Name: ______________________________________________________________ Period: _____________________
7.2 The Plasma Membrane
What is the Plasma Membrane?
 The plasma membrane is a ________ , ____________ and ________________________ boundary between
a cell and its surroundings
 Selective Permeability: _______________________________________________________
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Selective Permeability Example
 What types of sports ball would fit through a chain link fence? What types wouldn’t?
o Would fit: _____________________________________________________________
o Would not fit: __________________________________________________________
o Think: What do the balls that will fit through the fence have in common?
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 Think back to the bubble lab, what would go through the bubble? How did we get around the bubble’s semi-permeability later in the lab?
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Homeostasis
 The main job of the plasma membrane (or cell membrane) is to help the body maintain ___________________
 Video Notes (What is homeostasis?): _____________________________________
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A Connection to Biochemistry (Ch 6)
 The plasma membrane is made up of a _______________________________________
o What does that mean? ________________________________________________
o Reminder: A lipid is a molecule that
contains a phosphate-group and two
fatty acid chains. Draw one here →
The Phospholipid Bilayer
 _________ layers of phospholipids that are arranged
_________ ____ __________ this allows the membrane
to exist in ___________ environments
 A phospholipid has 2 main parts, a ______________________ Head (Polar, charged) and a
____________________ Tail (Nonpolar, no charge)
 Describe the benefit of the bilayer structure of the plasma membrane ____________
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Other Parts of the Plasma Membrane
 Cholesterol (structure), Proteins (many functions), Carbohydrates (structure)
 _________________- special proteins that transmit signals to the inside of the cell
o Like a microscopic satellite
 ________________ Proteins- Used to move
substances and waste in and out of the cell (these
contribute to the semi-permeability of the membrane)
The Fluid Mosaic Model
 Describe the fluid mosaic model in your own words:
_______________________________
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