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Biochemistry > Lipids > Flashcards

Lipids Flashcards

1
Q

____ and ___ fatty acidsare sufficiently soluble to pass through the intestinal epithelial cells to enter the circulation without being incorporated into triglycerides.

A

Medium and short-chain fatty acids

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2
Q

_____ digests TG to 2-monoacyglycerols and FFA which are packaged into micelles

A

pancreatic lipase

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3
Q

FA from the micelles are activated by this enzyme to form fatty acyl-CoA

A

fatty acyl-CoA synthetase (thiokinase)

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4
Q

The regulatory enzyme acetyl-CoA carboxylase is inhibited by phosphorylation by this enzyme

A

AMP-activated protein kinase (not protein kinaseA)

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5
Q

A fat synthesis enzyme that is activated by dephosphorylation, by citrate and insulin

A

acetyl CoA carboxylase

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6
Q

This provides 2 carbon units that add to palmitoyl-CoA to elongate the FA

A

malonyl CoA

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7
Q

Location (carbon) at which human can introduce double bonds

A

Carbon 5,6,9

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8
Q

The major sources of essential FA required in the human diet. This is used for the synthesis of arachindonic acid.

A

Linoleate (18:2, delta 9,12) and a-linolenate (18:3 delta 9,12,15)

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9
Q

Adipose tissue cannot generate G3P from glycerol because it lacks this enzyme

A

glycerol kinase

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10
Q

Phospholipids are synthesized from

A

phosphatidic acid

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11
Q

Inhibition of this enzyme prevents newly synthesized fatty acids from entering the mitochondria

A

carnitine acyltransferase I

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12
Q

This apolipoprotein activates lipoprotein lipase. This is transferred from HDL to chylomicrons and VLDL

A

Apo CII

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13
Q

The key intermediates of cholesterol synthesis are ___, ___, ____, and ____.

A

HMG-CoA, mavelonic acid, isopentenyl pyrophosphate, and squalene

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14
Q

___ and ___ are major carriers of triglyceride.

A

Chylomicrons and VLDL. TG are degraded by lipoprotein lipase. In terms of density, chylomicrons < VLDL.

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15
Q

Cholesterol obtained by HDL is converted to cholesterol esters by this reaction.

A

LCAT reaction which is activated by ApoAI

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16
Q

The liver lacks this enzyme thus it cannot use ketone bodies as energy source.

A

succiny-CoA-acetoacetate-CoA transferase (a thiotransferase)

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17
Q

Oleic acid has how many double bonds?

A

One double bond

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18
Q

What is the trans form of oleic acid

A

Elaidic acid

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19
Q

What is the end product of mammalian FA synthesis?

A

palmitic acid

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20
Q

What is the predominant FA in olive oil

A

Oleic acid

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21
Q

What are your essential FA

A
  1. Linoleic

2. Linolenic acid

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22
Q

____ is an essential fatty acid with 2 double bonds

A

Linoleic acid

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23
Q

___ is an essential fatty acid with 3 double bonds

A

Linolenic acid

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24
Q

Arachidonic acid can be derived in what essential fatty acid?

