Organelle

Introduction

Theorganellesofanimalcellsandplantcells(2photos)

Theorganellesaredividedinto:mitochondria;Chloroplast;endoplasmicreticulum;Golgiapparatus;lysosome;vacuole,ribosome,centrosome.Amongthem,chloroplastsonlyexistinplantcells,vacuolesonlyexistinplantcellsandloweranimals,andcentrosomesonlyexistinlowerplantcellsandanimalcells.Inaddition,inthemiddleschoolstage,thenucleusisnotrecognizedasanorganelle,whileintheuniversitystage,thenucleusisconsideredtobethelargestandmostimportantorganelleinthecell.

Organellesaretinystructureswithspecificstructuralfunctionssuspendedinthecytoplasmicmatrix.Thenucleusisthemostimportantpartofthebasicstructureofeukaryoticcells,controllingheredityandmetabolism.Thelargestvolumeinmatureplantcellsisthevacuole.Thelargestareaorganelleinanimalcellsistheendoplasmicreticulum.

Endoplasmicreticulum

Introduction

Theendoplasmicreticulumisanetworkstructureconnectedbymembranes,asinglelayerofmembrane,whichistheprocessingofintracellularproteins,and"Workshop"forlipidsynthesis.Itcanbedividedintoslipperyendoplasmicreticulumandroughendoplasmicreticulum,roughendoplasmicreticulumprocessingproteins,andslipperyendoplasmicreticulumsyntheticlipids.Eukaryoticanimalandplantcellsallcontainendoplasmicreticulum.

Monolayermembrane:Generally,eukaryoticcellshaveendoplasmicreticulum,butafewhighlydifferentiatedeukaryoticcells(suchashumanmatureredbloodcells)andprokaryoticcellsdonothaveendoplasmicreticulum.Undertheelectronmicroscope,itcanbeseenthattheendoplasmicreticulumisacomplexintimalstructure,whichiscomposedofaflatsac-likecavityortubesurroundedbyasinglelayerofmembrane.Theselumensareconnectedtoeachotherandthenuclearenvelope.Through.Theendoplasmicreticulumisdividedintotwotypesaccordingtoitsfunction:roughERandsmoothER.Theparticlesattachedtotheroughendoplasmicreticulumareribosomes,whicharethesiteofproteinsynthesis.Therefore,themainfunctionoftheroughendoplasmicreticulumistosynthesizesecretedproteins,membraneproteins,andproteinsintheendoplasmicreticulumandlysosomes.Theglycosylationmodification,foldingandassemblyofthesynthesizedproteinalsooccurintheendoplasmicreticulum.Thesecondistoparticipateintheproductionofmoremembranes.Therearenoribosomesonthesmoothendoplasmicreticulum,butmanyactiveenzymesareembeddedinthemembrane.Themainfunctionofsmoothendoplasmicreticulumistosynthesizelipids,includingfats,phospholipidsandsterols.

Function

Theendoplasmicreticulumreferstoaseriesofcystsandtubulesinthecytoplasmthatcommunicatewitheachothertoformaductsystemisolatedfromthecytoplasmicmatrix.Itisacytoplasmicmembranesystem.Theoutsideisconnectedwiththecellmembrane,andtheinsideisconnectedwiththenuclearporecomplex.Itconnectsthevariousstructuresinthecellintoawhole,andhastheroleofundertakingthetransportationofintracellularmaterial.

Theendoplasmicreticulumcaneffectivelyincreasethemembraneareainthecell,andtheendoplasmicreticulumcanorganicallyconnectthevariousstructuresinthecellintoawhole.Theratioofthesetwotypesofendoplasmicreticulumiscloselyrelatedtothefunctionofcells.Forexample,theroughendoplasmicreticulumisparticularlydevelopedinpancreaticcells,whichisrelatedtothesynthesisandsecretionoflargeamountsofpancreaticdigestiveenzymeproteinsinthetestesandovaries.Amongcellsthatsecretesexhormones,theslipperyendoplasmicreticulumisparticularlydeveloped,whichisrelatedtothesynthesisandsecretionofsexhormones.Thedegreeofdevelopmentoftheendoplasmicreticuluminthecytoplasmispositivelycorrelatedwiththevigorousdegreeoflifeactivities.

