Transcript Ch. 7- Lecture #2 blanks

The Plasma
Membrane
7.2
I. Maintaining Homeostasis
A. ___________- The flexible
boundary between the cell and
its environment
1. A.K.A. Cell Membrane
2. Maintains ______ (balance)
by letting some things in and
keeping others out
Sniff and toss balloon activity
I. Maintaining Homeostasis
B. ______ PermeabilityFeature of the cell membrane
that allows some molecules in
to the cell while keeping
others out.
1. Ex: Strainer, screen, filter
I. Maintaining Homeostasis
2. Water moves freely
3. _____ such as calcium and
sodium have to enter the cell
in other ways
4. Selective permeability lab
II. Plasma Membrane Structure
A. ____________ bilayer
1. Bilayer = 2 layers
2. Phospholipid =
1 Phosphate group
+
2 fatty acid chains (lipid)
3. 2 layers of phospholipids
Note: _______ are important
because they do not dissolve
in water. What would
happen if the membrane was
made of water soluble
substances???
A. It would break down and the
cell would die!!!
I. Plasma Membrane Structure
4. The _______ group is polar
(likes water)
a. Face the outside
5. The fatty acids are nonpolar (repel water)
b. On the ______ of layer
c. Keeps water soluble
molecules from moving in too
easily
I. Plasma Membrane Structure
B. Fluid Mosaic Model1. The ________ is not
rigid
2. The phospholipids and
_______ are constantly
moving around each other
a. Like a tub of water
with ping-pong balls floating
I. Plasma Membrane Structure
C. ____________
1. Stabilizes the membrane
2. Keeps fatty acid tails
from getting tangled
3. Not all cholesterol is bad!
I. Plasma Membrane Structure
D. Transport Proteins1. ________ in the membrane
2. Allow movement of
substances in when needed
3. Allows for the movement of
_____ products out of the cell
4. Once again, maintains
____________
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I. Recap
Why is the plasma
membrane important?
What property allows the
membrane to let some things
in and keep others out?
What 2 main parts make up
the phospholipid bilayer?
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I. Recap
What is the role of
cholesterol in the
membrane?
How to large water soluble
molecules needed by the cell
get inside?