A

linoleic acid

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25
Fatty acid that may increase the risk of prostate and colon cancer
Staurated FA
26
FA associated with decreased risk of coronary heart disease, decrease sudden cardiac death, lower BP, decrease tendencies for thrombosis
omega 3 FA = linolenic
27
provide arachidonic acid which is an important precursor of prostaglandins and leukotrienes
omega 6 FA = linoleic
28
[Fatty Acid activation] What enzyme activates fatty acid so that it can participate in metabolic process? (happens in the cytosol)
1. Fatty acyl CoA synthetase
29
[Lipogenesis] What is the immediate substrate of for lipogenesis?
Acetyl CoA
30
[Lipogenesis] What is the product?
palmitoyl CoA
31
[Lipogenesis] What is the rate-limiting step?
AcetylCoa + HCO3 + ATP to Malonyl CoA via Acetyl CoA carboxylase
32
How will you transport Acetyl CoA to the cytosol?
via the citrate shuttle
33
Citrate outside the cytosol is converted to oxaloacetate and acetyl CoA via this enzyme
ATP-citrate lyase
34
Acetyl CoA in the cytosol is converted to malonyl CoA via this enzyme
Acetyl CoA carboxylase
35
What inhibits acetyl CoA carboxylase?
Glucagon and epinephrine
36
What enzyme is needed to elongate the fatty acid?
Fatty acid synthase
37
What is the primer needed by the fatty synthase enzyme to create palmitoyl CoA?
Acetyl CoA
38
After the primer acetyl CoA, what carbon units are subsequently added to elongate the fatty acid?
malonyl CoA
39
What are the steps in FA elongation that is repeated 7x?
1. Condensation 2. Reduction 3. Dehydration 4. Reduction CRDR
40
What is the role of NADPH in fatty acid synthesis?
required as donor of reducing equivalents in both reduction reactions
41
Fatty acid elongation happens in which part of the cell
Smooth Endoplasmic Reticulum
42
[Synthesis of TAG] How will you synthesize TAG?
1. Sequential addition of two fatty acyl CoA to G3P 2. Removal of phosphate 3. Addition of third fatty acyl CoA
43
Where will you source glycerol 3 phosphate?
1. DHAP from glycolysis | 2. Phosphorylation of free glycerol
44
What enzyme phosphorylates free glycerol which happens in the liver only?
Glycerol kinase
45
what enzyme converts DHAP to G3P?
glycerol-3-dehydrogenase Needs NADH Happens in liver and adipose tissue
46
What activates hormone sensitive lipase?
1. low insulin 2. high epinephrine 3. high cortisol
47
Conversion of glycerol to glucose is activated by what hormones?
1. Increase in glucagon | 2. Increase in cortisol
48
What hormone is active during a fasting state which hydrolyzes TAG to FA and glycerol
Hormone-sensitive lipase 1. low insulin 2. High epinephrine 3. High cortisol
49
Hormone sensitive lipase removes fatty acid in what carbons?
Carbon 1 and Carbon 3
50
What are the products of beta-oxidation?
1. acetyl Coa | 2. NADH and FADH2
51
What are the fates of AcetylCoA from beta oxidation?
1. enters the citric acid cycle 2. Cholesterol synthesis 3. Ketone body metabolsm
52
Fatty acid activation occurs where?
cytosol
53
Beta oxidation occurs where?
mitochondria
54
What is substrate of beta oxidation?
palmitate
55
What are the products of beta oxidation
1. 8 acetyl CoA 2. 7 NADH 3. 7 FADH2
56
What is the rate limiting step of beta oxidation?
Translocation of fatty acyl CoA from the cytosol to the mitochondria via Carnitine-palmitoyl transferase
57
What enzyme activates fatty acid to transport fatty acid to the mitochondria?
Fatty acyl synthetase
58
How will you transport fatty acyl CoA to the mitochondria?
1. Activate fatty acid 2. Attach carnitine to activated fatty acyl in the outer mitochondrial membrane via the enzyme carnitine acyltransferase -1 3. Fatty acyl-carnitine is shuttled through the inner membrane 4. Carnitine acyltransferase-2 transfers fatty acyl group back to a CoA in the mitochondrial matrix
59
