Test for Diffusion, Osmosis and Dialysis activity
Name____________________ Teacher _________________________
Date________________________ Class ________________________
1. A cell was placed in distilled
water. What will happen to the
cell over time if a cellular
membrane is permeable to water
but not to the salt ions? Draw a
picture below.
A cell was placed in a highly
concentrated solution of table
salt. What will happen next to
the cell over time if its
membrane is permeable to water
but not to salt? Draw a picture.
Water
Salt
Cell
Membrane
Permeable
to water but
not to salt
1
A
B
2. In figure A there are two water reservoirs connected by a semi-permeable
membrane that lets water through it but does not let salt ions go through it. Some
salt was added to one of the reservoirs, and the result was (Fig B). Explain, where
the salt was added and why the water level changed?
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3. When blood passes through the kidneys, small molecules of waste are removed from the
blood, while large molecules, such as proteins, and red blood cells remain.
When kidneys do not work
well, people need to be on
hemodialysis, using a set up
similar to the one in the
picture to the left. Blood
goes go through cellophane
tubings surrounded by a large
volume of moving fluid that
takes wastes away.
Cellophane
tubings
Waste product
such as urea
..
Red Blood
cells
.. ....
Pores in the
tubings
..
..
White Blood
cells
Proteins
..
..
Dialysis
Fluid
This is a close up of the
cellophane tubing with
blood in it. The dialysis
fluid surrounds the tubing.
3a. What size should the
pores in the tubing be
compared with the size of
waste and other
components of blood
shown in the illustration?
..
.. ..
3b. Suppose the dialysis liquid is not renewed but is recirculated again and again. Describe what
would happen.
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4. A lab technician needs to remove molecules of urea (white
dots) from a protein solution in order to restore the protein’s
structure (urea was used as a denaturation agent). To do so, she
placed the sample in a dialysis bag and placed the bag in a large
jar of water.
4a. She made sure the volume of the surrounding water was much
greater than the volume of the bag. Why did she do need to do
this?
4b. She kept replacing the water in the jar. Why?
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