Slide 1
Cell Structure and Function
BIOLOGYA Global Approach
Campbell Reece Urry Cain Wasserman Minorsky Jackson 2015 Pearson Education Ltd TENTH EDITION
Global Edition
Lecture Presentation by Nicole Tunbridge andKathleen Fitzpatrick7
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The Fundamental Units of LifeAll organisms are made of cellsThe cell is the simplest collection of matter that can be aliveAll cells are related by their descent from earlier cellsCells can differ substantially from one another but share common features
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Figure 6.1
2015 Pearson Education LtdFigure 6.1 How do your cells help you learn about biology? 3
Concept 6.1: Biologists use microscopes and the tools of biochemistry to study cellsCells are usually too small to be seen by the naked eye
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MicroscopyMicroscopes are used to visualize cellsIn a light microscope (LM), visible light is passed through a specimen and then through glass lensesLenses refract (bend) the light, so that the image is magnified
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Three important parameters of microscopyMagnification, the ratio of an objects imagesize to its real sizeResolution, the measure of the clarity of the image, or the minimum distance of two distinguishable pointsContrast, visible differences in brightness between parts of the sample
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Figure 6.210 m1 m0.1 m1 cm1 mm100 m10 m1 m100 nm10 nm1 nm0.1 nmAtomsSmall moleculesLipidsProteinsRibosomesVirusesSmallest bacteriaMitochondrionMost bacteriaNucleusMost plant andanimal cellsHuman eggFrog eggChicken eggLength of somenerve andmuscle cellsHuman heightUnaided eyeLMEMSuper-resolutionmicroscopy
2015 Pearson Education LtdFigure 6.2 The size range of cells 7
Figure 6.2a10 m1 m0.1 m1 cm1 mm100 mHuman eggFrog eggChicken eggLength of somenerve andmuscle cellsHuman heightUnaided eyeLM
2015 Pearson Education LtdFigure 6.2a The size range of cells (part 1: LM to unaided eye) 8
Figure 6.2b100 m10 m1 m100 nm10 nm1 nm0.1 nmAtomsSmall moleculesProteinsLipidsRibosomesVirusesSmallest bacteriaNucleusMost bacteriaMitochondrionSuper-resolutionmicroscopyLMEM
Most plant andanimal cells
2015 Pearson Education LtdFigure 6.2b The size range of cells (part 2: EM to LM) 9
Figure 6.2cUnaided eyeLight microscopyElectron microscopySuper-resolutionmicroscopyHumanheightLengthof somenerveandmusclecellsChickeneggFrogeggHumaneggMostplantandanimalcellsNucleusMostbacteriaMito-chondrionSmallestbacteriaVirusesRibo-somesProteinsLipidsSmallmoleculesAtoms10 m1 m0.1 m1 cm1 mm100 m10 m1 m100 m10 nm1 nm0.1 nm
2015 Pearson Education LtdFigure 6.2c The size range of cells (part 3: horizontal version) 10
Light microscopes can magnify effectively to about 1,000 times the size of the actual specimenVarious techniques enhance contrast and enable cell components to be stained or labeledThe resolution of standard light microscopy is too low to study organelles, the membrane-enclosed structures in eukaryotic cells
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Figure 6.350 m10 m50 m10 m1 m2 m2 mBrightfield(unstainedspecimen)Brightfield(stained specimen)Phase-contrastDifferential-interference-contrast(Nomarski)FluorescenceConfocal (without)Confocal (with)DeconvolutionSuper-resolution(without)Super-resolution(with)Scanningelectronmicroscopy (SEM)Transmissionelectronmicroscopy (TEM)
2015 Pearson Education LtdFigure 6.3 Exploring microscopy 12
Figure 6.3aBrightfield(unstained specimen)Brightfield(stained specimen)Phase-contrastDifferential-interference-contrast(Nomarski)50 mLight Microscopy (LM)
2015 Pearson Education LtdFigure 6.3a Exploring microscopy (part 1) 13
Figure 6.3aaBrightfield (unstained specimen)50 m
2015 Pearson Education LtdFigure 6.3aa Exploring microscopy (part 1a: brightfield, unstained) 14
Figure 6.3abBrightfield (stained specimen)50 m
2015 Pearson Education LtdFigure 6.3ab Exploring microscopy (part 1b: brightfield, stained) 15
Figure 6.3acPhase-contrast50 m
2015 Pearson Education LtdFigure 6.3ac Exploring microscopy (part 1c: phase-contrast) 16
Figure 6.3adDifferential-interference-contrast(Nomarski)50 m
2015 Pearson Education LtdFigure 6.3ad Exploring microscopy (part 1d: differential-interference contrast) 17
Figure 6.3bLight Microscopy (LM)FluorescenceDeconvolutionConfocal (without)Confocal (with)10 m10 m50 m
2015 Pearson Education LtdFigure 6.3b Exploring microscopy (part 2) 18
Figure 6.3baFluorescence10 m
2015 Pearson Education LtdFigure 6.3ba Exploring microscopy (part 2a: fluorescence) 19
Figure 6.3bbDeconvolution10 m
2015 Pearson Education LtdFigure 6.3bb Exploring microscopy (part 2b: deconvolution) 20
Figure 6.3bcConfocal (without)50 m
2015 Pearson Education LtdFigure 6.3bc Exploring microscopy (part 2c: confocal, without) 21
Figure 6.3bdConfocal (with)50 m
2015 Pearson Education LtdFigure 6.3bd Exploring microscopy (part 2d: confocal, with) 22
Figure 6.3cSuper-resolution (without)1 mSuper-resolution (with)Scanningelectronmicroscopy (SEM)Transmissionelectronmicroscopy (TEM)Electron Microscopy (EM)2 m2 mLight Microscopy (LM)
2015 Pearson Education LtdFigure 6.3c Exploring microscopy (part 3) 23
Figure 6.3caSuper-resolution (without)1 m
2015 Pearson Education LtdFigure 6.3ca Exploring microscopy (part 3a: super-resolution, without) 24
Figure 6.3cb1 mSuper-resolution (with)
2015 Pearson Education LtdFigure 6.3cb Exploring microscopy (part 3b: super-resolution, with) 25
Figure 6.3ccScanningelectronmicroscopy (SEM)2 m
2015 Pearson Education LtdFigure 6.3cc Exploring microscopy (part 3c: SEM) 26
