Lipids I Flashcards
1
Q
what is not typically found in a phospholipid?
A
cholesteryl ester
2
Q
In a patient with high cholesterol, gallstones, and chronic deficiency of fat soluble vitamins which enzyme is involved?
A
cholesterol 7-hydroxylase
3
Q
common name for methanoic acid
A
formic acid
4
Q
common name for ethanoic acid
A
acetic acid
5
Q
common name for propanoic acid
A
propionic acid
6
Q
common name for butanoic acid
A
butyric acid
7
Q
common name for pentanoic acid
A
valeric acid
8
Q
common name for octadecanoic acid
A
steric acid
9
Q
Is palmitic acid saturated or unsaturated?
A
saturated
10
Q
Is arachidonic acid saturated or unsaturated?
A
unsaturated
11
Q
does saturated or unsaturated FA have higher mp?
A
saturated
12
Q
does saturated or unsaturated FA have lower mp?
A
unsaturated
13
Q
why do saturated FA have higher mp?
A
harder to break up their consistency because no kinks
14
Q
what forces hold long hydrocarbons together?
A
VDW
15
Q
what effects do kinks have on the membrane?
A
change:
- packing
- density
- mp
- fluidity
16
Q
how do trans fats cause atherosclerosis?
A
- pack together
- form grease glob
- decreases HDL/LDL ratio
- impairs normal PUFA metabolism
17
Q
FA functions
A
- energy stores
- structural substrates
18
Q
what makes up a TAG?
A
3 FA + esters of glycerol
19
Q
what are glycerolphospholipids?
A
esterified PA
20
Q
what constitutes the main matrix of the phospholipid bilayers?
A
glycerolphospholipids
21
Q
what makes up phosphatidic acid?
A
replace one FA with a phosphate
22
Q
which carbon has the phosphate instead of FA on the PA molecule?
A
C3 (SN3)
23
Q
which carbon on the PA is unsaturated (kinked)?
A
SN2
24
Q
which carbon on the PA is usually liberated in cell signaling processes especially if it has an arachidonic acid attached?
A
SN2
25
how are glycerol phospholipids made?
esterify phosphatidic head group to another water soluble molecule (ex. choline)
26
what part of the glycerolphospholipid often has a charge?
hydrophilic head group
27
which carbon on the PA is saturated?
SN1
28
where on the PL does PLA1 cleave?
SN1
29
where on the PL does PLA2 cleave?
SN2
30
where on the PL does PLC cleave?
phospho-ester bond closest to SN3
31
where on the PL does PLD cleave?
phospho-ester bond closest to membrane
32
what do PLA1, PLA2, PLC, and PLD do?
hydrolyze the release of FA from the bilayer
33
2 ways cholesterol is made
- from acetyl units (HMG-CoA)
| - from diet
34
cholesterol is a precursor for what 3 things?
- bile salts
- steroid hormones
- vitamin D
35
which precursor does the OH group on cholesterol make?
bile salts
36
which precursor does the 7 carbon on cholesterol make?
vitamin D
37
which precursor does the 17 carbon on cholesterol make?
steroids
38
what is the major component of cholesterol in the diet?
TAGs (this is how animals we eat are storing fat)
39
what are the minor components of cholesterol in the the diet?
- TAG derivatives
| - Non-TAG derivatives
40
TAG derivatives
- glycerol
- free FA
- monoglycerides
- diglycerides
41
Non-TAG derivatives
- phospholipids
- sterols
- pigments
- vitamins
- antioxidants
- oxidation products
- trace metals
- hydrocarbons
42
2 essential FA
Linoleic acid
| a-Linolenic acid
43
which essential FA is omega-6?
Linoleic acid
44
which essential FA is omega-3?
a-Linolenic acid
45
humans can't introduce double bonds past carbon ____
9 (need to obtain through diet after C9)
46
Linoleic acid is a precursor to what?
- arachidonic acid
| - eicosanoids
47
overall pathway for fat digestion
1-Intake
2-Transport on lipoproteins
3-Metabolism
48
List serum lipoproteins from lowest density to highest density
Chylomicrons
VLDL
LDL
HDL
49
what composes the hydrophobic layer of a chylomicron?
- Cholesterol
| - Cholesteryl esters
50
what composes the hydrophilic layer of a chylomicron?
