structure & property of lipids Flashcards
why is aggregation of lipids favourable
it increases the entropy of the surrounding water
what method is used to demonstrate mobility of membrane lipids & proteins
FRAP (fluorscence recovery after photobleaching)
why is phosphate important in the phospholipid structure
it gives phospholipids amphiphatic properties (chemically opposing), phosphate is negative so its hydrophilic
what 2 things does phospholipid bilayer fluidity depend on
saturation & fatty acid chain length
why are saturated fatty acids less fluid
they allow close packing due to lack of kinks
why are unsaturated fatty acids fluid
they have double bonds which cause kinks, more spaced packing so more fluidity
what 3 classes of lipids do biomembranes contain
phosphoglycerides, sphingolipids, sterols
what are sphingholipids
long chain fatty acid with amide linkage to sphingosine amino group
importance of sterols
provide structural support to membranes, maintain fluidity and also rigidity for support
what is the effect of cholesterol on phospholipid fatty acid tails
at normal concentrations, steroid ring interacts with tails to immobilise lipids and reduce fluidity
at low concentrations, steroid ring separates and disperses tails to increase fluidity
what does cholesterol do when it interacts with phosphoglycerides?
increases thickness of phosphoglyceride bilayer
what are lipid rafts
detergent resistant microdomains in bilayers made of cholesterol & sphingomyelin. thicker than rest of phospholipid bilayer
