Animal Gell
Manipulative Models r
Student Guide
INTRODUCTION
In the followingactivitiesyou are going to explorethe ever ongoingprocessesof the cell as a vital part of a bigger
syslem - your body or any animal'sbody. Usingthe parts in this kit, you will createa model of an animal cell.
Keep in mind that this manipulativeshows a "typical"animalcell. However,just as there is enormousvariety in
the types of animalswhich exist,there is also enormousvariationin the cells that comprisethem. Additionally,
cellswithina singleanimalwillvaryfrom one another,basedon the functionof the tissuethey comprise.Foi
instance,humanlivercellshave hundredsof mitochondria,
whileskin cellshaveonly a few, if any, mitochondria.
By the end of this activityyou should be able to identifyeach structurewithin lhe cell and to understandand
explain its function.Before startingthis activity,check to make sure you have all of the pieces shown below.
Blackline
cellbase:
Complete
animal
cell
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3
5.
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11
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a
12. t"-
13.,
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BACKGROUND
INFORMATION
Thinkof the cellas a factory,andeachorganelleas a depadment
withinthefactory.Likeanyfactory,the cellhas
to producea produetsafelyandetficiently,
overandover,andto makesurethat it endsup safelyin the handsof
performsa specificfunctionas partof a wholesystem.
a customer.To do this,eachdepartment,
or organelle,
producing
Thesefunctionsincludeimporting
the rawmaterials,
the product,packaging
the productandthen
delivering
the product.Wheredoesthe cellget its rawmaterials
from?Whatsortof fueldoesit requireto make
the product?Whatdepartment
exportsthe goods?Whatdepartment
takescareof the garbageandwastein the
factory?Didyou knowthatthiscelllactoryalsorecyclesmanyof its by-producis?
you'llneedto determine
Of course,beforeyou go aboulanswering
all of thesequestions,
whatproductthis
fantasticfactoryproduces.We knowthatthereare manytypesof cellsin the body,andthatall cellswith a
nucleushavechromosomes.
Withinthe chromosomes
arethe codesfor allthe proteinsneededto maintainthe
body.Whatdoeseachchromosome
contain?DNA.Whatis thejob of DNA?To givedirectionfor makingproteins.
Thus,the principalproductof ourfactoryis protein.
So, if we wereto giveDNAa job titlein ourtaetory,it wouldbe thatof Director.
In thefollowingactivity,youwill be givena description
of lhe partsof the cell.As you readeachdescription,
keep
the imageof the "cellas a factory"in mind.Youwill be askedto determine
whichorganelles
areessentialforeach
"department"
of thefactory.
ACTIVITYl: THE PARTSOF THECELLAND THEIRFUNCTIONS
No chemicalapparatusin theworldcan matchthe eukaryotic
cellfor the sheernumberof chemicalreactions
that
occurin sucha smallspace.However,manyof thesereactionsare incompatible.
Forexample,a starchmolecule
can be synthesized
by somereactionsanddegradedby others.Thus,a cellhasseparatesub-unils,called
organelles,
whichphysically
separatechemicalreactions
withinthe cell.
Followingis a description
of eachsub-unitof the cell.Afterreadingeachdescription,
whichof the
determine
(listedbelow)thatpartol the cellwouldworkin. Forinstance,
1actory"departments
the nucleuswouldbe the
Officeof the Director,
whilethe nuclearmembrane
wouldbe the Securityand Doorman,
sinceit separatesthe
nuclearmaterialfromotherpartsof the cell,andonlyallowsthe propermaterialwithin
the "officeof the director."
Keepin mindthatorganelles
canbelonglo morethanonedepartment.
Onceyou havedetermined
whichdepartmentthe organelles
belongto, explain(eitherverbally,and/orin writtenform,as directedby yourteacher)the
reasoningbehindyouranswer.
