Transcript Mitosis

Mitosis
5.2
I. Purpose
To grow more cells
Example: Growing taller, growing roots
To reproduce asexually
Example: Hydra buds to reproduce
Repair damaged tissue
Example: A tear in skin –cells multiply to repair
the tissue.
II. Overview
 Mitosis – the division of the eukaryotic cell’s
nucleus
 Cells divide into 2 daughter cells
 Daughter cells are identical to parent cells
 Each receives an exact copy of the chromosomes present in
the parent cell
 Done in somatic cells - typical body cells
II. Overview
Chromosome – coiled structures made of
DNA and proteins; consists of two identical
copies linked together (sister chromatids)
Gene – organized chromosomal units that
contain the instructions for a single protein
II. Overview
There are 4 stages of mitosis:
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase / Cytokinesis
The rest of the cell’s life is spent in interphase.
IPMAT!!
III. Stage #1- Prophase
 Chromatin in the
nucleus coils and
becomes distinct
chromosomes.
 Chromosomes that
were duplicated
during the “S” phase
join with their sister
chromatid.
 Join at the centromere
III. Stage #1 - Prophase
 A mitotic spindle grows
out from centrioles in the
cytoplasm.
 The nuclear envelope
disappears.
 Spindle attaches to the
centromere (kineticore)
and pulls the
chromosomes to the
center.
III. Stage #1 - Prophase
IV. Stage #2 - Metaphase
 Centrioles are positioned
at the poles.
 The chromosomes are
lined up in the middle the metaphase plate.
EQUATOR = MIDDLE
 Metaphase =
Meet (in the Middle)
IV. Stage #2 - Metaphase
 The sister
chromatids are lined
up on either side of
the plate
 The spindle is
attached to each
chromatid and
prepares for
separation.
V. Stage #3 - Anaphase
 The spindle fibers “reel”
in the chromatids.
 The poles move farther
apart.
V. Stage #3 - Anaphase
The microtubules
which make up the
spindle get shorter,
pulling the chromatids
toward the poles.
Anaphase = Away
VI. Stage #4 - Telophase
 A nucleus begins to reform in
the new cell.
 Chromosomes lengthen into
chromatin.
 Mitotic spindle disappears.
 Telophase = Terminal = End
VI. Stage #4 - Telophase
 A cleavage furrow
appears, separating
the two cells.
Checkpoint !
 Cytokinesis pinches the cell into
two separate cells.
VII. Cytokinesis
 Division of cytoplasm
 Animal cells
cell membrane pinches together until the cell membrane
separates forming 2 daughter cells
 Plant cells
relatively rigid; a cell plate formed in the middle
of the dividing cell from membrane vesicles
VIII. Plant Cell Cytokinesis
 Plant cells form a
plate between the two
new cells that later
becomes a cell wall.
Stages of Mitosis
Stages of Mitosis
Stages of Mitosis
Quick Review of Mitosis
Online Activity
Exploring Life
Online Activity 2
Help Remembering Cell Division
*IPMAT*
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