Lipids Flashcards
What are lipids defined by?
Hydrophobicity
How are they linked together?
Covalently
How to separate lipids?
TLC/gel = polarity (np elutes first)
Methyl esters = chain length and saturation
What are fatty acids the building blocks for?
Lipids
Structure feature of fatty acids
Carboxylic acid and hydrocarbon tail
Saturated fatty acids
no dbl bonds (max hydrogens)
What do unsaturated fatty acids have?
Why is it less Energy to disrupt packing?
dbl bonds (cis formation)
bcs of the kink in the double bond
Labelling fatty acids - Where is C1 located? What is the last C
Carboxyl C
Omega
Labelling fatty acids - delta = describe this 18:2 (triangle 9,12)
18 = number of carbons
2 = number of double bonds
9 and 12 = location of double bonds
Labelling fatty acids - omega
start at omega carbon and only tellus us location of first double bond
Features of fatty acids
even number of carbons. unbranched, dbl-single-single-d-s-s
Name the 5 saturated fatty acids
Laureate (12), Myristate (14), Palmitate (16), Stearate (18), Arachidate (20)
What are trans fatty acids?
partial hydrogenation of unsatt fatty acids
What happens to the solubility and mp of fatty acids when chain length increases?
mp increases
solubility decreases
Anhydride
O=C-O-C=O
Ester
CH2-O-C=O
What is a triglyceride? What are they linked by?
3 fatty acids and a glycerol (ester linkages)
Are triglycerides hydrophobic?
yes
Phosphoglycerides are amphipathic because…?
Hydrophobic tail and hydrophilic head
Phosphoglycerides - What are the highly polar charged groups?
Choline (lecithin)
Ethanolamine
Serine
Glycerol
Phosphoglycerides - draw choline
-CH2-CH2-N+(CH3 above and below)-CH3
Phosphoglycerides - draw Ethanolamine
-CH2-CH2-NH3+
Phosphoglycerides - draw Serine
-CH2-CH(-COO above)-NH3+
Phosphoglycerides - draw glycerol
-CH2-CH-(-OH above)CH2-OH
Phosphoglycerides - draw the hydrolysis of choline (1 glycerol, 2 fatty acids, 1 phosphoric acid, 1 choline)
Refer to notes for answer
What are the structural properties that determine the melting temperatures of various fatty acids?
Chain length
Degree of unsaturation
Why are triacylglycerols such a good source of fuel storage?
Because they are insoluble in water large amounts can be stored in cells without increasing the osmotic pressure of the cytosol. The hydrophobicity also allows the storage of TAGs without the added weight of hydration
What is the best way to identify fatty acids?
gas liquid chromatography
