LIPOPROTEIN Flashcards
(116 cards)
1
Q
soluble in organic solvents & insoluble in H2O
A
LIPIDS
2
Q
Diverse in terms of structure and function human plasma lipids:
A
cholesterol, triglycerides, phospholipids and free FA
3
Q
from digestion of cholesterol esters [with fatty acid chain] and triglycerides
A
free FA
4
Q
Three fatty acids attached to a glycerol backbone (trihydric alcohol) with FA attached to it
A
TRIGLYCERIDE
5
Q
Secondary energy source
A
TRIGLYCERIDE
6
Q
Serves as a thermal insulator Protects tissues from physical trauma
A
TRIGLYCERIDE
7
Q
Protects tissues from physical trauma
A
TRIGLYCERIDE
8
Q
In depletion of stored glycogen, it can be mobilized to provide energy
A
Secondary energy source
9
Q
Every gram of fat produces 9 kilo calories (measure of heat)
A
Serves as a thermal insulator
10
Q
Greater heat is generated from the metabolism of fat
A
Serves as a thermal insulator
11
Q
Specific vital organs are surround by adipose tissue
A
Protects tissues from physical trauma
12
Q
Chole ester with an FA attached to a hydroxyl group (esterification) distinguishes itself from free cholesterol
A
13
Q
Precursor of biological hormones
A
CHOLESTEROL
14
Q
biological hormones
A
(steroid – aldosterone, progesterone, testosterone)
15
Q
Source of bile acids
A
CHOLESTEROL
16
Q
Component of the Cell membrane
A
CHOLESTEROL
17
Q
Produced in the liver
A
Source of bile acids
18
Q
Fat digestion is more effective if + blie (emulsifier of fat) – easier for lipase to digest fat
A
Source of bile acids
19
Q
Cholic acid, phenodeoxycholic acid, kenodeoxycholic acid
A
Source of bile acids
20
Q
Proportional with the cholesterol in blood
A
Component of the Cell membrane
21
Q
Two fatty acids and a phosphoric acid with a NB (X) attached to a glycerol backbone
A
PHOSPHOLIPID
22
Q
Cell membrane component
A
PHOSPHOLIPID
23
Q
Associated with vital life processes (e.g. CNS)
A
PHOSPHOLIPID
24
Q
PHOSPHOLIPID
Components:
A
2 Fatty acids
Glycerol
H3PO4
Nitrogenous base (choline, cholamine, etc.)
25
Depend of the phospholipid it represents
Nitrogenous base
26
Phospholipid Ex.
lecithin, cephalin
27
– has the affinity for water molecules; found on the outer layer ;water-soluble
Phosphate group
28
– found on the middle layer water-insoluble
Fatty acids
29
Part of the cell membrane that contributes to its highly selective nature
PHOSPHOLIPID
30
Dietary sources – lipids from small intestine w/c undergo digetsion
MICELLE
31
Consists of bile acids, free fatty acids & monoglycerides, cholesterol & phospholipid
MICELLE
32
These lipids are products of digestion that combin w/ bile acids to form a micelle
bile acids, free fatty acids & monoglycerides, cholesterol & phospholipid
33
Essential for intestinal absorption
MICELLE
34
Diffusion of substances from the small intestine to the circulation
MICELLE
35
Outer layer (water-soluble)
Protein
Phospholipid
Cholesterol
36
Middle layer (water-insoluble)
Triglyceride
Cholesterol esters
37
macromolecule which consists of varying proportions of 1) protein, 2) cholesterol, 3) triglyceride and 4) phospholipid
LIPOPROTEIN
38
water-soluble
LIPOPROTEIN
39
blood – aqueous (↑% of water)
water-soluble
40
facilitates the transport of the lipids in the circulation
water-soluble
41
transported by LDL to the cells (Chole ester; ¾ of total)
Transport of Cholesterol
42
transported by HDL out of the cells (Free chole; ¼ of total)
Transport of Cholesterol
43
bad cholesterol
abundant in cholesterol
Chole ester
44
good cholesterol
abundant in protein
Free chole
45
secreted unchanged into bile (free cholesterol) or metabolized to form bile acids
Catabolism (LIVER)
46
- Synthesized & released from the small intestines (Exogenous pathway)
CHYLOMICRON
47
- Transport of dietary fat
CHYLOMICRON
48
- Consists of 80% TG, Apo B-48, AI, AII, AIV, C (1-2%)
CHYLOMICRON
49
- From lymphatics to systemic circulation: hydrolyzed by lipoprotein lipase (LPL) to monoglycerides, glycerol & FA
CHYLOMICRON
50
Lipase acts on TG and cause digestion of fats in the CM to release the three
CHYLOMICRON
51
- Synthesized & released from the liver
VERY LOW DENSITY LIPOPROTEINS (VLDL)
52
- Rich in TG
VERY LOW DENSITY LIPOPROTEINS (VLDL)
53
- Transports liver-synthesized TG & Cholesterol (Endogenous pathway)
VERY LOW DENSITY LIPOPROTEINS (VLDL)
54
- Contains Apo B-100 & Apo CII (cofactor for apo-protein lipase)
VERY LOW DENSITY LIPOPROTEINS (VLDL)
55
- Produced from VLDL hydrolysis by LPL
INTERMEDIATE DENSITY LIPOPROTEIN (IDL)