What are the enzymes included in fatty acid oxidation?
1. Fatty acyl CoA dehydrogenase 2. delta 2 enol CoA hydratase 3. 3-hydroxyacyl-CoA dehydrogenase 4. Thiolase
60
Each cycle of Fatty acyl CoA yields?
1. FADH2 2. NADH 3. AcetylCoA Repeated 7x
61
What are the steps in fatty acyl CoA breakdown?
OHOT 1. Oxidation 2. Hydration 3. Oxidation 4. Thiolysis
62
1 unit palmitate yields how many ATPs?
106 ATPs
63
Oxidation of fatty acid with an odd number will yield what byproducts?
1. Acetyl Coa | 2. Propionyl CoA
64
What is the fate of propionyl Coa after undergoing breakdown??
Converted to succinyl CoA (used in TCA)
65
What is the intermediate product of propionyl before it is converted to succinyl Coa?
Methylmalonyl CoA
66
Propionyl CoA is converted to methylmalonyl CoA via this enzyme
Propionyl-CoA carboxylase needs biotin
67
Methylmalonyl CoA is converted to Succinyl CoA via this enzyme
Methylmalonyl-CoA mutase needs B12
68
___ oxidize very long chains of FA
peroxisome
69
What enzyme is required to oxidize unsaturated FA
3,2 enoyl-CoA isomerase
70
[diagnosis] ichthyosis, hair loss, poor wound healing, visual, neurologic abnormalities
deficiency of EFA
71
[diagnosis] hypoglycemia due to impaired fatty acid oxidation, lipid accumulation and muscular weakness, patient undergoing hemodialysis
Carnitine deficiency
72
[diagnosis: CPT I or CPT II] reduced FA oxidation leading to hypoglycemia, coma and death
carnitine-palmitoyl transferase I deficiency
73
[diagnosis: CPT I or CPT II] cardiomyopathy, muscle weakness with myoglobinemia after prolonged exercise, affect cardiac and skeletal muscle
Carnitine-palmitoyl transferase II deficiency
74
What is the most common inborn error of FA oxidation?
Medium Chain Fatty acyl CoA dehydrogenase deficiency
75
[diagnosis] severe hypoglycemia, accumulation of dicarboxylic acids in the urine
MCAD
76
[diagnosis] caused by eating the unripe fruit of akee tree
Jamaican vomiting sickness
77
What toxin is seen in the unripe fruit of akee tree?
hypoglycin
78
What is the MOA of hypoglycin (from unripe fruit of akee tree)
Inactivates medium and short chain Acyl CoA dehydrogenase inhibiting beta oxidation and causing hypoglycemia
79
[diagnosis] deficiency of phytanoyl-CoA hydroxylase leads to accumulation of phytanic acid
refsum disease
80
[diagnosis] peripheral neuropathy, ataxia, retinitis pigmentosa, abnormal skin and bone
refsum disease
81
[diagnosis] ____ syndrome is an inherited absence of peroxisome in all tissues; can lead to cerebrohepatorenal syndrome
Zellweger syndrome
82
[diagnosis] mental retardation, weakness, hypotonia, craniofacial dysmorphism, liver dysfunction with jaundice
Zellweger syndrome
83
[diagnosis] inability to transport VLCFA across the peroxisomal membrane leading to accumulation in the brain, adrenals, and testes
Adrenoleukodystrophy
84
Lorenzos Oil can be used to treat ____
adrenoleukodystrophy
85
What is the substrate of ketogenesis
Acetyl CoA
86
What are the products of ketogenenis?
1. Acetoacetate 2. beta hydroxybutyrate 3. Acetone
87
What is the rate limiting step of ketogenesis?
Acetoacetyl CoA + Acetyl CoA to HMG CoA enzyme: HMG CoA synthase
88
of the 3 ketone bodies, which of them can be used as fuel
1. Acetoacetate | 2. Beta hydroxybutyrate
89
Acetoactyl CoA is converted to HMG CoA via what enzyme
HMG CoA synthase
90
What enzyme converts HMG CoA to acetoacetate?
HMG CoA lyase
91
What converts acetoacetate to 3 hydroxybutyrate?
3-hydroxybutyrate dehydrogenase
92
What enzyme is lacking in the liver making it unable to use ketone bodies as fuel
Succinyl CoA-acetoacetate-CoA transferase
93
Ketosis in alcoholics is due to the excess NADH which shunts what path?
Oxaloacetate to malate
94
What is measured by the sodium nitroprusside reaction?
1. Acetone | 2. Acetoacetate

Biochemistry (28 decks)

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