Download Diffusion Through a Membrane Lab

Where is the water moving?
• The water is moving
out of the cell.
• Why?
• Remember where
ever salt is water
follows!
Salt
SALT
Where is the water moving?
• Water is moving out
of the cell.
• Why?
• Because where ever
salt is water follows.
Light blue = Salt
Dark blue = water
There is a lot of salt out side the
cell what will happen? Why?
What will happen if there is a lot of
salt inside the cell?
• Normal
Red Onion Cells
• In Salt Water
• What happened to the
cytoplasm and cell
membrane?
Making The Cell
What is located inside the cell in
the beginning?
• Starch, Glucose, and
Water.
This is what the experiment looks
like in the beginning
• Water and Starch
Indicator Solution are
located on the outside
of the cell.
• Starch and Glucose
are located inside the
cells.
What’s happening after the 1st 10
minutes?
• The cell is starting to
turn blue black
• Why?
• Because Starch
Indicator solution is
moving across the
membrane.
Is This The Final or Initial State?
Label The Contents Of Your Cells
• Initial State
H20 and Starch Indicator Solution
Starch and Glucose
• Final State
H20, Glucose, & Starch
Indicator Solution
Glucose, Starch,
and Starch
Indicator
Solution
7) In the initial state diagram below, Starch Indicator
Solution is indicted by the letters “I”. The letters “S” Stand
for Starch and G for Glucose.
Indicate the areas where each of these molecules are
located in both diagrams.
I I
I
I I I I
S G S G S G
S S G G S G
G S S G G S
I I
I
I
I
I I I I III
I G I G I G I G I
G
SG I GI S S
GIG IS GI SI
SGI SI S IS
I G
I G I G I
G I
Question #1
• During the lab, one
group of students
messed up. They
poured the starch
indicator solution
into the cell and filled
the beaker with starch
and glucose solution.
State what their
results would look
like.
• The outside of the cell
would turn blue black
instead of the inside
of the cell.
What Went Wrong?
Question #2
• Plant cell in salt
environment.
• Normal plant cell
• The salt would damage or
kill the plants. The salt
environment would cause
water to move out of the
http://ccollege.hccs.edu/instru/Biology/Wagle/Plasmolysis.swf
plant cell
Question # 3
• When a person is
given an I.V., the fluid
has a little salt in it
just like our blood.
• Explain how the use
of distilled water in
place of saline
solution would up set
homeostasis.
Question # 3
• Homeostasis would
be upset because
their would be more
salt inside a cell then
outside a cell. The
water would move
into the cell causing it
to burst.
Question # 4
• Fresh water fish have a
contractile vacuole which
pump out extra water.
Explain why once celled
organism in salt water
would not need a
contractile vacuole?
• Contractile vacuoles are
of no value to salt water
organisms because there
is no excess water to be
removed.
Salt Water
Fresh Water
Question #5
• Why does eating
popcorn make you
thirsty?
• Popcorn is very salty
and may cause water
to leave the cells of
your mouth and
through due to
diffusion. This makes
a person thirsty.
6) Why is the digestion of starch to
glucose necessary?
• Starch is big and
must be broken down
into glucose so it can
diffuse across a cell
membrane. Glucose
is small enough to
diffuse across a cell
membrane.
Glucose
Starch (carbohydrate)
Your homework Is to
finish your lab! If it
is not done it will be
Zero
a
. No
excuses!
The Mad Scientist