This is a Foldable
* Use 4 sheets of paper.
It should look like this.. (Next slide)
How to make a flip book..
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LAYERED-LOOK BOOK
Collect 4 sheets of paper and layer them about 1.5 cm apart vertically. Keep the edges even.
Fold up the bottom edges of the paper to form 8 equal tabs.
Fold the papers and crease well to hold the tabs in place. Staple along the fold. Label each tab.
Tabs for Foldable
• Title= Plasma membrane
• Functions of Cell mbn
• Fluid mosaic model
– Phospolipid
– Bilayer
– Layer structure
– Mbn structure
• Proteins
Cell Membrane & Function
FYI: The Plasma Membrane
• The Plasma Membrane Isolates the Cell While
allowing communication with its
surroundings.
3 Major General Functions.
1. Isolates internal environment
(cytoplasm) from external
environment.
2. Regulates exchange of essential
substances.
3. Communicates with other cells.
Plasma
Membrane
• Membrane function is dependent on
membrane structure.
Fluid Mosaic Model
•
The Membranes are “Fluid Mosaics”
–
Proteins Move Within Layers of Lipids.
•
Phospholipids are “grout” & membrane proteins,
are the “tiles”.
•
FYI: Fluid Mosaic Model was developed in 1972 by S.
J. Singer and G. L. Nicholson
Phospholipids- draw this!!
• Phospholipids have a polar “head” and two
nonpolar “tails”
• Double bonds in the tail increase fluidity of
membrane
The Bilayer.
• Amphipathic
• The tails point in toward each other, and the heads
point toward the outside, or inside of the cell.
• Polar heads form hydrogen bonds with water;
• Hydrophobic interactions keep tails facing each
other.
Look at What Happens!!(You don’t write this down)
• Phospholipid bilayer selectively
isolates internal environment
from external environment
• Most biological molecules are
hydrophilic and cannot easily
pass through the membrane
• Some very small molecules or
uncharged, lipid-soluble
molecules can freely pass
through membrane
The Phospholipid Bilayer Is the Fluid Portion
of the Membrane
Phospholipid Bilayer Structure
• Cholesterol in animal cell membranes makes
the bilayer stronger.
– more flexible, less fluid, and less permeable to
water-soluble substances.
• Flexibility and fluidity is very important to the
function.
Membrane Structure
All of the following can be found
in the mbn:
– Phospholipids
– Cholesterol
– Proteins
• regulate the movement of
substances across the membrane
• communicate with the
environment.
Types of Proteins
• Transmembrane Proteins
(Integral)
– Transport proteins
– receptor proteins
– recognition proteins
• Glycoprotein- have a carbohydrate group
attached.
• Peripheral proteins- attached to the
cytoskeleton
Let’s Review !!