Lipids

Question 1

phospholipids

Answer 1

• phosphate and alcohol that comprise polar head
• phosphodiester linkage joins this head to the FA hydrophobic tail

Question 2

glycerol forms the backbones of…

Answer 2

• phosphoglycerides

Question 3

true or false: sphingolipods are phospholipids

Answer 3

false; some are some aren’t

Question 4

fully saturated fatty acids

Answer 4

• only have single bonds
• carbon saturated w no pi bonds
• solid at room temp
• greater van der Waals forces, more stable overall structure

Question 5

unsat FA

Answer 5

• double bonds
• kinks
• fluidity
• liquid at room temp

Question 6

glycerophospholipids

Answer 6

• glycerol backbone bonded by ester linkages to 2 FA and by a phosphodiester linkage to a highly polar head group
• head group can be neutral or have a charge
• important for cell signaling, recognition, and binding

Question 7

phosphatidylcholine

Answer 7

• glycerophospholipid
• choline head group

Question 8

phosphatidylethanolamine

Answer 8

• glycerophosholipid with ethanol-amine head group

Question 9

sphingolipids

Answer 9

• example is the cell-surface antigens on RBCs vital to ABO blood typing
• sphingoid backbone OR sphingosine
• long-chain nonpolar FA tails and polar head groups
• many are also phospholipids because of phosphodiester linkage
• others contain glycosidic linkages to sugars; glycolipid

Question 10

4 types of sphingolipids

Answer 10

1) ceramides
2) sphingomyelins
3) glycosphingolipids
4) gangliosides

Question 11

ceramides

Answer 11

• sphingolipids
• has a single H atom as it’s head group

Question 12

sphingomyelins

Answer 12

• sphingolipid
• phospholipid
• either have phosphocholine or phosphoethanolamine group, meaning there is a phosphodiester bond somewhere
• head groups have no net charge
• major components in the plasma membranes of cells producing myelin (oligoden. & Schwann)

Question 13

glycosphingolipids

Answer 13

• sphingolipid
• not phospholipids
• contain no phosphodiester linkage
• found outside of plasma membrane
• can be split into cerebroside or globoside
• neutral, no net charge in physiological pH

cerebroside: singular sugar
globoside: have two or more sugars

Question 14

gangliosides

Answer 14

• sphingolipid
• polar head groups and composed of oligosaccharides with one or more N-acetylneuraminic acid (NANA) molecules at the terminus and a negative charge
• glycolipids, glycosidic linkage and no phosphate group
• major role in cell interaction, recognition, and signal transduction

Question 15

waxes

Answer 15

• esters of long FA chains w long-chain alcohols
• pliable solids at room temp
• keep water in and from getting in and pests out

Question 16

terpenes

Answer 16

• odiferous
• metabolic precursors to steroids and other lipid signaling molecules
• varied independent functions
• built from isoprene (C5H8)
• steroid synthesis

Question 17

monoterpenes

Answer 17

• terpene
• (C10H16)
• 2 isoprene units
• essential oils and

Question 18

sesquiterpenes

Answer 18

• terpene
• 3 isoprene units

Question 19

diterprene

Answer 19

• terpene
• 4 isoprene units

Question 20

triterpene

Answer 20

• terpene
• 6 isoprene units
• converted to cholesterol and various steroids

Question 21

carotenoids

Answer 21

• terpene
• tetraterpenes w 8 isoprene units

Question 22

terpenoids

Answer 22

• isoprenoids
• derivatives of terpenes that have undergone oxygenation and rearrangement of the carbon skeleton
• adding a variety of functional groups to modify
• similar functions as terpenes
• similar naming conventions (diterpenoids meaning 4 isoprene units)
• important in steroid formation

Question 23

steroids

Answer 23

• derivatives of terpenes
• 4 cycloalkane rings fused together: 3 cyclohexane, 1 cyclopentane
• functionality determined by oxidation status of rings, as well as functional groups they carry
• nonpolar

Question 24

steroid hormones

Answer 24

• travel on protein carriers
• bind to specific high-affinity receptors and alter gene expression levels

Question 25

cholesterol

Answer 25

• major component in phospholipid bilayer and is responsible for mediating membrane fluidity
• amphipathic
• hydrophilic heads and hydrophobic tails
• keeps cell membrane from solidifying or becoming too permeable
• precursor to steroid hormones, bile acids, and vitamin D

Question 26

prostaglandins

Answer 26

• unsat CA derived from arachidonic acid
• contain 1 five-C ring
• paracrine or autocrine signaling
• regulate cAMP synthesis
• intracellular messenger, mediating the actions of many other hormones
• NSAIDs aid in inhibiting COX, which aids in prostaglandin production

Question 27

vitamin A

Answer 27

• carotene
• unsat hydrocarbon important in growth and development, vision, and immune function
• most significant metabolite of it is the aldehyde form, retinal important in light-sensing in eye
• retinol is the storage form, oxidized to retinoic acid which is a hormone that regulates gene expression during epithelial development

Question 28

vitamin D

Answer 28

• cholecalciferol
• UV light-driven skin rxn
• converted to calcitriol in the liver and kidneys
• inc Ca and phosphate uptake in the intestines
• promotes bone production
• lack causes rickets

Question 29

vitamin E

Answer 29

• tocopherols (biological antioxidants) and tocotrienols
• substituted aromatic ring with a long isoprenoid side chain
• hydrophobic
• aromatic ring reacts with free radicals destroying them
• prevents oxidative damage (this damage contributed to cancer and aging)

Question 30

vitamin K

Answer 30

• group of compounds (phylloquinone and menaquinone)
• vital to postransaltional modifications required to form prothrombin (aromatic ring undergoes redox to form this)
• important for calcium binding

Question 31

triacylglycerols

Answer 31

• more reduced, oxidation yields double the energy as carbs
• hydrophobic
• energy storage and insulation
• 3 FA bonded by ester linkages
• oily droplets in cytosol
• metabolic fuel
• adipocytes
• travel bidirectionally between liver an adipose tissue

Question 32

free FA

Answer 32

• unesterified FA
• free carboxylate group
• circulate in blood bonded noncovalently to serum albumin
• make up soap via saponification

Question 33

saponification

Answer 33

• ester hydrolysis of triacylglycerols using a strong base
• base usually used as lye (sodium or potassium hydroxide)
• result in basic cleave of a FA leaving the sodium salt of the FA and glycerol

Question 34

surfactant

Answer 34

• lowers surface tension at the surface of a liquid, serving as a detergent or emulsifier
• micelles

Question 35

micelles

Answer 35

• important in absorption of fat soluble vitamins and complicated lipids