Theendoplasmicreticulumandribosomesarethe"workshops"forintracellularproteinsynthesisandprocessingandlipidsynthesis.

Classification

Accordingtowhetherribosomesareattachedtotheendoplasmicreticulummembrane,theendoplasmicreticulumisdividedintosmoothendoplasmicreticulum(alsocalledsmoothendoplasmicreticulum)(SmoothER)androughER(roughER).Therearenoribosomesattachedtotheslipperyendoplasmicreticulum.Thistypeofendoplasmicreticulumoccupiesasmallproportion,butitsfunctionismorecomplicated.Itisrelatedtolipidandcarbohydratemetabolism.Ribosomesareattachedtotheroughendoplasmicreticulum,andtheirarrangementismoreregularthanthatofthesmoothendoplasmicreticulum.Thefunctionismainlyrelatedtoproteinsynthesis.Undertheelectronmicroscope,theendoplasmicreticulumisaflatsac(pool)andtubulescomposedofunitmembranes,andtheyareconnectedtoeachother.Theroughendoplasmicreticulumiscomposedofflatsacsandribosomesattachedtoitsoutersurface.Thesurfaceisrough.Theroughendoplasmicreticulumaroundthenucleuscancommunicatewiththeouterlayerofthenuclearmembrane.Themainfunctionistosynthesizeandsecreteproteins.Thesmoothsurfaceoftheendoplasmicreticulumhasnoribosomesattachedtoit.Itismainlyinvolvedinthesynthesisandtransportofsteroidsandlipids,glucosemetabolismandtheinactivationofhormones.

Ribosome

Introduction

Ribosomeisamembranelessstructure,dividedintoattachedribosomesandfreeribosomes.TheaminoacidsynthesisproteinismadeofrRNAandribose.Thetinyparticlesmadeofnucleoproteinaretheplacewhereproteinissynthesized,andallcellscontainribosomes.

Ribosomeisakindofribonucleoproteinparticleinthecell.ItismainlycomposedofRNA(rRNA)andprotein.ItsonlyfunctionistosynthesizeaminoacidsintoproteinpolypeptidechainsaccordingtotheinstructionsofmRNA.Therefore,ribosomesareintracellularMolecularmachineryforproteinsynthesis.Theribosomehasnomembranestructureandismainlycomposedofprotein(40%)andRNA(60%).Ribosomesaredividedintotwotypesaccordingtothesedimentationcoefficient,onetype(70S)existsinprokaryotessuchasbacteria,andtheothertype(80S)existsinthecytoplasmofeukaryoticcells.Someofthemfloatinthecells,andsomeareclusteredtogether.

Theribosomeisthesiteofproteinsynthesis.ItiscomposedofrRNAandprotein.Theproteinisonthesurface(calledthelargesubunit),andtherRNAisinside(calledthesmallsubunit).Keycombination.Theribosomeisacollectionofmultipleenzymes,andtherearemultipleactivecentersthatsharethefunctionofproteinsynthesis.Andeachactivecenteriscomposedofagroupofspecialproteins,andeachenzymeorproteinhascatalyticactivityonlyintheoverallstructure.

Thenumberofribosomespercellcanreachmillions,mostofwhichareinthecytosol,andsomeareinmitochondriaandchloroplasts.Freeribosomessynthesizeproteinsretainedinthecytoplasm,suchasstructuralproteinsinthemembrane;whileribosomesattachedtotheendoplasmicreticulumsynthesizeproteinssecretedtotheoutsideofthecell,andthentransportthemtotheS-ERaftersynthesistoformsecretoryvesicles,whicharetransportedtotheGolgiapparatus.Golgibodyprocessinganddischarge.

Classification

Accordingtothelocationofribosomes,itcanbedividedintothreetypes:cytoplasmicribosomes,mitochondrialribosomes,Chloroplastribosomes.

Accordingtothebiologicaltype,itcanbedividedintotwotypes:eukaryoticribosomesandprokaryoticribosomes.

