Cell Structure & Function

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Cell Structure & Function. Microscope History. Hooke’s (1665) drawings of cork. Early light microscope. Electron microscope. Microscopic Images. Paramecium. Light Micrograph. Scanning Electron Micrograph. Transmission Electron Micrograph. Scanning Electron Micrograph. Cell Theory. - PowerPoint PPT Presentation

Transcript of Cell Structure & Function

  • Cell Structure & Function

    Chapter 5

  • Microscope HistoryHookes (1665) drawings of corkEarly light microscopeElectron microscope

    Chapter 5

  • Microscopic ImagesParameciumLight MicrographScanning Electron MicrographTransmission Electron MicrographScanning Electron Micrograph

    Chapter 5

  • Cell TheoryAll living things are composed of one or more cellsCells are:Basic unit of structureBasic unit of functionAll cells come from preexisting cells

    Chapter 5

  • Basic Cell StructureAll cells possess a plasma membrane, cytoplasm, genetic materialPlasma membrane has phospholipid bilayer, embedded glycoproteinsIsolates cytoplasm from environmentRegulates molecular movement into and out of cellInteracts with other cells/environment

    Chapter 5

  • Amoeba

    Chapter 5

  • Relative Sizes100 m10 m1 m10 cm1 cm1 mm100 m10 m1 m100 nm10 nm1 nm0.1 nmEukaryotic CellsVirusProteinsAtoms

    Chapter 5

  • Cell TypesProkaryotic:Smaller, 15 mNo organellesNo nucleusDNA in circular loop Eukaryotic:Larger, 8100 mMembranous organellesNucleusDNA in linear chromosomes

    Chapter 5

  • Generalized ProkaryoteCapsuleCell WallPlasma MembraneCytosolNucleoid DNAFlagellumPlasmid DNA

    Chapter 5

  • Bacilli (1000x)

    Chapter 5

  • Eukaryotic CellsGenetic material - DNA, found in the nucleusCytoplasm everything else within the plasma membraneCytosol (the fluid part)WaterSaltsOrganic monomers and polymersOrganelles

    Chapter 5

  • Generalized Cell Animal CellPlant CellNucleusGolgiMitochondriaEndoplasmic ReticulumCentriolesChloroplasts

    Chapter 5

  • Generalized CellAnimal CellPlant CellNucleolusRibosomesCentral VacuoleSmooth E.R.Cell Wall

    Chapter 5

  • Control Structuresa. Nucleusa. Nucleus Structure:about 5 mm in diameterbound within the nuclear envelopecontains DNA complex (chromatin)Function:genes within DNA include instructions for production of proteins to control metabolism and other cell functions

    Chapter 5

  • The NucleusNucleolusPoresChromatin Threads (Chromosomes)Nuclear Envelope

    Chapter 5

  • ChromosomesNucleoliNucleusCell WallChromosomes

    Chapter 5

  • Control Structures b. Nuclear Envelope Structure:double membrane (two bilipid layers)nuclear lamina (protein network)between membrane layers (20-40 nm)perforated by pores (100 nm diameter)Function: stabilizes shape part of endomembrane system (transport)

    Chapter 5

  • Control Structuresc. NucleolusStructure:spherical region in nucleus composed of RNAFunction:packages ribosome subunits

    Chapter 5

  • Control Structures d. Ribosomes Structure:complexes of RNA and proteins composed of two subunitsFunction: (as either free or bound)free ribososmes make proteins that function in the cytoplasm bound (to ER) ribosomes make proteins destined for membranes or for export

    Chapter 5

  • Ribosomes

    Chapter 5

  • 2. Endomembrane Systema. ER (Endoplasmic Reticulum)Structure:continuous with outer membrane of nuclear envelope folded membrane networkFunction: (as either smooth or rough) rough ER (studded with ribosomes) makes proteins and membranes (grow in place)smooth ER makes lipids, phospholipids, and steroids

    Chapter 5

  • Rough vs. Smooth ER: TEMRough ERSmooth ERRibosomes

    Chapter 5

  • The Endoplasmic ReticulumRibosomesUnit MembraneVesicles forming

    Chapter 5

  • 2. Endomembrane System b. Golgi ApparatusStructure:stack of flattened membrane sacstwo faces cis receiving trans shippingFunction: receives molecules from ER for processingmolecules are modified and packaged as they are passed from sac to sac

    Chapter 5

  • The Golgi ComplexMaterial Received From ERMaterial Destined for ExportTEM

    Chapter 5

  • 2. Endomembrane System c. LysosomesStructure:Small membrane sacs made by GolgiVesicles contain hydrolytic enzymesFunction:Digest material engulfed by cellDigest and recycle damaged organelles

    Chapter 5

  • 2. Endomembrane System d. Central VacuolesStructure:Large, water-filled spaces (cell sap)Can take up over 90% of cell volumeEnclosed by tonoplast (single membrane)Function:Storage of pigments (red/blue), acids, salts, wastesMaintain cell pressure (turgor pressure)

    Chapter 5

  • Plant Wilting &the Central VacuoleVacuole (tonoplast)Cell WallCytoplasm Normal Plant CellIn Salt WaterSpace between Cell Wall and Cell MembraneNormalIn Salt Water

