Lecture 12 - Lipids and lipid membranes Flashcards
what does lipid refer to?
-a large heterogeneous group of fat soluble biological compounds
what compounds are considered lipids? (7)
- fatty acids
- triglycerols
- glycerophospholipids
- sphingolipids
- steroids
- isoprenoids (terpenoids)
- eicosanoids
what are 4 major functions of lipids?
- membranes
- energy storage
- signaling (as hormones)
- vitamins
what are fatty acids?
-carboxylic acids with long hydrocarbon tail?
what are the most common types of fatty acids?
C16 or C18 fatty acids
what are saturated carbon bonds?
single C-C bonds
what are partially unsaturated?
some C=C double bonds
double C=C bonds on fatty acid tails are always ____
cis
where does the first C=C bond often start for unsaturated fatty acids?
C9
if there is more than one C=C bond, how often do they usually repeat?
-every 3 carbons
C9, C12, C15 etc.
what do cis double bonds create?
rigid kinks in the fatty acid tail
what are triglycerols?
esters made from attaching fatty acids to a glycerol
what are examples of triglycerols?
- fats and oils in plants and animals
- usually complex mixtures
what do animals use triglycerols for?
-long-term energy storage
where is fat deposited in?
fat cells in side adipose tissues, mostly subcutaneous
what is a function of glucose?
-glucose stored in the form of glycogens can release energy rapidly
what is characteristic of glycogens and energy storage?
- lower density
- highly hydrated and more oxidized
do fats contain O?
- anhydrous
- contain almost no O
-typical fat content of humans allow them to survive starvation for ______
2-3 months
how are glycerophospholipids obtained?
-by replacing a fatty acid branch in triglycerol by a PO4-linked polar head group
what can cleave glycerophospholipids be cleaved by?
various phospholipase enzymes
what are the hydrolysis products of cleaved phospholipids used as? why?
- signal transducers
- they are fat-soluble but easily distinguishable from membrane lipids
what are plasmalogens?
- variation of a glycerophospholipid
- one of the ester is modified to an ether with an alpha C=C bond