7.2 cell membrane - oak park independent · 2011-09-19 · 7.2 cell membrane the cell membrane...

7.2 Cell Membrane

The Cell MembraneSection 7.2

· a.k.a. plasma membrane· functions

a. maintains integrity of cell (forms a boundary) like a gate or border

b. controls passage of materials into and out of cell(selectively permeable)

like a gatekeeper, bouncer, or border control

Cell Membrane Function

Selective Permeability

· a.k.a. semipermeable or selectively permeable· only certain substances can enter or leave cell· helps maintain homeostasis b/c cell need very specific conditions to function properly

· phospholipid bilayer (two layers)hydrophilic heads (polar) - love waterhydrophobic tails (non polar) - fear water and turn in

Cell membrane Structure

Cell Membrane Structure· cholesterol - keeps phospholipids from sticking together· proteins - help materials cross the membrane and form part of the cytoskeleton· carbohydrates - tags for identification

· cell membrane is flexible and moves from side to side

behaves like a liquid· embedded proteins and other molecules create patterns

looks like mosaic tiles

FLUID MOSAIC MODEL

7.2 Cell Membrane

A. phospholipidA1 - hydrophilic heads A2 - hydrophobic tails

C, F, G. ProteinsD. CarbohydratesE. Cholesterol