Department(s)
Officeof the Director
Production
WasteTreatmentand Recycling
Securityand Doorman
Storage
Fueland Energy
Transportation
Packaging
Receiving
Maintenance
A.
NUCLEUS:
The nucleusis the controlcenterfor all cellactivity.The nucleuscontainshereditary
instructions
(DNA)andothermolecules
thatare involvedin howthe instructions
are read,modifiedanddispersed.
B.
NUCLEARMEMBRANE:
The nuclearmembrane
separates
the nuclearmaterialfrom
otherpartsof lhe cell.
c.
NUCLEOLUS:
Thenucleolus
is a thickkindof protoplasm
foundin the nucleus.
Thenucleolus
carriesout
production
andassemblyof ribosomes.
D.
CHROMOSOMES/CHROMATIN:
Chromosomes
containthe DNAthatcodesfor protein.Chromatinis
composedof thread-like
sirandsof geneticmaterial.Duringcelldivision,chromatincondensesintorodshapedbodiescalledchromosomes.
E,
RIBOSOMES:Ribosomes
arethe "workbenches"
for proteinsynthesis;
newpolypeptide
chains,as coded
for by DNA,are constructed
ai theirsurface.
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F.
RETICULUM:
Thesmoothendoplasmic
reticulumcurvesthroughthe cytoplasm
SMOOTHENDOPLASMIC
pipelines.
to passthroughthe cytoplasm,
wherethey
likeinterconnecting
These"pipelines"
allowmaterials
and,thus,
are synthesized
and/or'treated"
andthensenton theirway.ThesmoothER lacksribosomes
proteins.However,it is the majorsiteof lipidsynthesisin manycells;in musclecells,
doesnotsynthesize
the smoothER cansynthesize
steroids,metabolize
carbohydrates
andstorecalcium;in livercells,the
in developing
seedsand animal
smoothERcandetoxifymanypoisons.ThesmoothER is highlydeveloped
cellsthatsecretesteroidhormones.
G.
ROUGHENDOPLASMIC
RETICULUM:
TheroughER is thesameas thesmoothER,exceptthatit is
wherethey
Thus,likethe smoothER,materialscanpassthroughthe cytoplasm,
studdedwith ribosomes.
those
are synthesized
andlor"treated"andthensenton theirway;becauseit is studdedwith ribosomes,
To enterthe roughER,the proteinchainsmust
materialsare usuallyproteinchainsdestinedfor secretion.
havea specificsequenceof aminoacids;thosewithoutthissequencedo notenterthe roughER and,
poolof proteins.RoughER is especially
instead,jointhe cytoplasmic
abundantin secretorycells,suchas
pancreatic
cellsthatproduceandsecretedigestiveenzymes,and in immatureeggcellsthatgrowrapidlyin
size(suchas frog andamphibian
eggs).
H.
The
MITOCHONDRIA:
Mitochondria
organelles
thatarecentersfor cellrespiration.
aredoublemembraned
mitochondria
carryoutthe chemicalreactions
that releaseenergystoredin carbohydrates
to formmolecules
Forthis reason,the mitochondria
suchas ATP,whichprovidesenergyto drivea varietyof cellularreactions.
needoxygen;
are oftencalledthe "powerhouses"
of the cell.In orderto performtheirfunction,mitochondria
to releaseenergy.A eukaryotic
thus,whenyou breathein,you aretakingin oxygenfor yourmitochondria
Animalcellsgenerallyhavemore
celltypicallycontainsanywhere
froma dozento a thousandmitochondria.
mitochondria
thanplantcellsdo. Mitochondria
areabundantin musclecells,partsof nervecellsand near
Whatdo all of thesetypesof cells
the sudaceof cellsthatspecialize
in absorbing
or secretingsubstances.
havein common?Theyall havehighenergydemands.
reticuGOLGICOMPLEX:TheGolgicomplexreceivesmolecules
of proteinand lipidsfromendoplasmic
lum.Actingas a packagingandshippingfactory,it formsa membrane
aroundthe proteins,hormones,
enzymesandotherproteinsfor "export"to the properdestination.
