cell reproduction chromosomes cell division. chromosomes chromatinchromatin structure...
TRANSCRIPT
Cell ReproductionCell Reproduction
ChromosomesChromosomes
Cell DivisionCell Division
ChromosomesChromosomes
• Chromatin StructureChromatin Structure
• Chromosome StructureChromosome Structure
• Chromosome CondensationChromosome Condensation
• Sister ChromatidsSister Chromatids
LearningLearningObjectivesObjectives
• TSW …TSW …1.1. Distinguish between chromatin & Distinguish between chromatin &
condensed chromosomescondensed chromosomes
2.2. Describe the location & structure Describe the location & structure of a chromosomeof a chromosome
3.3. Describe chromosome Describe chromosome condensationcondensation
4.4. Explain what sister chromatids areExplain what sister chromatids are
ChromosomesChromosomes
• Chromosome StructureChromosome Structure DNADNA – deoxyribonucleic acid – deoxyribonucleic acid ProteinsProteins
HistonesHistones• Serve as “spools” for long DNA moleculeServe as “spools” for long DNA molecule• Maintain chromosome shapeMaintain chromosome shape
Nonhistone proteinsNonhistone proteins• Control regional activity of DNAControl regional activity of DNA
• Chromosome FunctionChromosome Function Genetic CodeGenetic Code – hereditary material – hereditary material
When NOT involved in cell When NOT involved in cell division, chromosomes division, chromosomes exist as chromatin – a exist as chromatin – a mixture of DNA & proteins mixture of DNA & proteins w/in the nucleusw/in the nucleus
Chromosome Chromosome CondensationCondensation
coiling around histonescoiling around histones
coiling into supercoilscoiling into supercoils
further coiling into visible further coiling into visible structures (light microscope)structures (light microscope)
histoneshistones
Chromosome & Sister Chromosome & Sister ChromatidsChromatids
• Terminology:Terminology: centromerecentromere
constricted regionconstricted region of chromosome of chromosome
sister chromatids are sister chromatids are joinedjoined here here
kinetochorekinetochore – structure w/in centromere – structure w/in centromere where spindle microtubules attach to sister where spindle microtubules attach to sister chromatidschromatids
1 kinetochore for each chromatid1 kinetochore for each chromatid
Roles of Cell DivisionRoles of Cell Division
• Asexual ReproductionAsexual Reproduction prokaryotesprokaryotes protistansprotistans fungifungi
• Growth & DevelopmentGrowth & Development multicellular organismsmulticellular organisms
• Repair & RegenerationRepair & Regeneration multicellular organismsmulticellular organisms
plantsplants primitive animalsprimitive animals
Growth & DevelopmentGrowth & Development
Multicellular Multicellular OrganismsOrganisms
Fertilized eggFertilized egg
Ist divisionIst division
Early embryoEarly embryo
Late embryoLate embryo
FetusFetus
ToddlerToddler
Young childYoung child
Young adultYoung adult
Tissue RenewalTissue Renewal
Multicellular Multicellular OrganismsOrganismsbone marrow bone marrow
stem cellsstem cells
Tissue RepairTissue Repair
The Cell Cycle MovieThe Cell Cycle Movie
• To View Video:To View Video:– Move mouse cursor over slide title-linkMove mouse cursor over slide title-link– When hand appears, click onceWhen hand appears, click once
• MOV Video plays about 1 minMOV Video plays about 1 min
Cell DivisionCell Division
• The Cell CycleThe Cell Cycle InterphaseInterphase MitosisMitosis CytokinesisCytokinesis
LearningLearningObjectivesObjectives
• TSW …TSW …1.1. Describe each phase of the cell Describe each phase of the cell
cyclecycle
2.2. Summarize the phases of mitosisSummarize the phases of mitosis
3.3. Compare cytokinesis in plant & Compare cytokinesis in plant & animal cellsanimal cells
Cytoskeletal Elements of Cytoskeletal Elements of DivisionDivision
• Terminology:Terminology: centrosomecentrosome
microtubule organizing center (MTOC)microtubule organizing center (MTOC)
synthesizes synthesizes mitoticmitotic spindlespindle
centriolescentrioles
animal cells onlyanimal cells only
2/centrosome2/centrosome
9 sets of triplet microtubules arranged in 9 sets of triplet microtubules arranged in ringring
Mitotic Cell Cycle: Mitotic Cell Cycle: OverviewOverview
• Major StagesMajor Stages of Mitotic Cell of Mitotic Cell Division:Division: InterphaseInterphase
Divided into Divided into 3 phases3 phases
Mitosis (M phase)Mitosis (M phase)Divided into Divided into 4 main phases4 main phasesPhases Phases oftenoften subdivided subdivided
Cytokinesis (M phase)Cytokinesis (M phase)Animal cell processAnimal cell processPlant cell processPlant cell process
““mitotic phase” = mitotic phase” = division of the cell:division of the cell:
mitosismitosis
cytokinesiscytokinesis
InterphaseInterphase::Phases of InterphasePhases of Interphase
• Preparatory StagePreparatory Stage:: GG11 phase phase
cell growthcell growth; ; organelles duplicateorganelles duplicate; ; mitochondria & chloroplasts self-replicatemitochondria & chloroplasts self-replicate
S phaseS phaseDNA replicationDNA replication
GG22 phase phaseenzymes & other materialsenzymes & other materials necessary for necessary for
division division synthesizedsynthesized; cell growth ; cell growth continuescontinues
DNA ReplicationDNA Replication
InterphaseInterphase
InterphaseInterphase
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• MOV Video plays about 25 secMOV Video plays about 25 sec
Phases of MitosisPhases of Mitosis
• PProphaserophase• PPrometaphaserometaphase• MMetaphaseetaphase• AAnaphasenaphase• TTelophaseelophase
PProud roud
PPittsburghittsburgh
MMadeade
AA
TTouchdownouchdown
A A
PneumonicPneumonic
Aide!Aide!
