Lipids Flashcards
1
Q
Waxes
simple or complex lipids
A
Simple
2
Q
Precursor lipid composed of long chains of Carboxylic acids
A
Fatty acids
3
Q
Palmitic acid
Saturated or unsaturated FA
A
Saturated. 16C:0 double bond
4
Q
Predominant FA found in COCONUT oil and give its structure
A
Lauric acid. 12:0
5
Q
End product of mammalian FA synthesis
A
Palmitic acid. 16:0
6
Q
Predominant FA in olive oil
A
Oleic acid. 18:1 (9)
7
Q
Essential fatty acid with 2 double bonds at position 9 and 12
A
Linoleic acid 18:2 (9, 12)
8
Q
Essential fatty acid with 3 double bonds at position 9, 12 and 15
A
Linolenic acid 18:3 (9,12,15)
9
Q
Prostaglandin precursor FA derived from Linoleic acid
A
Arachidonic acid 20:4 (5, 8, 11, 14)
10
Q
Also known as OMEGA-6 FA
A
Linoleic acid
11
Q
Also known as OMEGA-3 FA
A
Linolenic acid
12
Q
FA solid at room temperature
A
Saturated FA
13
Q
By-product of of saturation of FA during hydrogenation
A
Trans fatty acid
14
Q
Enzyme responsible for activation of FA
A
Acyl-CoA synthetase
15
Q
Activation of FA occurs in
cytosol or mitochondria or both
A
Cytosol
16
Q
Immediate substrate of Lipogenesis
A
Acetyl CoA
17
Q
Common end product of Lipogenesis
A
Palmitoyl CoA
18
Q
Rate limiting step and enzyme of Lipogenesis
A
Acetyl CoA + HCO3 + ATP → Malonyl CoA
Acetyl CoA Carboxylase
19
Q
Acetyl CoA from mitochondria is transported to the cytosol using _______ shuttle.
A
Citrate shuttle
20
Q
Coenzyme used in conversion of Acetyl CoA to Malonyl CoA
A
Biotin.
Acetyl CoA Carboxylase
21
Q
How many carbons present in Malonyl CoA
A
3 carbons
22
Q
Sequence of steps in elongation of fatty acid
A
Condesation → Reduction → Dehydration → Reduction
ConReDRed
23
Q
Primer used in Palmitoyl CoA synthesis
A
Acetyl CoA
24
Q
Required donor of reducing equivalents in reduction reactions in FA synthesis
A
(1) NADPH per reduction reaction = (2) NADPH per cycle
25
How many NADPH is used up per elongation of acetyl coA to Palmitoyl CoA?
14 NADPH
26
3 Sources of NADPH
Pentose Phosphate Pathway or HMP shunt
Malic enzyme
Isocitrate Dehydrogenase
27
Further elongation and desaturation of FA occurs in what part of the cell?
Smooth endoplasmic reticulum
28
Storage form of fatty acids
Triacylglycerol (TAG)
29
What substrate needs two Acyl CoA to form TAG?
Glycerol-3-Phosphate
30
2 Sources of Glycerol-3-Phosphate
1. DHAP
| 2. Phosphorylation of free glycerol
31
TAG is hydrolyzed to release FA using what enzyme?
Hormone Sensitive Lipase
32
By-products of TAG hydrolysis
Glycerol and 3 FA
33
Carbon position in TAG breakdown
Carbon 1 and Carbon 3
34
Removal of Acetyl CoA fragments from ends of FA
Beta-Oxidation (Lipolysis)
35
Beta oxidation occurs in what part of the cell?
Mitochondria
36
Substrate of Beta Oxidation
Palmitate
37
End products of Palmitate beta oxidation
(8) Acetyl CoA
(7) NADH
(7) FADH2
38
Rate limiting step and enzyme in Beta Oxidation
Translocation of FA from the cytosol to mitochondria.
Carnitine-palmitoyl transferase
39
Enzyme that activates FA for transport of Acyl CoA to mitochondria
Fatty Acyl Synthetase
40
Enzyme that attaches FA to carnitine in the outer mitochondrial membrane
Carnitine AcylTransferase - 1
41
Enzyme that transfer FA back to CoA in the mitochondrial matrix
Carnitine AcylTransferase - 2
42
Steps in degradation of fatty acyl coA
Oxidation → Hydration → Oxidation → Thiolysis
| OHOT
43
Chain length specific enzyme used in degradation of Fatty Acyl CoA
Fatty Acyl CoA dehydrogenase
44
Gross ATP yield in degradation of Palmitate
108 ATPs.
(8) Acetyl CoA (10 ATPs ea) = 80
(7) NADH (2.5 ATP ea) = 17.5
(7) FADH2 (1.5 ATP ea) = 10.5
45
Net ATP yield in degradation of Palmitate
106 ATPs.
(8) Acetyl CoA (10 ATPs ea) = 80
(7) NADH (2.5 ATP ea) = 17.5
(7) FADH2 (1.5 ATP ea) = 10.5
Activation uses 2 ATP
46
Product of odd number FA
Propionyl CoA
47
(2) Sequential enzymes used in oxidation of FA with an odd number of carbons
Propionyl CoA carboxylase
| Methylmalonyl CoA mutase
48
Coenzyme of Methylmalonyl CoA
Vitamin B12
49
Used in oxidation of very long chain FA (C20, C22)
Peroxisomes
50
What additional enzyme is required for oxidation of unsaturated very long chain FA?