Theribosomesofprokaryoticcellsaresmall,withasedimentationcoefficientof70Sandarelativemolecularmassof2.5x103kDa,consistingoftwosubunitsof50Sand30S;whiletheribosomesofeukaryoticcellsarelargerandsedimentThecoefficientis80S,therelativemolecularmassis3.9～4.5x103kDa,anditiscomposedoftwosubunits,60Sand40S.ThetypicalprokaryoticEscherichiacoliribosomeiscomposedof50Slargesubunitand30Ssmallsubunit.Inanintactribosome,rRNAaccountsforabout2/3,andproteinisabout1/3.The50Slargesubunitcontains34polypeptidechainsandtwoRNAmolecules.ThesedimentationcoefficientofrRNAwithlargerelativemolecularmassis23S,andtherelativemolecularmassThesmallrRNAis5S.The30Ssmallsubunitcontains21polypeptidechainsanda16SrRNAmolecule.

Ineukaryoticcells,ribosomescanbefreedinthecytoplasmduringproteinsynthesis,whichiscalledfreeribosome.Itcanalsobeattachedtothesurfaceoftheendoplasmicreticulum,calledparamembraneribosomesorattachedribosomes.ParticipatingintheformationofRER,calledfixedribosomeorparamembraneribosome,isthefreeribosomefollowedbythecone-shapedpartofthelargesubunitandthemembrane.Theribosomesdistributedinthemitochondriaaresmallerthannormalribosomes,about55S(35Sand25Slargeandsmallsubunits),calledorganellesormitochondrialnucleosomes.Allnaive,undifferentiatedcells,embryoniccells,culturedcells,andtumorcellsgrowrapidlyandgenerallyhavealargenumberoffreeribosomesinthecytoplasm.Eukaryoticcellscontainmoreribosomes,withanaverageof10⁶～10⁷percell,whileprokaryoticcellshavefewerribosomespercellwithanaverageofonly1.5×10⁴～1.8×10⁴pieces.Thesedimentationcoefficientofeukaryoticribosomesis80S,thelargesubunitis60S,andthesmallsubunitis40S.Inthelargesubunits,thereareabout49proteins,andtherearethreeotherrRNAs:28SrRNA,5SrRNA,and5.8SrRNA.Thesmallsubunitcontainsabout33proteins,an18SrRNA.

Nomatterwhatkindofribosome,whenperformingafunction,thatis,whenperformingproteinsynthesis,3to5ordozensormoreareoftenaggregatedandcombinedwithmRNA.Thebasegrooveiscombinedwiththelargesubunitstoformastring,calledpolyribosomes(freepolyribosomesandfixedpolyribosomes),PolyribosomeorPolysome.ThelengthofmRNAdeterminesthenumberofpolyribosomes,whichcanbearrangedintothreads,beads,etc.Polyribosomesarefunctionalgroupsthatsynthesizeproteins.Atthistime,eachribosomeusesthemRNAcodeasatemplatetotranslateintotheaminoacidsequenceoftheprotein.Inlivingcells,thelargeandsmallsubunitsofribosomes,monoribosomesandpolyribosomesareinadynamicequilibriumofcontinuousdepolymerizationandpolymerization,whichchangeswithfunction.Theexecutivefunctionispolyribosomes,andthefunctionsarecompleted.Afterdisaggregationintolargeandsmallsubunits.

Accordingtothedistributioninthecell,itcanbedividedintofreeribosomesandattachedribosomes.Freeribosomesarelocatedinthecytoplasmicmatrixandmainlysynthesizeintracellularproteinsandaresecretedinthecell;attachedribosomesaremainlyattachedtotheroughendoplasmicreticulum,responsibleforthesynthesisofforeigntransportproteins,andaresecretedoutsidethecell.

Golgiapparatus

Golgiapparatus(Golgicomplex)isalsoknownasGolgiapparatus,Golgiapparatus.Itisoneofthecomponentsoftheinnermembranesystemineukaryoticcells.ItwasfirstdiscoveredinnervecellsbysilverstainingmethodbyItaliancytologistGolgiin1898.Itisavesiclesystemcomposedofasmoothmask,whichconsistsofthreebasiccomponents:flatmembranevesicles(saccules),largevesicles(vacuoles),andsmallvesicles(vesicles).

