Download Chapter 5.1 Notes

Chapter 5
Membrane Structure and Function
part I
Page ref. 84-86
Memorize these words!!!
 inter – within ie. Hilo to Honolulu
 intra – between, among ie. Hilo to Kona
 extra – outside of (extracellular would be
outside the cell)
 glyco – containing sugar/carbohydrates
(sugar-coated)
The fluid-mosaic model of
the plasma membrane
 The cell membrane
is a fluid,
phospholipid bilayer
in which protein
molecules are either
fully or partially
embedded. (see fig.
5.1 and 5.2)
Plasma membrane
functions
 to separate the internal from external
environment of the cell
 Regulates materials entering and leaving
the cell.
 Helps the cell, in turn the organism,
maintain homeostasis
Plasma membrane
structure
 Made up of a
phospholipid bilayer
 Phospholipid: a
molecule with a
hydrophilic (waterloving) head and a
hydrophobic (waterfearing) tail
Plasma Membrane
Components
 Cholesterol: a lipid found in bilayer, for strength
of membrane
 Proteins: peripheral (inside surface of
membrane) or integral (embedded in
membrane)
 Some integral proteins protrude from one surface of
bilayer, some protrude from both (transmembrane)
 Phospholipids and proteins can have attached
carbohydrate (sugar) chains. These are called
glycolipids, and glycoproteins, respectively
Carbohydrate Chains
 Carbohydrate chains of proteins in
animal cell give cell a “sugar coat” called
the glycocalyx.
 Functions of the glycocalyx include
protection of the cell, enables cells to
adhere to one another, reception of
signal molecules, and for cell-to-cell
recognition
Fluidity of Plasma
Membrane
 Membrane fluidity critical to it’s
functioning
 At body temperature, it has the
consistency of olive oil
 This allows the cell to do all it needs to
do – it makes the cell pliable
Homework
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Due Thursday
All vocab AND
Reviewing chapter - #1-3
Testing yourself 2,3,11,12,13,14