Download Stem cells

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.
Cancer is uncontrolled mitosis with no differentiation.
Licentious division - prostate cancer cells during division.
A cell’s life:
DNA is Packaged into Chromosomes
duplicated
chromosome
chromatin
The packaging is impressive – 2 meters of human DNA fit into a sphere about
0.000005 meters in diameter.
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.
During Mitosis
Chromosomes divide.
Cytokinesis occurs
*
1.Prophase
2.Metaphase
3.Anaphase
4.Telophase
interphase
Interphase – DNA
replication is completed.
prophase
metaphase
Prophase – Chromosomes shorten and
thicken, centrioles appear, nuclear
membrane disintegrates.
Metaphase – chromosomes line up on
equatorial plate in middle of cell.
Anaphase – chromatids are pulled
apart, chromosomes pulled to
opposite sides of the cell
Telophase – Cytokinesis
occurs, 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=VlN7K19QB0