Single-layermembrane,the"workshop"and"deliverystation"forreprocessing,sortingandpackagingproteinsfromtheendoplasmicreticulum.EukaryoticanimalandplantcellscontainGolgi,whichisfoundinanimalcells.Itisinvolvedintheformationofsecretionsandtheformationofcellwallsinplantcells.

TheGolgiapparatusplaysanimportantroleasatransportationhubinthesynthesisandtransportationofsecretedproteins.

ThestructureoftheGolgiapparatus(2photos)

iscomposedofaseriesofflatvesiclesandvesicles,whichsecretevigorouslycellsandaremoredeveloped.TheGolgiapparatusconfirmedundertheelectronmicroscopeareflatsacsandvesiclessurroundedbyasinglelayerofmembrane.Thepilesofsacsarenotconnectedtoeachotherliketheendoplasmicreticulum.ThereareonlyafewpilesofGolgiinacell,butnomorethanhundreds.

(1)Itistheplacewherecellsecretionsarefinallyprocessedandpackaged.Thesecretoryvesiclesaredischargedoutofthecellthroughefflux.

(2)Itcansynthesizepolysaccharides,suchasmucus,variousextracellularpolysaccharidesofplantcells.

(3)Lysosomesareformedafterfracture.

TheGolgiapparatusismainlya"workshop"and"deliverystation"forprocessing,classifyingandpackagingproteinsfromtheendoplasmicreticulum.

(Note:ThedirectionofvesicleproductionisthatthematuresurfaceofthecellmembraneorGolgibodyfacesthecellmembrane,andtheformingsurfacefacesthecytoplasm.)

Lysosome

Thelysosomeisasingle-layermembranestructure,whichisa"digestionworkshop".Itcontainsavarietyofhydrolyticenzymes,whichcanbreakdownaginganddamagedorganelles,swallowandkillinvadingvirusesorbacteria.Eukaryoticanimalandplantcellscontainlysozymes.body.

LysosomesareproducedbythebreakageoftheGolgiapparatus.Theyarevesiclesencapsulatedbyasinglelayerofmembrane.Thenumbercanbemoreorless,andthesizecanvary.Itcontainsmorethan60kindsofhydrolyzedpolysaccharides,phospholipids,nucleicacidsandproteins.Acidenzymes,someoftheseenzymesarewater-soluble,andsomeareboundtothemembrane.ThepHofthelysosomeisabout5,whichistheoptimumpHfortheenzymaticreaction.Accordingtothedifferentstagesoflysosomesthatcompletetheirphysiologicalfunctions,theycanberoughlydividedintoprimarylysosomes,secondarylysosomesandresidualbodies.

Thelysosomehastwofunctions:

Thefirstistofusewithfoodbubbles,digestthefoodorpathogenicbacteriaandotherlargeparticlesthatcellsswallowintobiologicalmacromolecules,residuesExcretionofcellsthroughefflux;

Second,intheprocessofcelldifferentiation,certainsenescentorganellesandbiologicalmacromoleculesfallintothelysosomeandaredigested.Thisisthebody’sneedtoreorganizeitself.

Mitochondria

Theshapeofmitochondriaisrod-shaped,whichisthemainplaceforcellstocarryoutaerobicrespiration.Enzymeattachmentsite).Mitochondriaarealsocalled"powerworkshops".About95%oftheenergyrequiredforcelllifeactivitiescomesfrommitochondria.Theycontainribosomes,whichcanproduceDNAandRNAandcanbeinheritedrelativelyindependently.Existinalleukaryoticcells(exceptanaerobicbacteriaandmatureredbloodcellsofmammals),animalandplantcellsallcontainmitochondria(exceptmatureredbloodcellsofmammals),whicharedistributedinplaceswheremetabolismisvigorousandbelongtosemi-autonomousorganelles.

Mitochondriahaveadouble-layermembranestructure,theoutermembraneisasmoothandcontinuousboundarymembrane;theinnermembraneisrepeatedlyextendedandfoldedintotheinternalspacetoformacristae.Theinnerandoutermembranesarenotconnected,formingamembranecavity.Underthelightmicroscope,themitochondriaaregranularorshortrod-shaped,withatransversediameterof0.2umto8um,andthesizeofbacteria.MitochondriaareanimportantpartofthecelltoproduceATP,andarethepowerfactoryorenergyconverterinthecell.Mitochondriaaresemi-autonomous.TherearecircularDNAmolecules,asmallamountofRNAand70Sribosomesinthecavity.Theycandifferentiateontheirown,butsomeproteinsarealsosynthesizedinthecytoplasm.

