Transcript Mitosis and The Cell Cycle

Mitosis and The Cell Cycle
reproducing cell after
cell..
Mitosis
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The definition of mitosis is part of cellular
division in which the nucleus divides
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It occurs in somatic cells
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Somatic cells (body cells) are all the cells that are
not associated with gametes (sex cells).
The 4 Stages of Mitosis
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In order, they are:
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Prophase
Metaphase
Anaphase
Telophase
PMAT (Please Make Another Taco) 
There is a longer phase that takes place before
mitosis—this phase is called interphase.
The 4 Stages of Mitosis
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What happens during Prophase:
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Chromatin condenses into chromosomes
Centrioles begin to separate
Spindle fibers begin to form
Nuclear membrane begins to break down
Prophase “Prepare”
The 4 Stages of Mitosis
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What happens during Metaphase:
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The chromosomes line up in the middle of the cell
Each chromosome is attached to a spindle fiber
Metaphase “Middle”
The 4 Stages of Mitosis
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What happens during Anaphase:
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Chromosomes separate to form sister chromatids,
they pull apart
Sister chromatids begin to migrate to the poles of
the cell
Anaphase “Apart”
The 4 Stages of Mitosis
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What happens during Telophase:
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Chromosomes gather at opposite ends of the cell
They lose their distinct shape
Spindle fibers disappear
A new Nuclear Membrane begins to reform at
each pole
The cell is about to tear apart! (Peanut shape)
Telophase “Tear”
Cytokinesis
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After the cell goes through mitosis, it is
quickly followed by cytokinesis
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This is the division of the cytoplasm
What actually makes 1 cell into 2 new cells
The new cells are called daughter cells.
Mitosis plus Cytokinesis make up the M phase of
the cell cycle.
The Cell Cycle
Phases of the Cell Cycle
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There are 4 phases to the Cell Cycle:
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G1 phase
S phase
G2 phase
M phase
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Lets take a closer look at each stage..
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G1 Phase of Cell Cycle
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G1 phase is the beginning of Interphase.
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It is characterized by cell growth
The cell does the majority of its growth during this
phase.
Cells actually divide because they become too
large to function at an optimal level. Becoming too
large would cause a “DNA overload”
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The cell’s DNA would no longer be able to serve the
increasing needs of the growing cell
S Phase of the Cell Cycle
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The S phase is characterized by DNA
replication
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Before the cell splits, it must make a copy of it’s
DNA
This is to ensure that both new daughter cells will
have exact copies of that particular organism’s
DNA
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The S phase is the 2nd part of Interphase
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G2 Phase of the Cell Cycle
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The G2 phase is the last stage of Interphase.
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It is characterized by the preparation for mitosis.
Here the cell has grown to a maximum size, made
a copy of it’s DNA
Now the organelles needed for cellular division
are produced as the cell prepares for mitosis
M phase of the Cell Cycle
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The M phase is not a part of Interphase, it is
classified under Cell Division
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The cell first goes through the 4 stages of mitosis:
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Prophase
Metaphase
Anaphase
Telophase
Cytokinesis takes place shortly after telophase and the cell division
is complete and the cycle begins again.
M phase includes all the steps of mitosis and cytokinesis.
Picture in book…
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Can be found on page 245!
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There will be a quiz on this exact picture
coming up soon!
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The End