Transcript Diffusion (Dialysis Equipment)

Diffusion and Osmosis
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TABLE OF CONTENTS
Diffusion
Osmosis
Living Cell Osmosis
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Diffusion and Osmosis
DIFFUSION
Dialysis Equipment
Equipment Set Up
Results
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Diffusion and Osmosis
Diffusion (Dialysis Equipment)
glass dish
dialysis
tubing
glucose
test strips
closures
pipet
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Diffusion and Osmosis
Initially, the dialysis tubing is filled with a super saturated
glucose + starch solution
Starch
Water
dialysis tubing
Glucose
continue
animation
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Diffusion and Osmosis
The filled dialysis tubing is placed in a dish with a
solution of iodine and water
Iodine
Water
Starch
Water
Glucose
The dialysis tubing membrane is selectively permeable
continue
animation
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Diffusion and Osmosis
Diffusion (Equipment Set Up)
DIALYSIS TUBING
starch, glucose
and water
iodine and water
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Diffusion and Osmosis
In DIFFUSION, particles travel from
an area of high concentration to an
area of low concentration
As particles migrate through a
membrane in this way, movement is
described to be traveling
“down a concentration gradient”
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Diffusion and Osmosis
When particles migrate through a
selectively permeable membrane
some particles are able to
pass through but not others
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Diffusion and Osmosis
There is a GLUCOSE gradient across the membrane
Iodine
Water
NONE
HIGH
Starch
Water
Glucose
GLUCOSE molecules fit through the membrane and travel
“down a concentration gradient” to the outside of the
dialysis tubing … testing indicates GLUCOSE now in dish
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continue
animation
Diffusion and Osmosis
There is a IODINE gradient across the membrane
HIGH
Iodine
NONE
Starch Water Glucose
Water
IODINE molecules fit through the membrane and travel “down a
concentration gradient” to the inside of the dialysis tubing … testing
indicates IODINE now in dialysis tubing as Starch turns PURPLE
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continue
animation
Diffusion and Osmosis
There is a STARCH gradient across the membrane
NONE
Iodine
HIGH
Starch Water Glucose
Water
However, STARCH molecules cannot fit through the dialysis
tubing membrane … water in dish is not PURPLE
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continue
animation
Diffusion and Osmosis
There is a WATER gradient across the membrane
Iodine
Water
HIGH
LOW
Starch
Water
Glucose
WATER molecules fit through the membrane and travel
“down a concentration gradient” to the inside of the dialysis
tubing … dialysis tubing is much fuller than before
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continue
animation
Diffusion and Osmosis
Diffusion (Results)
dialysis tubing in iodine and water
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Diffusion and Osmosis
OSMOSIS
Osmometer Equipment
Equipment Set Up
Results
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Diffusion and Osmosis
OSMOSIS (Osmometer Equipment)
cup
animal disc
membrane
bell
straw
rubber
band
cover
pipet
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Diffusion and Osmosis
ASSEMBLING THE OSMOMETER
straw
inserted into
narrow end of
bell
cup
with lid
bell
opened at both
ends
selectively
permeable
membrane
stretched
across wide
end of bell
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animation
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Diffusion and Osmosis
FILLING THE OSMOMETER
The position
of the
solution in
the bell is
marked
The bell is filled
with a super saturated
lactose solution
(lactose and water)
The cup is filled
The solution is dyed
to make it visible in
one half full of water
the bell
continue
animation
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Diffusion and Osmosis
A super saturated solution has
a relatively low water
concentration because of a
VERY HIGH
solute concentration
The osmometer solution has a
large amount of lactose solute
dissolved in a small amount of
water
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Diffusion and Osmosis
The osmometer is assembled
continue
animation
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Diffusion and Osmosis
Osmosis (Equipment Set Up)
fluid level
super saturated
lactose and water
solution
water
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Diffusion and Osmosis
Diffusion of
water takes place
through the
membrane. Water
is pulled from an
area of
high
concentration
(in the cup)
to an area of
low
concentration
(in the bell)
OSMOMETER
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animation
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Diffusion and Osmosis
As water
diffuses
through the
membrane
OSMOMETER
“down the gradient”
from the cup
into the bell
the overall
fluid level
rises up the
straw
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animation
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Diffusion and Osmosis
The membrane
is selectively
permeable
OSMOMETER
the lactose
solute
particles
because of
their larger
size
are
prevented
from
migrating
through the
membrane
and rise up
the straw
along with
the water
continue
animation
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Diffusion and Osmosis
Osmosis (Results)
fluid level
osmometer solution rises
up the straw
water is pulled in through
selectively permeable
membrane
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Diffusion and Osmosis
LIVING CELL OSMOSIS
Elodea Before NaCl Application 400x
Elodea Before NaCl Application 1000x
Elodea After NaCl Application 400x
Elodea After NaCl Application 1000x
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Diffusion and Osmosis
Elodea Before NaCl Application 400x
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Diffusion and Osmosis
Elodea Before NaCl
Application 1000x
cell
wall
cell
membrane
chloroplasts
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animation
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Diffusion and Osmosis
The cell is initially in an isotonic solution
Water within the cell keeps the
cell membrane against the
cell wall
100%
water
100%
water
100%
water
Chloroplasts are evenly spread
throughout the cytoplasm
continue
animation
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Diffusion and Osmosis
Elodea
1000x
The cell is placed
in a hypertonic
salt solution
continue
animation
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Diffusion and Osmosis
When the cell is placed in a hypertonic solution
there is a salt gradient across the cell wall and membrane
Water goes “down the gradient” from a high
water concentration inside of the cell ...
90%
water
100%
water
water
10%
salt
Hypertonic
Solution
water
water
water
90%
water
10%
salt
Hypertonic
Solution
to a low water concentration outside of the cell
continue
animation
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Diffusion and Osmosis
Elodea After NaCl Application 400x
continue
animation
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Diffusion and Osmosis
The rigid cell wall is porous and remains intact ...
but without water inside of the cell,
the cell membrane is pulled from the cell wall
water
water
Hypertonic
Solution
Hypertonic
Solution
water
water
Chloroplasts are draw in with the
cell membrane and collect in the
middle of the cell
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continue
animation
Diffusion and Osmosis
Elodea After NaCl
Application 1000x
cell
membrane
cell
wall
chloroplasts
Water is pulled out
of cell through the
cell wall into
hypertonic
solution
The cell membrane
crenates pulling
chloroplasts into a
small bunch
The cell
membrane
separates from
the cell wall
End
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Diffusion and Osmosis