Mitosis
Step by Step
The Cell Cycle
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All of the cells in
your body go
through a life
cycle.
Some divide often
(skin cells)
Some cells never
divide (nerve and
brain cells)
pictures from
http://learninglab.co.uk/head
start/images/cycle1a.jpg
What is the cell cycle?
Mitosis is the process of cellular
division.
 One cell divides into 2 exact copies
of itself.
 Mitosis is only a short portion of the
cells entire cycle.
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pictures from
www.biology.arizona.edu/
Interphase
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During interphase
the cells go through
3 stages
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G1 (growth)
S (DNA is copied)
G2 (cell gets
ready to divide)
Some cells stay in
interphase and
never divide.
pictures from
www.biology.arizona.edu/
Prophase
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During prophase, the
nucleus disappears
The chromosomes
are duplicated
We can see the
chromosomes as a
big bundle in the
middle of the cell.
pictures from
www.biology.arizona.edu/
Metaphase
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During metaphse a cell
lines up its chromosomes
in the middle region of
the cell.
Centrioles at each side of
the cell send out spindle
fibers that grab each
chromosome.
The cell is preparing to
separate the
chromosomes
pictures from
www.biology.arizona.edu/
Anaphase
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During anaphase the
cell chromosomes
are separated.
The chromosomes
are pulled to opposite
sides
pictures from
www.biology.arizona.edu/
Telophase.
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During telophase,
separation of
chromosomes is
complete.
The cell begins to
separate apart into
two cells.
pictures from
www.biology.arizona.edu/
Cytokinesis
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During cytokinesis
new cell membranes
form
In plant cells a new
cell wall begins to
form
Check out the
animation of mitosis
pictures from
www.biology.arizona.edu/
Meiosis
Meiosis is a form of cell division that
happens in sex cells.
 After meiosis the sex cells have half
the number of chromosomes.
 In mitosis the number of
chromosomes is the same.
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pictures from
www.biology.arizona.edu/
Review
1.
2.
3.
4.
How many steps are in mitosis?
Are the daughter cells exact
copies?
In which cell part does mitosis
begin?
Why is mitosis important?
pictures from
www.biology.arizona.edu/
Think you’re smart?
Try the onion root tip interactive lab
that the University of Arizona
developed.
 Click here
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pictures from
www.biology.arizona.edu/