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Flashcards in Biochem metabolism Deck (102):
1

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

+ AMP, fructose 2,6 bisphosphate

- ATP, citrate

2

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

+ ATP, acetyl-CoA

- AMP fructose 2,6 bisphosphatase

3

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

+ ADP

- ATP, NADH

4

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

Hexokinase

Glucose-6-phosphatase

5

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

GP isomerase

6

Where is Hexokinase found in highest quantities? Glucokinase?

Hexokinase = most tissues

Glucokinase = Liver and Beta cells of pancreas

7

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?

Km = (K2+K3)/K1

8

Which is induced by insulin, hexokinase, or glucokinase?

Hexokinase

9

Which is feedback inhibited by glucose, hexokinase or glucokinase?

hexokinase

10

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

Glucokinase

11

What is the MOA or Arsenic?

Blocks ATP generation by phosphoglycerate kinase

12

What are the two downregulators of hexokinase?

G6P
Fructose-6-phosphate

13

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

Lysine and Leucine

14

What are the findings of pyruvate dehydrogenase deficiency?

Neurological defects, lactic acidosis

15

What is the treatment for pyruvate dehydrogenase deficiency?

Increase ketogenic nutrients

16

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

NADH

Hemolytic anemia

17

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

Glutathione reductase

Glutathione peroxidase

18

What is the cause of essential fructosuria? Symptoms?

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

19

What is the enzymatic cause of fructose intolerance?

Deficiency of aldolase B

20

What is the effect of galactokinase deficiency?

Galactouria, infantile cataracts,

21

What is the cause of classic galactosemia? Symptoms = ?

Absence of galactose-1-phosphate uridyltransferase

Symptoms = Infantile cataracts, MR, jaundice

22

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

Aldose reductase
Sorbitol dehydrogenase

23

Why is it that DM can damage the eye?

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

24

Which type of aminoacids are needed, L or D?

L

25

What are the three amino acids that are only glucogenic?

M
V
H

26

What are the two acidic amino acids?

Aspartic acid
Glutamic acid

27

What are the three basic amino acids?

R
K
H

28

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

Ornithine
Carbamoyl phosphate
Citrulline
Argininosuccinate
Fumarate
Arginine
Urea

29

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

Loss of alpha-keto glutarate

30

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

Limit protein intake
Benzoate
Phenylbutyrate

31

What is the MOA of lactulose?

Acidify's the Gi tract to trap NH4

32

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

A required cofactor for carbamoyl phosphate synthetase I

33

What is the universal NH4 carrier?

Glutamate/ alpha ketoglutarate

34

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

XLR loss of ornithine transcarbamylase

Orotic acid increased in the blood

35

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

ornithine transcarbamylase deficiency

36

What is the rxn that ornithine transcarbamylase catalyses"

Ornithine to citrulline

37

Orotic acid increased in the blood = ?

Ornithine transcarbamylase deficiency

38

What is the vitamin necessary to convert Y to niacin?

B6

39

What is the vitamin necessary to convert histidine to histamine?

B6

40

What is the enzyme necessary to convert E to GABA?

B6

41

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

Deficiency or defect in phenylalanine hydroxylase or THF cofactor

42

What are the symptoms of phenylketonuria?

MR
SZs
Musty body odor

43

Musty baby = ?

Phenylketonuria

44

What is the treatment for phenylketonuria?

Decrease F, increase Y.

45

What is the cause of alkaptonuria?

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

46

What are the symptoms of alkaptonuria?

Dark CT, brown pigmented sclera

Urine turns black

47

What are the three causes of homocystinuria?

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

48

What are the symptoms of homocystinuria?

Increased homocysteine in urine
MR

49

Review methionine to Cysteine pathway.

M
(M adenosyltransferase)
SAM
(methyltransferases)
Homocysteine
(CBS)
Cystathionine
(Cystathionase)
Cysteine

50

What are the causes of cystinuria?

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

51

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

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

Alpha ketoacid dehydrogenase

52

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

I
L
V

(I love vermont)

53

What are the symptoms of maple syrup urine disease?

Maple syrup urine
Ketoacidosis
MR

54

What is the treatment for maple syrup urine disease?

Restrict Leucine, Isoleucine, and valine

55

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

alpha(1,4)
alpha (1,6) for branches

56

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

Glucose-1-phosphate
Glucose-6-phosphate

57

What are the two enzymes that are needed for glycogenolysis?

Glycogen phosphorylase
Debranching enzyme

58

What is the receptor for insulin?

Y kinase dimer

59

What is the receptor for glucagon?

G protein with PKA and calmodulin

60

What are the enzymes responsible for the synthesis of glycogen?

Glycogen synthase
Branching enzymes

61

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

UDP-glucose

62

What are the two intermediates of glucose to glycogen?

G6P
G1P

63

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

Von Gierke---G-6-Phosphatase

64

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

Pompe's disease
Acid maltase

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

65

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

Cori disease
Debranching enzyme

66

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

McArdle's disease
Muscle glycogen phosphorylase
Muscle weakness

67

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

Iduronate sulfatase--XLR

68

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

alpha-L-iduronidase (AR)

69

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

alpha-galactosidase
Peripheral neuropathy
Ceramide trihexoside

70

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

Glucocerebrosidase
Crumpled tissue paper macrophages
Glucocerebroside

71

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

Sphingomyelinase
Sphingomyelin
Progressive neurodegeneration

(No Man picks his nose with his sphinger

72

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

Hexosaminidase A
GM2 ganglioside
Progressive neurodegeneration

(tay sax lacks hexosaminidase)

73

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

galactocerebrosidase
Galactocerebroside
Peripheral neuropathy, MR

74

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

Arylsulfatase A
Cerebroside sulfate
Central and peripheral demyelination

75

What is carnitine deficiency?

Inability to transport LCFAs into mito, causing weakness, hypotonia

76

What is acyl-coa dehydrogenase deficiency?

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

77

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

Carnitine palmitoyl transferase I and II

Acyl-carnitine

78

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

beta-hydroxybutyrate

79

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

HMG-CoA reductase

80

What is the MOA of statins?

Inhibit HMG-CoA reductase

81

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

Pancreatic lipase

82

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

Lipoprotein lipase (LPL)

83

What is the function of apoprotein A?

activators of LCAT

84

What is the function of apoprotein B?

Structural

85

What is the function of lipoprotein C?

Modulate the function of LPL

86

What is the function of lipoprotein E?

Message

87

What is the lipase that degrades TGs stored in adipocytes?

Hormone sensitive lipase

88

What is the function of LCAT?

Catalyzes esterification of cholesterol

89

Can the body breakdown cholesterol?

No

90

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?

ABCA-1

LCAT

91

What is the function of LDL?

Transports cholesterol from the Liver to body

92

What is the function of HDL?

Transports cholesterol from the body to liver

93

What is the effect of EtOH on HDL synthesis?

Increases

94

What is Type I hypercholesterolemia?

AR lipoprotein lipase deficiency

95

What is type II hypercholesterolemia?

AD absent LDL receptors

96

What is type IV hypercholesterolemia?

AD hepatic overproduction of VLDLs

97

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

I

98

Which type of hypercholesterolemia: Increased LDLs, cholesterol

II

99

Which type of hypercholesterolemia: increase VLDL, Tgs

IV

100

Which type of hypercholesterolemia: hyperchylomicronemia

I

101

Which type of hypercholesterolemia: familial hypercholesterolemia

IIa

102

Which type of hypercholesterolemia: hypertriglyceridemia

IV