(Note:Anaerobicbiologicalwirelessmitochondria)Mitochondriaarethemainplacewherecellscarryoutaerobicrespiration,andtheyarethe"powerworkshop"ofcells.About95%oftheenergyrequiredforcelllifeactivitiescomesfrommitochondria

Therearemoremitochondriainthebreastmusclecellsofflyingbirdsthaninnon-flyingbirds.Athleteshavemoremitochondriainmusclecellsthanthosewholackexercise.Whencellsareculturedinvitro,therearemoremitochondriainnewlyborncellsthaninsenescentordiseasedcells.

Note:Cellscapableofaerobicrespirationdonotnecessarilycontainmitochondria,suchasbacteria(containingrespiratoryenzymes)

Mitochondriaarethemainplaceforaerobicrespiration,"cellpowerworkshop".

Chloroplast

Chloroplasthasadoublemembrane.Itistheorganellecontainedinthecellsofgreenplantsthatcancarryoutphotosynthesis,whichproducesoxygenandorganicmatter.Itisthe"nutrientmanufacturingworkshop"and"energyconversionstation"forplantcells.Thedouble-layermembraneisaflatellipsoidalorsphericalshape.ItcontainsribosomesthatcanproduceDNAandRNA,andisasemi-autonomousorganelle.

Note:1.Thecellscapableofphotosynthesisdonotnecessarilycontainchloroplasts,suchascyanobacteria(whichonlycontainchlorophyll);2.NotallplantcellscontainchloroplastsandareonlydistributedingreenplantsInthegreenorgans,suchasonionepidermalcells,roottipcellsandsoon.

Chloroplastsarecoloredbodies(asopposedtowhitebodies),whicharedevelopedfromplastidprecursorsstimulatedbylight.

Thechloroplastsofhigherplantsareshapedlikeconvexlenses,withadouble-layermembranestructure,andthereisnoconnectionbetweenthetwomembranes.Thereisacomplexlayeredmembranestructureinsidethechloroplast,whichissuspendedinthematrix.Theselayeredmembranesarealsocalledthylakoids.Thylakoidsarethestructuralunitsofthechloroplastinnermembranesystemandareaflatbag-likestructure.Thylakoidsareusuallydozensofstackedtogethertoformabasalgranule(grana).Thethylakoidmembranehasphotosyntheticpigmentsandanelectrontransportsystem.

Chloroplasts,whichareubiquitousingreenplantsandalgae,arethesitesofphotosynthesis.Atthesametime,chloroplastsalsohavetheirownuniquedouble-strandedcircularDNA,asmallamountofRNA,ribosomesandenzymesforproteinbiosynthesis,whichcansynthesizesomeoftheirnecessaryproteins.Therefore,thehypothesisofsymbiosisorigininchloroplastsisrecognizedbymanypeople.

Chloroplastsareorganellescontainedinthephotosynthesiscellsofgreenplants,andarethe"nutrientmanufacturingworkshop"and"energyconversionstation"forplantcells.

Centrosome

Introduction

Thecentrosomeisanimportantorganellewithoutmembranestructureincells,whichexistsinanimalandlowerplantcells.Eachcentrosomemainlycontainstwocentrioles.Itisthecenterofinternalactivityduringcelldivision.Highschool"Biology"described"centrosomesandcentrioles"asfollows:"Therearecentrosomesinanimalcellsandlowerplantcells.Itisalwayslocatedinthecytoplasmnearthenucleus,closetothecenterofthecell,soitiscalledthecenter.Itcanbeseenunderanelectronmicroscopethateachcentrosomecontainstwocentrioles,whicharearrangedperpendiculartoeachother.Thecentrosomeisrelatedtothemitosisofthecell.”Theauthorthinksthatthisdescriptionisnotveryprecise,andtherearethefollowingpointsItisdebatable:

Thecentrosomeisgenerallylocatedbesidethenucleus,inthecenteroftheGorkyarea.Beforecelldivision,thecentrosomecompletesitsself-replicationintotwo,andthenmovestothecellpolesrespectively;inthemetaphase,thetwocentrosomesmovetothecellpolesrespectively;inthelateandterminalphasesofcelldivision,theyareassignedtotwodaughtersasthecelldivides.Inthecell.Moreover,thecenterofmostanimalcellsisthenucleararea,andthecentrosomeisonlylocatedinthecenteroftheGolgiareaonthesideofthenucleus.

