MitosiMitosiss

Prepared by: Clarissa Marie M. Laruan BSEd Biological Sciences-3

MitosisMitosisMitosisMitosis

DivisionDivision of the of the nucleusnucleus Also called Also called karyokinesiskaryokinesis Only occurs in Only occurs in eukaryoteseukaryotes Has Has four stages Doesn’t occur in some cells such Doesn’t occur in some cells such as as brain cellsbrain cells

Four Mitotic StagesFour Mitotic Stages

ProProphasephaseMetaMetaphasephaseAnaAnaphasephaseTeloTelophasephase

Early ProphaseEarly Prophase

ChromatinChromatin in nucleus condenses to formin nucleus condenses to form visible chromosomesvisible chromosomes

Mitotic spindle Mitotic spindle forms from fibers in forms from fibers in cytoskeleton orcytoskeleton or centrioles (animal)centrioles (animal)

NucleolusNucleolus

ChromosomesChromosomesNuclear MembraneNuclear Membrane

CytoplasmCytoplasm

Late ProphaseLate Prophase

Nuclear membrane & nucleolusNuclear membrane & nucleolus are are broken downbroken down

ChromosomesChromosomes continue condensing continue condensing & are& are clearly visibleclearly visible

Spindle fibers calledSpindle fibers called kinetochoreskinetochores attach to the centromereattach to the centromere of each of each chromosomechromosome

SpindleSpindle finishes forming between thefinishes forming between the poles of the cellpoles of the cell

Chromosomes Chromosomes

Nucleus & Nucleolus have disintegratedNucleus & Nucleolus have disintegrated

Spindle FibersSpindle Fibers

The mitotic spindle form from the microtubules in plants and centrioles in animal cells

Polar fibers extend from one pole of the cell to the opposite pole

Kinetochore fibers extend from the pole to the centromere of the chromosome to which they attach

Asters are short fibers radiating from centrioles

SketchSketch of of The Spindle The Spindle

MetaphaseMetaphase

Chromosomes, Chromosomes, attached to attached to the the kinetochore kinetochore fibersfibers, move to , move to the center of the center of the cellthe cell

Chromosomes Chromosomes are now lined are now lined up at the up at the equatorequator Pole of the CellPole of the Cell

Equator of CellEquator of Cell

AnaphaseAnaphase

OccursOccurs rapidlyrapidly Sister chromatidsSister chromatids are pulled apart toare pulled apart to

opposite polesopposite poles of the cell by kinetochore of the cell by kinetochore fibersfibers

Sister Chromatids Sister Chromatids being separatedbeing separated

TelophaseTelophase

Sister chromatids at Sister chromatids at opposite polesopposite polesSpindleSpindle disassemblesdisassemblesNuclear envelopeNuclear envelope forms around forms around

each set of sister chromatidseach set of sister chromatidsNucleolusNucleolus reappearsreappearsCYTOKINESISCYTOKINESIS occursChromosomes reappear asChromosomes reappear as

chromatinchromatin

Daughter Cells of MitosisDaughter Cells of Mitosis

Have theHave the same number of same number of chromosomes as each other and as chromosomes as each other and as the parent cellthe parent cell from which they were from which they were formedformed

IdenticalIdentical to each other, butto each other, but smaller smaller than parent cellthan parent cell

MustMust grow in sizegrow in size to become mature to become mature cells cells (G(G11 of Interphase) of Interphase)

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