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Biochemistry-Block 2 CC > Fatty Acid Metabolism > Flashcards

Fatty Acid Metabolism Flashcards

1
Q

MCAD deficiency is _____ ______ disorder

A

autosomal, recessive

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2
Q

Name the 3 ketone bodies

A

acetoacetate
3-hydroxybutyrate
Acetone

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3
Q

Ketone bodies are produced in the

A

liver mitochondria from Beta-oxidation derived acetyl CoA

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4
Q

________ is/are transported in the blood to peripheral cells/tissues

A

Acetoacetate and 3-Hydroxybutyrate

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5
Q

____ is a dead-end by-product

A

Acetone

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6
Q

Peripheral cells convert ___ back into acetyl CoA, a substrate for the TCA cycle

A

ketone bodies

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7
Q

Ketoacidosis can be caused by _____

A

fasting

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8
Q

Diabetic Ketacidosis causes

A

fruity smelling breath from acetone

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9
Q

_____ associated fatty acids serve as major concentrated fuel store for the body

A

TAG

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10
Q

______: constitutive, low level release of fatty acids from adipose, TAG –> DAG + FA

A

Adipose lipase

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11
Q

______ has a major role in regulated TAG lipolysis and release of fatty acids from adipose, TAG–>DAG + FA

A

Hormone-sensitive lipase (HSL)

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12
Q

_______: releases fatty acids from TAG in the circulating lipoprotein particles to free fatty acids and glycerol
-this is a more complete release of FA’s

A

Lipoprotein Lipase

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13
Q

HSL is phosphorylated and activated by ____________

A

cAMP dependent protein kinases

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14
Q

Phosphorylation of HSL causes:
1)
2)

A

1) activates its enzymatic lipase activity

2) HSL binding to perilipin (lipid droplet surface protein)

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15
Q

Insulin promotes dephosphorylation of HSL by _______. This shuts off HSL catalyzed hydrolytic release of fatty acids from TAG

A

activating phosphatases

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16
Q

_____ can participate in glycolysis or gluconeogenesis

A

DHAP

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17
Q

Adipocytes lack _____ and cannot metabolize glycerol released in TAG degradation if all FAs are released from a TAG molecule

A

glycerol kinase

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18
Q

Glycerol is
1)
or
2)

A

1) released to blood and taken up by liver; phosphorylated in the liver to be used in TAG synthesis
2) reversibly converted to DHAP by glycerol phosphate dehydrogenase

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19
Q

Free fatty acids leave adipocytes to the blood where they bind ____ ____

A

serum albumin

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20
Q

After binding to serum albumin, the fatty acids are taken up by cells and are activated to CoA by _______

A

fatty acyl CoA synthetase (thiokinase)

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21
Q

Fatty acyl CoA is oxidized for ______

A

energy production/release

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22
Q

~50% of free fatty acids released from adipose TAG are resterified to ______. This process functions to decrease the plasma free fatty acid level associated with insulin resistance in type 2 diabetes and obesity

A

glycerol 3-phosphate

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23
Q

The major pathway for obtaining energy from fatty acids is ______

A

Beta-oxidation

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24
Q

Beta-oxidation occurs in the ______

A

mitochondria

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25
Q

For Beta-oxidation, the fatty acid must be in the form of __________

A

(activated) fatty acyl CoA

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26
Q

Beta-oxidation involves the successive removal of ______. Where are they removed from?

A

2-carbon fragments; the carboxyl end

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27
Q

What are the products of Beta-oxidation?

A

Acetyl CoA, NADH, FADH2

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28
Q

__________ is located on the cytosolic side of mitochondrial outer membrane and generates LCFA CoA in the cytosol

A

Long-chain Fatty Acid CoA synthase (thiokinase)

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29
Q

________ cannot directly cross the inner membrane of the mitochondria due to the presence of the CoA

A

LCFA CoA

30
Q

The ________ imports LCFAs into the mitochondria (required)

A

Carnitine Shuttle Process

31
Q

In the 1st step of the Carnitine Shuttle Process, acyl groups are transferred from CoA to carnitine by ________, an outer mitochondrial membrane enzyme

A

Carnitine Acyl Transferase-1 (CAT-1)

32
Q

In the 2nd step of the Carnitine Shuttle Process, acyl carnitine is transported into the mitochondrial matrix in exchange for free carnitine by _____________

A

carnitine-acyl carnitine translocase

33
Q

In the 3rd step of the Carnitine Shuttle Process, ______ on the matrix side of the inner mitochondrial membrane catalyzed acyl group transfer from carnitine to CoA

A

CAT-II

34
Q

CAT-1 is inhibited by _____; thus preventing LCFA transfer from CoA to carnitine

A

malonyl CoA

35
Q

The inhibition of CAT-1 by malonyl CoA prevents
1)
2)

A

1) mitochondrial import and beta-oxidation of newly synthesized LCFAs
2) Beta-oxidation of LCFAs to generate energy while in the well-fed state

36
Q

Name the sources of carnitine.