Figure 6.3cdTransmissionelectronmicroscopy (TEM)2 m
2015 Pearson Education LtdFigure 6.3cd Exploring microscopy (part 3d: TEM) 27
Two basic types of electron microscopes (EMs) are used to study subcellular structures Scanning electron microscopes (SEMs) focus a beam of electrons onto the surface of a specimen, providing images that look 3-DTransmission electron microscopes (TEMs) focus a beam of electrons through a specimen TEMs are used mainly to study the internal structure of cells
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Recent advances in light microscopyConfocal microscopy and deconvolution microscopy provide sharper images of three-dimensional tissues and cellsNew techniques for labeling cells improve resolution
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Cell FractionationCell fractionation takes cells apart andseparates the major organelles from one anotherCentrifuges fractionate cells into theircomponent partsCell fractionation enables scientists to determine the functions of organellesBiochemistry and cytology help correlate cell function with structure
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Figure 6.4HomogenateHomogenizationTissue cellsCentrifugationSupernatant poured into next tube1,000 g10 min20,000 g20 min80,000 g60 min150,000 g3 hrPellet rich inribosomesPellet rich inmicrosomesPellet rich inmitochondriaand chloroplastsPellet rich innuclei andcellular debrisDifferentialcentrifugation
2015 Pearson Education LtdFigure 6.4 Research method: cell fractionation 31
Figure 6.4aHomogenateHomogenizationTissue cellsCentrifugation
2015 Pearson Education LtdFigure 6.4a Research method: cell fractionation (part 1: homogenization) 32
Figure 6.4b1,000 g10 min20,000 g20 min80,000 g60 min150,000 g3 hrPellet rich inribosomesPellet rich inmicrosomesPellet rich inmitochondriaand chloroplastsPellet rich innuclei andcellular debrisDifferentialcentrifugation
Supernatant poured into next tube
2015 Pearson Education LtdFigure 6.4b Research method: cell fractionation (part 2: differential centrifugation) 33
Concept 6.2: Eukaryotic cells haveinternal membranes that compartmentalizetheir functionsThe basic structural and functional unit of every organism is one of two types of cells: prokaryotic or eukaryoticOnly organisms of the domains Bacteria and Archaea consist of prokaryotic cellsProtists, fungi, animals, and plants all consist of eukaryotic cells
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Comparing Prokaryotic and Eukaryotic CellsBasic features of all cells Plasma membraneSemifluid substance called cytosolChromosomes (carry genes)Ribosomes (make proteins)
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Prokaryotic cells are characterized by havingNo nucleusDNA in an unbound region called the nucleoidNo membrane-bound organellesCytoplasm bound by the plasma membrane
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Figure 6.5FimbriaeNucleoidRibosomesPlasma membraneCell wallCapsuleFlagellaA typicalrod-shapedbacterium(a)Bacterialchromosome0.5 mA thin section throughthe bacterium Bacilluscoagulans (TEM)
(b)
2015 Pearson Education LtdFigure 6.5 A prokaryotic cell 37
Figure 6.5aNucleoidRibosomesPlasma membraneCell wallCapsuleA thin section through the bacteriumBacillus coagulans (TEM)0.5 m(b)
2015 Pearson Education LtdFigure 6.5a A prokaryotic cell (part 1: TEM) 38
Eukaryotic cells are characterized by havingDNA in a nucleus that is bounded by a membranous nuclear envelopeMembrane-bound organellesCytoplasm in the region between the plasma membrane and nucleusEukaryotic cells are generally much larger than prokaryotic cells
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The plasma membrane is a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell
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Figure 6.6(a)TEM of a plasma membraneOutside of cellInsideof cellCarbohydrate side chainsHydrophilicregionHydrophobicregionHydrophilicregionStructure of the plasma membrane(b)PhospholipidProteins0.1 m
2015 Pearson Education LtdFigure 6.6 The plasma membrane 41
Figure 6.6aOutside of cellInsideof cell0.1 m
2015 Pearson Education LtdFigure 6.6a The plasma membrane (part 1: TEM) 42
Metabolic requirements set upper limits on the size of cells The surface area to volume ratio of a cell is criticalAs a cell increases in size, its volume grows proportionately more than its surface area
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Figure 6.7Surface area increases whiletotal volume remains constantTotal surface area[sum of the surface areas(height width) of all boxsides number of boxes]51166615075012512511.2Total volume[height width length number of boxes]Surface-to-volume(S-to-V) ratio[surface area volume]
2015 Pearson Education LtdFigure 6.7 Geometric relationships between surface area and volume 44
A Panoramic View of the Eukaryotic CellA eukaryotic cell has internal membranes that partition the cell into organellesThe basic fabric of biological membranes is a double layer of phospholipids and other lipidsPlant and animal cells have most of the same organelles
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Figure 6.8aFlagellumCentrosomeCYTOSKELETON:MicrofilamentsIntermediate filamentsMicrotubulesMicrovilliPeroxisomeMitochondrionLysosomeGolgi apparatusRibosomesPlasmamembraneNuclearenvelopeNucleolusChromatinNUCLEUSENDOPLASMICRETICULUM (ER)Rough ERSmooth ER
2015 Pearson Education LtdFigure 6.8a Exploring eukaryotic cells (part 1: animal cell cutaway) 46
Figure 6.8bNUCLEUSNuclearenvelopeNucleolusChromatinRough ERSmooth ERRibosomesCentral vacuoleMicrofilamentsMicrotubulesCYTOSKELETONChloroplastPlasmodesmataWall of adjacent cellCell wallPlasmamembranePeroxisomeMitochondrionGolgiapparatus
