1
Q
Major lipids (5)
A
Fatty acids
Triacylglycerols
Phosphoacyglycerols (phospholipids)
Sterols
Fat soluble vitamins
2
Q
Lipids cannot be transported freely in the blood as it is a … environment
A
Polar
3
Q
Lipids are transported either bound to a … or as …
A
Specific transport protein or as a lipoprotein complex
4
Q
Lipoproteins contain varying amounts of…
A
Triacylglycerols
Phosphoacylglycerols
Free cholesterol
Cholesterol esters
Apoproteins
5
Q
What gives rise to different classes of lipoproteins with different functions?
A
Relative amounts of different components
6
Q
Apoproteins mediate what?
A
Lipoprotein remodelling
7
Q
Apo B-100 functions
A
Secretion of VLDL from liver
Structural protein of VLDL, IDL and HDL
Ligand for LDL receptor
8
Q
Apo B-48 function
A
Secretion of chylomicrons from intestine
9
Q
Apo E function
A
Ligand for binding of IDL and remnants to LDR and LRP
10
Q
Apo C-11
A
Activator of LPL
11
Q
How are lipoprotein classes differentiated?
A
According to their density
12
Q
The lower the density of the lipoprotein, the higher the ratio of … : ….
A
Lipid : protein
13
Q
Chylomicrons are produced where?
A
Enterocytes
14
Q
Integral proteins
A
ApoB-48, ApoA-I, ApoA-11, ApoA-1V
15
Q
Peripheral apoproteins
A
ApoC-1, ApoC-11, ApoC-111, ApoE
16
Q
How are peripheral apoproteins gained?
A
From exchange of PAG with HDL
17
Q
What is the main function of chylomicrons?
A
Transport of dietary TAG from small intestine to adipose tissue and heart/skeletal muscle
18
Q
What is the core structural protein?
A
ApoB-48
19
Q
What allows recognition and binding to lipoprotein lipase (LPL) on capillary wall?
A
ApoC-11
20
Q
What hydrolyses TAGs in the chylomicron core to yield free fatty acids?
A
LPL
21
Q
What are picked up by HDL?
A
Surface PAG
FC
ApoC
ApoE
22
Q
The chylomicron remenant does what?
A
High in cholesterol esters -> goes to liver
23
Q
VLDL are produced where?
A
Liver hepatocytes
24
Q
What is the integral protein of VLDL?
A
ApoB-100
25
VLDL are secreted by … into circulation
Exocytosis
26
What are the peripheral proteins that are gained from exchange of PAG with HDL?
ApoC-1
ApoC-11
ApoC-111
Apo-E
27
What is the main function of VLDL?
Transport new TAG, FC from liver to adipose tissue and heart/skeletal muscle
28
What is the core structural protein of VLDL?
ApoB-100
29
What hydrolyses TAGs in the VLDL core to yield FFA which pass across capillary wall and into target cells?
Lipoprotein lipase
30
Surface FC and PAG are picked up by what?
HDL
31
What two apoproteins are transferred to HDL?
ApoC and ApoE
32
IDL retains which two apoproteins?
ApoB-100 and ApoE
33
What are particles that have lost TAG and some of their peripheral proteins but still have ApoE?
Chylomicron and VLDL remnants
34
What allows recognition of chylomicron and VLDL remnants?
ApoE
35
VLDL are high in CE, making them …
Pro-atherogenic
36
Proathrogenic
Increases the risk of atherosclerosis (condition where the arteries become narrow and hardened due to the build up of plaque that can lead to heart disease and stroke)
37
LDL are formed from which two things?
VLDL and IDL
38
Integral protein in LDL
ApoB-100
39
What allows recognition and binding to LDL receptors?
ApoB-100
40
What is the glycoprotein present on surface of target cells?
