Transcript dnaisolation

DNA Isolation
Where is the DNA?

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
Eukaryotes (that is
us!) have nucleated
cells.
The nucleus contains
chromosomes made
out of DNA.
What about
organisms that don't
have a nucleus?
Where is their DNA?
Step 1: Cells in Solution
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Peas + blender → cell soup
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Why are we adding salt?

Osmotic Pressure
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This is a hypertonic solution.→
(high concentration outside cell)
Step 1: Cells in Solution

Peas + blender → cell soup

Why are we adding salt?

Osmotic Pressure


The concentrations outside
of the cell and inside of the
cell will try to balance.
Water will run out of the cell,
and it will shrivel up.
Step 1: Cells in Solution

Peas + blender → cell soup

Why are we adding salt?

Osmotic Pressure

This is a hypotonic solution. →
(low concentration outside cell)
Step 1: Cells in Solution

Peas + blender → cell soup

Why are we adding salt?

Osmotic Pressure


The concentrations outside
of the cell and inside of the
cell will try to balance.
Water will run in to the cell,
and it will swell.
Step 1: Cells in Solution

Peas + blender → cell soup

Why are we adding salt?

Osmotic Pressure


The concentrations outside
of the cell and inside of the
cell will try to balance.
Or burst.
Step 1: Cells in Solution

Peas + blender → cell soup

Why are we adding salt?

Osmotic Pressure


If our solution has just the right
number of molecules dissolved, it
will match the concentration of
the cell.
This is an isotonic solution.→
(Now, everyone is happy.)
Step 2: Removing the Membranes
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Plasma membrane
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Nuclear membrane
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Bilayers
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Hydrophilic = water loving
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Hydrophobic = water fearing
Step 2: Removing the Membranes
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Detergent
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Breaks down membranes
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Also breaks down some proteins
Step 3: Eliminating the Proteins
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Histones
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Nucleases
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Stuck to DNA
Will destroy your DNA
We will use a
protease to chew up
the proteins in
solution.
Step 4: Separating the DNA
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Isopropyl Alcohol
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Will precipitate DNA
Water
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Will dissolve DNA