Lipids Flashcards
(65 cards)
1
Q
Phospholipids
A
contain a phosphate and alcohol that comprise the polar head group, joined to a hydrophobic fatty acid tail by phosphodiester linkages
2
Q
Saturated Fatty Acid
A
- tails that only have single bonds
- carbon atom is considered saturated when it is bonded to 4 other atoms with no pi bonds
- greater van der waals forces and stable overall structure
- solid at room temperature
- high melting point
- decrease membrane fluidity
3
Q
Unsaturated Fatty Acid
A
- has one or more double bonds, or rings
- liquid at room temperature
- increase membrane fluidity
- create kinks in chain so inhibition of stacking and solidifying
- at low temperatures these help increase membrane fluidity
4
Q
Glycerophospholipids
A
- phospholipids that contain a glycerol backbone bonded by ester linkages to two fatty acids and a phosphodiester linkage to a highly polar head group
- named according to their head group
5
Q
Sphingolipids
A
- have a sphingosine or sphingoid backbone that is a long carbon chain that becomes one of the nonpolar tails of the lipid
- long-chain nonpolar fatty acid tails and polar head groups
- contain a phosphodiester linkage or glycosidic linkages to sugars
- sites of biological recognition at cell surface
6
Q
Glycolipid
A
any lipid linked to a sugar
7
Q
What are the 4 subclasses of spingolipids?
A
- ceramide
- sphingomyelins/sphingophospholipids
- glycosphingolipids
- gangliosides
8
Q
Ceramide
A
has a single hydrogen atom as its head group
9
Q
Sphingomyelins
A
- major component of cells that produce myelin
- type of sphingophospholipid
10
Q
Sphingophospholipid
A
- sphingolipids that are also phospholipids
- head group is either phosphatidylcholine or phosphatidylethanolamine so contain a phosphodiester bond
- head groups don’t have a net charge
11
Q
Glycosphingolipids
A
- sphingolipids with head groups composed of sugars bonded by glycosidic linkages
- type of glycolipid, not a phospholipid
- found on outer surface of membrane
- no net charge
12
Q
Gangliosides
A
- glycolipids with polar head groups made of oligosaccharides with one or more N-acetylneuraminic acid (NANA) molecules at the terminus
- contain glycosidic linkages
13
Q
Waxes
A
- contain long-chain fatty acids esterified to long-chain alcohols, do not have a polar head group
- used as protection against evaporation and parasites in plants/animals
- entirely nonpolar and hydrophobic
- pliable solids at room temp
- most soluble in pure organic solvents (“like dissolves like”)
- prevent water loss across the plasma membrane
14
Q
Terpenes
A
- chemicals that are the metabolic precursors to steroids and other lipid signaling molecules
- lipids built from isoprene (C5H8) moieties
15
Q
Monoterpenes
A
- contain 2 isoprene units
- C10H16
16
Q
Sesquiterpenes
A
contain 3 isoprene units
17
Q
Diterpenes
A
- contain 4 isoprene units
- Ex. Vitamin A
18
Q
Triterpenes
A
- contain 6 isoprene units
- can be converted to cholesterol and other steroids
19
Q
Tetraterpenes
A
- contain 8 isoprene units
- Ex. carotenoids
20
Q
Terpenoids
A
- isoprenoids
- derivatives of terpenes that have undergone oxygenation or rearrangement of carbon skeleton
- contribute to steroid biosynthesis
21
Q
Steroids
A
- signaling lipid
- have 4 cyclo-alkane rings fused together
- nonpolar
- Ex. cholesterol
22
Q
Steroid Hormones
A
- secreted by endocrine glands into bloodstream then travel on protein carriers to distant sites
- can alter gene expression levels and metabolism
23
Q
Cholesterol
A
- major component of phospholipid bilayer
- mediates membrane fluidity
- amphipathic (both hydrophobic and hydrophilic)
- precursor to steroid hormones, bile acid, and vitamin D
24
Q
What does cholesterol do for the membrane at high temperatures?