3, 2 enoyl-CoA isomerase
51
Inhibitor of Lipogenesis
Long chain fatty acyl CoA
Glucagon
Catecholamines
52
Inhibitor of Beta oxidation
Malonyl CoA
| Insulin
53
General characteristic of Essential fatty acid deficiency
```
Ichthyosis (scaly dermatitis)
Hair loss
Poor wound healing
Visual abnormalities
Neurologic abnormalities
```
54
Preterm infant presents with scaly dermatitis, occasional hypotonia and hypoglycemia.
A. Carnitine Deficiency
B. CPT I deficiency
C. CPT II deficiency
D. MCAD deficiency
Carnitine Deficiency
Generally mild in presentation
55
A 70/m with severe infection, ichthyosis and impaired wound healing presents with myoglobinuria
A. Carnitine Deficiency
B. CPT I deficiency
C. CPT II deficiency
D. MCAD deficiency
CPT II Deficiency
Affects primarily cardiac and skeletal muscle
56
Generalities of EFA deficiency + coma/death
A. Carnitine Deficiency
B. CPT I deficiency
C. CPT II deficiency
D. MCAD deficiency
CPT I deficiency
Toxic looking!
57
Most common inborn error of FA oxidation associated with Sudden infant death syndrome
Medium chain fatty acyl coA dehydrogenase (MCAD) deficiency
58
Toxin in Jamaican vomiting sickness
Hypoglycin
from unripe fruit of Akee tree
59
Enzyme deficient in Refsum disease that leads to accumulation of phytanic acid.
A. Phytanoyl-CoA dehydrogenase
B. Phytanoyl-CoA carboxylase
C. Phytanoyl-CoA hydroxylase
D. Phytanoyl-CoA reductase
Phytanoyl-CoA hydroxylase
60
Child presents with hypertelorism, icthyosis, hepatomegaly, renal cyst, and frontal bossing.
Most probable Dx and enzyme deficient?
Zellweger syndrome (Cerebrohepatorenal syndrome)
Absence of Peroxisomes, marked accumulation of VLCFA in LIVER and CNS
61
Child undergone appendectomy suddenly presents with progressive ataxia, increased DTR, neurodegenerative changes, darkening of the skin and hypotension?
Most probable Dx and pathology?
Adrenoleukodystrophy (ALD)
Inability to transport VLCFAs, Marked accumulation in CNS, ADRENALS and GONADS.
Neurodegeneration
Adrenocortical insufficency
Hypogonadism
62
Substrate of Ketogenesis
Acetyl CoA
63
End products of Ketogenesis
Acetoacetate
Beta-hydroxybutyrate
Acetone
64
Rate limiting step and enzyme in Ketogenesis
Acetoacetyl CoA + Acetyl CoA → HMG CoA
| HMG CoA Synthase
kHetoneS
65
Ketogenesis occurs in?
Liver mitochondria
66
Ketolysis occurs in?
Extrahepatic mitochondria
Liver is NOT able to use ketone bodies
67
Deficient enzyme which hinders ketolysis to occur in hepatocytes?
Succinyl-CoA-Acetoacetate-CoA transferase (thiophorase)
68
Storage form of Cholesterol
Cholesteryl Esters
69
Cholesterol structure
27-Carbon compound
4 fused hydrocarbon rings
A ring has Hydroxyl group at C3
B ring has double bond between C5 and C6
D ring has 8 branched hydrocarbon chain at C17
70
Substrate of Cholesterol synthesis
Acetyl CoA
71
Cholesterol synthesis occurs in?
Cytosol and ER
72
Rate limiting step and enzyme of Cholesterol synthesis
HMG-CoA → Mevalonate
| HMG-CoA Reductase
cHolesteRol
73
2 primary bile acids
Cholic and Chenodeoxycholic (CC)
74
2 Secondary bile acids
Deoxycholic and Lithocolic
| Digested by bacteria
75
Enzyme that converts cholesterol to pregnenolone
Desmolase
76
Enzyme that converts cholesterol to 7-a-hydroxycholesterol
7-a-hydroxylase
77
How many percent of bile salts is reabsorbed in the intestine?
95%
78
Most common form of CAH
21 a- hydroxylase deficiency
79
CAH that presents with low renin hypertension
11-B1-hydroxylase deficiency
80
Lipoprotein with highest TAG content
Chylomicron
81
Lipoprotein with lowest protein content
Chylomicron
82
Lipoprotein with highest cholesterol content
LDL
83
Lipoprotein with highest protein content
HDL
84
Apolipoprotein mediates secretion of VLDL
APO B-100
85
Apolipoprotein mediates secretion of Chylomicrons
APO B-48
86
Apolipoprotein mediates uptake of Chylomicron
APO E
87
Apolipoprotein cofactor of lipoprotein lipase
APO C-II
88
Apolipoprotein cofactor of cholesterol acyltransferanse
Apo A-1
89
APO C II deficiency
```
Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
```
Type I. Familial Lipoprotein Lipase def
90
Defective LDL receptor
```
Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
```
Type IIa. Familial Hypercholesterolemia
91
Low LDL, low HDL, recurrent pancreatitis
```
Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
```
Type I. Familial Lipoprotein Lipase def
92
High LDL and cholesterol + atherosclerosis
```
Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
```
Type IIa. Familial Hypercholesterolemia
93
Abnormal Apo E
```
Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
```
Type III. Familial Dysbetalipoproteinemia
94
High VLDL, High cholesterol, Low LDL, Low HDL
```
Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
```
Type IV. Familial Hypertriacylglycerolemia
95
Hypolipoproteinemia present with Absent chylomicrons or VLDL
Abetalipoproteinemia
96
Hypolipoproteinemia present with absent HDL
Familial alphalipoproteinemia
