The Cell Cycle

The Cell Cycle copyright cmassengale11Five Phases of the Cell CycleG1 - primary growth phaseS synthesis; DNA replicatedG2 - secondary growth phasecollectively these 3 stages are called interphaseM - mitosisC - cytokinesiscopyright cmassengale22Cell Cyclecopyright cmassengale3

3Interphase - G1 Stage1st growth stage after cell divisionCells mature by making more cytoplasm & organellesCell carries on its normal metabolic activitiescopyright cmassengale44Interphase S StageSynthesis stageDNA is copied or replicated

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Two identical copies of DNAOriginal DNA5Interphase G2 Stage2nd Growth StageOccurs after DNA has been copiedAll cell structures needed for division are made (e.g. centrioles)Both organelles & proteins are synthesizedcopyright cmassengale66Whats Happening in Interphase?copyright cmassengale7

What the cell looks likeAnimal CellWhats occurring7Sketch the Cell Cyclecopyright cmassengale8

Daughter CellsDNA CopiedCells MatureCells prepare for DivisionCell Divides into Identical cells8Mitosiscopyright cmassengale99MitosisDivision of the nucleusAlso called karyokinesisOnly occurs in eukaryotesHas four stagesDoesnt occur in some cells such as brain cells

copyright cmassengale1010Four Mitotic StagesProphaseMetaphaseAnaphaseTelophase

copyright cmassengale1111Early ProphaseChromatin in nucleus condenses to form visible chromosomesMitotic spindle forms from fibers in cytoskeleton or centrioles (animal)copyright cmassengale12

ChromosomesNucleolusCytoplasmNuclear Membrane12Late ProphaseNuclear membrane & nucleolus are broken downChromosomes continue condensing & are clearly visibleSpindle fibers called kinetochores attach to the centromere of each chromosomeSpindle finishes forming between the poles of the cell copyright cmassengale1313Late Prophasecopyright cmassengale14

Nucleus & Nucleolus have disintegratedChromosomes 14Spindle Fiber attached to Chromosomecopyright cmassengale15

Kinetochore FiberChromosome15Review of Prophasecopyright cmassengale16

What the cell looks likeWhats happening16Spindle FibersThe mitotic spindle form from the microtubules in plants and centrioles in animal cellsPolar fibers extend from one pole of the cell to the opposite poleKinetochore fibers extend from the pole to the centromere of the chromosome to which they attachAsters are short fibers radiating from centrioles

copyright cmassengale1717Sketch The Spindle

copyright cmassengale1818MetaphaseChromosomes, attached to the kinetochore fibers, move to the center of the cellChromosomes are now lined up at the equatorcopyright cmassengale19

Pole of the CellEquator of Cell19Metaphasecopyright cmassengale20

Chromosomes lined at the EquatorAsters at the polesSpindle Fibers20Metaphasecopyright cmassengale21

AsterChromosomes at Equator21Review of Metaphasecopyright cmassengale22

What the cell looks likeWhats occurring22AnaphaseOccurs rapidlySister chromatids are pulled apart to opposite poles of the cell by kinetochore fibers

copyright cmassengale2323Anaphasecopyright cmassengale24

Sister Chromatids being separated24Anaphase Reviewcopyright cmassengale25

What the cell looks likeWhats occurring25TelophaseSister chromatids at opposite polesSpindle disassemblesNuclear envelope forms around each set of sister chromatidsNucleolus reappearsCYTOKINESIS occursChromosomes reappear as chromatin

copyright cmassengale2626Comparison of Anaphase & Telophasecopyright cmassengale27

27CytokinesisMeans division of the cytoplasmDivision of cell into two, identical halves called daughter cellsIn plant cells, cell plate forms at the equator to divide cellIn animal cells, cleavage furrow forms to split cellcopyright cmassengale2828Cytokinesiscopyright cmassengale29

Cleavage furrow in animal cellCell plate in plant cell29Mitotic Stagescopyright cmassengale30

30Daughter Cells of MitosisHave the same number of chromosomes as each other and as the parent cell from which they were formedIdentical to each other, but smaller than parent cellMust grow in size to become mature cells (G1 of Interphase)

copyright cmassengale3131Identical Daughter Cellscopyright cmassengale32

Chromosome number the same, but cells smaller than parent cellWhat is the 2n or diploid number?232Review of Mitosiscopyright cmassengale33

33Draw & Learn these Stagescopyright cmassengale34

34Draw & Learn these Stagescopyright cmassengale35

35Name the Mitotic Stages:copyright cmassengale36

InterphaseProphaseMetaphaseAnaphaseTelophaseName this?Name this?36Eukaryotic Cell DivisionUsed for growth and repairProduce two new cells identical to the original cellCells are diploid (2n)copyright cmassengale37

Chromosomes during Metaphase of mitosis

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis37Mitosis Animationcopyright cmassengale38

Name each stage as you see it occur?38Mitosis in Onion Root Tipscopyright cmassengale39Do you see any stages of mitosis?

39Test Yourself over Mitosiscopyright cmassengale4040Mitosis Quizcopyright cmassengale41

41Mitosis Quizcopyright cmassengale42

42Name the Stages of Mitosis:

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InterphaseEarly prophaseMid-ProphaseLate ProphaseMetaphaseLate AnaphaseEarly AnaphaseEarly Telophase, Begin cytokinesisLate telophase, Advanced cytokinesis43Identify the Stages

copyright cmassengale44Early, Middle, & Late Prophase Late ProphaseMetaphaseAnaphaseLate AnaphaseTelophaseTelophase & Cytokinesis???????44Locate the Four Mitotic Stages in Plantscopyright cmassengale45

MetaphaseProphaseAnaphaseTelophase45Uncontrolled MitosisIf mitosis is not controlled, unlimited cell division occurs causing cancerous tumorsOncogenes are special proteins that increase the chance that a normal cell develops into a tumor cell

copyright cmassengale46Cancer cells46