Download CELL DIVISION: MITOSIS

Cell Division: Mitosis
Focus Question:
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Why is cell division such a
complicated process?
Review:
What are the two types of cells?
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Eukaryotic
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Prokaryotic
What are prokaryotic cells?
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Simple cells
Few internal
structures
No membrane
bound organelles
One-celled
organisms, Bacteria
What are eukaryotic cells?
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Cells that contain membrane-bound
organelles, including a nucleus
Most living organisms
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Plants
Animals
Fungi
Protists
Cell Division
New cells are formed by the division of older cells
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1.
2.
When a cell divides, DNA is first copied & then
distributed
Each cell ends up with a complete set of DNA
How do prokaryotic cells divide?
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Binary Fission
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One cell replicates
its DNA and splits
to become two
How do eukaryotic cells divide?
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Mitosis!
Where is DNA located in a Eukaryotic cell?
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The nucleus!
DNA in Eukaryotic Cells
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Since the cell has already replicated its
DNA during the S stage of interphase, it
now has enough DNA for TWO nuclei
The Many shapes of DNA…
•During interphase, DNA forms a tangled mass called
chromatin.
•Chromatin looks like a plate of spaghetti.
•Right before a cell divides, the chromatin (DNA)
coils up and condenses into structures called
chromosomes (still DNA)
Chromosomes = Tightly coiled, rod-shaped DNA
made of chromatin
Chromatin
(MOST OF THE TIME)
Replicated Chromosomes
(During Cell Division)
chromatid
chromatid
genes
centromere
The DNA molecule
condenses to form
A chromosome
has ONE copy of
the DNA
A replicated chromosome
has TWO identical copies
of the DNA
What is mitosis?
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Mitosis is the series of phases during which
the nucleus of a cell divides into 2 nuclei
with identical genetic material
A continuous process of four phases that
results in the division of the nucleus.
Followed by cytokinesis
Making more cells!
Why do we care?
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Once upon a time we were
all one little cell.
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Because of mitosis we are
now made of trillions of
cells.
The 4 Phases of Mitosis:
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Prophase
Metaphase
Anaphase
Telophase
So the Stages of the Cell Cycle are…
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Interphase
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Mitosis
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G1
S
G2
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Cytokinesis
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After the nucleus divides through mitosis,
the cytoplasm and membrane of the cell
divide into two separate and identical cells.
Focus Question:

What would happen if cells didn’t divide
through the structured process of mitosis?