Membrane Structure And Function

Front 1

plasma membrane

What does it do?

Back 1

1. separates the living cell from its surrounding

2. controls what comes in and out of the cell

3. selectively permeable - allows some substances to come in/out more easier than others

Front 2

plasma membrane

What are main molecules in plasma membrane?

Back 2

Mainly
1. lipids
2. proteins
Some
3. carbohydrates

Front 3

plasma membrane

Main lipids

Back 3

phospholipids - main lipid in plasma membrane

phospholipids are amphipathic which means they have both hydrophobic and hydrophilic regions

Front 4

plasma membrane

lipids are amphipathic

Back 4

lipids are amphipathic - means - they have both kinds of regions:
hydrophobic - afraid of water

hydrophilic - love water

Front 5

plasma membrane

mosaic model

Back 5

the arrangement of phospholipids and proteins in biological membranes

Front 6

plasma membrane

Structure

Back 6

the membrane is a fluid structure attached to a double layer (bilayer) of phosphlipids

Front 7

plasma membrane

bilayer

Back 7

molecules in bilayer arranged so that hydrophoic fatty acid TAILS -is away from water - in middle of membrane away from water

hydrophilic fatty acid HEADS -interacts with the water - near the ends of the membrane

Front 8

plasma membrane

are fluid - changes with temperature
- colder - goes to solid

Back 8

held in place by weak hydrophobic interactions

they drift laterally but RARELY flip flop from one layer to the other

Front 9

plasma membrane

fluid impacted by

Back 9

colder temperature - goes solid
warm temperature -cholestoral reduces fluidity

at colder temperatures - cholesterol helps maintain fluidity by
and components like fatty acids - why cholesterol reduces fluidity

Front 10

plasma membrane

Cold-Adapted organism

Back 10

increase the percentage of unsaturated phosphoipids to prevent them from becoming solid during the winter

Front 11

plasma membrane

What part of membrane determines it function

Back 11

proteins

Front 12

Two major population of

Membrane PROTEINS

Back 12

1. peripheral proteins - loosely bound to the surface of membranes
2. integral proteins - lives in hydrophobic core of the lipid bilayer and spans middle of membrane

Front 13

plasma membrane

Integral proteins

Back 13

some extend partway into the hydrophic core

Front 14

plasma membrane

integral proteins

Back 14

hydrophobic core regions- consist of stretches of nonpolar amino acids

hydrophilic regions - are in contact with the water (aqueous environment)

Front 15

plasma membrane

Cytoplasmic Side

Back 15

proteins are attached by cytoskeleton

Front 16

plasma membrane

Exterior Side

Back 16

proteins attach to the fibers of the extracellular matrix

both attachments make membrane stronger

Front 17

plasma membrane

Proteins 6 FUNCTIONS

Back 17

1. transport proteins
2. enzyme activity
3. recoptors - signal transduction
4. cell recognition
5. interellular joining
6. attachment to the cytoskeleton 7. and extracellular matrix