2015 Pearson Education LtdFigure 6.8b Exploring eukaryotic cells (part 2: plant cell cutaway) 47
Figure 6.8cAnimal CellsFungal CellsPlant CellsUnicellularEukaryotesHuman cells from liningof uterus (colorized TEM)Yeast cells budding(colorized SEM)A single yeast cell(colorized TEM)Cells from duckweed(colorized TEM)Chlamydomonas(colorized SEM)Chlamydomonas(colorized TEM)CellNucleusNucleolusParentcellBudsCell wallVacuoleNucleusMitochondrionCell wallCellChloroplastMitochondrionNucleusNucleolusFlagellaVacuoleCell wallChloroplastNucleusNucleolus10 m 5 m 5 m 1 m 8 m 1 m
2015 Pearson Education LtdFigure 6.8b Exploring eukaryotic cells (part 3: micrographs) 48
Figure 6.8caHuman cells from liningof uterus (colorized TEM)CellNucleusNucleolus10 m
2015 Pearson Education LtdFigure 6.8ca Exploring eukaryotic cells (part 3a: animal cell, TEM) 49
Figure 6.8cbYeast cells budding(colorized SEM)ParentcellBuds5 m
2015 Pearson Education LtdFigure 6.8cb Exploring eukaryotic cells (part 3b: fungal cell, SEM) 50
Figure 6.8ccA single yeast cell(colorized TEM)Cell wallVacuoleNucleusMitochondrion1 m
2015 Pearson Education LtdFigure 6.8cc Exploring eukaryotic cells (part 3c: fungal cell, TEM) 51
Figure 6.8cdCells from duckweed(colorized TEM)Cell wallCellChloroplastMitochondrionNucleusNucleolus5 m
2015 Pearson Education LtdFigure 6.8cd Exploring eukaryotic cells (part 3d: plant cell, TEM) 52
Figure 6.8ceChlamydomonas(colorized SEM)8 m
2015 Pearson Education LtdFigure 6.8ce Exploring eukaryotic cells (part 3e: unicellular eukaryote, SEM) 53
Figure 6.8cfChlamydomonas (colorized TEM)FlagellaVacuoleCell wallChloroplastNucleusNucleolus1 m
2015 Pearson Education LtdFigure 6.8cf Exploring eukaryotic cells (part 3f: unicellular eukaryote, TEM) 54
BioFlix: Tour of a Plant Cell
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BioFlix: Tour of an Animal Cell
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Concept 6.3: The eukaryotic cells genetic instructions are housed in the nucleus and carried out by the ribosomesThe nucleus contains most of the DNA in a eukaryotic cellRibosomes use the information from the DNA to make proteins
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The Nucleus: Information CentralThe nucleus contains most of the cells genes and is usually the most conspicuous organelleThe nuclear envelope encloses the nucleus, separating it from the cytoplasmThe nuclear membrane is a double membrane; each membrane consists of a lipid bilayer
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Figure 6.91 m NucleusNucleolusChromatinNuclear envelope:Inner membraneOuter membraneNuclear poreNucleusRoughERChromatinNuclear lamina (TEM)Close-upof nuclearenvelopePore complexes (TEM)0.25 m0.5 mPorecomplexRibosomeSurface ofnuclear envelope(TEM)
2015 Pearson Education LtdFigure 6.9 The nucleus and its envelope 59
Figure 6.9aNucleolusChromatinNuclear envelope:Inner membraneOuter membraneNuclear poreNucleusRoughERChromatinPorecomplexRibosomeClose-upof nuclearenvelope
2015 Pearson Education LtdFigure 6.9a The nucleus and its envelope (part 1: detail of art) 60
Figure 6.9b1 m Nuclear envelope:Inner membraneOuter membraneNuclear poreSurface of nuclear envelope(TEM)
2015 Pearson Education LtdFigure 6.9bThe nucleus and its envelope (part 2: nuclear envelope, TEM) 61
Figure 6.9cPore complexes (TEM)0.25 m
2015 Pearson Education LtdFigure 6.9c The nucleus and its envelope (part 3: pore complexes, TEM) 62
Figure 6.9dNuclear lamina (TEM)0.5 m
2015 Pearson Education LtdFigure 6.9d The nucleus and its envelope (part 4: nuclear lamina, TEM) 63
Pores regulate the entry and exit of molecules from the nucleusThe nuclear size of the envelop is lined by the nuclear lamina, which is composed of proteins and maintains the shape of the nucleus
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In the nucleus, DNA is organized into discrete units called chromosomesEach chromosome is composed of a single DNA molecule associated with proteins The DNA and proteins of chromosomes are together called chromatinChromatin condenses to form discrete chromosomes as a cell prepares to divideThe nucleolus is located within the nucleus and is the site of ribosomal RNA (rRNA) synthesis
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Ribosomes: Protein FactoriesRibosomes are complexes made of ribosomal RNA and proteinRibosomes carry out protein synthesis in two locationsIn the cytosol (free ribosomes)On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes)
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Figure 6.10RibosomesERTEM showing ERand ribosomesFree ribosomes in cytosolEndoplasmicreticulum (ER)Ribosomes bound to ERLarge subunitSmall subunitDiagram of aribosomeComputer modelof a ribosome0.25 m
2015 Pearson Education LtdFigure 6.10 Ribosomes 67
Figure 6.10aTEM showing ERand ribosomesFree ribosomes in cytosolEndoplasmicreticulum (ER)Ribosomes bound to ERLarge subunitSmall subunitDiagram of aribosome0.25 m
2015 Pearson Education LtdFigure 6.10a Ribosomes (part 1: detail of art) 68
Figure 6.10bTEM showing ERand ribosomesFree ribosomesin cytosolEndoplasmicreticulum (ER)Ribosomes bound to ER0.25 m
2015 Pearson Education LtdFigure 6.10b Ribosomes (part 2: TEM) 69
Figure 6.10cLarge subunitSmall subunitComputer modelof a ribosome
2015 Pearson Education LtdFigure 6.10c Ribosomes (part 3: computer model) 70
Concept 6.4: The endomembrane system regulates protein traffic and performs metabolic functions in the cellThe endomembrane system consists ofNuclear envelopeEndoplasmic reticulumGolgi apparatusLysosomesVacuolesPlasma membraneThese components are either continuous or connected via transfer by vesicles
