Cell division occurs through the process of mitosis in somatic cells. Mitosis involves five phases - interphase, prophase, metaphase, anaphase, and telophase. During interphase, the cell grows and DNA is duplicated in preparation for division. In prophase, chromosomes condense and the mitotic spindle begins to form. Metaphase sees chromosomes aligned at the center. Anaphase involves the separation of sister chromatids to opposite sides. Finally, in telophase, division is complete and two identical daughter cells have formed, each with the full complement of chromosomes. Mitosis results in the reproduction of body cells for growth and tissue repair.

1. Cell Division

2. The Basics
Who: Mitosis
What: Cell division
When: New cells are needed
Where: Somatic cells (body cells)
Why: Growth

3. The Basics
Who: Somatic cells (Normal cells like in your toes)
What: Cellular reproduction for growth, the cell cycle
Where: Happens in somatic cells, regular body cells like in
your toes
Why: For growth (baby to adult) and to replace damaged
cells (heal a cut)
How: Duplicate cell parts making an exact copy of
cell; one "mother" cell becomes two identical "daughter"
cells.
Remember: Toes as is mi-toes-is (mitosis)

4. Mitosis

5. Mitosis & Chromosomes
Mitosis is the duplication of chromosomes

6. Chromosomes
are made of
DNA

7. Genes are part of
Chromosomes

8. Cell Division
• One parent cell
becomes two
daughter cells.
• Happens in
somatic cells,
every day cells in
the body
• For growth
StartStart
FinishFinish
1 cell
2 cells

9. Cell Plate (Plants)

10. Mitosis in an animal cell
• 1 cell to 4 cells

11. Uneven Division
Division of cytoplasm is
not always even

12. The Phases
There are five phases

13. Cell Cycle

14. A. Interphase
Inter = in between
Actual Phases
1.Prophase
Pro = first
2.Prometaphase
Between First & Middle
3.Metaphase
Meta = middle
•Anaphase
Ana = away
•Telophase
T
All the phases
1
2
3
4
A
5
B

15. Mitosis
with
emphasis
on
metaphase

16. Mitosis Onion Root Tip

17. Interphase
• Interphase is
NOT a part of
mitosis.
• Interphase the
cell grows
before the DNA
is duplicated,
then DNA is
duplicated, and
lastly, prepares
for division.

18. Prophase
• During
prophase, the
DNA and
proteins start to
condense.
• The microtubles
are assembled
start moving to
one of the two
centriole pairs
toward the
opposite end of
the cell.
Dark region
= condensing
chromatin
Onion root
tip image

19. Prometaphase • Sometimes
considered part of
the prophase.
• Nuclear membrane
disintegrates
• Centrioles reach the
poles of the cell
• Chromosomes
continue to
contract.
• Proteins attach to
the centromeres.
• The chromosomes
begin moving.
Dark region = condensing
chromatin, animal cell

20. Metaphase
• During metaphase,
the microtubules
penetrate nuclear
region forming a
spindle apparatus.
• They attach to sister
chromatids of each
chromosome.
• All chromosomes
line up at spindle
equator.
• Now in their most
tightly condensed
form.

21. Anaphase
• During
anaphase,
attachments
between the two
sister chromatids
of each
chromosome
break.
• Now separate
chromosomes
move to
opposite spindle
poles.
Mid Anaphase
Onion root tip

22. Telophase
• Lastly, in
telophase, the
chromosomes
decondense,
texture of
chromatin
loosens.
• New patches of
membrane fuse
to form new
nuclear
envelopes
around them.

23. Cytokinesis & Daughter Cells
Animal cells.
•Pinching of cytoplasm into
two cells.
Plant cells
•Cell plate forms between
the two “new” cells.
After cytokinesis
•Cells now in interphase
Called daughter cells.
•Cells diploid, two each
type of chromosome – same
as parent cell's nucleus.

24. Mitosis on the run

25. Stages
1. Interphase
Thecell isengagedinmetabolicactivityandpreparingformitosis(thenextfourphasesthatleaduptoandinclude nucleardivision).
Chromosomesarenotclearlydiscernedinthenucleus,althougha darkspotcalledthenucleolusmaybevisible.Thecellmaycontaina pairofcentrioles(or
microtubule organizingcentersinplants)bothofwhichareorganizational sitesformicrotubules.Thisisthe longest stage.
2. Prophase
Chromatin in the nucleus begins to condense and becomes
visible in the light microscope as chromosomes. The nucleolus
disappears. Centrioles begin moving to opposite ends of the cell and
fibers extend from the centromeres. Some fibers cross the cell to form the
mitotic spindle.
3.

26. Stages
3. Prometaphase
Sometimes considered part of the prophase. When the nuclear membrane
disintegrates, the centrioles reach the poles of the cell, and the
chromosomes continue to contract. Proteins attach to the centromeres.
The chromosomes begin moving.
4. Metaphase
Spindle fibers align the chromosomes along the middle of the
cell nucleus. This line is referred to as the metaphase plate. This
organization helps to ensure that in the next phase, when the
chromosomes are separated, each new nucleus will receive one copy of
each chromosome

27. Stages
5. Anaphase
The paired chromosomes separate at the kinetochores and move to opposite
sides of the cell. Motion results from a combination of kinetochore
movement along the spindle microtubules and through the physical
interaction of polar microtubules.
6. Telophase
Chromatids arrive at opposite poles of cell, and new membranes form
around the daughter nuclei. The chromosomes disperse and are no longer
visible under the light microscope. The spindle fibers disperse, and
cytokinesis or the partitioning of the cell may also begin during this stage.
7. Cytokinesis
In animal cells, cytokinesis results when a fiber ring composed of a protein
called actin around the center of the cell contracts pinching the cell into two
daughter cells, each with one nucleus. In plant cells, the rigid wall requires
that a cell plate be synthesized between the two daughter cells.

28. Interphase

29. Prophase

30. Prometaphase

31. Metaphase

32. Early Anaphase

33. Late Anaphase

34. Telophase

35. Daughter Cells

36. Mitosis

37. Can you identify the stages?
1. Are these
plant or
animal
cells?
2. How can
you tell?
3
4
5

38. Can you identify the stages?
6. Are these
plant or
animal
cells?
7. How can
you tell?
8
10
9

39. Purpose of Mitosis
• Increase the size of an organism.
• Replace worn out cells or repair
damaged tissue.
• Reproduce identical organisms, or
clones.

40. Comparing Mitosis & Meiosis
• Mitosis
– Happens in somatic
cells, every day cells
in the body
– For growth
– Think: toestoes as is mi-as is mi-
toestoes-is-is
• Meiosis
– Happens in sex cells
(pre-embryonic cells)
– For sexual
reproduction
– Think: e as in sex as
in meiosis

41. Bibliography
•Bio Review Cell Division
http://library.thinkquest.org/28751/review/division/4.html
•Access Excellence at the National Health Museum About Biotech
http://www.accessexcellence.org/AB/GG/meiosis.html
•About http://biology.about.com/cs/celldivision/
•“The Cell Cycle & Mitosis Tutorial” The Biology Project University of
Arizona http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/cells3.html
• Mitosis http://www.stanford.edu/group/Urchin/mitosis.htm
•eMuseum Minnesota State University
http://www.anthro.mankato.msus.edu/biology/evolution/genetics/cellsmitosismeosis
.html
•Molecular Expressions
http://micro.magnet.fsu.edu/micro/gallery/mitosis/mitosis.html
•Universlity of North Carolina at Charlotte
http://www.bioweb.uncc.edu/biol1110/Stages.htm