Lipids Flashcards Preview

Topnotch Biochemistry (Sept 2017) > Lipids > Flashcards

Flashcards in Lipids Deck (96)
Loading 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
Q

How many NADPH is used up per elongation of acetyl coA to Palmitoyl CoA?

A

14 NADPH

26
Q

3 Sources of NADPH

A

Pentose Phosphate Pathway or HMP shunt
Malic enzyme
Isocitrate Dehydrogenase

27
Q

Further elongation and desaturation of FA occurs in what part of the cell?

A

Smooth endoplasmic reticulum

28
Q

Storage form of fatty acids

A

Triacylglycerol (TAG)

29
Q

What substrate needs two Acyl CoA to form TAG?

A

Glycerol-3-Phosphate

30
Q

2 Sources of Glycerol-3-Phosphate

A
  1. DHAP

2. Phosphorylation of free glycerol

31
Q

TAG is hydrolyzed to release FA using what enzyme?

A

Hormone Sensitive Lipase

32
Q

By-products of TAG hydrolysis

A

Glycerol and 3 FA

33
Q

Carbon position in TAG breakdown

A

Carbon 1 and Carbon 3

34
Q

Removal of Acetyl CoA fragments from ends of FA

A

Beta-Oxidation (Lipolysis)

35
Q

Beta oxidation occurs in what part of the cell?

A

Mitochondria

36
Q

Substrate of Beta Oxidation

A

Palmitate

37
Q

End products of Palmitate beta oxidation

A

(8) Acetyl CoA
(7) NADH
(7) FADH2

38
Q

Rate limiting step and enzyme in Beta Oxidation

A

Translocation of FA from the cytosol to mitochondria.

Carnitine-palmitoyl transferase

39
Q

Enzyme that activates FA for transport of Acyl CoA to mitochondria

A

Fatty Acyl Synthetase

40
Q

Enzyme that attaches FA to carnitine in the outer mitochondrial membrane

A

Carnitine AcylTransferase - 1

41
Q

Enzyme that transfer FA back to CoA in the mitochondrial matrix

A

Carnitine AcylTransferase - 2

42
Q

Steps in degradation of fatty acyl coA

A

Oxidation → Hydration → Oxidation → Thiolysis

OHOT

43
Q

Chain length specific enzyme used in degradation of Fatty Acyl CoA

A

Fatty Acyl CoA dehydrogenase

44
Q

Gross ATP yield in degradation of Palmitate

A

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
Q

Net ATP yield in degradation of Palmitate

A

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
Q

Product of odd number FA

A

Propionyl CoA

47
Q

(2) Sequential enzymes used in oxidation of FA with an odd number of carbons

A

Propionyl CoA carboxylase

Methylmalonyl CoA mutase

48
Q

Coenzyme of Methylmalonyl CoA

A

Vitamin B12

49
Q

Used in oxidation of very long chain FA (C20, C22)

A

Peroxisomes

50
Q

What additional enzyme is required for oxidation of unsaturated very long chain FA?

A

3, 2 enoyl-CoA isomerase

51
Q

Inhibitor of Lipogenesis

A

Long chain fatty acyl CoA
Glucagon
Catecholamines

52
Q

Inhibitor of Beta oxidation

A

Malonyl CoA

Insulin

53
Q

General characteristic of Essential fatty acid deficiency

A
Ichthyosis (scaly dermatitis)
Hair loss
Poor wound healing
Visual abnormalities
Neurologic abnormalities
54
Q

Preterm infant presents with scaly dermatitis, occasional hypotonia and hypoglycemia.

A. Carnitine Deficiency
B. CPT I deficiency
C. CPT II deficiency
D. MCAD deficiency

A

Carnitine Deficiency

Generally mild in presentation

55
Q

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

A

CPT II Deficiency

Affects primarily cardiac and skeletal muscle

56
Q

Generalities of EFA deficiency + coma/death

A. Carnitine Deficiency
B. CPT I deficiency
C. CPT II deficiency
D. MCAD deficiency

A

CPT I deficiency

Toxic looking!

57
Q

Most common inborn error of FA oxidation associated with Sudden infant death syndrome

A

Medium chain fatty acyl coA dehydrogenase (MCAD) deficiency

58
Q

Toxin in Jamaican vomiting sickness

A

Hypoglycin

from unripe fruit of Akee tree

59
Q

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

A

Phytanoyl-CoA hydroxylase

60
Q

Child presents with hypertelorism, icthyosis, hepatomegaly, renal cyst, and frontal bossing.