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The Endoplasmic Reticulum: Biosynthetic FactoryThe endoplasmic reticulum (ER) accounts for more than half of the total membrane in many eukaryotic cellsThe ER membrane is continuous with the nuclear envelopeThere are two distinct regions of ERSmooth ER, which lacks ribosomesRough ER, whose surface is studded with ribosomes
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Figure 6.11Smooth ERRough ERNuclearenvelopeER lumenCisternaeRibosomesTransport vesicleTransitionalERSmooth ERRough ER0.20 m
2015 Pearson Education LtdFigure 6.11 Endoplasmic reticulum (ER) 73
Figure 6.11aSmooth ERRough ER0.20 m
2015 Pearson Education LtdFigure 6.11a Endoplasmic reticulum (ER) (part 1: TEM) 74
Video: ER and Mitochondria in Leaf Cells
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Video: Staining of Endoplasmic Reticulum
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Functions of Smooth ERThe smooth ERSynthesizes lipidsMetabolizes carbohydratesDetoxifies drugs and poisonsStores calcium ions
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Functions of Rough ERThe rough ERHas bound ribosomes, which secrete glycoproteins (proteins covalently bonded to carbohydrates)Distributes transport vesicles, secretory proteins surrounded by membranesIs a membrane factory for the cell
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The Golgi Apparatus: Shipping and Receiving CenterThe Golgi apparatus consists of flattened membranous sacs called cisternaeFunctions of the Golgi apparatusModifies products of the ERManufactures certain macromoleculesSorts and packages materials into transport vesicles
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Figure 6.120.1 mTEM of Golgi apparatusCisternaeGolgiapparatuscis face(receiving side ofGolgi apparatus)trans face(shipping side of Golgi apparatus)
2015 Pearson Education LtdFigure 6.12 The Golgi apparatus 80
Figure 6.12a0.1 mTEM of Golgi apparatus
2015 Pearson Education LtdFigure 6.12a The Golgi apparatus (part 1: TEM) 81
Video: Golgi Complex in 3-D
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Lysosomes: Digestive CompartmentsA lysosome is a membranous sac of hydrolytic enzymes that can digest macromoleculesLysosomal enzymes work best in the acidic environment inside the lysosomeHydrolytic enzymes and lysosomal membranes are made by rough ER and then transferred to the Golgi apparatus for further processing
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Some types of cell can engulf another cell by phagocytosis; this forms a food vacuoleA lysosome fuses with the food vacuole and digests the moleculesLysosomes also use enzymes to recycle thecells own organelles and macromolecules,a process called autophagy
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Figure 6.131 m(a)NucleusVesicle containingtwo damagedorganellesMitochondrionfragmentPeroxisomefragmentLysosomePeroxisomeMitochondrionVesicleDigestionAutophagy: lysosome breaking downdamaged organelles(b)DigestionPhagocytosis: lysosome digesting foodFoodvacuolePlasmamembraneDigestiveenzymesLysosomeLysosome1 m
2015 Pearson Education LtdFigure 6.13 Lysosomes 85
Figure 6.13a1 m(a)NucleusDigestionPhagocytosis: lysosome digesting foodFoodvacuolePlasmamembraneDigestiveenzymesLysosomeLysosome
2015 Pearson Education LtdFigure 6.13a Lysosomes (part 1: phagocytosis) 86
Figure 6.13aa1 mNucleusLysosome
2015 Pearson Education LtdFigure 6.13aa Lysosomes (part 1a: phagocytosis, TEM) 87
Figure 6.13bMitochondrionfragmentPeroxisomefragmentVesicle containingtwo damagedorganellesLysosomePeroxisomeDigestionMitochondrionVesicleAutophagy: lysosome breaking downdamaged organelles(b)1 m
2015 Pearson Education LtdFigure 6.13b Lysosomes (part 2: autophagy) 88
Figure 6.13baMitochondrionfragmentPeroxisomefragmentVesicle containingtwo damagedorganelles1 m
2015 Pearson Education LtdFigure 6.13ba Lysosomes (part 2a: autophagy, TEM) 89
Animation: Lysosome Formation
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Video: Phagocytosis in Action
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Vacuoles: Diverse Maintenance CompartmentsVacuoles are large vesicles derived from the ER and Golgi apparatusVacuoles perform a variety of functions in different kinds of cells
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Food vacuoles are formed by phagocytosisContractile vacuoles, found in many freshwater protists, pump excess water out of cellsCentral vacuoles, found in many mature plant cells, hold organic compounds and water
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Figure 6.145 mCentral vacuoleNucleusCell wallChloroplastCentralvacuoleCytosol
2015 Pearson Education LtdFigure 6.14 The plant cell vacuole 94
Figure 6.14a5 mNucleusCell wallChloroplastCentralvacuoleCytosol
2015 Pearson Education LtdFigure 6.14a The plant cell vacuole (part 1: TEM) 95
Video: Paramecium Vacuole
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The Endomembrane System: A ReviewThe endomembrane system is a complex and dynamic player in the cells compartmental organization
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Figure 6.15Smooth ERNucleusRough ERcis Golgitrans GolgiPlasmamembrane
2015 Pearson Education LtdFigure 6.15 Review: relationships among organelles of the endomembrane system 98
Video: ER to Golgi Traffic
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Video: Secretion from the Golgi