LDLR
41
Binding of … to LDLR initiates endocytosis giving vesicles with LDL inside
ApoB-100
42
What causes the release of LDLR to cell membrane to be recycled?
pH drop
43
Vesicles containing LDL fuse with …
Lysosomes
44
Where does the degradation of lipids and apoprotein from LDL occur?
Lysosome
45
Amino acids and free fatty acids are released for what?
Cell metabolism
46
FC can enter the FC pool which is used for …
Membranes or steroid synthesis
47
FC may be converted to CE by enzyme … for storage
ACAT
48
What is produced in the liver in the nascent form?
HDL
49
What are the integral structural proteins for HDL?
ApoA-1 and ApoA-11
50
What does HDL receive from chylomicron and VLDL remnants?
PAG
ApoC
ApoE
51
What is the key role for HDL?
Reverse cholesterol transport
52
Excess FC from cell membranes in peripheral tissue is taken up by what?
HDL
53
FC is converted to CE via…
LCAT
54
Some CE are delivered directly to …
Liver
55
What is recognised by the liver to facilitate the uptake of HDL?
ApoE
56
Liver synthesises … which is secreted into plasma, mainly bound to HDL
CETP
57
What enables the exchange of TAG and CE between lipoproteins?
CETP
58
CETP promotes the transfer of CE from VLDL, VLDL remnants and LDL, enabling HDL to take up … from VLDL and chylomicrons
TAG
59
Initial uptake of cholesterol by HDL enhances reverse cholesterol transport via indirect pathway where…
HDL CE are delivered to liver via VLDL, IDL and LDL
60
Cholesterol is transported from … to … for excretion in faeces or bile
Peripheral cells to liver
61
HDLs are anti…
Anti-atherogenic
Anti-oxidant
Anti-inflammatory
Anti-thrombotic
Anti-apoptotic
62
What is a risk factor for CVD?
High plasma cholesterol
63
What 3 things increase risk of CVD?
High LDL cholesterol, low HDL cholesterol and high TAG in plasma
64
What is associated with atherosclerosis?
LDL-cholesterol
65
How do LDLs cause atherosclerosis?
LDL in bloodstream
Oxidative stress - ROS
Damaged LDLs accumulate beneath leaky endothelial mono layer of arterial walls
Oxidised LDL removed by macrophages
High concentration of cholesterol esters in macrophages - lipid droplets
Called foam cells and give rise to fatty streaks
Cells in fatty streaks produce collagen as extra-cellular protein
Gives rise to fibrous plaque which narrows arterial lumen
Reduced blood flow encourages blood to clot
66
Can reduce risk by deducting total fat consumption and altering fatty acid composition
Good
MUFA
n-6 PUFA
n-3 PUFA
trans-FA
SFA
Bad
67
What has less influence on plasma levels than might be expected due to poor absorption from gut and tight control of endogenous synthesis
Dietary cholesterol
68
Glycerol is mainly metabolised in the … and converted to glyceraldehyde 3-phosphate, which can be used in … or … depending on the energy state of the individual
Liver and glycolysis or gluconeogenesis
69
FFA can undergo … in mitochondria to yield acetyl-CoA which enters the …
B-oxidation and TCA cycle
70
In what state do FFA undergo ketogenesis in the liver to form ketone bodies as an energy supply following depletion of glycogen stores?
Starved state
71
Glycerol and FFA within cell cytosol are reincorporated into …
TAG and PAG
72
What are PAG and TAG used for?
PAG - membrane biosynthesis
TAG - energy store liver and adipose tissue
73
Long chain fatty acids are derived from which two essential fatty acids?
