Bellwork- HAVE SLATE ON DESK!
1. How is the cell membrane like a screened in porch or
window?
2. How is it not like a screened in porch?
3. Copy the picture below. If the solute is a LARGE or
CHARGED molecule, what is the ONLY thing that can pass
the cell membrane?
4. What is osmosis?
5. Draw arrows on a circle showing which direction(s) water
would move (in the pic below).
Announcements
12 days until science fair data due
Cell Membrane Unit
1. Notes
-3.5 Outline
-Cell Membrane & Transport Notes
2. Labs
-Egg Lab graph & conclusion
3. Assignments
4. Tests
Essential Question
How do our cells maintain
equilibrium (balance) in a
constantly changing
environment?
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Cell Membrane & Transport Notes
What does osmosis tell us about the salt
& sugar concentrations INSIDE of the egg
if “water follows the salt”?
0%
salt
25%
sugar
50%
salt
Does this make sense? Think
about what an egg is…
Names for concentrations:
Isotonic
• Iso= same
• Same concentration outside the cell as inside
Hypertonic
• Hyper= more/too much
• Higher concentration solution outside the cell
Hypotonic
• Hypo= less/too little
• Lower concentration solution outside the cell
This duck egg GAINED weight in a 15%
sugar solution
• Which direction must water have moved?
• Where is the higher concentration of solute (think
about which direction water moves during osmosis)?
• Is the 15% sugar solution iso-, hyper-, or hypo- tonic?
• What % concentration is the sugar inside of the egg?
• Why couldn’t the sugar have moved?
This duck egg LOST weight in a 75%
sugar solution
• Which direction must water have moved?
• Where is the higher concentration of solute (think about
which direction water moves during osmosis)?
• Is the 75% sugar solution iso-, hyper-, or hypo- tonic?
• What % concentration is the sugar inside of the egg?
• Why is water able to move passively across membranes?
Bio 1-2
1.
Finish graphing solute/concentration vs change in weight
2.
Complete conclusion (1 P) on back of graph paper
Answer the 6 lab Qs AND include the following:
-Use correct vocabulary (from notes, textbook) throughout to
describe the results
-Cite the textbook 1-3 times in support of your claims
When finished- turn in graph & conclusion to front
basket & pick up article on osmosis
misconceptions