired, and is transportwith or againsttheconcentrationgradient.

FactorsAffecting Diffusion

SurfaceArea Vs.Volume

Nutrients( )enteracellwhilewastes(carbon dioxide andurea)exitacell acrossthecell membrane.

The amount of cellmembrane- =

•Insidethecell,organellesuseupnutrientsandproduce .

Thelargerthecell,themore

.

The sizeof the cell(#of organelles) =

•Small cells have a high SA:Volumeratio. They can supply the organelleswith plenty ofnutrients and removewastes.

•Largecellshavea

because volume increases fasterthansurface area.Ifa cell gets too big,wastes will build up and nutrients will run out.

•Therefore,cellsarelimitedin

size. Activecellsmust be thanless activecells. Activecellsneed more .

•Cells reproduce bymitosis tobecomesmaller

•Somecellareable to getlargerthan theyshould be able tobyproducing

•Thesefoldsallowthecelltogainmoresurfaceareawithoutalargeincreasein volume

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FactorsThatWillIncreaseDiffusion

Movement of themedium-

•Example: Stirringcreamincoffee.

Endocytosisversus Exocytosis

Endocytosis- process inwhichlargematerialsenter acell

.

•Phagocytosis-

--"Cell eating"-verylarge pieces

•Pinocytosis-Atypeofendocytosisinwhichmoleculessuchaproteinsare takenin(liquid).

--""-smaller "larger"pieces

Exocytosis

•Exocytosis-Aprocessbywhichproductsorwastesexitacell.

.

YOU SHOULD WATCH THEFACILITATED TRANSPORT VIDEOBEFOREPROCEEDINGANYFURTHER!

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U4L2PRACTICE:CELLMEMBRANEFUNCTION

1. Pleasedefinethefollowingtermsandprovideoneexamplewhereitisinvolvedin transportingasubstanceinthehumanbody:

a. diffusion

b. osmosis

c. facilitatedtransport

d. activetransport

2. There are several ways to transport substances across the cell membrane.

Please complete the table below, indicating whether the form of transport requiresamembrane,carrier,energy intheformofATP,andiswiththe concentrationgradient.

Typeof
Transport / Membrane Required (or) / Carrier Required (or) / Energy/ATP Required
(or) / With concentration Gradient
(or)
Diffusion
Osmosis
Facilitated
Transport
Active
Transport

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3. Whichmodeoftransportisusedtomovethefollowingmoleculesacrossthecell membrane?

a. oxygenmolecules

b. water

c. sodiumions

d. glucose

4.Whyis thecell membraneimportanttothecell?

5.Whatfactorsinfluencetherateatwhichspecificmoleculesdiffuseacrossthecell

membrane?

6. Whydoeswinter roadsaltcausedamagetoplantsonthe roadside?

7. Saltingfishwasacommonpractice. Howdidthispracticepreventthefishfrom rotting?

8.Compareandcontrastendocytosis,includingbothphagocytosisandpinocytosis,andexocytosis. Includeanexampleoftheuseofeachprocessinthebody.

~ENDOFBIOLOGY12UNIT4 LEARNINGGUIDE~

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UNIT4ANSWERKEY

U4L1PRACTICE:INTRODUCTION

1. Describethefluidmosaicmodel.(2marks)

=statesthatthecellmembrane (akatheplasmamembrane) ismadeupofasemi- fluid(dynamicandchanging)phospholipid bilayerwithavariety ofproteinsfloating withinthatbilayer

2. Whatprefixis usedto indicateaproteinorlipidthathasacarbohydratechainattached?(1mark)

=glycolas inglycoproteinorglycolipid

3. Pleaselabelthefollowingcellmembranediagramwithasmuchdetailaspossible.(5marks)

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U4L2PRACTICE:CELLMEMBRANEFUNCTION

4. Pleasedefinethefollowingtermsandprovideoneexamplewhereitisinvolvedintransportinga substanceinthehumanbody:

a. diffusion(2marks)=themovement ofparticlesfromareasofhigherconcentrationtoareas oflowerconcentrationsuntil equilibriumismet

b. osmosis(2marks)=themovementofwatermoleculesfromareasoflowerconcentration (notelowerconcentration ofsolutionactuallymeansgreateramountsofwater)toareasof higherconcentrations(notehigherconcentrationofsolutionactuallymeansgreateramounts ofwater)acrossasemi-permeable membraneuntilequilibriumismet…insteadof concentration simplythinkofthemovementofwaterfromareaswithgreater/higher amountsof waterto areasoflesser/loweramountsofwater

