HOW DO CELLS
MULTIPLY?
Cell division (Crucial questions)
•  How do cells multiply?
•  What happens when we get a cut on our finger?
•  How do plants grow into trees or large plants?
•  How do earthworms grow their tails back?
Cell division (Mitosis)
•  Cells must divide in order to grow
•  Cells undergo cell division to grow
•  The scientific word for cell division is mitosis
•  Mitosis undergoes several stages or phases
Mitosis (cell division)
•  The main part of mitosis occurs in the nucleus
Why the nucleus?
Where the genetic material, the chromosomes
(bundles of DNA) are found.
Special features of mitosis
•  The cells before and after are completely identical
•  Genetic material are not exchanged
•  1 cell give rise to 2 cells
•  The resulting cells are diploid (has both sets of
chromosomes) One from father, other from mother
Chromosomes
•  The genetic material of a cell
•  Carries all the ‘instructions’ of
what an organism will look like.
•  Strands and strands of DNA are
wrapped around to form
chromosomes.
•  Found in the nucleus
The phases of mitosis
The phases are continuous and occurs in one big phase
but scientists separate them into specific phases
The phases
•  I - Interphase
•  P - Prophase
•  M - Metaphase
•  A - Anaphase
•  T – Telophase
•  C - Cytokinesis
Only P M A T are
part of MITOSIS
Interphase
•  During this phase the cell is preparing
for mitosis.
•  Has 3 substages – G1 (gap 1), S
(synthesis) and G2 (gap 2)
•  G1 – Regular cell functioning
•  S – Cell copies its DNA for cell
division
•  Chromatin (condense soup of DNA) is
getting ready for chromosomes (visible
condensed structures of DNA)
•  G2 – Prepares division of nucleus
•  Chromosomes are not yet visible,
though the nucleolus very well could
be.
Prophase
• 
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The chromosomes are now visible from chromatin to chromosomes
Chromosomes form an ‘X’ shape.
Mitosis begins here! (cell begins to divide)
Centrioles (or poles) appear and begin to move to opposite ends of the cell.
Spindle fibers and aster fibers form between poles and at poles
Metaphase
•  Chromatids (or pairs of chromosomes) attach to the
spindle fibers
•  Spindle and aster fibers assist the movement of
chromosomes
Anaphase
•  Chromatids (or pairs of chromosomes) separate and
begin to move to opposite ends of the cell.
•  Spindle fibers pull on centromere of each sister chromatid
(separate chromosome)
Telophase
•  Two nuclei form.
•  Nuclear membranes form and spindle fibers disappear
•  Chromosomes appear as chromatin (threads rather than
rods).
•  Cleavage furrow forms
Cytokinesis
•  Occurs after telophase
•  Cell membrane moved inward to create two daughter cells
– each with its own nucleus with identical chromosomes.
Video: Mitosis Animation:
http://www.youtube.com/watch?v=VlN7K1-9QB0
http://www.youtube.com/watch?v=DD3IQknCEdc
Mitosis stop animation
•  You will need Stop Motion App – on your ipads
•  Variety of items such as straws, playdoh, pipe cleaners
etc.
•  You will be making a Stop motion video to showcase the
process of mitosis (IPMATC) with all the appropriate info.