Ch. 5: Lipid Structure and Function

Question 1

solubility of lipids

Answer 1

insoluble in water

soluble in nonpolar organic solvents

Question 2

a phospholipid contains what elements

Answer 2

phosphate and alcohol head linked to a fatty tail by phosphodiester linkage

Question 3

properties of saturated fatty acid tails

Answer 3

only single bonds

more stable, solids at room temp

Question 4

properties of unsaturated fatty acid tails

Answer 4

occasional double bonding

kinks are difficult to stack, liquid at room temp

Question 5

glycerophospholipids (phosphoglycerides)

Answer 5

phospholipids that contain a

• glycerol backbone bonded by
• esters linkages to two fatty acids and by a
• phosphodiester linkage to a polar head group

Question 6

glycerol

Answer 6

a three carbon alcohol

Question 7

what kind of backbone do sphingolipids have

Answer 7

a sphingosine or sphingoid back-bone (instead of a glycerol)

Question 8

glycolipid

Answer 8

sphingolipid with

• glycosidic linkage to a sugar head group
• no net charge at physiological pH
• cerebrosides (single sugar) or globosides (2+ sugars)

Question 9

ceramide

Answer 9

sphingolipid which has a

- single hydrogen atom as its head group

Question 10

sphingomyelins

Answer 10

a sphingomyelin that is also a phospholipid

- head groups have no net charge

Question 11

gangliosides

Answer 11

glycolipid that has

• oligosaccharides
• terminal sialic acid

Question 12

structure of waxes

Answer 12

esters of long-chain fatty acids with long-chain alcohols

Question 13

what are terpenes built from

Answer 13

isoprene moieties; at least two isoprene units

Question 14

what are terpenes the metabolic precursors to

Answer 14

steroids and other lipid signaling molecules

Question 15

structure of steroid backbone

Answer 15

three cyclohexane and one cyclopentane bonded together

Question 16

polarity of steroids

Answer 16

nonpolar

Question 17

amphipathic

Answer 17

molecule with hydrophilic and hydrophobic components

Question 18

role of prostaglandins

Answer 18

paracrine or autocrine signaling molecules

Question 19

which vitamins are fat soluble

Answer 19

A, D, E, K

Question 20

function of vitamin A

Answer 20

vision, growth and development, immune function

Question 21

function of vitamin D

Answer 21

promotes bone production

Question 22

function of vitamin E

Answer 22

biological antioxidants, destroys free radicals and prevents oxidative damage

Question 23

function of vitamin K

Answer 23

clotting factor

Question 24

why are lipids good for energy storage

Answer 24

• fatty acids are more reduced than sugars, so oxidation yields twice amount of energy per gram
• hydrophobic, do not require water for stability, so low weight
• retains heat

Question 25

triacylglycerols/triglycerides

Answer 25

three fatty acids bonded by ester linkages to glycerol

Question 26

adipocytes

Answer 26

cells that store large amounts of fat

Question 27

what are free fatty acids

Answer 27

unesterified fatty acids with a free carboxylate group

Question 28

saponification

Answer 28

ester hydrolysis of triacylglycerols using a strong base