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Animalcules and Beasties

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Animalcules and Beasties InsideInside thethe DynamicDynamic CellCell ChaptersChapters 44 && 55 AnimalculesAnimalcules andand BeastiesBeasties VanVan LeeuwenhoekLeeuwenhoek waswas thethe firstfirst toto describedescribe smallsmall organismsorganisms seenseen throughthrough aa microscope,microscope, whichwhich hehe calledcalled animalculesanimalcules andand beastiesbeasties HookeHooke waswas thethe firstfirst toto sketchsketch andand namename cellscells WeWe havehave asas manymany asas 100100 trilliontrillion cellscells inin ourour body!body! TheThe CellCell TheoryTheory EmergesEmerges InIn 1839,1839, SchleidenSchleiden andand SchwannSchwann proposedproposed thethe basicbasic conceptsconcepts ofof thethe modernmodern cellcell theorytheory AllAll organismsorganisms consistsconsists ofof oneone oror moremore cellscells EachEach newnew cellcell arisesarises fromfrom divisiondivision ofof another,another, preexistingpreexisting cellcell TheThe BasicsBasics ofof CellCell StructureStructure AllAll cellscells havehave aa plasmaplasma membranemembrane andand cytoplasm,cytoplasm, andand allall startstart outout lifelife withwith DNADNA 22 mainmain typestypes ofof cellscells EukaryoticEukaryotic cellcell CellCell interiorinterior isis divideddivided intointo functionalfunctional compartments,compartments, includingincluding aa nucleusnucleus ProkaryoticProkaryotic cellcell Small,Small, simplesimple cellscells withoutwithout aa nucleusnucleus DNADNA inin nucleoidnucleoid regionregion AllAll CellsCells HaveHave ThreeThree ThingsThings InIn CommonCommon PlasmaPlasma membranemembrane ControlsControls substancessubstances passingpassing inin andand outout ofof thethe cellcell DNADNA containingcontaining regionregion NucleusNucleus inin eukaryoticeukaryotic cellscells NucleoidNucleoid regionregion inin prokaryoticprokaryotic cellscells CytoplasmCytoplasm AA semifluidsemifluid mixturemixture containingcontaining cellcell componentscomponents Organisms from the domains Bacteria and Archaea – Prokaryotic cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. capsule gel-like coating outside the cell wall nucleoid location of the bacterial chromosome ribosome site of protein synthesis plasma membrane sheet that surrounds the cytoplasm and regulates fimbriae entrance and exit of molecules hairlike bristles that allow cell wall adhesion structure that provides support to surfaces and shapes the cell cytoplasm semifluid solution surrounded by the plasma membrane; conjugation pilus contains nucleoid and elongated, hollow ribosomes appendage used to transfer DNA to other cells flagellum rotating filament that propels the cell VisualVisual SummarySummary ofof EukaryoticEukaryotic CellsCells –– PlantPlant CellCell VisualVisual SummarySummary ofof EukaryoticEukaryotic CellsCells –– AnimalAnimal CellCell OrganizationOrganization ofof CellCell MembranesMembranes TheThe basicbasic structurestructure ofof allall cellcell membranesmembranes isis thethe lipidlipid bilayerbilayer withwith manymany embeddedembedded proteinsproteins AA membranemembrane isis aa continuous,continuous, selectivelyselectively permeablepermeable barrierbarrier TheThe LipidLipid BilayerBilayer PhospholipidPhospholipid moleculesmolecules inin thethe plasmaplasma membranemembrane havehave twotwo partsparts HydrophilicHydrophilic headsheads interactinteract withwith waterwater moleculesmolecules HydrophobicHydrophobic tailstails interactinteract withwith eacheach other,other, formingforming aa barrierbarrier toto hydrophilichydrophilic moleculesmolecules BasicBasic StructureStructure ofof CellCell MembranesMembranes Animation:Animation: LipidLipid bilayerbilayer organizationorganization http://www.youtube.com/v/ULR79TiUj80 TheThe FluidFluid MosaicMosaic ModelModel FluidFluid mosaicmosaic modelmodel DescribesDescribes thethe organizationorganization ofof cellcell membranesmembranes PhospholipidsPhospholipids driftdrift andand movemove likelike aa fluidfluid TheThe bilayerbilayer isis aa mosaicmosaic mixturemixture ofof phospholipids,phospholipids, steroids,steroids, proteins,proteins, andand otherother moleculesmolecules MembraneMembrane ProteinsProteins CellCell membranemembrane functionfunction beginsbegins withwith thethe manymany proteinsproteins associatedassociated withwith thethe lipidlipid bilayerbilayer MembraneMembrane ProteinsProteins EachEach typetype ofof proteinprotein inin aa membranemembrane hashas aa specialspecial functionfunction RecognitionRecognition proteinsproteins ReceptorReceptor proteinsproteins EnzymesEnzymes TransportTransport proteinsproteins (active(active andand passive)passive) JunctionJunction proteinsproteins CellCell membranes:membranes: animation!animation! http://www.youtube.com/v/GW0lqf4Fqpg CellCell TransportTransport IonsIons andand moleculesmolecules tendtend toto movemove fromfrom oneone regionregion toto another,another, inin responseresponse toto gradientsgradients ConcentrationConcentration gradientgradient TheThe differencedifference inin concentrationconcentration (#(# moleculesmolecules inin fluid)fluid) betweenbetween twotwo adjacentadjacent regionsregions MoleculesMolecules movemove fromfrom aa regionregion ofof higherhigher concentrationconcentration toto oneone ofof lowerlower concentrationconcentration TheThe cellcell membranemembrane isis selectivelyselectively permeablepermeable TheThe SelectivelySelectively PermeablePermeable NatureNature ofof CellCell MembranesMembranes 33 WaysWays ToTo EnterEnter thethe MembraneMembrane PassivePassive TransportTransport –– higherhigher toto lowerlower concentrations,concentrations, nono energyenergy neededneeded DiffusionDiffusion FacilitatedFacilitated diffusiondiffusion ActiveActive TransportTransport –– lowerlower toto higherhigher concentration,concentration, requiresrequires energyenergy BulkBulk TransportTransport –– independentindependent ofof gradients,gradients, requiresrequires energy,energy, largelarge moleculesmolecules ExamplesExamples ofof DiffusionDiffusion ActiveActive Transport:Transport: CalciumCalcium PumpPump http://www.youtube.com/v/STzOiRqzzL4 Membrane-CrossingMembrane-Crossing MechanismsMechanisms Bulk Transport BulkBulk TransportTransport -- EndocytosisEndocytosis andand ExocytosisExocytosis VesiclesVesicles taketake substancessubstances inin oror outout ofof thethe cellcell http://www.youtube.com/v/HndmASfmI8Y ExocytosisExocytosis –– outout ofof cellcell EndocytosisEndocytosis –– intointo cellcell http://www.youtube.com/watch?v =U9pvm_4-bHg&feature= player_embedded WhichWhich WayWay WillWill WaterWater Move?Move? WaterWater diffusesdiffuses acrossacross cellcell membranesmembranes byby osmosisosmosis TheThe movementmovement ofof waterwater downdown itsits concentrationconcentration gradientgradient –– fromfrom aa regionregion ofof lowerlower solutesolute concentrationconcentration toto aa regionregion ofof higherhigher solutesolute concentrationconcentration OsmosisOsmosis isis drivendriven byby tonicitytonicity TonicityTonicity TheThe relativerelative concentrationsconcentrations ofof solutessolutes inin twotwo fluidsfluids separatedseparated byby aa selectivelyselectively permeablepermeable membranemembrane TonicityTonicity WaterWater movesmoves fromfrom aa regionregion ofof lowerlower solutesolute concentrationconcentration toto aa regionregion ofof higherhigher solutesolute concentrationconcentration EukaryoticEukaryotic CellsCells –– aa closercloser looklook EukaryoticEukaryotic organismsorganisms PlantsPlants AnimalsAnimals ProtistansProtistans FungiFungi EukaryoticEukaryotic (“true(“true nucleus”)nucleus”) cellscells carrycarry outout muchmuch ofof theirtheir metabolismmetabolism insideinside membrane-membrane- enclosedenclosed organellesorganelles OrganelleOrganelle AA structurestructure thatthat carriescarries outout aa specializedspecialized functionfunction withinwithin aa cellcell OrganellesOrganelles ofof EukaryoticEukaryotic CellsCells 4 categories of organelles: 1. Nucleus and ribosomes 2. Endomembrane system 3. Energy-related 4. Cytoskeleton 1.1. NucleusNucleus && RibosomesRibosomes TheThe nucleusnucleus keepskeeps eukaryoticeukaryotic DNADNA awayaway fromfrom potentiallypotentially damagingdamaging reactionsreactions inin thethe cytoplasmcytoplasm TheThe nuclearnuclear envelopeenvelope controlscontrols whenwhen DNADNA isis accessedaccessed cytoplasm NucleusNucleus nucleus plasma membrane nuclear envelope nucleoplasm nucleolus chromatin TheThe NuclearNuclear EnvelopeEnvelope NuclearNuclear envelopeenvelope TwoTwo lipidlipid bilayersbilayers pressedpressed togethertogether asas aa singlesingle membranemembrane surroundingsurrounding thethe nucleusnucleus OuterOuter bilayerbilayer isis continuouscontinuous withwith thethe ERER NuclearNuclear porespores allowallow certaincertain substancessubstances toto passpass throughthrough thethe membranemembrane one of two lipid bilayers (facing nucleoplasm) nuclear pore (protein complex one of two lipid bilayers NUCLEAR that spans both lipid bilayers) (facing nucleoplasm) ENVELOPE TheThe NucleoplasmNucleoplasm andand NucleolusNucleolus NucleoplasmNucleoplasm ViscousViscous fluidfluid insideinside thethe nuclearnuclear envelope,envelope, similarsimilar toto cytoplasmcytoplasm NucleolusNucleolus AA densedense regionregion inin thethe nucleusnucleus wherewhere subunitssubunits ofof ribosomesribosomes areare assembledassembled fromfrom proteinsproteins andand RNARNA • RibosomesRibosomes helphelp inin makingmaking proteins!proteins!
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