- Protein
| - Phospholipid
51
3 Dietary Lipids
Cholesteryl ester
Phospholipid
Triacylglyceride
52
What emulsifies dietary lipids to aid in adsorption by the intestine?
bile salts
53
enzymes secreted from where, degrade dietary lipids?
pancreatic enzymes
54
which enzyme breaks Cholesteryl Ester (CE) into Cholesterol?
Cholesterol Esterase
55
which enzyme breaks Phospholipids (PL) into glycerylphosphotides?
ex: phosphatidylcholine >> glycerylphosphorylcholine
Lipases
56
which enzyme breaks Triacylglycerides (TAGs) into 2-Monoacylglycerol?
Pancreatic Lipase
57
If there is a deficiency in pancreatic lipase, which dietary lipid cannot be degraded?
triacylglyceride >> monoacylglycerol
58
esterification
H2O >> FA
replacement of carbonyl >> OH
59
what are the primary products of esterification in the duodenum?
- Free FA
- 2-monoacylglycerol
- Cholesterol
- Remaining pieces of Phospholipid
60
taurine
- non-proteogenic amino acid
| - contains sugar
61
where are bile acids made?
liver
62
what kind of bonds turn bile acids into bile salts?
amide bonds
63
What is added to the cholic acid to make a conjugated bile salt?
OH
64
which carbon is the OH added to, to make a conjugated bile salt?
C7
65
which enzyme puts an OH on C7 to make a bile salt?
7-a-hydroxylase
66
why is the glycine/taurine added to the cholesterol?
Glycine/taurine are more acidic (lower pKa) than carbohydrates >> helps stabilize the cholesterol in alkaline environment of the small intestine
67
what is the treatment for gallstones?
oral chenodeoxycholic acid
68
where are bile salts efficiently reclaimed?
enterohepatic circulation
69
how do the bile salts get from the duodenum to the liver?
portal vein
70
how do the bile salts get from the liver to the duodenum?
bile duct
71
lacteal
Takes up chylomicrons from internalized fat >> Forms milky lymph >> Goes through lymphatic system >> Thoracic Duct >> Left subclavian vein
72
where does the lymphatic system drain chylomicrons to?
Left Subclavian Vein
73
HDL donates which APO to the nascent chylomicron?
APO E
| APO C-II
74
which APO activates Lipoprotein Lipase?
APO C-II
75
which APO has a receptor on the liver?
APO E
76
what do VLDL and LDL transport?
endogenous cholesterol and lipids
77
which APO identifies a chylomicron?
APO B-48
78
which APO identifies LDL?
APO B-100
79
which APOs does VLDL have?
APO B-100
APO E
APO C-II
80
what is the result of hyperlipidemia on the HDL?
inhibits APO C-II and APO E release from HDL
81
what is the result of no activation of lipoprotein lipase?
no FA are made and cannot be picked up in the circulation
82
what is the result of hepatic steatosis (fatty liver)?
FA can't get out of the liver
83
what is the cause of hepatic steatosis (fatty liver)?
imbalance between hepatic TAG synthesis and secretion of VLDL
84
what population is hepatic steatosis common in?
- obesity
| - DM type 2
85
LDL function
shuttling cholesterol:
- to peripheral tissues
- return it to liver
86
where is about 70% of the plasma cholesterol located?
in LDL
87
VLDL exchanges TAG for cholesterol in _______ to become_______
VLDL exchanges TAG for cholesterol in HDL to become LDL
88
what catalyzes the exchange of TAG for cholesterol in the HDL to change the VLDL to LDL?
cholesteryl ester transfer protein (CETP)
89
why is CETP good?
it keeps the cholesterol moving and away from the HDL which is what makes HDL high density
90
what APO identifies HDL?
APOA1
91
what is considered a "cholesterol sponge"?
HDL
92
In HDL, what solubilizes cholesterol?
phospholipids
93
what does HDL pick up?
- Lipids and cholesterol in circulation (from VLDL)
| - Phospholipids from cell membrane
94
what enzyme esterifies cholesterol in HDL?
lecithin
95
what enzyme maintains the cholesterol gradient in HDL?
LCAT - Lecithin Cholesterol Acyltransferase
96
what is the result of CETP swapping cholesteryl esters with TAGs on VLDL?
- CE product removed
| - LCAT inhibited
97
HDL function
takes up cholesterol from non hepatic (peripheral) tissues >> returns it to liver as cholesteryl esters
