Download Hypertonic, Hypotonic and Isotonic

Hypertonic, Hypotonic
and Isotonic
Warm Up
• Using the terms
hypotonic and
hypertonic,
describe the cell
and the
environment.
Answer
• The cell is hypotonic
since it has a smaller
concentration of solute
& greater conc. of
water
• The environment is
hypertonic since it has
a greater conc. of
solute & smaller conc.
of water
Environments
Isotonic – “same strength”
Hypertonic – “above strength”
Hypotonic – “below strength”
• “strength” refers to the
amount of solute not water
Isotonic
• Isotonic means that
the two
environments
(separated by a
membrane) have
the same
concentration of
water and the same
concentration of
solutes.
Why are the terms Hypertonic and
Hypotonic Important?
• Hypertonic and hypotonic help us to predict the
direction that water and solutes will move.
• Keep in mind that since hypotonic means less
solutes (more water), Osmosis (the movement of
water) will move from hypotonic toward hypertonic.
• Water will move to dilute the solute
What about the cell in
each case?
The Fate of Animal Cells
Animal Cells do not have Cell Walls!
• There is no cell wall
to help combat
osmosis or create
pressure.
Plant Cells have Cell
Walls!
Plasmolysis
Plant Cells have Cell
Walls
• The pressure of the cell membrane against
the cell wall is known as turgor pressure.
• The cell wall pushes back so that water
can’t cause the cell to burst.
• When water rushes out of the plant cell, the
cell membrane pulls away from the cell wall
and plasmolysis occurs.
Passive Transport
• Diffusion is the process by which particles move
from an area of high concentration to an area of
lower concentration
o Examples: carbon dioxide and oxygen gas
• Facilitated diffusion is the process in which
molecules that cannot directly diffuse across the
membrane pass through special protein channels.
o Examples: glucose and water
• Osmosis is the diffusion of water through a
selectively permeable membrane from an area of
higher to lower concentration
Active Transport
• The movement of materials against a concentration
difference is known as active transport.
• Active transport requires energy
• Examples:
• Molecular transport – molecules and ions are carried
across by protein pumps (sodium-potassium pump)
• Bulk Transport
o Endocytosis – taking material into the cell by means
of infolding, or pockets, of the cell membrane
(WBC)
o Exocytosis – when cells release large amounts of
material (contractile vacuole)
Lipid Bilayer
Lipid Bilayer Structure