unit 2: biological membranes Flashcards
monomers in a polymer are connected by what kind of bonds
covalent
macromolecules are held together by what bonds
non-covalent
why is there no water within the hydrophobic core of the bilayer
water cannot H-bond with the fatty acid tail
why do plants and fungi have to change its lipids to maintain fluidity more than animals
since plants and fungi can’t move around, they need to maintain homeostasis more
true or false: the interior of the alpha helix forms a hydrophilic pore for the passage of small molecules
false
integral proteins
- directly attached to the membrane
- are amphipathic
- can be made up of a single subunit (monomeric) or multiple subunits (multimeric)
- held together in membrane through VDF associations
peripheral proteins
- bound to membrane surfaces through non-covalent association with other membrane proteins
how do integral proteins contribute to membrane asymmetry
the leaflet of attachment matters therefore there will be asymmetry when an integral protein is present
how do peripheral proteins contribute to membrane asymmetry
different proteins attach to different sides
transmembrane domain
part of a membrane protein that passes through lipid bilayer
- most are alpha helices, though some are beta barrels
how and where are new phospholipids synthesized
- synthesized by enzymes
- in the cytoplasmic face of the ER
flippases/floppases
enzymes in the membrane that move phospholipids from one leaflet to another
- uni-directional movement
scramblases
bi-directional movement
where are carbohydrates ALWAYS attached
non-cytosolic side of the membrane
function of the glycocalyx
- protects the cell
- acts in cell communication/identification
what do hydropathy plots do
predict the number of transmembrane segments and orientation
what do protein purification and biochemical experiments do
determine membrane protein type, components, and orientation