Mitosis: ProphaseMitosis: Prophase
• Division of the NucleusDivision of the Nucleus:: Early ProphaseEarly Prophase
chromosomes condensechromosomes condense as sister as sister chromatidschromatids
nucleoli dispersenucleoli dispersespindle apparatusspindle apparatus begins to form from begins to form from
centrosomes (centrosomes (MTOCMTOC))
Chromosome & Sister Chromosome & Sister ChromatidsChromatids
Mitosis:Mitosis:Early ProphaseEarly Prophase
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• MOV Video plays about 20 secMOV Video plays about 20 sec
Mitosis: Late ProphaseMitosis: Late Prophase
• Division of the NucleusDivision of the Nucleus:: Late ProphaseLate Prophase (Prometaphase) (Prometaphase)
nuclear envelope fragmentsnuclear envelope fragmentsmitotic spindle stretches across cellmitotic spindle stretches across cellspindle microtubulesspindle microtubules::
• Kinetochore tubulesKinetochore tubules – some – some attach to attach to chromosomeschromosomes at kinetochores at kinetochores
• Polar fibersPolar fibers – other microtubules stretch – other microtubules stretch toward poles toward poles
Mitosis:Mitosis:Late Prophase (Prometaphase)Late Prophase (Prometaphase)
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• MOV Video plays about 20 secMOV Video plays about 20 sec
Mitosis: MetaphaseMitosis: Metaphase
• Division of the NucleusDivision of the Nucleus: : (cont)(cont)
MetaphaseMetaphasespindlespindle across cell w/ centrosomes at across cell w/ centrosomes at
opposite polesopposite poleschromosomes line up acrosschromosomes line up across metaphasemetaphase
plateplate [ [cell equatorcell equator] ] with sister chromatids with sister chromatids on opposite sides of equatoron opposite sides of equator
• ““kinetochore tubules” attached to sister kinetochore tubules” attached to sister chromatidschromatids
• ““polar” microtubules span cell from equator to polar” microtubules span cell from equator to each poleeach pole
Spindle ApparatusSpindle Apparatus
CentrosomesCentrosomes
centrosomecentrosome
Kinetochore StructureKinetochore Structure
Mitosis:Mitosis:MetaphaseMetaphase
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• MOV Video plays about 12 secMOV Video plays about 12 sec
Mitosis: AnaphaseMitosis: Anaphase
• Division of the NucleusDivision of the Nucleus: : (cont)(cont)
AnaphaseAnaphasecentromeres separatecentromeres separatesister chromatids move to opposite cell sister chromatids move to opposite cell
polespoles as kinetochore tubules as kinetochore tubules shortenshortenPolar tubules Polar tubules lengthenlengthen to stretch cell to stretch cell
Kinetochore FunctionKinetochore Function
Mitosis:Mitosis:AnaphaseAnaphase
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• MOV Video plays about 22 secMOV Video plays about 22 sec
Mitosis: TelophaseMitosis: Telophase
• Division of the NucleusDivision of the Nucleus: : (cont)(cont)
(Early) Telophase(Early) Telophasepolar fibers polar fibers lengthenlengthen stretching cell stretching cellchromosomes (formerly sister chromosomes (formerly sister
chromatids) reach opposite poles of cellchromatids) reach opposite poles of cell
Mitosis: TelophaseMitosis: Telophase
• Division of the NucleusDivision of the Nucleus: : (cont)(cont)
(Late) Telophase(Late) Telophasedaughter nuclear envelopes reformdaughter nuclear envelopes reformdaughter nucleoli reformdaughter nucleoli reformchromosomeschromosomes decondensedecondense to to chromatinchromatin
Mitosis:Mitosis:TelophaseTelophase
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• MOV Video plays about 20 secMOV Video plays about 20 sec
CytokinesisCytokinesis
• Division of the CytoplasmDivision of the Cytoplasm:: Begins duringBegins during early telophaseearly telophase Finishes immediately Finishes immediately afterafter telophase telophase Daughter cells separated by different Daughter cells separated by different
mechanisms in plants & animalsmechanisms in plants & animals
CytokinesisCytokinesis
CytokinesisCytokinesis
• Cleavage furrowCleavage furrow formation: formation: animal cellsanimal cellsmicrofilaments attached to cell membrane microfilaments attached to cell membrane
shortenshortenCell isCell is pinched in twopinched in twoDaughter nuclei separatedDaughter nuclei separatedResults in 2 daughter cells with identical Results in 2 daughter cells with identical
genetic materialgenetic material
CytokinesisCytokinesis
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• MOV Video plays about 41 secMOV Video plays about 41 sec
Mitotic Cell Division:Mitotic Cell Division:Time LapseTime Lapse
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• ASF Video plays about 52 secASF Video plays about 52 sec
Review of Mitosis & Review of Mitosis & CytokinesisCytokinesis
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• MOV Video plays about 30 secMOV Video plays about 30 sec
Mitosis ReviewMitosis Review
Mitosis ReviewMitosis Review
Regulation of MitosisRegulation of Mitosis
CancerCancer
Cells & Human BiologyCells & Human Biology
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• ASX Video plays about 16 minASX Video plays about 16 min
Compound Light Compound Light MicroscopeMicroscope Arm
Base