Lipids
- Biomolecules that are **not water soluble **
- mostly hydrocarbon⇒london forces
- long term energy storage→Fats & Oils
- short term energy storage→Glycogen
- structual cell membrane
- chemical messengers→ Steriods & eicosanoids (do not have fatty acids)
Fatty acid
- long chain monocarboxyclic acids (12-24)
- always an even mumber of carbons
Saturated:
- all c-c bonds are single bonds
_Unsaturated: _
- conatin at least one c-c double bond
Polyunsaturated:
- two or more c-c double bonds
Cis double bonds
- put a kink in the carbon chain, that forces the hydrocarbons apart
- lower melthing point b/c fewer london forces
Essential fatty acids
- Linoleic (18:2)
- Linolenic (18:3)
Waxes
An ester of a fatty acid + a long chain alcohol
- simplest fatty acid in nature
- function: water proffing
triglycerides
glycerol + 3 Fatty acids
- animal fats & vegatable oils
- Function: long term energy storage
Adipocytes
- light yellow tissue under the skin
- storage occurs in adipocytes
Properties of fats & oils
Oil:
- a mixture of triglycerols that is liquid b/c it conations a high amount of unsaturated fatty acids
- liquid
Fat:
- a mixture of trigycerols that is solid b/c it contains high amounts of satutrated fatty acids
- solid
Good & Bad fats:
- High concetrations of saturated fat is considered to be bad
- trans fat is considered to be bad
- polyunsaturated fats can be good or bad. (Omega-6 is bad, Omega-3 is better)
Partial hydrogenation
Hydrogen is added to c-c double bonds to make them single bonds
Purose:
- convert liquid oils to solid fats
Can produce trans fats
(oils⇒fats); (less saturated⇒more saturated)
Saponification
soap making
- salt of the fatty acids = soap
Detergents
sythetic soaps where the carboxylate ion of a soap is replaced by a different higly polar group like an amine or sulfonic acid
Micelles
a spherical aggregation of soap molecules arranged w/ hydrophobic tail in the center and hydrophillic head on the outside
- soap molecules form micelles in water
Membrane lipids
molecules that form cell membranes
- two hydrophobic tails and a polar head
3 major kind:
- phospholipid- lipid w/ ester link between phosphoric acid and alcohol
- glycolipids- sphingosince w/attached carbohydrate (no phosphate)
- sphinogolipids-amide; sphinogosine & glycolipids
membrane lipid structures:
Choline:
- quanternary amine
- permanent + charge
lecithin
when an amino alcohol attached to phosphate in a glyceropholipid is choline the membrane is called lecithin
- emulsifying agent
Sphigomylein
phospholipids that use choline as their polar head
- foun din high concentrations in cells of the myelin sheath
Glycolipids:
Cerebrosides: monosaccarides as their polar head.
- Particually abundant in nerve cell membranes
- Amide
Gangliosides: oligilosaccarides as the polar head
Cholesterol
Starting material for synthesis of all other steriods
- regulate the fluidity of cell membranes
- hydrophobic
- nearly flat
Sterols( fluidity)
saturation
- Saturated with hydrogens
- saturated (single bonds to H) Most saturated
- monosaturated (double bonds to H)
- polysaturated ( multiplebonds to H) Less saturated
Integral proteins
- embedded in the membrane
- act as a gate or channel to let selected molecules pass across the membrane
passive & active transport
Passive (no energy):
- Simple (random)
- Facilitated- requires the protein to change
Active (energy):
- Na+/K+
chemical messengers
Eicosanoids “bobby pin”:
- made from arachidoric acid
- prostaglanding→inflammatory
- thromboxnes→ inflammatory
- leukotries→ 3 conjuated DB’s
