Transcript Mitosis ppt

Mitosis
Cell Reproduction
Mitosis
Definition: Cell Division that produces two
cells that are identical to each other and
to the parent cell.
 This produces body cells so the organism
can grow or replace dead/damaged cells.

“C” Words:
Chromatin-Strands of
DNA in a cell that is
not dividing—
unwound and
indistinct.
 ChromosomesStrands of DNA in a
cell that is dividing—
wound up and
distinct.

Chromatin is unwound and
indistinct in the nucleus of the cell.
More “C” Words:
Chromatids—one of 2
identical strands of
DNA in a chromosome
(called sister
chromatids)
 Centromere—the
structure that holds
together the 2 sister
chromatids.

Histones-protein “beads” that keep the
strand of DNA from tangling up.
Chromosome Structure

When cells begin to
divide, the first thing
that happens is that
the chromatin in the
nucleus begins to
wind up, separating
the strands from each
other.
Each chromosome consists of 2
identical strands of DNA (called
sister chromatids) held together
with a centromere.
More “C” Words
Centrosome/Centriole
-Structure found in
animal cells that
anchors the spindle
fibers
 Cytokinesis—the
division of the
cytoplasm following
mitosis (the dividing
of the nucleus)

Cell Cycle
Interphase
DNA is in the form
of chromatin here:
Interphase
A cell in Interphase is not actively
dividing. It is working very hard,
however—growth, replicating DNA
and preparing to divide.
Prophase
Prophase
Centrioles migrate to the poles.
Nuclear Membrane disappears.
Chromatin winds up to form
chromosomes.
Spindle forms.
Metaphase
Metaphase
Metaphase
Chromosomes move to the equator
of the cell.
Anaphase
Chromosomes split in half at
centromere.
Each chromatid moves to opposite
poles.
Chromosome Structure At
Anaphase
Chromosomes prior to Anaphase
^
Centromere splits and chromatids go to
opposite poles of cell
Telophase
Telophase
Chromosomes unwind to form
chromatin again.
New nuclear membranes form.
Spindle disappears
Cytokinesis
Cytokinesis in an Animal Cell: A
cleavage furrow forms, eventually
pinching in the cell membrane to
form 2 cells.
Cytokinesis in a Plant Cell: A cell plate
forms between the 2 new nuclei—
eventually dividing the cell into 2 cells.
The cell plate becomes the new cell wall.
Cytokinesis in Animal Cells (on left)
and Plant Cells (on right)
Summary of Mitosis
Mitosis Animation

http://www.cellsalive.com/mitosis.htm
http://highered.mcgrawhill.com/sites/0072495855/student_view0/
chapter2/animation__mitosis_and_cytokin
esis.html
 http://www.youtube.com/watch?v=VlN7K
1-9QB0
