Biochem metabolism Flashcards

1
Q

What are the regulators of phosphofructokinase 1 (PFK1)? (two +, two -)

A

+ AMP, fructose 2,6 bisphosphate

  • ATP, citrate
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2
Q

What are the regulators of fructose 1,6-bisphosphatase? (two +, two -)

A

+ ATP, acetyl-CoA

  • AMP fructose 2,6 bisphosphatase
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3
Q

What are the regulators of isocitrate dehydrogenase? (one +, 2 -)

A

+ ADP

  • ATP, NADH
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4
Q

What is the enzyme needed to take glucose to G6P? Other way?

A

Hexokinase

Glucose-6-phosphatase

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5
Q

What is the enzyme needed to take G6P to fructose-6-phosphate?

A

GP isomerase

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6
Q

Where is Hexokinase found in highest quantities? Glucokinase?

A

Hexokinase = most tissues

Glucokinase = Liver and Beta cells of pancreas

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7
Q

What is the equation for Km, if K1 = rate from substrates to enzyme/substrate complex, K2 = rate from complex back to substrates, and K3 = rate from complex to products?

A

Km = (K2+K3)/K1

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8
Q

Which is induced by insulin, hexokinase, or glucokinase?

A

Hexokinase

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9
Q

Which is feedback inhibited by glucose, hexokinase or glucokinase?

A

hexokinase

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10
Q

Which has a gene mutation that is associated with maturity onset DM, hexokinase or glucokinase?

A

Glucokinase

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11
Q

What is the MOA or Arsenic?

A

Blocks ATP generation by phosphoglycerate kinase

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12
Q

What are the two downregulators of hexokinase?

A

G6P

Fructose-6-phosphate

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13
Q

What are the only two amino acids that are strictly ketogenic?

A

Lysine and Leucine

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14
Q

What are the findings of pyruvate dehydrogenase deficiency?

A

Neurological defects, lactic acidosis

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15
Q

What is the treatment for pyruvate dehydrogenase deficiency?

A

Increase ketogenic nutrients

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16
Q

What is the cofactor that is needed to keep glutathione reduced? What happens if this enzyme is impaired?

A

NADH

Hemolytic anemia

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17
Q

What is the enzyme that uses NADH to reduce glutathione? Oxidize it?

A

Glutathione reductase

Glutathione peroxidase

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18
Q

What is the cause of essential fructosuria? Symptoms?

A

Fructokinase does not function properly. Benign loss of fructose in urine.

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19
Q

What is the enzymatic cause of fructose intolerance?

A

Deficiency of aldolase B

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20
Q

What is the effect of galactokinase deficiency?

A

Galactouria, infantile cataracts,

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21
Q

What is the cause of classic galactosemia? Symptoms = ?

A

Absence of galactose-1-phosphate uridyltransferase

Symptoms = Infantile cataracts, MR, jaundice

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22
Q

What is the enzyme that converts glucose to sorbitol? Sorbitol to fructose?

A

Aldose reductase

Sorbitol dehydrogenase

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23
Q

Why is it that DM can damage the eye?

A

Eye only has aldose reductase, therefore there is an accumulation of sorbitol

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24
Q

Which type of aminoacids are needed, L or D?

A

L

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25
Q

What are the three amino acids that are only glucogenic?

A

M
V
H

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26
Q

What are the two acidic amino acids?

A

Aspartic acid

Glutamic acid

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27
Q

What are the three basic amino acids?

A

R
K
H

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28
Q

What are the substrates of the urea cycle? (hint: Ordinarily, careless crappers are frivolous about urination)?

A
Ornithine
Carbamoyl phosphate
Citrulline
Argininosuccinate
Fumarate
Arginine
Urea
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29
Q

Why is it that hyperammonemia leads to inhibition of the TCA cycle?

A

Loss of alpha-keto glutarate

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30
Q

What is the treatment for hyperammonemia? What are the two drugs that can be given?

A

Limit protein intake
Benzoate
Phenylbutyrate

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31
Q

What is the MOA of lactulose?

A

Acidify’s the Gi tract to trap NH4

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32
Q

What is the cause of n-acetylglutamate deficiency (what enzyme is affected)?

A

A required cofactor for carbamoyl phosphate synthetase I

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33
Q

What is the universal NH4 carrier?

