M I T O S I S

MITOSIS

Mitosis is…•The process of cell growth & division

*The splitting of the nucleus.

• There are 5 parts of Mitosis:–I Interphase *Growth*–P Prophase–M Metaphase–A Anaphase–T Telophase

Anaphase

Interphase

Telophase

Prophase

Interphase

• This cell shows how all cells look before mitosis.

• Interphase is a phase of the cell cycle, but technically, NOT a stage of mitosis.

Prophase• The nuclear membrane breaks down.• The chromosomes shorten and

thicken. • The other structures important for

mitosis are also forming (ex. the centrioles).

Metaphase

*The chromosomes are pulled to the cell's equator by the spindle fibers.

*The chromosomes MEET IN THE MIDDLE

Detail…• Here's the confusing part -

When the individual chromatids (½ of the "X") are separated from the chromosome (the "X"),

• They are now, each referred to as a full chromosome.

• In other words, the chromosome, composed of two chromatids, separates into the separate chromatids, which are then renamed chromosomes, even though they were only one half of a chromosome only moments before! - Whew!

Anaphase

• The newly formed chromosomes are pulled by the spindle fibers toward opposite poles of the cell.

Telophase

• The chromosomes stop moving.• The spindle fibers break down. • The membrane of the cell pinches

creating two separate cells. • The nuclear membrane reforms.• The nucleolus reappears.

Very Last Part…Cytokinesis

• This is when the two new cells completely divide.

• Plant and Animal cells do this differently!

Animal Cell• A ring (contractile ring) tightens and

tightens until the two new cells pinch apart.

Cleavage Furrow

Plant Cell• A cell plate forms between the two cells

and this forms into the cell wall eventually.