Linoleic acid and a-linolenic acid
74
What are LCFA used in the synthesis of…
Eicosanoids (classic and non-classic)
Endocannabinoids (affects mood/behaviour)
Lipoxins and resolvins (inflammation)
Formation of lipid rafts (cell signalling)
75
Linoleic acid pathway
Linoleic acid
Arachidonic acid
2-series prostaglandins
76
a-Linolenic acid pathway
a-linolenic acid
Eicosapentaenoic acid (EPA)
3-series prostaglandins
77
Eicosanoids
Large group of compounds derived from C20 PUFA
Synthesised by oxidation reaction catalysed by cyclooxygenase or lipoxygenase
78
Cycloxygenase forms …
Prostaglandins
Prostacylins
Thromboxanes
79
Lipoxygenase forms …
Leukotrienes
80
Arachidonic acid forms what series
2 series and 4 series
81
EPA forms what series
3 series and 5 series
82
Function of thromboxanes (eicosanoid)
Act as vasoconstrictors
Stimulate platelet aggregation
Increase blood pressure
83
Function of prostacyclins (eicosanoid)
Act as vasodilators
Inhibit platelet aggregation
Reduce blood pressure
84
Function of prostaglandins (eicosanoid)
Affect smooth muscle contraction
Act as vasodilators
Reduce blood pressure
Inhibit gastric secretion
Are locally inflammatory
85
Function of leukotrienes (eicosanoid)
Potent muscle contractants
Are inflammatory
Constrict airways in lungs
86
Eicosanoids from the EPA (n-3) family are thought to be … potent/have … effects to those from the arachidonic acid (n-6) family
Less and opposite
87
Conjugated linoleic acid (CLA)
Food products from ruminants are a dietary source of CLA
Formed as intermediates during the biohydrogenation of dietary unsaturated FA
Double bonds are conjugated
Classified as functional food
88
Conjugation of linoleic acid
-C=C-CH2-C=C- -> conjugation -> -C=C=C-
89
Properties of conjugated linoleic acid
Inhibit carcinogenesis
Decrease body fat
Increase protein deposition
Modulate immune system
Prevent atherosclerosis
Reduce incidence of diabetes
90
Some PUFA can bind to … causing the interaction with specific sites of DNA, modifying the proteins produced
PPARs
91
Influence of PUFA binding to PPARs
Synthesis of lipid and apoproteins in liver
Differentiation of adipocytes
Effect of insulin on adipose tissue metabolism
92
What is the hormone secreted by adipose tissue?
Leptin
93
Larger adipocytes produce more …
Leptin
94
Leptin functions
An inhibitor of food intake
A stimulator of energy expenditure
A single to the reproductive system
Haematopoiesis
Growth of new blood vessels
95
Lipid is in diet as a source of … and …
Energy and essential fatty acids
96
Excess lipid intake over energy requirements stored as … in …
Fat in adipose tissue
97
UK DRVs
Total fat intake 33% energy intake
Total fat intake 35% of total food energy
Total FA intake 30% energy intake
SFA intake 10% total dietary energy
Cis-MUFA intake 12% total dietary energy
Cis-PUFA intake 6% total dietary energy
Trans-FA intake 2% total dietary energy
Mix n-6 and n-3
More linoleic (n-6) than a-linoleic (n-3)
98
Cholesterol daily intake
Average = 100-400 mg/day
No dietary requirements as tissues can synthesise cholesterol
Dietary cholesterol has little influence on plasma cholesterol
NUT2001
flashcards
Decks in class (28)
# Cards
-
Physiology Recap28
-
Nutrient Requirements33
-
Energy56
-
Iodine52
-
Carbohydrates99
-
Carbohydrates 261
-
Nutritional Toxicology72
-
Lipids48
-
Lipids 298
-
Fluoride26
-
Protein47
-
Protein 267
-
B Vitamins89
-
B Vitamins 256
-
B Vitamins Summary25
-
Calcium and Vitamin D97
-
Magnesium and Phosphorus40
-
Bone Micronutrients19
-
Antioxidants and Vitamin E74
-
Vitamin C and Selenium56
-
Vitamin K44
-
Zinc64
-
Vitamin A122
-
Electrolytes and Water153
-
Copper56
-
Iron79
-
Trace Minerals - Chromium, Manganese and Molybdenum97
-
Formative Questions71