A

Glutamate/ alpha ketoglutarate

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34
Q

What is ornithine transcarbamylase deficiency? Mode of inheritance? How is it diagnosed?

A

XLR loss of ornithine transcarbamylase

Orotic acid increased in the blood

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35
Q

What is the most common urea cycle disorder (which enzyme is deficient)?

A

ornithine transcarbamylase deficiency

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36
Q

What is the rxn that ornithine transcarbamylase catalyses”

A

Ornithine to citrulline

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37
Q

Orotic acid increased in the blood = ?

A

Ornithine transcarbamylase deficiency

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38
Q

What is the vitamin necessary to convert Y to niacin?

A

B6

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39
Q

What is the vitamin necessary to convert histidine to histamine?

A

B6

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40
Q

What is the enzyme necessary to convert E to GABA?

A

B6

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41
Q

What are the two possible causes of phenylketonuria? (enzyme/cofactor)

A

Deficiency or defect in phenylalanine hydroxylase or THF cofactor

42
Q

What are the symptoms of phenylketonuria?

A

MR
SZs
Musty body odor

43
Q

Musty baby = ?

A

Phenylketonuria

44
Q

What is the treatment for phenylketonuria?

A

Decrease F, increase Y.

45
Q

What is the cause of alkaptonuria?

A

Deficiency of homogentisate oxidase (in degradation of Y to fumarate)

46
Q

What are the symptoms of alkaptonuria?

A

Dark CT, brown pigmented sclera

Urine turns black

47
Q

What are the three causes of homocystinuria?

A
  1. Cystathionine beta-synthase deficiency (CBS)
  2. Decreased affinity of cystathionine synthase for PPP
  3. Homocysteine methyltransferase deficiency
48
Q

What are the symptoms of homocystinuria?

A

Increased homocysteine in urine

MR

49
Q

Review methionine to Cysteine pathway.

A
M
(M adenosyltransferase)
SAM
(methyltransferases)
Homocysteine
(CBS)
Cystathionine
(Cystathionase)
Cysteine
50
Q

What are the causes of cystinuria?

A

Defect in AA transporter for COLA (cysteine, Ornithine, Lys, Arg)

51
Q

What is the cause of maple syrup urine disease? What is the enzyme that is involved?

A

Blocked degradation of branched AAs (I, L, V)

Alpha ketoacid dehydrogenase

52
Q

What are the three AAs that are blocked in maple syrup urine disease?

A

I
L
V

(I love vermont)

53
Q

What are the symptoms of maple syrup urine disease?

A

Maple syrup urine
Ketoacidosis
MR

54
Q

What is the treatment for maple syrup urine disease?

A

Restrict Leucine, Isoleucine, and valine

55
Q

What is the bond between glycogen monomers (glucose)?/ What about the branches of the polymer?

A

alpha(1,4)

alpha (1,6) for branches

56
Q

What are the two metabolites that come from the degradation of glycogen?

A

Glucose-1-phosphate

Glucose-6-phosphate

57
Q

What are the two enzymes that are needed for glycogenolysis?

A

Glycogen phosphorylase

Debranching enzyme

58
Q

What is the receptor for insulin?

A

Y kinase dimer

59
Q

What is the receptor for glucagon?

A

G protein with PKA and calmodulin

60
Q

What are the enzymes responsible for the synthesis of glycogen?

A

Glycogen synthase

Branching enzymes

61
Q

What are the monomers that are added to a growing glycogen chain?

A

UDP-glucose

62
Q

What are the two intermediates of glucose to glycogen?

A

G6P

G1P

63
Q

What is type I GSD? What is the enzyme that is deficient?

A

Von Gierke—G-6-Phosphatase

64
Q

What is type II GSD? What is the enzyme that is deficient? Symptoms?

A

Pompe’s disease
Acid maltase

Pompe’s trashes the pump (heart, liver, muscle failure)

65
Q

What is type III GSD? What is the enzyme that is deficient?

A

Cori disease

Debranching enzyme

66
Q

What is type V GSD? What is the enzyme that is deficient? Symptoms?

A

McArdle’s disease
Muscle glycogen phosphorylase
Muscle weakness

67
Q

What is the enzyme that is deficient in Hunter’s syndrome? Mode of inheritance?

