MitosisMitosis

Cell ReproductionCell Reproduction

MitosisMitosis

Definition: Cell Division that produces Definition: Cell Division that produces two cells that are identical to each two cells that are identical to each other and to the parent cell.other and to the parent cell.

This produces body cells so the This produces body cells so the organism can grow or replace organism can grow or replace dead/damaged cells.dead/damaged cells.

““C” Words:C” Words:

Chromatin-Strands Chromatin-Strands of DNA in a cell of DNA in a cell that is not dividingthat is not dividing—unwound and —unwound and indistinct.indistinct.

Chromosomes-Chromosomes-Strands of DNA in a Strands of DNA in a cell that is dividingcell that is dividing—wound up and —wound up and distinct.distinct.

Chromatin is unwound and indistinct in the nucleus of the cell.

More “C” Words:More “C” Words:

Chromatids—one of Chromatids—one of 2 identical strands 2 identical strands of DNA in a of DNA in a chromosome (called chromosome (called sister chromatids)sister chromatids)

Centromere—the Centromere—the structure that holds structure that holds together the 2 sister together the 2 sister chromatids.chromatids. Histones-protein “beads” that keep

the strand of DNA from tangling up.

Chromosome StructureChromosome Structure

When cells begin to When cells begin to divide, the first divide, the first thing that happens thing that happens is that the is that the chromatin in the chromatin in the nucleus begins to nucleus begins to wind up, separating wind up, separating the strands from the strands from each other. each other.

Each chromosome consists of 2 identical strands of DNA (called sister chromatids) held together with a centromere.

More “C” WordsMore “C” Words

Centrosome/Centrosome/Centriole-Structure Centriole-Structure found in animal found in animal cells that anchors cells that anchors the spindle fibersthe spindle fibers

Cytokinesis—the Cytokinesis—the division of the division of the cytoplasm following cytoplasm following mitosis (the dividing mitosis (the dividing of the nucleus)of the nucleus)

Cell CycleCell Cycle

InterphaseInterphase

Interphase

A cell in Interphase is not actively dividing. It is working very hard, however—growth, replicating DNA and preparing to divide.

DNA is in the form of chromatin here:

ProphaseProphase

Centrioles migrate to the poles. Nuclear Membrane disappears.

Chromatin winds up to form chromosomes.

Spindle forms.

Prophase

MetaphaseMetaphase

Metaphase

Metaphase

Chromosomes move to the equator of the cell.

AnaphaseAnaphase

Chromosomes split in half at centromere.

Each chromatid moves to opposite poles.

Chromosome Structure At Chromosome Structure At AnaphaseAnaphase

Centromere splits and chromatids go to opposite poles of cell

Chromosomes prior to Anaphase ^

TelophaseTelophase

TelophaseChromosomes unwind to form chromatin again.

New nuclear membranes form.

Spindle disappears

CytokinesisCytokinesis

Cytokinesis in an Animal Cell: A cleavage furrow forms, eventually pinching in the cell membrane to form 2 cells.

Cytokinesis in a Plant Cell: A cell plate forms between the 2 new nuclei—eventually dividing the cell into 2 cells. The cell plate becomes the new cell wall.

Cytokinesis in Animal Cells (on Cytokinesis in Animal Cells (on left) and Plant Cells (on right)left) and Plant Cells (on right)

Summary of MitosisSummary of Mitosis

Mitosis AnimationMitosis Animation

http://www.cellsalive.com/mitosis.htmhttp://www.cellsalive.com/mitosis.htm

http://highered.mcgraw-hill.com/sites/http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/0072495855/student_view0/chapter2/animation__mitosis_and_cytokinesis.htanimation__mitosis_and_cytokinesis.htmlml

http://www.youtube.com/watch?http://www.youtube.com/watch?v=VlN7K1-9QB0v=VlN7K1-9QB0