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Concept 6.5: Mitochondria and chloroplasts change energy from one form to anotherMitochondria are the sites of cellular respiration, a metabolic process that uses oxygen togenerate ATPChloroplasts, found in plants and algae, are the sites of photosynthesisPeroxisomes are oxidative organelles
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The Evolutionary Origins of Mitochondria and ChloroplastsMitochondria and chloroplasts have similarities with bacteriaEnveloped by a double membraneContain free ribosomes and circular DNA moleculesGrow and reproduce somewhat independentlyin cellsThese similarities led to the endosymbiont theory
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The endosymbiont theory suggests that an early ancestor of eukaryotes engulfed an oxygen-using nonphotosynthetic prokaryotic cellThe engulfed cell formed a relationship with the host cell, becoming an endosymbiontThe endosymbionts evolved into mitochondriaAt least one of these cells may have then taken up a photosynthetic prokaryote, which evolved into a chloroplast
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Figure 6.16EndoplasmicreticulumNucleusNuclearenvelopeAncestor ofeukaryotic cells (host cell)Engulfing of oxygen-using nonphotosyntheticprokaryote, whichbecomes a mitochondrionNonphotosyntheticeukaryoteEngulfing ofphotosyntheticprokaryoteMitochondrionMitochondrionChloroplastPhotosynthetic eukaryoteAt leastone cell
2015 Pearson Education LtdFigure 6.16 The endosymbiont theory of the origins of mitochondria and chloroplasts in eukaryotic cells 104
Mitochondria: Chemical Energy ConversionMitochondria are in nearly all eukaryotic cellsThey have a smooth outer membrane and an inner membrane folded into cristaeThe inner membrane creates two compartments: intermembrane space and mitochondrial matrixSome metabolic steps of cellular respiration are catalyzed in the mitochondrial matrixCristae present a large surface area for enzymes that synthesize ATP
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Figure 6.17MitochondrionIntermembranespaceOutermembraneDNAInnermembraneFreeribosomesin themitochondrialmatrixCristaeMatrix(a)Diagram and TEM of mitochondrion0.1 m10 mMitochondriaMitochondrialDNANuclear DNANetwork of mitochondria inEuglena (LM)(b)
2015 Pearson Education LtdFigure 6.17 The mitochondrion, site of cellular respiration 106
Figure 6.17a
MitochondrionIntermembranespaceOutermembraneDNAInnermembraneFreeribosomesin themitochondrialmatrixCristaeMatrixDiagram and TEM of mitochondrion0.1 m(a)
2015 Pearson Education LtdFigure 6.17a The mitochondrion, site of cellular respiration (part 1: detail of art) 107
Figure 6.17aaOutermembraneInnermembraneCristaeMatrix0.1 m
2015 Pearson Education LtdFigure 6.17aa The mitochondrion, site of cellular respiration (part 1a: TEM) 108
Figure 6.17b(b)Network of mitochondria inEuglena (LM)MitochondriaMitochondrialDNANuclear DNA10 m
2015 Pearson Education LtdFigure 6.17b The mitochondrion, site of cellular respiration (part 2: LM) 109
Video: Mitochondria in 3-D
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Chloroplasts: Capture of Light EnergyChloroplasts contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesisChloroplasts are found in leaves and other green organs of plants and in algae
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Figure 6.18ChloroplastRibosomesStromaInnerand outermembranesGranumDNAThylakoidIntermembrane spaceDiagram and TEM of chloroplast(a)(b)Chloroplasts in analgal cell(b)1 m50 mChloroplasts(red)
2015 Pearson Education LtdFigure 6.18 The chloroplast, site of photosynthesis 112
Figure 6.18aRibosomesStromaInnerand outermembranesGranumDNAThylakoidIntermembrane spaceDiagram and TEM of chloroplast(a)1 m
2015 Pearson Education LtdFigure 6.18a The chloroplast, site of photosynthesis (part 1: detail of art) 113
Figure 6.18aaStromaInnerand outermembranesGranum1 m
2015 Pearson Education LtdFigure 6.18aa The chloroplast, site of photosynthesis (part 1a: TEM) 114
Figure 6.18b(b)Chloroplasts in analgal cell50 mChloroplasts(red)
2015 Pearson Education LtdFigure 6.18b The chloroplast, site of photosynthesis (part 2: fluorescence micrograph) 115
Chloroplast structure includesThylakoids, membranous sacs, stacked to form a granumStroma, the internal fluidThe chloroplast is one of a group of plant organelles, called plastids
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Peroxisomes: OxidationPeroxisomes are specialized metabolic compartments bounded by a single membranePeroxisomes produce hydrogen peroxide and convert it to waterPeroxisomes perform reactions with many different functionsHow peroxisomes are related to other organelles is still unknown
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Figure 6.19ChloroplastsPeroxisomeMitochon-drion1 m
2015 Pearson Education LtdFigure 6.19 A peroxisome 118
Concept 6.6: The cytoskeleton is a network of fibers that organizes structures and activities in the cellThe cytoskeleton is a network of fibers extending throughout the cytoplasmIt organizes the cells structures and activities, anchoring many organellesIt is composed of three types of molecular structuresMicrotubulesMicrofilamentsIntermediate filaments
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Figure 6.20
10 m
2015 Pearson Education LtdFigure 6.20 The cytoskeleton 120
Video: The Cytoskeleton in Neuron Growth Cone
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Video: Interphase Microtubule Dynamics
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Video: Microtubule Dynamics
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Video: Actin Visualization in Dendrites
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Video: Cytoskeletal Protein Dynamics
