Lipid Structure and Function

Question 1

lipids

Answer 1

characterized by insolubility in water and solubility in non-polar organic solvents

Question 2

amphipathic molecule

Answer 2

has both hydrophobic and hydrophilic regions

Question 3

phospholipids

Answer 3

a phosphate and alcohol that comprise the polar head group, joined to a hydrophobic fatty acid tail by phosphodiester linkages

Question 4

glycerol

Answer 4

3 carbon alcohol, forms phosphoglycerides or glycerophospholipids

Question 5

what kind of bonds will fully saturated fatty acids have?

Answer 5

only single bonds, a carbon atom is considered saturated when it is bonded to four other atoms, with no pi bonds

Question 6

unsaturated fatty acid

Answer 6

includes one or more double bonds, these introduce kinks into the fatty acid chain, makes it more difficult to stack and solidify

Question 7

glycerophospholipids (or phosphoglycerides)

Answer 7

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

Question 8

sphingolipids

Answer 8

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

Question 9

what is the simplest sphingolipid called?

Answer 9

ceramide

Question 10

sphingomyelins

Answer 10

major class of sphingolipids that are also phospholipids

Question 11

glycosphingolipids

Answer 11

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

Question 12

gangliosides

Answer 12

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

Question 13

waxes

Answer 13

esters of long-chain fatty acids with long-chain alcohols, form pliable solids at room temp

Question 14

terpenes

Answer 14

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

Question 15

sesquiterpenes

Answer 15

contains three isoprene units (sesqui means one and a half)

Question 16

diterpene

Answer 16

contains four isoprene units

Question 17

triterpene

Answer 17

contains six isoprene units and can be converted to cholesterol and various steroids

Question 18

carotenoids are what kind of terpene?

Answer 18

tetraterpene (have 8 isoprene units)

ex. B-carotene and lutein

Question 19

steroids

Answer 19

metabolic derivates of terpenes and are characterized by four cycloalkane rings fused together, three cyclohexanes and one cyclopentane

Question 20

steroid hormones

Answer 20

regulate gene expression and metabolism, can bind to specific high-affinity receptors and alter gene expression levels

Question 21

cholesterol

Answer 21

major component of the phospholipid bilayer and is responsible for mediating membrane fluidity, precursor molecule to steroid hormones, bile salts, and vitamin D

Question 22

prostaglandins

Answer 22

20 carbon molecules are unsaturated carboxylic acids derived from arachidonic acid and contain one five-carbon ring, act as paracrine or autocrine signaling molecules

Question 23

vitamin

Answer 23

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

Question 24

Vitamin A

Answer 24

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

Question 25

Vitamin D

Answer 25

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

Question 26

Vitamin E

Answer 26

group of closely related lipids called tocopherols and tocotrienols, biological antioxidants, form with free radicals, destroying them

Question 27

Vitamin K

Answer 27

group of compounds including phylloquinone (K1) and the menaquinones (K2), helps form prothrombin, an important clotting factor in the blood

Question 28

triacylglycerols

Answer 28

composed of three fatty acids bonded by ester linkages to glycerol

adipocytes store large amounts of fat

Question 29

saponification

Answer 29

ester hydrolysis of triacylglycerols using a strong base, base is often lye, name for sodium or potassium hydroxide

Question 30

surfactant

Answer 30

lowers the surface tension at the surface of a liquid, acting as a detergent or emulsifier

Question 31

colloid

Answer 31

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