lecutre 4

Question 1

plasma membrane

Answer 1

surrounds every cell
-thin bilayer composed of proteins lipids and some carbohydrates
-seprates the ECF AND ICF fluids and compartments
-controls movement of molecules into and out of the cell. it also selects which ions, nutrients and waste products to let in or out.

Question 2

most abundant membrane lipids include…

Answer 2

-PL and some cholesterol
-have 2 nonpolor fatty acid chain tails

Question 3

Fluid helps…

Answer 3

Fluid (not rigid): consistency more
like cooking oil than stick butter. PL
are constantly moving = twirl, vibrate,
and move around within their half of
the bilayer, exchanging places
millions/sec
* Cholesterol also contributes to the
fluidity and stability of the
membrane. Intercalated in between
the PL molecules

Question 3

PL do what to turn into a lipid bilayer

Answer 3

PL self-assemble into a lipid bilayer = double layer of lipid molecules

-

Question 4

fluid mosaic model

Answer 4

The Fluid Mosaic Model
refers to membrane
fluidity and the everchanging mosaic pattern
of the proteins embedded
in the lipid bilayer
* The fluidity of the lipid
bilayer enables many
membrane proteins to
float freely like “icebergs”
in a moving “sea” of lipids

Question 5

membrane proteins include

Answer 5

channels (water-soluble molecules such as small ions selective.
Carrier molecules (transfer of
specific substances; glucose)
* Docking-marker acceptors (for
secretory vesicles and
exocytosis process)
* Membrane-bound enzymes
* Receptors
* Cell adhesion molecules (CAMs)
* Peripheral proteins