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MCDB 108C: Lecture 1
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- 1lipidscharacterized by low solubility in water (hydrophobic)
many amphiphilic
structurally diverse (not related) - 2biological functions of lipidsstorage of energy
(reduced, good packing)
membrane structure
insulation from environment
low thermal conductivity, high heat capacity, mechanical protection
buoyancy control and acoustics in marine mammals
(incr density while diving)
water repellant (hydrophobic)
cofactors for enzymes
signaling molec
antioxidants
pigments - 3classification of lipidsbased on structure and fucntion
FAs
lipids w/ FAs (complex lipids)
==> storage, membrane lipids
lipids w/o FA
(cholesterol, waxes, etc) - 4Fatty AcidsCOO- w/ hydrocarbon chains
4-36 carbons
usually have even # carbons
natural FAs usually unbranced
sat/mono/polysaturated - 5conformation of FAssaturated - extended conformations
unsaturated - cis double bonds kink chain ==> not as good packing - 6omega-3 FAsessential nutrients
humans need but can't synthesize
ALA, DHA, EPA - 7Solubility / Melting Pointincr chain
==> decr solubility, incr MP
more double bonds
==> decr MP
trans has higher MP than cis b/c better packing - 8unsaturated lipid chains subject to....?free-radical oxidation
O-radicals from radiation
initiation, propogation, rpt cycle - 9breakdown of lipidsgives aldehydes and ketones
occurs by oxidation
antioxidants protect against lipid oxidation - 10Triacylglycerols (TAGs)1 glycerol group + 3 FA chains
most FA found as TAGs
solid TAGs = fats
liquid = oils
nonpolar b/c COO- in ester bond
less dense than water
primary storage form of lipids - 11Chemical Hydrogenation of unsat oilsMakes trans FA
add H: double ==> single bond
converts oils to fats
raises MP (removes double bond)
less oxidation, more heat resistance, shelf-life
pack more regularly
consuming trans FA incr risk of cardiovascular disease - 12Uses of lipidsnutrition
high energy/mass ratio
(high calorie content)
cooking
high-temp liquid for frying
add oil flavors to food
dissolve fat-soluble small molecules
emulsions
mixture of 2+ liquids that are normally immiscible
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- undergrad MCDB 108C Fichas sobre MCDB 108C: Lecture 1, creado por Phil Nosrat el 14/04/2016.
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- Phil Nosrat
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