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