Download 3.2 Osmosis

Osmosis
September 2, 2009
Objective: SWBAT predict water movement in
hyper/hypotonic solutions.
Catalyst: Define selectively permeable. Give an
example of diffusion in real life.
Agenda
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Catalyst Review
Diffusion Review
Osmosis
Hyper, Hypo, Iso
Predict Movement
Exit Question
Catalyst Review
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Selectively permeable means something that only
allows specific things through.
Diffusion— volunteers?
Diffusion Review
Movement of solutes from high to low until…
HIGH
LOW
Diffusion Review
…concentration is equal (EQUILIBRIUM)
EQUAL
=
EQUAL
By the end of today…
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You should be able to tell me why you shouldn’t
drink salt water if you are stranded in the middle of
the ocean.
You should be able to explain some of the
symptoms of diabetes.
It all relates to…
Osmosis!
Key Point #1:
Osmosis is the diffusion of water to equalize
concentrations.
Blue=water, Green=solute
Blue=water, Green=solute
Which way will it move?
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Think to yourself- which side has the
higher concentration of particles?
Which way do the particles want to
move?
In osmosis- WATER moves the
OPPOSITE direction as diffusion to
equalize concentrations.
OSMOSIS
The BLUE dots are moving in osmosis
Prefixes-write these in your notes
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Hypo-less than
Hyper-more than
Iso-same as
Make a table in your notes
Isotonic
Hypotonic
Hypertonic
Equal concentrations of impermeable solutes inside and
outside. No net movement of water.
Less concentration of impermeable solutes outside the
cell. Water moves into the cell. Cell may burst which is
called lysis.
Higher concentration of impermeable solutes outside
the cell. Water moves out of the cell. Cell shrinks.
Group thought time- do this for each
situation.
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Draw a picture of each of these situations.
Which way would solutes move if they could?
In osmosis, solutes are impermeable. Instead, water
will move the OPPOSITE way.
Example:
Hypertonic
Solutes would
want to move
inside, but they
can’t. So, water
will move
OUTSIDE.
See if you agree

If you got these correct in your group- you do not
need to take notes. Make sure to correct your stuff
in case it was incorrect.
Isotonic
Hypotonic
Solutes and water would stay
where they are since
concentrations are equal.
Solutes would want to move
outside, but they can’t. So, water
will move INSIDE.
Isotonic
Solution
Outside
Cell
Inside
Cell
Hypotonic
Solution
Inside
Cell
Outside
Cell
Hypotonic
Solution
Inside
Cell
Outside
Cell
Water
Water
Water
Hypotonic
Solution
Inside
Cell
Water
Outside
Cell
Water
Water
Hypertonic
Solution
Inside
Cell
Outside
Cell
Hypertonic
Solution
Inside
Cell
Outside
Cell
Water
Water
Water
Hypertonic
Solution
Water
Inside
Cell
Water
Outside
Cell
Water
Red blood cells in action
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http://www.coolschool.ca/lor/BI12/unit4/U04L06/
rbc.html
Hypo, hyper or isotonic?
More solute inside the cell
than outside
1) Write either hyper, hypo, or isotonic
2) Write which way the water is flowing (into or out of
the cell)
Hypo, hyper or isotonic?
Equal solute inside the cell
and outside the cell
1) Write either hyper, hypo, or isotonic
2) Write which way the water is flowing (into or out of
the cell)
Hypo, hyper or isotonic?
40% sugar inside the cell and 10%
sugar outside the cell
2) Where is the water flowing?
1) Write either hyper, hypo, or isotonic
2) Write which way the water is flowing (into or out of
the cell)
Hypo, hyper or isotonic?
10% sugar inside the cell and 90%
sugar outside the cell
2) Where is the water flowing?
1) Write either hyper, hypo, or isotonic
2) Write which way the water is flowing (into or out of
the cell)
Define
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What is lysis?
What kind of solution (hypo, iso, or hyper) does it
occur in?
Worksheet (IP)
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This is your worksheet- finish it here and anything
you do not finish is homework for tonight.
Exit Question
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Which one of these situations (left, middle, right)
represents a cell in a hypertonic solution? Would
water go into or out of the cell?