A

Diet (primarily in meat products) or synthesized by enzymatic pathway in the liver and kidney using amino acids lysine and methionine

37
Q

________ houses ~97% of carnitine in the body and must rely on uptake of synthesized and dietary sources from the blood

A

Skeletal Muscle

38
Q

Carnitine deficiency reduces the ability of tissues to _________

A

use LCFAs as a metabolic fuel

39
Q

What are secondary carnitine deficiencies caused by? (4)

A

1) decreased synthesis due to liver disease
2) dietary malnutrition or strict vegetarian diet
3) hemodialysis, which removes carnitine
4) conditions when carnitine requirements increase (pregnancy, severe infections, burns, trauma)

40
Q

Primary Carnitine Deficiencies are caused by congenital deficiencies in: (3)

A

1) Renal Tubular Reabsorption of Carnitine
2) Carnitine Uptake by Cells
3) CAT-1 or CAT-ll Function

41
Q

In primary carnitine deficiencies, the genetic defect of CAT-l results in _________, leading to severe hypoglycemia, coma or death

A

decreased liver use of LCFA during a fast

42
Q

In primary carnitine deficiencies, the genetic defect of CAT-ll results in the ____ and _____ ______ exhibiting symptoms that range from cardiomyopathy to muscle weakness with myoglobinemia following prolonged exercise

A

heart and skeletal muscle

43
Q

What is the treatment for Primary Carnitine Deficiencies?

A

1) Avoid prolonged Fasts
2) Adopt a diet high in carbs and low in LCGA
3) Supplement with medium-chain fatty acids and carnitine

44
Q

Acetyl CoA is a positive allosteric effector of ______ ______ linking fatty acid oxidation and gluconeogensis

A

pyruvate carboxylase

45
Q

Degrading 1 palmitoyl CoA to CO2 and H2O results in a net of _____ ATP produced

A

129

46
Q

The Beta-oxidation of fatty acids w/an odd number of carbons is similar to that of even number of carbons with the exception that the final thiolytic cleavage produces a ___________.

A

3-Carbon product: propionyl CoA

47
Q

Propionyl CoA Metabolic Pathway

In step 1, the synthesis of D-methylmalonyl CoA, propionyl CoA is carboxylated by _________

A

propionyl CoA carboxylase

48
Q

Propionyl CoA Metabolic Pathway

In step 2, the formation os L-methylmalonyl CoA: D–>L methylmalonyl CoA is an isomer conversion by

A

methylmalonyl CoA racemase

49
Q

Propionyl CoA Metabolic Pathway

In step 3, the synthesis of succinyl CoA: the carbons of L-methylmalonyl CoA are rearranged to form succinyl CoA by _____________: succinyl CoA enters TCA cycle

A

methylmalonyl CoA mutase

50
Q

_______ requires vitamin B12–the mutase reaction is 1 of 2 reactions in the body requiring vitamin B12

A

methylmalonyl CoA mutase

51
Q

_________ deficiency causes excretion of both propionate and methylmalonate in the urine

A

Vitamin B12

52
Q

Both heritable methylmalonic acidemia or aciduria is possible, both result in _______ and the potential for ________

A

metabolic acidosis and developmental retardation

53
Q

Unsaturated fatty acids release less energy than a similar saturated fatty acid because
1)
2)

A

1) they are less highly reduced

2) fewer reducing equivalents can be produced

54
Q

Monounsaturated fatty acids require an additional _________ enzyme for complete oxidation

A

isomerase

55
Q

Polyunsaturated fatty acids require an _______ and _______ enzyme for complete oxidation

A

isomerase and reductase

56
Q

VLCFA (22 carbons or longer) are initially oxidized in the ______

A

peroxisome

57
Q

Peroxisomal Beta-Oxidation does not generate ______

A

ATP

58
Q

Once initially oxidized in the peroxisome, the partially oxidized ‘shorter’ carbon chain fatty acid can be imported/diffuse to the __________ for complete oxidation

A

mitochondrial matrix

59
Q

This is a peroxisome biogenesis disorder that result in genetic defects resulting in failure to target matrix proteins to the peroxisome

A

Zellweger Syndrome

60
Q

This disease causes genetic defects causing the failure to transport VLCFA across the peroxisome membrane.

A

X-linked adrenoleukodystrophy

61
Q

Both Zellweger Syndrome and X-linked adrenoleukodystrophy cause ______________________

A

accumulation of VLCFA in the blood and tissues

62
Q

Branched-chain, 20 C fatty acid phytanic acid cannot function as a substrate for ________ due to the methyl group at its Beta-carbon

A

acetyl CoA dehydrogenase

63
Q

____________ hydroxylates the alpha-carbon and the carbon 1 is released as CO2

A

Paytanoyl CoA alpha-hydroxylase (PhyH)

64
Q

19-C _______ is activated to CoA and undergoes Beta-oxidation

A

pristanic acid

65
Q

_______ disease:

  • rare, autosomal recessive: caused by peroxisomal PhyH deficiency
  • phytanic acid accumulates in the blood and tissues
  • symptoms are primarily neurologic
  • treatment requires dietary restrictions to halt disease progession
A

Refsum Disease

66
Q

________ deficiency: decreased oxidation of 6- to 10- C fatty acids

A

MCAD

67
Q

What are the symptoms of MCAD deficiency?

A

Severe hypoglycemia, since the tissues rely on glucose

68
Q

What is the treatment of MCAD deficiency?

A

Avoid fasting

69
Q

_____ deficiency:

  • one of the most common inborn errors of metabolism
  • the most common inborn error of fatty acid oxidation
  • high incidence in Northern Europeans
A

MCAD

70
Q

_____ has recently been identified as a possible cause for some incidence of reported sudden infant death syndrome (SIDS) or Reye Syndrome

A

MCAD

Biochemistry-Block 2 CC (13 decks)

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