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Mitosis and the Cell Cycle
Big Idea:
Mitosis is the process in which
the nucleus divides to form two
new nuclei and two cells with
identical DNA.
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How do little elephants grow up
to be BIG elephants?
Mitosis begins after
fertilization
1 cell becomes 2 cells, becomes
4 cells…becomes TRILLIONS
Why do cells make more cells?
Somatic Cells – body cells
› Produced through mitosis
› Has 46 chromosomes (23 pairs)
 Homolog – each member of a
chromosome pair
 Diploid (2n) – total of 46 chromosomes in
people – zygote & somatic cells
 Haploid (n) – total of 23 chromosomes in
people, gametes (sperm & egg)

Animated Mitosis Cycle
http://www.cellsalive.com/mitosis.htm
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase & Cytokinesis
Chromosomes are copied (# doubles)
• Chromosomes appear as threadlike coils
(chromatin) at the start, but each chromosome
and its copy(sister chromosome) change to sister
chromatids at end of this phase
•
Nucleus
CELL
MEMBRANE
Cytoplasm
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
 Growth
Stage 1 (G1) – metabolic
activity of the cell
 Synthesis
Stage (S) – metabolic activity
of the cell, replication of DNA
 Growth
Stage 2 (G2) – metabolic
activity of the cell, prepare for division
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Mitosis begins (cell begins to divide).
Centrioles (or poles) appear and begin to
move to opposite ends of the cell.
Nuclear Envelope disappears.
Spindle fibers form between the poles.
Centrioles
Sister chromatids
Spindle fibers
Animal Cell
Plant Cell
Spindle fibers
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Chromatids (or pairs of chromosomes) attach
to the spindle fibers at the centromere.
• Chromosomes move to the equator of the
cell.
•
Centrioles
Spindle fibers
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
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Chromatids (or pairs of chromosomes)
separate and begin to move to opposite
ends of the cell.
Centromere is broken in half.
Centrioles
Spindle fibers
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Two new identical nuclei form (nuclear
envelopes reform).
• Chromosomes uncoil and appear as
chromatin (threads rather than rods).
• Mitosis ends.
•
Nuclei
Chromatin
Nuclei
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
•
Cell membrane moves inward to create two
daughter cells – each with its own nucleus
with identical chromosomes.
Animal Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Plant Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
IPMATC
I Prefer Meatloaf At Tennis Camp
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- Cell Division
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http://www.cellsalive.com/mitosis.htm