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Cell Concentrations
Solutions Notes
Page ___
•  A solution is a mixture of
two or more substances.
– Solute – dissolved
substance (salt/sugar)
– Solvent – dissolves
solute (water)
! 
Cell Concentrations
Isotonic Solution
Osmosis Animations
for isotonic,
hypertonic, and
hypotonic solutions
Isotonic: The concentration of solutes in the solution
is equal to the concentration of solutes inside the cell.
Substances will move
across the cell
membrane if their
concentrations are
unequal.
Result: Water moves equally in both directions and
the cell remains same size! (Dynamic Equilibrium)
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Hypotonic Solution
A cell in an isotonic solution
Water
moves in
and out
at the
same rate
10%
Solute
How much solvent
inside?
90%
solvent
Hypotonic: The solution has a lower concentration of
solutes and a higher concentration of water than
inside the cell. (Low solute; High water)
How much solvent
outside?
90%
solvent
Result: Water moves from the solution to inside the
cell): Cell Swells and bursts open (cytolysis)!
Hypertonic Solution
A cell in a hypotonic solution
20%
Solute
How much solvent
inside?
80%
solvent
Cell swells!
Osmosis Animations
for isotonic,
hypertonic, and
hypotonic solutions
10%
Solute
Cell remains the same!
Water
moves in
! 
! 
Osmosis Animations
for isotonic,
hypertonic, and
hypotonic solutions
Hypertonic: The solution has a higher concentration
of solutes and a lower concentration of water than
inside the cell. (High solute; Low water)
10%
Solute
How much solvent
outside?
90%
solvent
shrinks
Result: Water moves from inside the cell into the
solution: Cell shrinks (Plasmolysis)!
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What type of solution are these cells in?
A cell in an hypertonic solution
Water
moves
out
10%
Solute
How much solvent
inside?
20%
Solute
A
B
C
Hypertonic
Isotonic
Hypotonic
How much solvent
outside?
90%
solvent
80%
solvent
Cell shrinks!
Solutions Drawing & Questions
Notebook Page ____
Front--- Draw, Color, Label & Descriptions.
•  (Fig. 8.2 A,B,C) p. 197
•  (Fig. 8.3 A,B,C) p. 197
•  (Fig. 8.4 A,B,C) p. 197
Back---Write questions & answers
1.  Define isotonic solution, hypotonic solution, and
hypertonic solution.
2.  Explain why plant cells do not burst when in a
hypotonic solution.
3.  What happens to an animal cell in a hypertonic
solution?
Osmosis Drawing & Questions
Notebook Page ____
Draw, Color, Label & Descriptions.
•  (Fig. 8.1) p. 196
Write questions & answers.
1.  The diffusion of water across a selectively
permeable membrane is called ___.
2.  Water flows to the side of the membrane where the
water concentration is (higher/lower).
3.  (True/False) In a cell, water always moves to reach
an equal concentration on both sides of the
membrane.
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