This is a Foldable

* Use 4 sheets of paper.

It should look like this.. (Next slide)

How to make a flip book.. • 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 !!