J.
LYSOSOMES:Lysosomes
are roundedorganelles
thatbudfromthe edgesof the Golgibodies.Lysosomes
candegradeorganelles
thatarewornoutor thathaveservedtheirfunction;theycan alsodestroybacteria
containenzymesthatcausethe digestionof
andforeignparticles,andbreakdownold cellparts.Lysosomes
proteins,polysaccharides,
nucleicacidandsomelipids.Whenthe celltakesin theselargemolecules,
the
molecules
in
lysosomes
breakthemintosmallermolecules.
Forexample,whencholesterol
aretransported
whichbindat the surfaceof cells.A vesiclethenformsaround
the blood,theyjoinwithothersubstances
enzymesbreakdownthe complexandfreethe cholesterol,
them.Whenthisvesiclefuseswitha lysosome,
whichbecomesavailablefor cellularuse.
K.
VACUOLES:Vacuolesare membrane
structures
thatcontainfood,wateror waste.
L.
from
MICROTUBULES:
Microtubules
are straight,hollowrods.Thewallof eachhollowtubeis constructed
tubularproteins
calledtubulins.
Themicrotubules
helpto shapeandsupportthecell.
M.
MICROFILAMENTS:
Microfilaments
of actinand myosin.
aresolidrods.Theyarebuiltfrommolecules
Microfilaments
Alongwiththe restof the cytoskeleton,
are bestknownfor theirpartin musclecontraction.
microfilaments
helpto supportandshapethe cell.
N.
CENTRIOLES:
Cenlriolesaretwo structures
in the centerof animalcells,composedof ninetripletmicrotubulesin a ring.Centrioles
helporganizemicrotubule
assemblyduringcelldivision.Centrioles
arethe centers
in animalcells
of spindleformation
duringcelldivision.
o.
PLASMAMEMBRANE:The plasmamembrane
separates
the cell'sinternalreactionsandstructures
from
(and
movingintoandoutof a cell.Plasmamembranes
the environment,
and regulates
the substances
membranes
manycellorganelles)
molecules.
Scientists
surrounding
consistof a bi-layerof phospholipid
modelin 1972.ltstatesthatthe plasma
JonathanSingerand GarthNicolsonproposedthefluid-mosaic
membranebehaveslikea thinlayerof fluidcoveringthe cellsurface.The phospholipid
moleculesmove
Thereare proteinsscattered
or mosaic.The
aboutlaterally.
throughthe membrane
as in a patchwork
proteinsare likeicebergsfloatingin a lipidsea.
The hydrophilic
headsof the phospholipids
facetowardthe insideandoutsideof the cell.Thephospholipid
headshelpto forma stableboundarybetweentwo aqueouscompartments.
The hydrophobic
tailsare
arrangedtowardthe insideof the membrane,
andareshieldedfromthewaterin andout of the cell.
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Withinthe plasmamembranes,
thereareseveraltypesof proteins(i.e.,the "product"producedby our
factory),eachservinga differentfunction.Theseinclude:
a) TRANSPORT
PROTEIN:A proteinthatspansthe membrane
andprovidesa channelacrossthe membranefor passingparticular
ions.
b) ENZYMEPROTEIN:A proteinbuiltintothe membrane
maybe an enzymewithits activesiteexposedto
substances
in the cytoplasm.
In manycasesthereis a groupof organizedenzymesworkingtogether.
proteinexposedto the outsideof the
c) PROTEINS
AS RECEPTOR
SITES:Theportionof a membrane
cell,whichhasa bindingsitewitha specificshapethatmatchesthe shapeof a chemicalmessenger,
suchas a hormone.
proteinsof adjacentcellsmayadheretogether.
d) CELLADHESIONPROTEIN:Membrane
e) CYTOSKELETON
PROTEIN:Actinmicrofilaments
maybe bondedto membrane
of the cytoskeleton
proteins.Theseaid in maintaining
cellshape.