Most probable Dx and enzyme deficient?

A

Zellweger syndrome (Cerebrohepatorenal syndrome)

Absence of Peroxisomes, marked accumulation of VLCFA in LIVER and CNS

61
Q

Child undergone appendectomy suddenly presents with progressive ataxia, increased DTR, neurodegenerative changes, darkening of the skin and hypotension?

Most probable Dx and pathology?

A

Adrenoleukodystrophy (ALD)

Inability to transport VLCFAs, Marked accumulation in CNS, ADRENALS and GONADS.

Neurodegeneration
Adrenocortical insufficency
Hypogonadism

62
Q

Substrate of Ketogenesis

A

Acetyl CoA

63
Q

End products of Ketogenesis

A

Acetoacetate
Beta-hydroxybutyrate
Acetone

64
Q

Rate limiting step and enzyme in Ketogenesis

A

Acetoacetyl CoA + Acetyl CoA → HMG CoA

HMG CoA Synthase
kHetoneS

65
Q

Ketogenesis occurs in?

A

Liver mitochondria

66
Q

Ketolysis occurs in?

A

Extrahepatic mitochondria

Liver is NOT able to use ketone bodies

67
Q

Deficient enzyme which hinders ketolysis to occur in hepatocytes?

A

Succinyl-CoA-Acetoacetate-CoA transferase (thiophorase)

68
Q

Storage form of Cholesterol

A

Cholesteryl Esters

69
Q

Cholesterol structure

A

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
Q

Substrate of Cholesterol synthesis

A

Acetyl CoA

71
Q

Cholesterol synthesis occurs in?

A

Cytosol and ER

72
Q

Rate limiting step and enzyme of Cholesterol synthesis

A

HMG-CoA → Mevalonate

HMG-CoA Reductase
cHolesteRol

73
Q

2 primary bile acids

A

Cholic and Chenodeoxycholic (CC)

74
Q

2 Secondary bile acids

A

Deoxycholic and Lithocolic

Digested by bacteria

75
Q

Enzyme that converts cholesterol to pregnenolone

A

Desmolase

76
Q

Enzyme that converts cholesterol to 7-a-hydroxycholesterol

A

7-a-hydroxylase

77
Q

How many percent of bile salts is reabsorbed in the intestine?

A

95%

78
Q

Most common form of CAH

A

21 a- hydroxylase deficiency

79
Q

CAH that presents with low renin hypertension

A

11-B1-hydroxylase deficiency

80
Q

Lipoprotein with highest TAG content

A

Chylomicron

81
Q

Lipoprotein with lowest protein content

A

Chylomicron

82
Q

Lipoprotein with highest cholesterol content

A

LDL

83
Q

Lipoprotein with highest protein content

A

HDL

84
Q

Apolipoprotein mediates secretion of VLDL

A

APO B-100

85
Q

Apolipoprotein mediates secretion of Chylomicrons

A

APO B-48

86
Q

Apolipoprotein mediates uptake of Chylomicron

A

APO E

87
Q

Apolipoprotein cofactor of lipoprotein lipase

A

APO C-II

88
Q

Apolipoprotein cofactor of cholesterol acyltransferanse

A

Apo A-1

89
Q

APO C II deficiency

Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
A

Type I. Familial Lipoprotein Lipase def

90
Q

Defective LDL receptor

Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
A

Type IIa. Familial Hypercholesterolemia

91
Q

Low LDL, low HDL, recurrent pancreatitis

Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
A

Type I. Familial Lipoprotein Lipase def

92
Q

High LDL and cholesterol + atherosclerosis

Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
A

Type IIa. Familial Hypercholesterolemia

93
Q

Abnormal Apo E

Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
A

Type III. Familial Dysbetalipoproteinemia

94
Q

High VLDL, High cholesterol, Low LDL, Low HDL

Familial
A. Lipoprotein Lipase Deficiency
B. Hypercholesterolemia
C. Dysbetalipoproteinemia
D. Hypertriacylglycerolemia
A

Type IV. Familial Hypertriacylglycerolemia

95
Q

Hypolipoproteinemia present with Absent chylomicrons or VLDL

A

Abetalipoproteinemia

96
Q

Hypolipoproteinemia present with absent HDL

A

Familial alphalipoproteinemia