    Chapter 5

  • 2. Endomembrane System e. Contractile VacuoleStructure: Membrane-bounded sac Connected to canals radiating through cytoplasm Function:Control water balance in hypotonic environment.Fills with water entering cytoplasm (due to osmosis).Pumps water out of the cell by contractingRequires ATP

    Chapter 5

  • Contractile Vacuoles12Paramecium sp.Expelling Water to OutsideExpanded with Water

    Chapter 5

  • The Endomembrane SystemLysosomeVessicle for ExportGolgiEndoplasmic ReticulumVessicle Food Vacuole

    Chapter 5

  • 3. Other Membranous Organellesa. Plastidsa group of plant and algal membrane-bound organellesChromoplasts (chromo = color)pigment containing plastidsfruits, flowers, autumn leavesii. Amyloplasts (amylo = starch)colorless plastids that store starch found in roots and tubersChloroplasts (chloro = green)

    Chapter 5

  • The AmyloplastDouble Bilipid MembraneStarch Granules

    Chapter 5

  • a. Plastids iii. ChloroplastStructure:Contain chlorophyllBounded by a double membraneThylakoid staked into granaStroma (viscous fluid) outside thylakoidsContain ribosomes and some DNAFunction:Site of PhotosynthesisCaptures light energyProduces carbohydrate from CO2 and H2OSelf-replicating (semi-autonomous)

    Chapter 5

  • The ChloroplastThylakoidsOuter MembraneIntermembrane SpaceGranumStroma

    Chapter 5

  • Elodea (400x)

    Chapter 5

  • 3. Other Membranous Organelles b. MitochondriaStructure: Bounded by double membraneInner membrane folded into cristaeMitochondrial matrix within cristaeContain own DNA and ribosomes Function:Site of cellular respiration convert energy stored in food into ATPpowerhouse of the cell number varies, but related to cells metabolic activitySelf-replicating (semi-autonomous)

    Chapter 5

  • The MitochondrionCristaeMatrixOuter MembraneInner Membrane

    Chapter 5

  • 4. The Cytoskeleton

    Protein fibersCell shape; networks of intermediate filamentsCell movement; microfilaments & microtubulesAmoeboid movementMuscle contractionCell migration during developmentOrganelle movement & suspensionCyclosis; pathways for vesicle migrationCell division

    Chapter 5

  • The CytoskeletonMicrotubuleMicrofilamentsIntermediate FilamentsActin monomersTubulin dimerEndoplasmic ReticulumMitochondrionPlasma MembraneFibrous subunits

    Chapter 5

  • 4. The Cytoskeleton a. CentriolesStructure:Pair of cylindrical structures9 sets of triplet microtubulesArranged in a ring ~ 50 nm at right angles

    Function:Replicate during cell division

    Chapter 5

  • Centriole x.s. T.E.M.

    Chapter 5

  • 4. The Cytoskeleton b. Cilia and FlagellaStructure:Tubular extensions of plasma membraneAnchored by basal body (like centriole)9+2 arrangement9 doublet microtubules in complex2 single microtubules in centerFunction:Movement of fluid, or locomotionCilia: numerous, paddle-like, synchronizedFlagella: longer, fewer, more whip-like

    Chapter 5

  • Cilia & Flagellax.s.Cell MembraneShaftBase (a Centriole)T.E.M.ParameciumEuglena

    Chapter 5

  • Flagellum PartsShaft, l.s.Shaft, x.s.Microtubule DoubletsCell MembraneDynein ArmsCentral SingletsMicrotubule TripletsBasal BodyBasal Body, x.s.

    Chapter 5

  • Flagella MovementScanning E.M. of sperm on eggCorkscrew Movement (Pulls)Whipping Movement (Pushes)WaterWater

    Chapter 5

  • Movement of CiliaActive StrokeRecovery StrokeWaterCilia on trachea surface

    Chapter 5

  • 5. Surfaces and Junctionsa. Cell WallStructure:Microfibrils of Cellulose in a MatrixPrimary Cell WallThin, flexibleSecondary Cell WallDeposited in Laminated LayersMiddle LamellaSticky polysaccharides (pectins)Function:Protects and Maintains ShapeHolds Cells TogetherPrevents Excess Water Intake

    Chapter 5

  • The Cell Wall

    Chapter 5

  • 5. Surfaces and Junctionsb. Communication StructuresDesmosomedesmosomeProtein strands rivet cells together, but permit passage of substancesProtein filaments in cytoplasmSmall intestinePlasma membrane (edge view)Cells lining small intestine

    Chapter 5

  • 5. Surfaces and Junctionsc. Attachment StructuresGap JunctionsdesmosomeGap Junctions: pairs of channels connect insides of adjacent cellsLiverPlasma membraneLiver cells

    Chapter 5

    Biology: Life on Earth (Audesirk)Chapter 5Biology: Life on Earth (Audesirk)Chapter 5Biology: Life on Earth (Audesirk)Eukaryotic cells are best exemplified by the familiar plants and animals.The cell (plasma) membrane was discussed extensively in the previous chapter.Chapter 5Biology: Life on Earth (Audesirk)Some of the differences between these cell types are summarized in Table 6-1, and in the subsequent two slides.Chapter 5Biology: Life on Earth (Audesirk)Prokaryotic cells are exemplified by bacteria, like the one in Figure 6-3.The internal part of the cell is not broken up into compartments by membranes (no organelles).There is not even a membrane around the genetic material.The area that contains the genetic material is referred to as the nucleoid, and the genes are usually in one