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Roles of the Cytoskeleton: Support and MotilityThe cytoskeleton helps to support the cell and maintain its shapeIt interacts with motor proteins to produce motilityInside the cell, vesicles can travel along tracks provided by the cytoskeleton
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Figure 6.210.25 mVesiclesMicrotubuleSEM of a squid giant axon(b)(a)Motor proteins walk vesicles along cytoskeletalfibers.(a)Motor protein(ATP powered)Microtubuleof cytoskeletonReceptor formotor proteinVesicleATP
2015 Pearson Education LtdFigure 6.21 Motor proteins and the cytoskeleton 127
Figure 6.21a0.25 mVesiclesMicrotubuleSEM of a squid giant axon(b)
2015 Pearson Education LtdFigure 6.21a Motor proteins and the cytoskeleton (part 1: SEM) 128
Video: Movement of Organelles In Vitro
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Video: Movement of Organelles In Vivo
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Video: Transport Along Microtubules
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Components of the CytoskeletonThree main types of fibers make up the cytoskeletonMicrotubules are the thickest of the three components of the cytoskeletonMicrofilaments, also called actin filaments, are the thinnest componentsIntermediate filaments are fibers with diameters in a middle range
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Table 6.1
2015 Pearson Education LtdTable 6.1 The structure and function of the cytoskeleton 133
Table 6.1a
2015 Pearson Education LtdTable 6.1a The structure and function of the cytoskeleton (part 1: detail of table) 134
Table 6.1b
2015 Pearson Education LtdTable 6.1b The structure and function of the cytoskeleton (part 2: microtubules) 135
Table 6.1ba
2015 Pearson Education LtdTable 6.1ba The structure and function of the cytoskeleton (part 2a: microtubules, micrograph) 136
Table 6.1c
2015 Pearson Education LtdTable 6.1c The structure and function of the cytoskeleton (part 3: microfilaments) 137
Table 6.1ca
2015 Pearson Education LtdTable 6.1ca The structure and function of the cytoskeleton (part 3a: microfilaments, micrograph) 138
Table 6.1d
2015 Pearson Education LtdTable 6.1d The structure and function of the cytoskeleton (part 4: intermediate filaments) 139
Table 6.1da
2015 Pearson Education LtdTable 6.1da The structure and function of the cytoskeleton (part 4a: intermediate filaments, micrograph) 140
MicrotubulesMicrotubules are hollow rods about 25 nm in diameter and about 200 nm to 25 microns longFunctions of microtubulesShaping the cellGuiding movement of organellesSeparating chromosomes during cell division
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Centrosomes and CentriolesIn animal cells, microtubules grow out from a centrosome near the nucleusIn animal cells, the centrosome has a pair of centrioles, each with nine triplets of microtubules arranged in a ring
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Figure 6.220.25 mMicrotubuleCentriolesCentrosomeLongitudinalsection of onecentrioleMicrotubulesCross sectionof the other centriole
2015 Pearson Education LtdFigure 6.22 Centrosome containing a pair of centrioles 143
Figure 6.22a0.25 mLongitudinalsection of onecentrioleMicrotubulesCross sectionof the other centriole
2015 Pearson Education LtdFigure 6.22a Centrosome containing a pair of centrioles (part 1: TEM) 144
Cilia and FlagellaMicrotubules control the beating of flagella and cilia, microtubule-containing extensions thatproject from some cellsCilia and flagella differ in their beating patterns
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Figure 6.235 m15 m(a)(b)Motion of flagellaMotion of ciliaDirection of swimmingDirection of organisms movementPower strokeRecoverystroke
2015 Pearson Education LtdFigure 6.23 A comparison of the beating of flagella and motile cilia 146
Figure 6.23a5 m
2015 Pearson Education LtdFigure 6.23a A comparison of the beating of flagella and motile cilia (part 1: flagella, LM) 147
Video: Chlamydomonas
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Video: Flagellum Movement in Swimming Sperm
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Video: Motion of Isolated Flagellum
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Video: Paramecium Cilia
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Figure 6.23b15 m
2015 Pearson Education LtdFigure 6.23b A comparison of the beating of flagella and motile cilia (part 2: cilia, SEM) 152
Video: Ciliary Motion
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Cilia and flagella share a common structureA core of microtubules sheathed by theplasma membraneA basal body that anchors the cilium or flagellumA motor protein called dynein, which drives the bending movements of a cilium or flagellum
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Figure 6.240.1 m0.5 m0.1 mMicrotubulesPlasmamembraneBasalbodyLongitudinal sectionof motile cilium(a)TripletCross section ofmotile cilium(b)Outer microtubuledoubletMotor proteins(dyneins)CentralmicrotubuleRadial spokeCross-linkingproteins betweenouter doubletsPlasmamembraneCross section of basal body(c)
2015 Pearson Education LtdFigure 6.24 Structure of a flagellum or motile cilium 155
Figure 6.24a0.5 mMicrotubulesPlasmamembraneBasalbodyLongitudinal sectionof motile cilium(a)
2015 Pearson Education LtdFigure 6.24a Structure of a flagellum or motile cilium (part 1: longitudinal section of cilium, TEM) 156
Figure 6.24bOuter microtubuledoubletMotor proteins(dyneins)CentralmicrotubuleRadial spokeCross-linkingproteins betweenouter doubletsPlasmamembraneCross section ofmotile cilium(b)
0.1 m
