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WARM UP #4 11/29
Yesterday you saw a plant and animal cell
(yours). What 2 parts are
1. Only in plants?
2. Only in animals?
3. Do larger organisms = larger cells?
4. What is the purpose of the cell membrane?
5. What kinds of things do you think go into and
out of the cell membrane in our cells?
TODAY 11/29
1.
2.
3.
4.
Learning Targets for the week
Notes Ch 4 #2
Exploring Tonic Solutions
Make a foldable
LEARNING TARGETS 11/29
* I can explain 3 ways materials get into and
out of the cell membrane to maintain
homeostasis in the cell.
* I can explain and predict what will happen
in a hypotonic, hypertonic, or isotonic
solution.
NOTES Ch 4 #2
11/29
The cell membrane
HOMEOSTASIS
Maintaining a constant environment in the
body
Means:
Our body wants to
keep things the same
or balance
THINGS OUR BODY WANTS TO
KEEP CONSTANT
-
Water balance
Temperature
Blood pressure
pH (acid levels)
Minerals
Gases (O2 and CO2)
CELLS play a big role in homeostasis
CELL MEMBRANE – regulates what enters and
leaves the cell
SELECTIVELY PERMEABLE - allows only
certain things and amounts in and out
CELL
MEMBRANE
IS MADE OF
2 LAYERS
There is rarely equal amounts of
things on the inside and the
outside of the cell.
(like sugars, salts, water, fats, etc)
CONCENTRATION GRADIENT
Differences in
amounts from
one area to
another
Movement goes
naturally from
HIGH to LOW
(where there is a lot
to where there is a
little)
Example of concentration
gradient
If I sprayed a perfume at one end of the
room, what would happen?
Why would it happen?
What if I did it and no one was in the room to
cause any air movement?
Example of concentration
gradient
If you put a drop of one thing into another,
can they mix evenly without you mixing
it????
What if I put a drop of dye into
water?
What will happen?
•
•
EXPLAIN what happened?
PASSIVE TRANSPORT - movement of
particles WITH the concentration gradient
- high to low (or from a lot to a little)
Sometimes things need to get in where there is not a lot….
It needs to go backwards
ACTIVE TRANSPORT – movement of
particles AGAINST the conc gradient low to high (or from little to a lot)
What kind of transport – active or passive
and why?
* Uses energy to do this, more work
How do materials get in and out?
1) pushing through
membrane (large)
2) through protein
“pumps”
in the membrane
(sugar and salts)
3) Go right through the
membrane
(water and gases)
a) Diffusion – movement of
particles from high to low
a) Osmosis – diffusion of water
What were the 3 ways that
things get into a cell?
• Push
• Protein Pump
• Go right through
What were the two types of transport?
• Active
• Passive
Our cells are always in a
solution…..
What is a solution?
SOLUTE - material that gets dissolved
+
SOLVENT - liquid that does the dissolving
=
SOLUTION – mixture of solvents and
solutes
1
3
2
Blood is a solution of what?
Urine is a solution
• What are some other solutions in our
body?
Our cells are a solution!
Examples of solutes that go into
and out of our cell
Gases (O2, CO2)
Fats (lipids)
Sugar
Salts
Calcium
Hormones
Enzymes
Back to our dye example
earlier…
Cells are in solutions, but not always even
3 TYPES OF OSMOTIC (water)
SOLUTIONS OUR CELLS CAN
BE IN:
Hypertonic
Isotonic
Hypotonic
DO NOT WRITE
One type will keep things the same
One type will cause cells to swell or burst
One type will cause to shrink or shrivel
How does this work?????
EXPLORING the TONICS
GROUPS OF TWO
(see worksheet)
Have pictures of iso, hypo, and hyper tonic solutions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
What do you notice is different about the 3 solutions?
Which solution has a higher concentration of water inside the cell?
What do you would predict would happen to the cell in this type of environment?
Which has a higher concentration of water outside the cell?
Would water flow into or out of the cell?
What do you predict would happen to the cell in this type of environment?
Would water flow into or out of the cell?
If a person is lost at sea and drinks the salt water, what type of solution would his
body be in? Explain what would happen to him.
Predict what would happen to a cell that is 70% water being placed into a 30%
water solution. Draw a diagram showing this.
Predict what would happen to a cell that is 70% water being placed into a pure
water solution (100%). Draw a diagram showing this and label what type of
tonicity it is.
Why would a person studying to be a nurse need to know about this? What would
they need to do to a person that is coming in the hospital dehydrated – what kind
of solution of IV would they need to give them?
DESIGN AN EXPERIMENT
You want to know if what you just learned is
true, so you are going to design an
experiment to test hypertonic, isotonic,
and hypotonic.
Given – 3 cells that are 65% water
MATERIALS?
EXPERIMENT? (step by step)
ISOTONIC
Hypertonic
Hypotonic
Hemolysis – the rupture of red
blood cells
Due to the blood cell
being placed in a pure
water solution - the
pure water will go into
the blood cell
(hypotonic solution)
and cause it to burst
Crenation – the shrinking of red
blood cells
If red blood cell is
placed in a very
concentrated solution
of a chemical (EX:
very salty)
then the water in the
cell wants to leave to
where there is less
concentration of
water.
Cell will shrink