A
keeps membrane intact by moving phospholipids closer together and thus decreasing membrane fluidity
25
What does cholesterol do for the membrane at low temperatures?
increases distance between phospholipids and thus increasing membrane fluidity
26
Progstaglandins
- produced by nearly all cells in body
- 20-carbon molecules with unsaturated carboxylic acid derived from arachidonic acid (contain one 5 carbon ring)
- downstream effects including regulation of cAMP synthesis, smooth muscle function, influence on sleep-wake cycle, and increased body temperature
27
What vitamins are fat soluble?
A, D, E, K
28
Vitamin
- essential nutrient
| - not adequately synthesized by body so must include in diet
29
Vitamin A (Carotene)
-unsaturated, hydrocarbon important in vision, growth/development, immune function
30
Retinal
- metabolite of vitamin A
- often bound to protein opsin
- converts light energy in photons to chemical energy
31
Retinol
- storage form of vitamin A
| - can be oxidized to retinoic acid (hormone that regulates gene expression during epithelial development)
32
Vitamin D (Cholecalciferol)
consumed and formed by UV light driven reaction in skin
33
Calcitriol
- form that the liver and kidneys convert vitamin D to
- biologically active form of vitamin D
- increases calcium and phosphate uptake in intestines
34
Vitamin E
- group of lipids called tocopherols (biological antioxidants) and tocotrienols
- characterized by substituted aromatic ring with long isoprenoid side chain
- hydrophobic
- help prevent oxidative damage
35
Vitamin K
- vital to post-translational modifications required to form prothrombin (blood clotting factor)
- required to introduce calcium-binding sites on calcium-dependent proteins
36
Triacylglycerols
- used for energy storage
- oxidation of these results in 2x the amount of energy per gram as carbs
- hydrophobic. insoluble in water
- composed of 3 fatty acids bonded by ester linkages to glycerol
- nonpolar
37
Adipocytes
special cells in animals that store large amounts of fat
38
Free Fatty Acids
unesterified fatty acids with free carboxylate group
39
Saponification
ester hydrolysis of triacylglycerols using a strong base
40
Surfactant
- lowers the surface tension at the surface of a liquid
| - serves as a detergent or emulsifier
41
What phosphoglyceride is abundant in mitochondrial membranes?
Diphosphatidylglycerol (Cardiolipin)
42
12:0
Laurate
43
14:0
Myristate
44
16:0
Palmitate
45
18:0
Stearate
46
20:0
Arachidate
47
16:1
Palmitoleate
48
18:1
Oleate
49
18:2
Linoleate
50
20:4
Arachidonate
51
What are the 10 common phosphoglycerides found in membranes?
- Serine
- Ethanolamine
- Choline
- Inositol
- Glycerol
- Phosphatidylcholine
- Phosphatidylethanolamine
- Phosphatidylserine
- Phosphatidylinositol
- Diphosphatidylglycerol
52
What kind of bond is found in Triacylglycerol?
glycerol with 3 carbon chains bound by ESTER LINKAGES
53
What is the general structure of a phospholipid?
glycerol, 2 FA tails, PO4 bonded to ROH (alcohol)
54
What is the general structure of a Phosphatide?
glycerol, 2FAs, PO4
55
What type of bond is found in Sphingomyelin?
Amide Link
56
Which is more stable/less reactive, an amide link or an ester link?
Amide Link
57
What does it mean to glycosylate a phospholipid?
add sugar (glycosylate) to a fat
58
What is a cerebroside?
- it is a phospholipid that has a sugar attached (glucose, galactose)
- the sugar is almost always found on the extracellular side of the membrane
59
All ___ hormones are derived from cholesterol
steroid
60
Cholesterol in the membrane ___ fluidity at high temperatures. It does this by increasing __ __ ___ interactions.
- decreases
| - van der waals
61
The presence of cholesterol in the membrane __ boiling
prevents
62
In general, cholesterol ___ membrane fluidity. It does this by ___ FA tails of lipids from packing and sticking together.
- increases
| - preventing
63
Cholesterol is considered ___ because it has a polar -OH group, but is mostly nonpolar overall.
amphipathic
64
Prostaglandins are ____ molecules derived from ___ ___
- signaling
| - fatty acids (specifically arachidonate)
65
Fat Soluble Vitamins are ___ for enzymes that are non-polar.
cofactors
