membrane structure/function Flashcards
which region of a phospholipid is polar/non polar
polar, hydrophilic head
non polar, hydrophobic tails
what do phospholipids tend to form in aqueous solutions
micelle or lipid bilayer in order to expose hydrophobic regions to non-aqeuous solution and hydrophilic to aqueous
general functions of membranes
define boundaries protein localization transport/permeability role in signalling cell-cell interactions important for compartmentalization
when and why was there a breakthrough for membrane research?
1960 with the advance of microscopy
why is it hard to work with membrane proteins
because they must remain in non-polar residues
what are the 2 different types of backbones for phospholipids
- Glycerides –> phosphoglycerides
2. Spingosine –> phosphosphingolipids
what is the purpose of sterols in membranes
important for membrane fluidity, even out extremes
ex. cholesterol
what do scramblases do?
maintain equal numbers of lipids on either side of membrane
what is FRAP and what does it demonstrate
fluorescence recovery after photobleaching
measures recovery of lipids, proteins or both
shows membrane fluidity
how does fatty acid composition affect fluidity?
more VDW interactions the more solid a membrane becomes
how does the length of tail of fatty acids affect fluidity
longer tails will decrease fluidity because there are more VDW interactions
shorter tails will increase fluidity because there are less VDW interactions
how does saturation affect fluidity?
increase amount of unsaturation will increase the amount of fluidity
- more double bonds = more kinks and fatty acids cannot pack as tightly
increase saturation will decrease fluidity
- no double bonds can pack together very tightly
what fatty avid will cause the most fluid membrane? the most liquid?
most fluid –> short unsaturated tails
most solid –> long saturated tails
which are the components of the fluid mosaic model of membranes
membrane proteins –> mosaic component
lipid bilayer –> fluid component
what are integral and peripheral membrane proteins
integral = directly embedded in the membrane peripheral = not directly embedded
