Transcript Diffusion and Osmosis Notes

Diffusion and
Osmosis
DIFFUSION
• The process in
which molecules
move from areas
of HIGH
concentration to
areas of LOW
concentration
OSMOSIS
• The diffusion of
water molecules
through a
membrane
Osmosis
• The diffusion of water across a selectively
permeable membrane.
• Osmosis is a type of Passive Transport.
• Osmosis requires NO ENERGY.
When do the molecules stop
moving?
EQUILIBRIUM = molecules are evenly
distributed
Let’s Practice…
Osmosis
• Hypertonic- a solution
that causes a cell to shrink
because of Osmosis.
• Hypotonic- a solution that
causes a cell to swell
because of Osmosis.
• Isotonic- a solution that
causes no change in the
size of the cell
Why are osmosis & diffusion
important?
• All living things have certain requirements they
must satisfy in order to remain alive – maintain
homeostasis
• These include exchanging gases (usually CO2
and O2), taking in water, minerals, and food, and
eliminating wastes.
• These tasks happen at the cellular level.
• Molecules move through the cell membrane by
diffusion
• A balance, or EQUILIBRIUM, must be
maintained.
Summary
• Diffusion is the movement of molecules from an
area of higher concentration to an area of lesser
concentration.
• Osmosis is the movement of water thru a semi
permeable membrane.
• Active transport requires energy. (molecules
move from an area of lesser to higher
concentration)
• Passive transport needs NO ENERGY!
(molecules move from an area of higher to
lesser concentration).
Let’s Practice…
• 1. The concentration of oxygen particles
inside a cell is 45 percent and outside the
cell is 30 percent. Draw a picture in your
notes of this scenario.
• What will most likely happen? A. The Oxygen
will move from inside to outside.
– B. The Oxygen will move from outside to inside.
– C. Nothing – its isotonic
Let’s Practice…
• 2. The concentration of water molecules
inside a cell is 80 percent and outside the
cell is 25 percent. Draw a picture in your
notes of this scenario.
• What will most likely happen?
– A. The Water will move from inside to outside.
– B. The Water will move from outside to inside.
– C. Nothing – its isotonic
Let’s Practice…
• 3. The concentration of hydrogen particles
inside a cell is 33 percent and outside the
cell is 62 percent. Draw a picture in your
notes of this scenario.
• What will most likely happen?
– A. The Hydrogen will move from inside to outside.
– B. The Hydrogen will move from outside to inside.
– C. Nothing – its isotonic
Let’s Practice…
• 4. The concentration of water molecules
inside a cell is 52 percent and outside the
cell is 51 percent. Draw a picture in your
notes of this scenario.
• What will most likely happen?
– A. The water will move from inside to outside.
– B. The water will move from outside to inside.
– C. Nothing – its isotonic
Let’s Practice…
• What is your prediction for this diagram?
• Address BOTH the Salt and the Water
molecules.