ACTIVITYll: IDENTIFYING
THE PARTSOF THECELL
Rereadthe descriptions
of the cellstructures
in the previoussection.As you readabouteachstructure,referto
the numbereddrawingon page51 of thisguide.Matchthe numbershownnextto eachstructurein the diagram
to the nameof thatstructure,
below.Recordyouranswersin the appropriate
spacesbelow.Then,usingthe
Velcroattachedto eachpieceof the manipulative,
positionandattachthe structuredescribedontothe proper
placeon the cellbase.
Nucleuswithnuclearmembrane
Mitochondria
Chromosomes/Chromatin
Lysosomes
Nucleolus
Golgicomplex
Ribosomes
Vacuole(withlysosomes)
Smoothendoplasmic
reticulum
Microtubules
Roughendoplasmic
reticulum
Microfilaments
Plasmamembrane
Centrioles
ACTIVITYIII: USINGTHE MANIPULATIVES
TO ILLUSTRATE
CELLULARPROCESSES
lf necessary,
removeall of the organelles
fromthe cellbase.Then,placethe appropriate
organelles
usedin each
of the lifeprocessesdescribedbelowontothe cellbase.As you do this,explain(eitherverbally,to yourpanner,
you placedon the cellbasework,both
and/orin writtenform,as directedby yourteacher)howthe cellorganelles
individually
andtogether,to carryoutthe lifeprocessdescribed.
1.
NUTRITION:Foodmolecules
are necessary
to supplybothenergyandbuildingmaterialsin the cell.The
takingin of foodby the cellmembraneis calledphagocytosis.
2.
DIGESTION:Foodsare brokendownintosimplerformsin the cell.Enzymeproteinsspeedup those
reactions.
3.
ABSORPTION:
A celltakesin water,foodmolecules,
ionsandothernecessarymaterials
fromthe environment.The plasmamembraneis an essentialplayerin the controlofthesemolecules
and ions.The membraneproteinsfunctionas activeandfacilitated
transportfor materials
thatenterthe cell.
4.
BIOSYNTHESIS:
A cellorganizesmanyorganicsubstances
suchas carbohydrates,
fatsandproteins.
process.Theseincludethe nucleus,mitochondria,
Manyorganelles
are involvedin the biosynihesis
ribosomes,ERs,Golgicomplexandvacuoles.
5.
RESPIRATION:
Respiration
is the releaseof chemicalenergywhenthe bondsof cefiainorganicmolecules,
glucose,are broken.Theenergyis usedby all of the organelles
especially
in the cell.Theprotoplasm
and
mitochondria
arecentersfor cellularrespiration.
In mostcells,oxygenis usedfor cellularrespiration,
while
carbondioxideis usuallya wasteby-product.
Thesegasesareexchanged
acrossthe veryimportantplasma
membrane'
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EXCRETION:Wastematerialsof cellactivityare passedfromthe cellto the environmenl
by exocytosis.
Duringexocytosis
vesiclesfusewiththe plasmamembrane
anddumptheircontentsoutsideof the cell.
7.
SECRETION:Certaincellssynthesize
molecules
When
of substances
suchas vitaminsand hormones.
secretedout of the cell,thesesubstances
atfectothercellsandact as a communication
systemfor the cells.
Manyorganelles,
includingthe chromosomes,
ribosomes,
mitochondria,
ERs,Golgicomplexandvacuoles,
are involvedin the production
of hormones.
RESPONSE:Cellactivitiesmaychangein responseto stimulifromthe environment,
suchas heat,light,
pressureor chemicals.
The hormonereceptorproteinis involvedin accepting
from
the chemicalmessages
othercells.
L
REPRODUCTION:
Cellsdividefromtimeto time.Manyorganelles,
including
the centrioles
thatproduce
spindles,
aidin thisdivision.
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