2015 Pearson Education LtdFigure 6.24b Structure of a flagellum or motile cilium (part 2: cilium cross section) 157
Figure 6.24baOuter microtubuledoubletMotor proteins(dyneins)CentralmicrotubuleRadial spokeCross-linkingproteins betweenouter doubletsCross section ofmotile cilium(b)0.1 m
2015 Pearson Education LtdFigure 6.24ba Structure of a flagellum or motile cilium (part 2a: cilium cross section, TEM) 158
Figure 6.24c0.1 mTripletCross section of basal body(c)
2015 Pearson Education LtdFigure 6.24c Structure of a flagellum or motile cilium (part 3: basal body cross section) 159
Figure 6.24ca0.1 mTripletCross section of basal body(c)
2015 Pearson Education LtdFigure 6.24ca Structure of a flagellum or motile cilium (part 3a: basal body cross section, TEM) 160
Animation: Cilia and Flagella
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Video: Microtubule Sliding in Flagellum Movement
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How dynein walking moves flagella and ciliaDynein arms alternately grab, move, and release the outer microtubulesProtein cross-links limit slidingForces exerted by dynein arms cause doubletsto curve, bending the cilium or flagellum
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Microfilaments (Actin Filaments)Microfilaments are solid rods about 7 nm in diameter, built as a twisted double chain ofactin subunitsThe structural role of microfilaments is to bear tension, resisting pulling forces within the cellThey form a 3-D network called the cortex just inside the plasma membrane to help support the cells shapeBundles of microfilaments make up the core of microvilli of intestinal cells
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Figure 6.25MicrovillusPlasma membraneMicrofilaments (actinfilaments)Intermediate filaments
0.25 m
2015 Pearson Education LtdFigure 6.25 A structural role of microfilaments 165
Microfilaments that function in cellular motility contain the protein myosin in addition to actinIn muscle cells, thousands of actin filaments are arranged parallel to one anotherThicker filaments composed of myosin interdigitate with the thinner actin fibers
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Figure 6.26Muscle cell0.5 m ActinfilamentMyosinfilamentMyosinheadChloroplast(a)(b)(c)Myosin motors in muscle cell contractionCytoplasmic streaming in plant cellsAmoeboid movementExtendingpseudopodiumCortex (outer cytoplasm):gel with actin networkInner cytoplasm(more fluid)100 m 30 m
2015 Pearson Education LtdFigure 6.26 Microfilaments and motility 167
Figure 6.26aMuscle cell0.5 m ActinfilamentMyosinfilamentMyosinhead(a)Myosin motors in muscle cell contraction
2015 Pearson Education LtdFigure 6.26a Microfilaments and motility (part 1: muscle cell contraction) 168
Figure 6.26aa0.5 m
2015 Pearson Education LtdFigure 6.26aa Microfilaments and motility (part 1a: muscle cell contraction, TEM) 169
Figure 6.26b(b)Amoeboid movementExtendingpseudopodiumCortex (outer cytoplasm):gel with actin networkInner cytoplasm(more fluid)100 m
2015 Pearson Education LtdFigure 6.26b Microfilaments and motility (part 2: amoeboid movement) 170
Video: Actin Network in Crawling Cells
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Figure 6.26cChloroplast(c)Cytoplasmic streaming in plant cells30 m
2015 Pearson Education LtdFigure 6.26b Microfilaments and motility (part 3: cytoplasmic streaming) 172
Video: Cytoplasmic Streaming
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Video: Chloroplast Movement
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Localized contraction brought about by actin and myosin also drives amoeboid movementCells crawl along a surface by extending pseudopodia (cellular extensions) and moving toward them
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Cytoplasmic streaming is a circular flow of cytoplasm within cellsThis streaming speeds distribution of materials within the cellIn plant cells, actin-myosin interactions and sol-gel transformations drive cytoplasmic streaming
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Intermediate FilamentsIntermediate filaments range in diameter from 812 nanometers, larger than microfilamentsbut smaller than microtubulesThey support cell shape and fix organellesin placeIntermediate filaments are more permanent cytoskeleton fixtures than the other two classes
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Concept 6.7: Extracellular components and connections between cells help coordinate cellular activitiesMost cells synthesize and secrete materials that are external to the plasma membraneThese extracellular structures are involved in a great many cellular functions
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Cell Walls of PlantsThe cell wall is an extracellular structure that distinguishes plant cells from animal cellsProkaryotes, fungi, and some unicellular eukaryotes also have cell wallsThe cell wall protects the plant cell, maintains its shape, and prevents excessive uptake of waterPlant cell walls are made of cellulose fibers embedded in other polysaccharides and protein
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Plant cell walls may have multiple layersPrimary cell wall: Relatively thin and flexibleMiddle lamella: Thin layer between primary walls of adjacent cellsSecondary cell wall (in some cells): Added between the plasma membrane and the primary cell wallPlasmodesmata are channels between adjacent plant cells
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Figure 6.27Secondarycell wallPrimarycell wallMiddlelamellaCentral vacuoleCytosolPlasma membranePlant cell wallsPlasmodesmata1 m
2015 Pearson Education LtdFigure 6.27 Plant cell walls 181