56
- Partly depleted of TG
INTERMEDIATE DENSITY LIPOPROTEIN (IDL)
57
- Has equal amounts of Cholesterol & TG
INTERMEDIATE DENSITY LIPOPROTEIN (IDL)
58
- Contains Apo B & E
INTERMEDIATE DENSITY LIPOPROTEIN (IDL)
59
- Formed from IDL by LPL
60
- LDL binds to membrane receptors
61
- Once internalized, undergo lysosomal degradation
62
– acts on proteins
Proteolytic
63
– acts on esters
Esterases
64
: hydrolyzed to amino acids
- Apo B
65
: hydrolyzed to free cholesterol (scavenger molecule)
- Chole ester
66
- Produced & catabolized in the liver & intestine
HIGH DENSITY LIPOPROTEINS (HDL)
67
- Contains Apo AI & Apo AII
HIGH DENSITY LIPOPROTEINS (HDL)
68
- Components arise from the catabolism of VLDL & Chylomicrons due to transfer of apoproteins
HIGH DENSITY LIPOPROTEINS (HDL)
69
FUNCTIONS OF HDL
a. Cholesterol efflux (removal) from tissues: reduce stored cholesterol
b. Transport of cholesterol to the live for removal as bile acids (Reverse cholesterol transport)
c. Scavenger of lipids & apo-lipoprotein
d. Reservoir of Apo CII
70
- similar to LDL; apo (a) linked to apoB-100
Lp(a)
71
- Increased level = increased risk of Congestive Heart Disease, Cerebrovascular Disease & Stroke
Lp(a)
72
- Obstructive Biliary Disease & Familial Lecithin Cholesterol Acyl Transferase (Lipids 90% of its weight) deficiency (Lipids 90% of its weight)
LpX
73
[ – catalyzes the esterification of cholesterol]
LCAT
74
- Type 3 hyperlipoproteinemia
B-VLDL (“floating B” lipoprotein)
75
- Richer in cholesterol
B-VLDL (“floating B” lipoprotein)
76
: major protein of HDL and chylomicron
Apolipoprotein A
77
– involved in activation of LCAT and removal of free chole from extrahepatic tissues
Apo AI
78
– structural role in HDL
Apo AII
79
inhibits LCAT
Apo AII
80
: major protein of all lipoproteins except HDL
Apolipoprotein B
81
(found in lipoprotein formed in the liver)
Large B or B100
82
(found in lipoprotein formed in the S.I.)
Small B or B48
83
: major protein of VLDL and chylomicrons and a minor protein of HDL and LDL
Apolipoprotein C
84
– cofactor of lipoprotein lipase
Apo CII
85
– inhibits lipoprotein lipase
Apo CIII
86
: function as a transfer protein
Apolipoprotein D
87
- glycoprotein w/c enters plasma as part of the nascent HDL
Apolipoprotein E
88
- plays a role in the recognition & catabolism of chylomicron remnant and IDL via specific receptors in hepatic cells
Apolipoprotein E
89
Fasting - ideal fast is
NCEP guidelines :
12 hours
at least 9 hours
90
Posture -
NCEP guidelines :
standardize position during venipuncture
seated for 5 mins prior to sampling
91
Venous vs capillary samples -
capillary levels generally lower than venous
92
- either can be used when only lipid profile is to be measured
Plasma vs serum
93
preferred for Lipid Profile measurement by ultracentrifugation /electrophoresis
Plasma
94
: preferred additive
EDTA
95
- generally, frozen samples can be satisfactorily analyzed
Storage
96
A. Colorimetric/Stepwise Methods
1. Direct Colorimetric/One-Step
2. Two-Step Method
3. Three-Step Method
4. Four-Step Method
97
Serum + color reagent = color reaction
1. Direct Colorimetric/One-Step
98
Interferences from protein and other chromogens
1. Direct Colorimetric/One-Step
99
Unequal color reactions for cholesterol & its ester
1. Direct Colorimetric/One-Step
100
Involves ‘extraction step prior to colorimetric reaction
Two-Step Method
101
Separates lipids from proteins
Two-Step Method
102
Eliminates protein interference
Two-Step Method
103
Interference from other chromogen
Two-Step Method
104
Unequal color reaction due to esterified form
Two-Step Method
105
Requires 1) extraction, 2) saponification and then 3) colorimetric determination
Three-Step Method
106
Standard method
Three-Step Method
107
Eliminates protein interference
Three-Step Method
108
Chole esters are hydrolyzed: uniform color reaction
Three-Step Method
109
Interference from other chromogen
Three-Step Method
110
Greatest specificity; reference method
Four-Step Method
111
Requires 1) extraction, 2) saponification, 3) purification with digitonin then 4) colorimetric determination
Four-Step Method
112
Eliminates interference from protein & other chromogens
Four-Step Method
113
Uniformity in color reaction
Four-Step Method
114
chole ester + H2O --chole esterase -->
cholesterol + FFA
115
cholesterol + O2 --chole oxidase -->
cholest-4-ene-3-one + H2O2
116
Quantitation of H2O2 formed:
Trinder reaction
O2 consumption
Other methods
