BIOL 222 Ch 6 Cell part 2 2016
Transcript of BIOL 222 Ch 6 Cell part 2 2016
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• Phagocytosis
• Onecellengulfinganother
• formsafoodvacuole
• fuseswithlysosome
• Autophagy
• Lysosomesuseenzymes
• torecyclethecell’sownorganelles
andmacromolecules
Lysosomes
Fig.6-14
Nucleus 1 µm
LysosomeDigestive enzymes
Lysosome
Plasma membrane
Food vacuole
(a) Phagocytosis
Digestion
(b) Autophagy
Peroxisome
Vesicle
Lysosome
Mitochondrion
Peroxisome fragment
Mitochondrion fragment
Vesicle containing two damaged organelles 1 µm
Digestion
• Aplantcellorfungalcellmayhaveoneor
severalvacuoles
• Foodvacuoles
• formedbyphagocytosis
• Contrac9levacuoles
• foundinmanyfreshwaterproBsts,
pumpexcesswateroutofcells
• Centralvacuoles
• foundinmanymatureplantcells,
holdorganiccompoundsandwater
Vacuoles
Central vacuole
Cytosol
Central vacuole
Nucleus
Cell wall
Chloroplast
5 µm
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MitochondriaandChloroplasts
• Mitochondria
– sitesofcellularrespiraBon
– Inplantstoo
• Chloroplasts
• inplantsandalgaeonly
• sitesofphotosynthesis
• Bothchangeenergyfromoneform
toanother
• Mitochondriaandchloroplasts
• Arenotpartoftheendomembranesystem
• Haveadoublemembrane
• Haveproteinsmadebyfreeribosomes
• ContaintheirownDNA?!
• Endosymbionttheory
MitochondriaandChloroplasts
• h<p://www.sciencedaily.com/releases/2011/07/110725190046.htm
• h<p://www.nature.com/srep/2011/110614/srep00013/full/srep00013.html
Mitochondria• Mitochondria
• innearlyalleukaryoBccells
• AllhaveevoluBonarydescendants
ofmitochondria
• Cristae
• Foldsofinnermembranetoincreasesurfacearea
• innermembrane
• createstwocompartments:
• intermembranespace
• ForH+gradientofelectrontransportchain
• mitochondrialmatrix
• ForKrebsCycle
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Fig.6-17
Free ribosomes in the mitochondrial matrix
Intermembrane spaceOuter membrane
Inner membraneCristae
Matrix
0.1 µm
• Chloroplaststructureincludes:
• Thylakoids
• membranoussacs,stackedtoformagranum
• Stroma
• internalfluid
Chloroplasts
Ribosomes
Thylakoid
Stroma
Granum
Inner and outer membranes
1 µm
Peroxisomes:Oxida9on• Peroxisomes
• Specializedmetaboliccompartments
• Boundbyasinglemembrane
• Oxygenusedtobreakdowndifferenttypesofmolecules
• H2O2by-productconvertedtowater
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Cytoskeleton• Cytoskeleton
• networkofproteinfibersextending
throughoutthecytoplasm
• organizesthecell’sstructuresand
acBviBes
• anchorsmanyorganelles
• composedofthreetypesofmolecular
structures:
• Microtubules
• Microfilaments
• Intermediatefilaments
Cytoskeleton:Support,Mo9lity,andRegula9on• Cytoskeleton
• supportthecellandmaintainitsshape
• motorproteins
• producemoBlity
• vesiclescantravelalong“monorails”
• providedbythecytoskeleton
• Recentevidencesuggests
• cytoskeletonmayhelpregulatebiochemical
acBviBes
PLAY
ComponentsoftheCytoskeleton
• Threemaintypesoffibersmakeup
thecytoskeleton:
• Microtubules
• thickest
• Intermediatefilaments
• Mediumsizeddiameter
• Microfilaments
• Thinnest
• alsocalledacBnfilaments
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• Centrosomes
• Structurenearnucleusfromwhere
microtubulesgrow
• a“microtubule-organizingcenter”
• Inanimalcells
• Consistsoftwocentrioles
• Centrioles
• PairedstructuresconsisBngofnine