Figure 6.27aSecondarycell wallPrimarycell wallMiddlelamella1 m
2015 Pearson Education LtdFigure 6.27a Plant cell walls (part 1: TEM) 182
The Extracellular Matrix (ECM) of Animal CellsAnimal cells lack cell walls but are covered by an elaborate extracellular matrix (ECM)The ECM is made up of glycoproteins such as collagen, proteoglycans, and fibronectinECM proteins bind to receptor proteins in the plasma membrane called integrins
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Figure 6.28CollagenFibronectinPlasmamembraneA proteoglycancomplexPolysaccharidemoleculeMicrofilamentsCarbo-hydratesCore proteinProteoglycanmoleculeCYTOPLASM
IntegrinsEXTRACELLULAR FLUID
2015 Pearson Education LtdFigure 6.28 Extracellular matrix (ECM) of an animal cell 184
Figure 6.28aCollagenFibronectinPlasmamembraneA proteoglycancomplexMicrofilamentsCYTOPLASM
IntegrinsEXTRACELLULAR FLUID
2015 Pearson Education LtdFigure 6.28a Extracellular matrix (ECM) of an animal cell (part 1: detail of art) 185
Figure 6.28bPolysaccharidemoleculeCarbo-hydratesCore proteinProteoglycanmolecule
2015 Pearson Education LtdFigure 6.28b Extracellular matrix (ECM) of an animal cell (part 2: proteoglycan complex) 186
Video: Cartoon Model of a Collagen Triple Helix
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Video: E-Cadherin Expression
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Video: Fibronectin Fibrils
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Video: Staining of the Cell-Cell Junctions
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The ECM has an influential role in the lives of cellsECM can regulate a cells behavior by communicating with a cell through integrinsThe ECM around a cell can influence the activity of gene in the nucleusMechanical signaling may occur through cytoskeletal changes, that trigger chemical signals in the cell
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Cell JunctionsNeighboring cells in tissues, organs, or organ systems often adhere, interact, and communicate through direct physical contact
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Plasmodesmata in Plant CellsPlasmodesmata are channels that perforate plant cell wallsThrough plasmodesmata, water and small solutes (and sometimes proteins and RNA) can pass from cell to cell
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Figure 6.29
Interiorof cellInteriorof cell0.5 mPlasmodesmataPlasma membranesCell walls
2015 Pearson Education LtdFigure 6.29 Plasmodesmata between plant cells 194
Tight Junctions, Desmosomes, and Gap Junctions in Animal CellsThree types of cell junctions are common in epithelial tissuesAt tight junctions, membranes of neighboring cells are pressed together, preventing leakage of extracellular fluidDesmosomes (anchoring junctions) fasten cells together into strong sheetsGap junctions (communicating junctions) provide cytoplasmic channels between adjacent cells
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Figure 6.30Tight junctions preventfluid from movingacross a layer of cells.TightjunctionTEM0.5 mTight junctionDesmosomeIntermediatefilamentsGapjunctionIons or smallmoleculesPlasmamembranes ofadjacent cellsSpacebetween cellsExtracellularmatrixDesmosome(TEM)1 m0.1 mGap junctionsTEM
2015 Pearson Education LtdFigure 6.30 Exploring cell junctions in animal tissues 196
Figure 6.30aTight junctions prevent fluid from movingacross a layerof cells.Tight junctionDesmosomeIntermediatefilamentsGapjunctionIons or smallmoleculesPlasmamembranes ofadjacent cellsSpacebetween cellsExtracellularmatrix
2015 Pearson Education LtdFigure 6.30a Exploring cell junctions in animal tissues (part 1: detail of art) 197
Figure 6.30bTightjunctionTEM0.5 m
2015 Pearson Education LtdFigure 6.30b Exploring cell junctions in animal tissues (part 2: tight junction, TEM) 198
Figure 6.30c1 mDesmosome(TEM)
2015 Pearson Education LtdFigure 6.30c Exploring cell junctions in animal tissues (part 3: desmosome, TEM) 199
Figure 6.30d0.1 mGap junctionsTEM
2015 Pearson Education LtdFigure 6.30d Exploring cell junctions in animal tissues (part 4: gap junctions, TEM) 200
Animation: Desmosomes
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Animation: Gap Junctions
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Animation: Tight Junctions
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The Cell: A Living Unit Greater Than the Sum of Its PartsCells rely on the integration of structures and organelles in order to functionFor example, a macrophages ability to destroy bacteria involves the whole cell, coordinating components such as the cytoskeleton, lysosomes, and plasma membrane
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Figure 6.315 m
2015 Pearson Education LtdFigure 6.31 The emergence of cellular functions 205
Figure 6.UN01a1 mBuddingcellMature parentcell
2015 Pearson Education LtdFigure 6.UN01a Skills exercise: using a scale bar to calculate volume and surface area of a cell (part 1) 206
Figure 6.UN01bV=43_r3rd
2015 Pearson Education LtdFigure 6.UN01b Skills exercise: using a scale bar to calculate volume and surface area of a cell (part 2) 207
Figure 6.UN02Nucleus5 m
2015 Pearson Education LtdFigure 6.UN02 In-text figure, nucleus, p. 102 208
Figure 6.UN03
2015 Pearson Education LtdFigure 6.UN03 Summary of key concepts: nucleus and ribosomes 209
Figure 6.UN04
2015 Pearson Education LtdFigure 6.UN04 Summary of key concepts: endomembrane system 210
Figure 6.UN05
2015 Pearson Education LtdFigure 6.UN05 Summary of key concepts: mitochondria, chloroplasts and peroxisomes 211
Figure 6.UN06Epithelial cell
2015 Pearson Education LtdFigure 6.UN06 Test your understanding, question 12 212