The Cell Cycle

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The Cell Cycle
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Order of cell organization
Cell ? Tissue ? Organ ? Organ System ? Organism
Cells must divide and create many cells in
order for this process to occur
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The Cell Cycle ? Interphase, Mitosis and
Cytokinesis
Interphase (G1, S and G2)
G1 (Organelles Duplicate)
S DNA synthesizes (also called duplicates or
replicates)
G2 (Cell prepares to divide)
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The Cell CycleInterphase ? Organelles
replicate, DNA synthesizes and cell prepares to
divide Mitosis is Asexual Reproduction?
Divides Nucleus Cytokinesis ? Divides
Cytoplasm
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Interphase Prepares for Mitosis
Majority of time for a cell is in this phase
Cell grows
Organelles duplicated (G1) DNA synthesizes
(S) Only chromatin (uncoiled chromosomes)
visible
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Chromosomes Duplicate In the S Phase of Interphase

• Carriers of genes
• Some genes carry the instructions for protein
  production
• Remember, chromosomes are duplicated during the S
  phase of Interphase prior to mitosis!
• You have 46 total chromosomes in the nucleus of
  most of your cells!!

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Nuclear Division Called Mitosis
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After Interphase
Four phases of mitosis (cell division) are
Prophase
Metaphase
Anaphase
Telophase
Recall Mitosis Divides the nucleus, Cytokinesis
Divides the Cytoplasm
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Prophase
Duplicated chromosomes become visible
A spindle, football shape structure that
contains many fibers, moves to opposite poles
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Metaphase
Chromosomes line up in the MIDDLE of the cell )
its equator)
Each chromatid is attached to a separate
spindle fiber by its centromere (in the middle!!)
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Anaphase
Centromeres split pulling apart sister
chromatids.
Chromatids move to opposite poles
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Telophase
Animal Cell
Chromosomes uncoil back into chromatin
Two nuclei appear
In animals a cleavage furrow forms (plants
have a cell plate)
In plants a cell plate forms between the 2
cells
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Cytokinesis Division of Cytoplasm
Two new identical daughter cells after
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Mitosis at a Glance Cell Division
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Cytokinesis in an Animal Cell
ONLY in animal cells
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Cytokinesis in a Plant Cell
Only in Plants
Only in Plants
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Onion Root Tip Can You Find the Stages of
Mitosis
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Mitosis in Real Time
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Modeling Mitosis
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Really Cool Animation
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Cell Cycle in Prokaryotes (Bacteria)
NO TRUE NUCLEUS!!! DNA replicates and the
plasma membrane just pinches inward to form two
new cells.