tripletsofmicrotubulesarranged
inaring
MicrotubulesandCellDivision
Centrosome
Microtubule
Centrioles0.25 µm
Longitudinal section of one centriole
Microtubules Cross section of the other centriole
ExtracellularMatrix
• Mostcellssynthesizeandsecrete
materials
• thatareexternaltotheplasma
membrane
• Theseextracellularstructuresinclude:
• Cellwallsofplants
• Theextracellularmatrix(ECM)of
animalcells
• IntercellularjuncBons
CellWallsofPlants• cellwall
• extracellularstructure
• disBnguishesplantcellsfromanimalcells
• madeofcellulosefibers
• embeddedinotherpolysaccharidesandprotein
• protectstheplantcell,maintainsitsshape,andpreventsexcessiveuptakeofwater
• Prokaryotes,fungi,andafewproBstsalsohavecellwalls
• Bacteria-pepBdoglycan
• Fungi-chiBn
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TheExtracellularMatrix(ECM)ofAnimalCells
• Extracellularmatrix(ECM)
• AnimalcellslackcellwallsbutarecoveredbyECM
• madeupofglycoproteins
• Collagen
• Proteoglycans
• fibronec9n
• Integrins
• ReceptorproteinsintheplasmamembranetowhichECMproteinsbind
• FuncBonsoftheECM:
• Support
• AnchorageandseparaBonofdifferentBssues
• Adhesion
• BindcellstogetherwithinBssues
• Movement
• GuideforcellmigraBoninembryonicdevelopment
• RegulaBon
• PropagaBonofexternalsBmulitonucleus
ExtracellularMatrix
Fig.6-30
EXTRACELLULAR FLUIDCollagen
Fibronectin
Plasma membrane
Micro- filaments
CYTOPLASM
Integrins
Proteoglycan complex
Polysaccharide molecule
Carbo- hydrates
Core protein
Proteoglycan molecule
Proteoglycan complex
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IntercellularJunc9ons
• IntercellularjuncBons
• facilitatecontactbetweenneighboringcellsinBssues,organs,ororgan
systems
• adhere,interact,andcommunicatethroughdirectphysicalcontact
• Types
• Plasmodesmata
• Plantsonly
• TightjuncBons
• Desmosomes
• GapjuncBons
PlasmodesmatainPlantCells
• Plasmodesmata
• channelsthatperforateplantcellwalls
• waterandsmallsolutes
• someBmesproteinsandRNA
• canpassfromcelltocell
• PlasmamembraneconBnuous
• fromonecelltoanother
Fig.6-31
Interior of cell
Interior of cell
0.5 µm Plasmodesmata Plasma membranes
Cell walls
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TightJunc9ons,Desmosomes,andGapJunc9ons• 9ghtjunc9ons
• Leak-proofbarrier
• Plasmamembranessqueezedtogether
• DigesBvesystem
• Desmosomes
• anchoringjuncBonsfastencellstogetherintostrongsheets
• rivets
• Gapjunc9ons
• communicaBngjuncBonsprovidecytoplasmicchannelsbetweenadjacentcells
Tight junctions prevent fluid from moving across a layer of cells
Tight junction
Intermediate filaments
Desmosome
Gap junctions
Extracellular matrixSpace
between cells
Plasma membranes of adjacent cells
Youshouldnowbeableto:1. DisBnguishbetweenthefollowingpairsofterms:magnificaBonand
resoluBon;prokaryoBcandeukaryoBccell;freeandboundribosomes;smoothandroughER
2. DescribethestructureandfuncBonofthecomponentsoftheendomembranesystem
3. Brieflyexplaintheroleofmitochondria,chloroplasts,andperoxisomes
4. DescribethefuncBonsofthecytoskeleton
5. ComparethestructureandfuncBonsofmicrotubules,microfilaments,andintermediatefilaments
6. ExplainhowtheultrastructureofciliaandflagellarelatetotheirfuncBons
7. Describethestructureofaplantcellwall
8. Describethestructureandrolesoftheextracellularmatrixinanimalcells
9. DescribefourdifferentintercellularjuncBons