MitosisMitosis

Chapter 10Chapter 10

Depending on cell type…Depending on cell type…

Mitosis can take a few minutes or a few Mitosis can take a few minutes or a few daysdays

Muscle cells Muscle cells Nerve cellsNerve cells Skin cellsSkin cells Digestive Tract cellsDigestive Tract cells

ProphaseProphase 50-60% of time50-60% of time Chromosomes become visibleChromosomes become visible Centrioles develop in cytoplasm near nuclear Centrioles develop in cytoplasm near nuclear

envelopeenvelope Centrioles separate and migrate to opposite ends Centrioles separate and migrate to opposite ends

of nuc. Env.of nuc. Env. CentrosomeCentrosome

Region where Centrioles are foundRegion where Centrioles are found Organize the “spindle”Organize the “spindle”

Fan like microtubule structure that helps separate Fan like microtubule structure that helps separate chromosomeschromosomes

Plants do NOT have CentriolesPlants do NOT have Centrioles

End of prophaseEnd of prophase

Chromosomes coil together tightlyChromosomes coil together tightly Nucleolus disappearsNucleolus disappears Nuclear envelope breaks downNuclear envelope breaks down

MetaphaseMetaphase

Few minutesFew minutes Chromosomes line up in middle (M in Chromosomes line up in middle (M in

metaphasemetaphase MIDDLE) MIDDLE) Microtubules connect centromere of each Microtubules connect centromere of each

chromosome to the 2 poles of spindlechromosome to the 2 poles of spindle

AnaphaseAnaphase

Centromeres joining sister chromatids Centromeres joining sister chromatids separate and become individual separate and become individual chromosomeschromosomes

They are dragged by fibers to opposite They are dragged by fibers to opposite polespoles

Ends when chromosomes stop movingEnds when chromosomes stop moving

TelophaseTelophase

Opposite of prophaseOpposite of prophase Condensed chromosomes disperse into Condensed chromosomes disperse into

tangle of materialtangle of material Nuclear envelope reformsNuclear envelope reforms Spindle breaks apartSpindle breaks apart Nucleolus becomes visibleNucleolus becomes visible At the endAt the end 2 identical nuclei in one cell 2 identical nuclei in one cell

CytokinesisCytokinesis Happens at the same time as TelophaseHappens at the same time as Telophase Division of cytoplasmDivision of cytoplasm Animal CellsAnimal Cells

Cell membrane drawn inward until it pinches Cell membrane drawn inward until it pinches off and forms 2 id daughter cellsoff and forms 2 id daughter cells

Plant CellsPlant Cells Cell plate forms between nucleiCell plate forms between nuclei Cell Plate develops into separate membrane Cell Plate develops into separate membrane Cell wall appearsCell wall appears