Therefore,itisnotscientifictonamethe"centrosome"as"located...closetothecenterofthecell".Itcanonlybesaidthat"thecentrosomeisusuallylocatedinthecytoplasmonthesideofthenucleus."

Compositionandvisibility

1.Discoveryandcomposition

Asearlyasthe19thcentury,VonBeneden(1876)observedthecentrioles(centrioles).Itcanbeseenthatcentriolesexistinpairsunderanopticalmicroscope.Whenthecentriolesaredividing,abrighterareacalledcentriolesappearsaroundthem.Thereisalsoacircleofdarkerstainedareasoutsidethecentrioles,whichtogetherarecalledcentrospheres.Thepairedcentriolesandtheirattachedcentrospheresarecollectivelycalledcentrosomes.

2.Visibility

Theultrastructureofcentriolescanbeseenundertheelectronmicroscope.Centriolesarepairsofcylindricalbodieswithalengthofabout0.3to0.5micronsandadiameterof0.15to0.20microns.Eachcentriolesiscomposedof27veryshortmicrotubules.Onthecrosssection,itcanbeseenthatthecylindricalwallofthecentriolesiscoiledintoaringstructureby9groupsoftripletmicrotubes.Althoughtheresolutionofanordinaryopticalmicroscopeis0.2microns,theexistenceofpairsofcentriolescanalreadybeseen.

Therefore,itcanbeseenunderanordinaryopticalmicroscopethateachcentrosomemainlycontainstwocentrioles.Andundertheelectronmicroscope,youcanalreadyseethefinerstructuressuchasthetriadcompositionofthecentrioles.

Centriolesandcelldivision

IntheSphaseoftheinterphase,twomutuallyperpendicularcentrioleshavereplicatedthemselvestoformtwopairsofcentrosomes.Intheearlystageofcelldivision,thetwopairsofcentrosomesmovetothepolesofthecellrespectively,andtheyareconnectedbygelledspindlefilaments.Inthemid-term,thepairedcentrioles(centrosomes)movetothepolesofthecell,andthespindlefilamentsinthecenterformaspindle.Inthelateandfinalstagesofdivision,thespindlefilamentsandspindlesgraduallybecomeunclear,andthecentrosomesthatarealreadyatthecellpolesarealsodistributedtothetwodaughtercellsasthecelldivides.

Duringcelldivision,thecentrosomealsoundergoescertainchangesinstructure.Thefirstistogrowsomeroundcorpusclesaroundthecentrioles.Eachroundcorpusclehasashortrodconnectedtoeachtripletmicrotubuleonthecentrioles.Therefore,infact,eachcentriolesareconnectedwithninepairsofcircularspindlefilaments,andthespindlefilamentsradiatetothesurroundingwiththecentrioles.Theradiatedspindlefilaments-starraysconstitutethestarsaroundthecentrioles.Thespindlefilaments(starrays)betweenthecentrosomespullthechromosomesandcausethechromosomestomove,sotheyarecalledchromosomalfilaments.

Therefore,thecentrosome(centrosome)participatesintheactivitiesofcelldivisionandisthecenterofinternalmovementduringcelldivision.Thatis,centriolesarerelatedtocelldivision,notjust"relatedtocellmitosis."However,thecentrosomewasdiscoveredduringmitosisandhasbeenstudiedmoreduringmitosis.

Tosumup,the"centrosomeandcentrioles"shouldbedescribedasfollows:"Therearecentrosomesinanimalcellsandlowerplantcells,whichareusuallylocatedinthecytoplasmonthesideofthenucleus.InopticalItcanbeseenunderthemicroscopethateachcentrosomemainlycontainstwocentrioles,whicharearrangedperpendiculartoeachother,andthecentrosomeisrelatedtocelldivision.”

