Lipid

Lipid

1. Steroid

   • Cholestrol
     • LDL
       • bad cholestrol
     • HDL
       • good cholestrol
     • synthesized in liver precursor to many steroid hormone
     • have OH functional group attached to particular site
   • prostaglandin
     • hormone like structure
     • eicosanoids
     • formed from arachidonic acid, 20 carbons atoms
   • three-six membered ring and one fiive membered ring fused together

2. FATTY ACID

   • Unsaturated
     • cis
       • two H associated with bond on the same side
     • trans
       • produce in industrial procedure called partial hydrogenation (H gas is passed through oils convert some but not all double bond to single bond
       • two H associated with the bond are on the opposite side.
     • Mono
       • one double bond C=C bond
       • found in natural food (nuts,olives,avocado,peanut oil,sesame oil, corn oil, sunflower oil)
     • Poly
       • two or more double C=C bond
       • found in nuts,fish,algae,leafy greens
   • Saturated
     • contain only single C-C bonds
     • comes mainly from animal sources
     • some plant base (palm oil,palm kernel oil, coconut oil) contain primarily saturated acid but not cholestrol
     • higher melting point
   • WHAT IS?
     • long, unbranched carbon chains
     • composed of hydrocarbon chain(tail) and terminal carboxyl group (head)
     • 12-18 carbon atoms long
     • insoluble in water

3. FUNCTIONS

   • store energy
   • provide insulation
   • form water repellent layers on leave
   • provide building blocks for hormones
   • make up cell membrane

4. TYPES

   • glycerolphospholipids
     • FA chain are hydrophobic and phosphate containing group is hydrophilic (because of charge)
     • Two FA attached to 1st and 2nd C of glycerol
     • highly polar or charged group attached to 3rd C through phosphodiester linkages
     • known as phosphoglycerides
   • sphingolipids
     • glycophingolipid
       • one or more sugar connected to ceramide
       • found in outer layer of plasma membrane of plants (glucosylceramide)
       • found in the brain tissue of vertebrate (galactosylceramide)
     • contain one long chain of amino acid called sphingosine, one molecule of long chain FA and polar head group
     • role: signal transmission and cell recognition
     • examples of siubstituent are choline and sugar
     • consist of no glycerol
   • waxes
     • found on surface of fruits,leaves and stem- help them prevent loss of water damage from pests
     • on skin,fur,feathers-provide a waterproof coating
     • Ester of saturated FA+long chain alcohols- 14 to 30 C
   • triaglycerols
     • Glycerols + FA
     • in human and animals, triaglycerols stored in fat cells(adipocytes) to make up tissue known as adipose tissue

5. WHAT IS?

   • make up building block of structure and function of living cell
   • contain hydrocarbon
   • soluble in organic solvent but not in water