MITOSIS

PROPHASE Chromatin fibers become coiled into chromosomes with each

chromosome having two chromatids joined at a centromere The mitotic spindle, composed of microtubules and proteins, forms in

the cytoplasm In animal cells, the mitotic spindle initially appear as asters which

surround each centriole pair The two pairs of centrioles move away from one another toward

oppostie ends of the cell The nuclear envelope breaks up Polar fibers, which are microtubules that make up the spindle fibers,

reach from each cell pole to the cell’s equator Kinetochores attach to kinetochore fibers The kinetochore fibers interact with the spindle polar fibers connecting

the kinetochores to the polar fibers The chromosomes begin to migrate toward the cell center

ANIMAL PLANT

METAPHASE Nuclear membrane disappears completely In animal cells, the two pair of centrioles align at opposite

poles of the cell Polar fibers continue to extend from the poles to the

center of the cell Chromosomes move randomly until they attach to polar

fibers from both sides of their centromeres Chromosomes align at the metaphase plate at right angles

to the spindle poles Chromosomes are held at the metaphase plate by the

equal forces of the polar fibers pushing on the centromeres of the chromosomes

the nuclear membrane fragmention is complete and the duplicated chromosomes line up along the cell's equator.

ANIMAL PLANT

ANAPHASE The paired centromeres in each distinct chromosome

begin to move apart The paired sister chromatids separate from one another,

each is considered a full chromosome. They are referred to as daughter chromosomes

The daughter chromosomes move to the poles at opposite ends of the cell

Daughter chromosomes migrate centromere first and the kinetochore fibers become shorter as the chromosomes near a pole

In preparation for telophase the two cell poles also move further apart during the course of anaphase.

At the end of anaphase, each pole contains a complete compilation of chromosomes

ANIMAL PLANT

TELOPHASE Polar fibers continue to lengthen Nuclei begin to form at opposite poles The nuclear envelope of these nuclei are formed from

remnant pieces of the parent cell’s nuclear envelope and from pieces of the endomembrane system

Nucleoli reappear Chromatin fibers of chromosomes uncoil After these changes, mitosis is largely complete and

the genetic contents of one cell have been divided equally into two

Cytokinesis begins prior to the end of mitosis and completes shortly after, at the end of cytokinesis there are two distinct daughter cells

ANIMAL PLANT

WORKS CITED http://student.ccbcmd.edu/~gkaiser/bio

tutorials/dna/mitosis/mitosis.html http://student.ccbcmd.edu/~gkaiser/bio

tutorials/dna/mitosis/pcprophaseA.html http://biology.about.com/od/mitosis/ss/

mitosisstep.htm