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Mitosis – Asexual Cell Division
Cells eventually need to Reproduce.
Mitosis is Asexual Cell Division in which Cells
reproduce to form Identical Daughter Cells.
In Unicellular
Organisms, this is
Reproduction.
Mitosis is used by
these cells when they
want to form identical
Offspring Fast, or
they are well adapted
and Do Not Need to
Change/Adapt.
EASY!
In Multicellular
Organisms, Mitosis
occurs to Replace
Cells relative to
Healing or in
Growth, etc…
Very Precisely
controlled to
maintain
Organization and
Balance.
Who Does IT!
Mitosis – Asexual Cell Division
The Cell is “Active” and Functional. It
is either Growing (Stem Cells) or Doing
”its” “Job”.
1
Chromatin is loose and
uncoiled (not visible) and
ACTIVE. The Nucleus is
Intact and Large.
Between
INTERPHASE
4
The Cytoskeleton
maintains Cell Shape
Internally. But since the
Cell Divides, it is Round
and Simple!
5
2
The Genes are available
for Use!
You Should be able to
Always Identify
Interphase due to:
3
The Nucleus is Present
and has an obvious
Nucleolus as it
manufactures
Ribosomes.
The Cell is making
Proteins = Working!
Mitosis – Asexual Cell Division
Many Things occur during Prophase as
the Cell Prepares for actually Dividing.
First
PROPHASE
The Mitotic Spindle begins to Form. This is the Cytoskeleton and the Centrioles
that have changed their Role from Cell Shape and Organization to Moving the
Chromosomes.
As such, Cells in Mitosis do not have defined Shapes = OFF!
The DNA become Visible as
CHROMOSOMES!
These “Colored Bodies” are the
same DNA as before, but
Supercoiled and Condensed.
This DNA is “OFF”. The Cell is
inactive during Mitosis! Cells that
Divide CANNOT PERFORM A
JOB!
First
Mitosis – Asexual Cell Division
PROPHASE
1
The Mitotic Spindle forms a Cage-like
structure that extends around the
Chromosomes and then attaches to them
at their Centromeres.
2
The Nucleus Disappears!
This is necessary to allow the
Chromosomes to Move.
You Should be able to
Always Identify
Prophase due to:
3
Mitosis – Asexual Cell Division
Metaphase is EASY! The Chromosomes
are Lined-Up!
Middle
METAPHASE
The Mitotic Spindle Pulls on the
attached Chromosomes.
Since both sides are exerting
force, the chromosomes are
pulled to the EQUATOR of the
Cell and Lined-Up.
You Should be able to
Always Identify
Metaphase due to:
Apart
Mitosis – Asexual Cell Division
Anaphase is EASY! The Chromosomes
are Pulled Apart!
ANAPHASE
You Should be able to
Always Identify
Metaphase due to:
The Identical Sister Chromatids are SEPARATED and then PULLED
APART toward the POLES of the Cell.
Mitosis – Asexual Cell Division
Telophase is the Final Phase! The Nuclei
Reform as Separated with Complete
suites of the DNA.
You Should be able to
Always Identify
Telophase due to:
End
TELOPHASE
The Mitotic Spindle disappears as the
Cytoskeleton Mostly goes back to Cell
Structure/Organization Roles.
NOW, the
separated Sister
Chromatids are
packed back
into their Nuclei
with identical
copies of their
DNA.
The Nuclei
Reform!
EXCEPT for Splitting the Cytoplasm in Animal Cells. The
Cytoskeleton forms the Cleavage Furrow that Separates the
Cells = CYTOKINESIS!!
Mitosis – Asexual Cell Division
THE END!
What are they going to do NOW?!
TWO IDENTICAL DAUGHTER CELLS!!
For Replacement and Growth – Equal Cells!!!