Questions and CORRECT Answers
naming fatty acids simplified - CORRECT ANSWER - -specifies number of Cs followed
by number of double bonds separated by a colon
-position of double bonds is specified relative to the carbonyl carbon
naming fatty acids pufa - CORRECT ANSWER - -specify position of double bonds
relative to the methyl carbon
commonly occurring saturated fatty acids - CORRECT ANSWER - 12 laurate, 14
myristate, 16 palmitate, 18 stearate, 20 arachidate (LMPSA)
trans fatty acids - CORRECT ANSWER - -partial hydrogenation of unsaturated fats
isomerizes double bonds
-allows fatty acid to adopted extended configuration
solubility and melting point of saturated fats - CORRECT ANSWER - -saturated chains
adopt extended configurations and pack in an orderly way
-as chain length increases melting point increases and solubility decreases
melting point and double bonds - CORRECT ANSWER - - unsaturated fats pack less
regularly due to kink cause by cis double bonds, lowering favourable interactions
-less thermal energy is required to disrupt disordered packing
-melting temperature is drastically lowered
-trans fatty acids can pack more regularly and have higher melting points than cis forms
triacylglycerols - CORRECT ANSWER - -3 fatty acids linked to a glycerol molecule
through ester linkages
-major constituent of bulk fats and oils
,-highly hydrophobic, as the polar carboxylic acids are tied up as esters
-melting point depends on the length and degree of saturation
phosphate derivatives - CORRECT ANSWER - -phosphoric acid is a triprotic acid
-at neutral pH it exists as an equilibrium of H2PO4- and HPO4-2
-mixture is represented as Pi
-phosphoylation adds negative charges to molecules, leading to an increase in water solubility
glycerophospholipids - CORRECT ANSWER - -primary constituent of biological
membranes
-carbon atoms 1 and 2 of glycerol are esterified to 2 fatty acids (tail) with a highly charged group
attached through a phosphodiester linkage to the third (head)
-they are ampiphatic, allowing them to form lipid bilayers
phosphatidylcholine - CORRECT ANSWER - -net charge 0
phosphatidylethanolamine - CORRECT ANSWER - -net charge 0
phosphatidylserine - CORRECT ANSWER - -net charge -1
phosphatidylglycerol - CORRECT ANSWER - -net charge -1
lipid complexes - CORRECT ANSWER - -fatty acids aggregate to form spherical micelles
-hydrophobic tails are too bulky to pack together in micells, so they form bilayers which fold
back on themselves to form liposomes/vesicles
analysis of lipids - CORRECT ANSWER - -separated based on polarity on a column of
silica or through TLC
-elute from column in increasing polarity
, monocasscharides - CORRECT ANSWER - -very water soluble
-poorly soluble in organic solvents
-colorless and sweet
-(CH2O)n
-combines a carbonyl (C=O) and a hydroxyl group
emil fischer - CORRECT ANSWER - studied the analysis, synthesis and sterochemistry of
simple sugars and intriduced terminology and notation
fischer projection - CORRECT ANSWER - -represents 3D sugars on paper
-vertical bonds project behind the plane
-horizontal bonds project out of the plane
perspective formula - CORRECT ANSWER - -drawing of sugar structures
-solid wedge project in front
-dashed bonds point away
enantiomers - CORRECT ANSWER - -mirror images
-differ in configuration at every chiral C atom
-left handed and right handed forms of molecule
-differ in optical activity
diastereomers - CORRECT ANSWER - -some chiral C atoms are configured differently,
while some aren't
-dont have identical chemical properties
-can be epimers, but not enantiomers