c. facilitatedtransport(2marks)=anyformofdiffusionthatrequirestheassistanceofa carrierorchannelprotein,theprotein'sassistance isgenerally requiredtoeitherlimitthe transportedsubstance'sinteractionswiththecellmembrane(suchaswithnegativeions that wouldberepelledby orpositiveionsthat wouldbe attractedtothenegativemembrane withouttheassistance)orbecausethetransportedsubstanceis simplytoo largeto diffuse directlyacrossthemembrane,processisenergy-independentasitisdiffusionandparticles aremovingalongtheirconcentrationgradientfromhightolow

d. activetransport (2marks)=anyformoftransport thatrequires energy(typically supplied in theform ofATP)suchaswhensubstances aremovedagainsttheirconcentrationgradients (fromlowerconcentrationstohigherconcentrations)ofmovedwithinvesicles

5. Thereareseveralwaystotransportsubstancesacrossthecellmembrane. Pleasecompletethe table below,indicating whethertheformoftransportrequiresamembrane,carrier,energyintheform of ATP,and iswiththeconcentrationgradient.(8marks)

Typeof
Transport / Membrane Required (or) / Carrier Required (or) / Energy/ATP Required(or) / With concentration Gradient
(or)
Diffusion /  /  /  / 
Osmosis /  /  /  / (with respectto watermovingfrom areasof higher waterto areasof lowerwater)
Facilitated
Transport /  / (or channel) /  / 
Active
Transport /  /  /  / 

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6. Whichmodeoftransportisusedtomovethefollowingmoleculesacrossthecellmembrane?(4 marks)

a. oxygenmolecules _

b. water_

c. sodiumions

d. glucose_

4.Whyis thecellmembraneimportanttothecell?(2marks)

=definestheboundariesofthecellfromthesurroundingenvironment

=controlswhatentersandexitsthecell

5.Whatfactorsinfluencetherateatwhichspecificmoleculesdiffuseacrossthecellmembrane?(3 marks)

Answershouldincludeany 3 ofthefollowing:

=surfacearea…greatersurfaceare=fasterdiffusion

=temperature…highertemperature=fasterdiffusion

=concentrationgradient…greatergradient(thegreaterthedifferencebetweenthehigher andlowerconcentrationareas)=fasterdiffusion

=sizeofdiffusingparticle…smallerparticle=fasterdiffusion

=diffusionmedium…solid=slower,liquid=faster,gas=fastest

6.Whydoeswinterroadsaltcausedamageto plantson theroadside?(1 mark)

=theexcesssaltmixeswithwaterintheenvironmentandessentiallyplacesthe plantinahypertonic solutionthatthencauseswatertoexittheplantcellthereby damagingtheplant

7.Saltingfishwasacommonpractice.Howdidthispracticepreventthefishfromrotting?(1 mark)

=theexcesssaltmixeswithwaterintheenvironmentandessentiallyplacesany potential bacteriathat could leadthefishtorotinahypertonicsolutionthat draws thewaterfromthebacteriacausingittodie

8.Compareandcontrastendocytosis,includingbothphagocytosisandpinocytosis,andexocytosis.

Includeanexampleof theuseof eachprocessinthebody.(4marks)

=endocytosis andexocytosisbothactivetransportprocessesthatuseATPand vesiclestotransportsubstances

= endocytosis specifically refers to the use of vesicles to actively move substancesintothecellandincludesphagocytosisor"celleating"wherebylarger particlesarebroughtintothecellandpinocytosis or"celldrinking"whereby fluids andsmallerparticlesarebroughtintothecell;alsoincludesreceptor-mediated

endocytosiswhichonlyoccursinresponsetoaligandofsomesortspecifically

bindingtoareceptorto initiatetheprocessofendocytosis

= exocytosis specifically refers to the use of vesicles to actively move substancesoutofthecell andincludesconstitutiveexocytosisorsecretionwhereby asubstancesiscontinuallysecretedfromthecellandreceptor-mediated or regulatedexocytosiswherebyasubstanceisonlymovedoutofthecellinresponse tosomesortofligandspecifically bindingtoareceptortoinitiatetheprocessof exocytosis

=phagocytosis…uptakeof bacteriapathogensfor destructionwithinthecell

=pinocytosis…uptakeof nutrientsbycellsinthesmallintestine

=receptor-mediatedendocytosis…ironandcholesteroluptake

=constitutiveexocytosis…collagenandplasmamembranelipids

=regulatedexocytosis…

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