Download Mitosis

Mitosis
When Cells Divide
By: Your teacher!©
1998
About Mitosis
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What is mitosis?
Why is it important?
The Phases of Mitosis
Test your knowledge
Review
What is Mitosis?
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• How cells with nuclei reproduce
• One cell divides into 2 identical
daughter cells.
• 5 stages (I.P.M.A.T.)
Why Mitosis?
• Allows multicellular organisms to grow
• 10 m of DNA in 10 um nuclear diameter
• Chromosomes = compact DNA & proteins,
easy to move - facilitates division
versus
Phases of
Mitosis
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Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
• Period In-between divisions
• Nuclear membrane present
• DNA in loose strands for
transcription
• Cell grows, DNA replicates
(doubled)
Prophase
• Cell Prepares to divide
• DNA condenses into doubled
chromosomes
• Nuclear membrane disappears
• Spindle apparatus forms
Metaphase
• Chromosomes move to Middle
• Spindle fibers attach at centromere
(Kinetochores)
• Spindle apparatus stretches from
pole to pole
Anaphase
• Chromatids move Away to poles
• Centromere splits  2
kinetochores
• Each chromosome  2 chromatids
• Spindle fibers contract pulling
kinetochore/chromatid away
Telophase
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Cell Tears in Two
Nuclear membrane forms
Chromosomes disperse
Cytokinesis  2 identical
“daughter” cells
• Both new cells in interphase
Phases of Mitosis
• Interphase - cell life In-between divisions
• Prophase - cell Prepares to divide
• Metaphase - chromosomes move to Middle
• Anaphase - chromatids move Away
• Telophase - cell Tears in Two
What is Mitosis ?
What is Mitosis ?
• How cells with nuclei
reproduce
• One cell divides into 2
identical daughter
cells.
• 5 stages (I.P.M.A.T.)
Why Mitosis
• Which of these cells can
divide it’s DNA evenly
without damaging it?
?
Why Mitosis
• The bottom one!
• It’s DNA is condensed into
chromosomes
• DNA in the top one cannot
be divided
?
What Phase
• Chromosomes lined up in
Middle
• Spindle fibers attach at
centromere (Kinetochores)
• Spindle apparatus stretches
from pole to pole
?
It’s Metaphase!
The chromosomes
moved to the
Middle!
What Phase
• Period In-between
divisions
• Nuclear membrane
present
• DNA in loose strands
for transcription
• Cell grows, DNA
replicates (doubled)
?
It’s Interphase!
• The cell is In-between
divisions
What Phase
• Chromatids move Away to poles
• Centromere splits  2
kinetochores
• Each chromosome  2 chromatids
• Spindle fibers contract pulling
kinetochore/chromatid away
?
It’s Anaphase!
• Chromatids move Away
to poles
What Phase
•
•
•
•
Cell Tears in Two
Nuclear membrane forms
Chromosomes disperse
Cytokinesis  2 identical
“daughter” cells
• Both new cells in interphase
?
It’s Telophase!
• Cell Tears in Two
What Phase!
• Cell Prepares to divide
• DNA condenses into
doubled chromosomes
• Nuclear membrane
disappears
• Spindle apparatus forms
It’s Prophase!
• The cell is
to divide.
Preparing
Mitosis = I.P.M.A.T.
• Interphase - cell life In-between divisions
• Prophase - cell Prepares to divide
• Metaphase - chromosomes move to Middle
• Anaphase - chromatids move Away
• Telophase - cell Tears in Two