Lipid Structure and Function Flashcards
lipids
characterized by insolubility in water and solubility in non-polar organic solvents
amphipathic molecule
has both hydrophobic and hydrophilic regions
phospholipids
a phosphate and alcohol that comprise the polar head group, joined to a hydrophobic fatty acid tail by phosphodiester linkages
glycerol
3 carbon alcohol, forms phosphoglycerides or glycerophospholipids
what kind of bonds will fully saturated fatty acids have?
only single bonds, a carbon atom is considered saturated when it is bonded to four other atoms, with no pi bonds
unsaturated fatty acid
includes one or more double bonds, these introduce kinks into the fatty acid chain, makes it more difficult to stack and solidify
glycerophospholipids (or phosphoglycerides)
specifically those phospholipids that contain a glycerol backbone bonded by ester linkages to two fatty acids and by a phosphodiester linkage to a highly polar head group
sphingolipids
have a sphingosine or sphingoid backbone (as opposed to the glycerol backbone), have a long-chain, nonpolar fatty acid tail and polar head group, many sphingolipids are also phospholipids bc they contain a phosphodiester linkage, other have glycosidic linkages
what is the simplest sphingolipid called?
ceramide
sphingomyelins
major class of sphingolipids that are also phospholipids
glycosphingolipids
sphingolipids, head groups have glycolipids, NOT a phospholipids bc they contain no phosphodiester linkages
cerebrosides –> have 1 single sugar
globosides–> have two or more sugars
gangliosides
glycolipids that have polar head groups composed of oligosaccharides with one or more N-acetylneuraminic acid (NANA, also called sialic acid), most complex structure and functional groups
waxes
esters of long-chain fatty acids with long-chain alcohols, form pliable solids at room temp
terpenes
class of lipids built from isoprene (C5H8), moieties and share a common structure pattern with carbons grouped in multiples of five, produced mainly by plants and some insects, grouped by number of terpene units
a single terpene unit contains two isoprene units (C10H16) –> monoterpene
sesquiterpenes
contains three isoprene units (sesqui means one and a half)
diterpene
contains four isoprene units
triterpene
contains six isoprene units and can be converted to cholesterol and various steroids
carotenoids are what kind of terpene?
tetraterpene (have 8 isoprene units)
ex. B-carotene and lutein
steroids
metabolic derivates of terpenes and are characterized by four cycloalkane rings fused together, three cyclohexanes and one cyclopentane
steroid hormones
regulate gene expression and metabolism, can bind to specific high-affinity receptors and alter gene expression levels
cholesterol
major component of the phospholipid bilayer and is responsible for mediating membrane fluidity, precursor molecule to steroid hormones, bile salts, and vitamin D
prostaglandins
20 carbon molecules are unsaturated carboxylic acids derived from arachidonic acid and contain one five-carbon ring, act as paracrine or autocrine signaling molecules
vitamin
essential nutrient that cannot be adequately synthesized by the body and therefore must be consumed in the diet
lipid-soluble–> accumulate in stored fat
water-soluble–> excreted in the urine
Vitamin A
DEAK–> fat soluble
carotene, unsaturated hydrocarbon that is important in vision, growth and development and immune function…metabolite of vitamin A is the aldehyde form retinal, component of the light-sensing molecular system in the human eye. Retinol, storage form, oxidized to retinoic acid, a hormone that regulates gene expression during epithelial development
Vitamin D
cholecaliferol, can be consumed or formed in a UV driven reaction in the skin, increases calcium and phosphate uptake in the intestines, which promotes bone production, lack of vitamin D can cause rickets, seen in kids with underdeveloped, curved bones
Vitamin E
group of closely related lipids called tocopherols and tocotrienols, biological antioxidants, form with free radicals, destroying them
Vitamin K
group of compounds including phylloquinone (K1) and the menaquinones (K2), helps form prothrombin, an important clotting factor in the blood
triacylglycerols
composed of three fatty acids bonded by ester linkages to glycerol
adipocytes store large amounts of fat
saponification
ester hydrolysis of triacylglycerols using a strong base, base is often lye, name for sodium or potassium hydroxide
surfactant
lowers the surface tension at the surface of a liquid, acting as a detergent or emulsifier
colloid
when two phases appear to combine into a single phase, occurs bc the formation of micelles, tiny aggregates of soap with the hydrophobic tails turned inward and the hydrophilic heads turned outward