Vacuole

Thereisoftenalargefluid-filledcentralvacuoleinmaturelivingplantcells,whichisformedbythefusionofsmallvacuolesduringcellgrowthanddevelopment.Yes,itisabubblefilledwithwatersurroundedbyasinglefilm.Vacuolescontainmetabolitessuchasinorganicsalts,aminoacids,sugarsandvariouspigments,andevencontaintoxiccompounds,andareinahypertonicstate,makingthecellsinastateofswellingandfullness.

Single-layermembrane,whichonlyexistsinplantcells,regulatestheenvironmentwithinthecellandistheorganelleforplantcellstomaintainfirmness.Containscellfluid,pigments(anthocyanins,etc.).

Note:Notallplantcells(suchasroottipmeristemcells)containlargevacuoles,onlymatureplantcells.

Organelleobservationmethod

Golgicomplexobservation

1.Lightmicroscopicsectionofguineapigspinalganglionstainedbysilverplatingmethod:nervecellsaretransportedinlargequantitiesduetosynthesisTheproteincontainsadevelopedendoplasmicreticulumandGolgicomplex.Observedunderalowmagnificationmicroscope,thepseudo-monopolarcellbodiesofthegangliaaredividedintogroupsbynervebundles.

2.Thebodyofnervecellsisroundoroval.

3.Convertedtohigh-powerobservation,theuncoloredcircularareainthecenterofthecellisthenucleus.

4.Therearedarkbrowngranularorirregularstrand-likestructuresaroundthenucleus,whichistheGolgicomplex.

ObservationofNisslbody

1.Toluidinebluestainedbovinespinalcordsmear,Nisslbodyistheroughendoplasmicreticulumunderlightmicroscope.

2.Observedatlowmagnification,thelargetrianglesandastrocytesstainedbluearethespinalcordanteriorhornnervecells,andthedarkerstainedsmallcellsareglialcells.

3.Convertedtohigh-powerobservation,itcanbeseenthatmanyblueparticlesornet-likestructuresinthecytoplasmofthespinalcordanteriorhornnervecellsareNisslbodies.

Centrosomeobservation

1.Iron-hematoxylinstainedhorseroundwormuterussection,underlowpowermicroscope,manyfertilizedeggcellscanbeseen.Thereareeggshellsoutsidethecells,andthecellsandeggshellsThecavitybetweeniscalledtheeggshellcavity.

2.Insomeeggcells,therearesmallroundparticlesnearthenucleus—centrioles,whichformacentrosomewiththesurroundingdensecytoplasm—centriospheres.

3.Convertedtohigh-powerobservation,itcanbeseenthattherearestar-shapedradiatingfilamentsorstarsontheperipheryofthecentralbody.

Extension

TheAmericancellbiologistK.R.Porterobservedtheinvitroculturedcellsfixedwithglutaraldehydewithahigh-penetrationhigh-pressureelectronmicroscope,onlytofindamicrobeamnetworkinthecellmatrix.Therefore,thematrixis​​dividedintotwoparts:①Themicrobeamnetwork,whichisdistributedthroughoutthecell,iscomposedofprotein-likemicrobeamfibers.②Awater-likecyberspace,inwhichavarietyofsmallmolecules,suchassugars,aminoacids,inorganicsalts,etc.,aredissolvedorsuspended.Theedgeofthemicrobeamnetworkisattachedtotheplasmamembraneofthecell,andisinterwovenwiththecytoskeletoncomponentssuchasmicrotubulesandmicrofilamentstoformanetworkframe,whichsupportsorganellessuchasendoplasmicreticulumandmitochondria.Freepolysomesaresuspendedattheintersectionsofthemicrobeamnetwork.Theentirecytoplasmpresentsacomplexstructuralorder.

Someonefirsttreatsthecellswithdetergenttoremovesolubleproteins,andthenpreparescellspecimensusingamodifiedwater-dryingmethod.Themicrobeamstructurecannotbeseenunderanelectronmicroscope.Ifitisnottreatedwithdetergents,amicrobeamnetworkwillappear.Therefore,whetherthemicrobeamnetworkreallyexistsisstilluncertain.