Mitosis is cell division in somatic cells.

Somatic cells = All the cells in your body that are not sex cells (eggs and sperm)

*Why?

*Unicellular organisms use it to reproduce.

*Why? Multicellular organisms use it for

growth

*Why?

Multicellular organisms use it to repair tissues

*Muscle and Nerve tissues do not normally do mitosis.

*Stem cells are cells that do mitosis, then the daughter cells undergo differentiation to become a specific type of cell in the multicellular organism.

Licentious division - prostate cancer cells during division.

Cancer is uncontrolled mitosis with no differentiation.

A cell’s life:

DNA is Packaged into Chromosomes

The packaging is impressive – 2 meters of human DNA fit into a sphere about 0.000005 meters in diameter.

chromatin

duplicatedchromosome

DNA replication:

It happens during INTERPHASE.

The Link Between DNA Replication and Chromosome Duplication

DNA is Condensed into Visible Chromosomes Only For Brief Periods in the Life of a Cell

95% of the time, DNA is like this.

CHROMATIN

SISTER CHROMATIDS: Duplicate chromosomes bound together by a centromere.

Chromosomes divide.

Cytokinesis occurs

During Mitosis

1.Prophase

2.Metaphase

3.Anaphase

4.Telophase

Prophase – Chromosomes shorten and thicken, centrioles appear, nuclear membrane disintegrates.Metaphase – chromosomes line up on equatorial plate in middle of cell.

interphase

prophase metaphase

Interphase – DNA replication is completed.

Anaphase – chromatids are pulledapart, chromosomes pulled to opposite sides of the cell

Telophase – Cytokinesisoccurs, cell returns to normal.

Mitosis in Action

Blue shows DNA, green shows spindle fibers.

In Animal Cells, a Cleavage Furrow Forms and Separates Daughter Cells during cytokinesis.

Cleave furrow in a dividing frog cell.

A cell plate forms between two plant cells to separate them.

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