Week 4 (cell membranes) Flashcards
fluid mosaic model
-membranes are not rigid
-proteins are embedded and float freely
-selectively permeable
which way do lipid molecules move in a membrane
laterally <->
why are cell membranes said to be fluid
lipid bilayers are not bonded to one another allowing movement like a fluid
sterols
maintain constant fluidity of the membrane
are membranes symmetrical?
no
each half is different
3 types of membrane proteins
Integral- go right thru membrane
Peripheral- either side
Amphitropic - right thru
integral membrane proteins interact with what?
hydrophobic core
peripheral membrane proteins interact with what?
hydrophilic surface
what molecules are able to pass thru the phospholipid bilayer?
-non polar molecules (O2,CO2)
-small uncharged polar molecules (hydrophobic)
what molecules are not able to pass thru the phospholipid bilayer?
-large uncharged polar molecules (sugars) (hydrophilic)
-Ions (have a charge)
facilitated diffusion
-facilitated by membrane proteins
-follows concentration gradient
carrier proteins
-bind specific solutes and transfer them across the lipid bilayer
isotonic
-equal solutes in the cell and outside
hypertonic
more solutes outside the cell (water rushes out )
hypotonic
more solute inside the cell (water rushes in )