A

Iduronate sulfatase–XLR

68
Q

What is the enzyme that is deficient in Hurler’s syndrome? Mode of inheritance?

A

alpha-L-iduronidase (AR)

69
Q

What is the enzyme that is deficient in fabry’s disease? Symptoms? What accumulates?

A

alpha-galactosidase
Peripheral neuropathy
Ceramide trihexoside

70
Q

What is the enzyme that is deficient in Gaucher’s disease? Symptoms? What accumulates?

A

Glucocerebrosidase
Crumpled tissue paper macrophages
Glucocerebroside

71
Q

What is the enzyme that is deficient in Niemann-Pick’s disease? Symptoms? What accumulates?

A

Sphingomyelinase
Sphingomyelin
Progressive neurodegeneration

(No Man picks his nose with his sphinger

72
Q

What is the enzyme that is deficient in Tay-Sach’s disease? Symptoms? What accumulates?

A

Hexosaminidase A
GM2 ganglioside
Progressive neurodegeneration

(tay sax lacks hexosaminidase)

73
Q

What is the enzyme that is deficient in Krabbe disease? Symptoms? What accumulates?

A

galactocerebrosidase
Galactocerebroside
Peripheral neuropathy, MR

74
Q

What is the enzyme that is deficient in Metachromatic leukodystrophy? Symptoms? What accumulates?

A

Arylsulfatase A
Cerebroside sulfate
Central and peripheral demyelination

75
Q

What is carnitine deficiency?

A

Inability to transport LCFAs into mito, causing weakness, hypotonia

76
Q

What is acyl-coa dehydrogenase deficiency?

A

Inability to transport carnitine inside the mito, d/t lack of carrier.

77
Q

What is the enzyme that transports FAs into the mitochondria? What is the intermediate produce between the two?

A

Carnitine palmitoyl transferase I and II

Acyl-carnitine

78
Q

What are FAs metabolized to, and is measured in DKA?

A

beta-hydroxybutyrate

79
Q

What is the rate limiting step of Cholesterol synthesis? (name the enzyme involved)

A

HMG-CoA reductase

80
Q

What is the MOA of statins?

A

Inhibit HMG-CoA reductase

81
Q

What is the enzyme that breaks down dietary triglycerides in the small intestines?

A

Pancreatic lipase

82
Q

What is the enzyme that degrades Tgs circulating in chylomicrons and VLDLs?

A

Lipoprotein lipase (LPL)

83
Q

What is the function of apoprotein A?

A

activators of LCAT

84
Q

What is the function of apoprotein B?

A

Structural

85
Q

What is the function of lipoprotein C?

A

Modulate the function of LPL

86
Q

What is the function of lipoprotein E?

A

Message

87
Q

What is the lipase that degrades TGs stored in adipocytes?

A

Hormone sensitive lipase

88
Q

What is the function of LCAT?

A

Catalyzes esterification of cholesterol

89
Q

Can the body breakdown cholesterol?

A

No

90
Q

What is the enzyme that transports cholesterol out of a cell into HDL, in order to form LDL? What is the enzyme that takes the cholesterol, and transfers to HDL particles?

A

ABCA-1

LCAT

91
Q

What is the function of LDL?

A

Transports cholesterol from the Liver to body

92
Q

What is the function of HDL?

A

Transports cholesterol from the body to liver

93
Q

What is the effect of EtOH on HDL synthesis?

A

Increases

94
Q

What is Type I hypercholesterolemia?

A

AR lipoprotein lipase deficiency

95
Q

What is type II hypercholesterolemia?

A

AD absent LDL receptors

96
Q

What is type IV hypercholesterolemia?

A

AD hepatic overproduction of VLDLs

97
Q

Which type of hypercholesterolemia: increased chylomicrons, TG, and cholesterol

A

I

98
Q

Which type of hypercholesterolemia: Increased LDLs, cholesterol

A

II

99
Q

Which type of hypercholesterolemia: increase VLDL, Tgs

A

IV

100
Q

Which type of hypercholesterolemia: hyperchylomicronemia

A

I

101
Q

Which type of hypercholesterolemia: familial hypercholesterolemia

A

IIa

102
Q

Which type of hypercholesterolemia: hypertriglyceridemia

A

IV