Biochemistry 2/2, First Aid for the USMLE Step 1 Flashcards Preview

Biochemistry > Biochemistry 2/2, First Aid for the USMLE Step 1 > Flashcards

Flashcards in Biochemistry 2/2, First Aid for the USMLE Step 1 Deck (174):
1

Vitamin B1

Thiamine

2

Vitamin B2

Riboflavin

3

Vitamin B3

Niacin

4

Vitamin B5

Pantothenic acid

5

Vitamin B6

Pyridoxine

6

Vitamin B7

Biotin

7

Vitamin B9

Folate

8

Vitamin B12

Cobalamin

9

Vitamin that reguates Cl- channel in nerve conduction

B1

10

Vitamin essential for normal differentiation of epithelial cells into specialized tissue

Vitamin A

11

Vitamin A is found in what food stuff

Liver and leafy vegetables

12

Vitamin A prevents what cellular adaptation

Squamous metaplasia

13

Vitamin A is used to treat what CA

AML M3

14

Seen in conjunctiva of patients with Vitamin A deficiency

Bitot spots

15

T/F Vitamin A is teratogenic

T

16

Drug which is a vitamin A derivative that is contraindicated in pregnancy

Isotretinoin

17

Deficient in beriberi

B1

18

Deficient in Wernicke-Korsakoff syndrome

B1

19

Classic triad of Wernicke Korsakoff syndrome

1) Confusion 2) Ophthalmoplegia 3) Ataxia

20

Dry vs wet beriberi: Polyneuritis, symmetrical muscle wasting

Dry beriberi

21

Dry vs wet beriberi: High-output cardiac failure (dilated cardiomyopathy), edema

Wet beriberi

22

Vitamin component of FAD and FMN, used as cofactors in redox reactions

B2

23

ATP per B2

2

24

2 Cs of B2

Cheilosis and corneal vascularisation

25

Vitamin component of NAD and NADP, used as cofactors in redox reactions

B3

26

Vitamin B3 is derived from what amino acid

Tryptophan

27

ATP per B3

3

28

3 Ds of B3

Diarrhea, dementia, and dermatitis (C3/4 dermatome; broad collar rash; Casal necklace)

29

Metabolic disorder that can cause pellagra due to decreased niacin from tryptophan (decreased tryptophan absorption)

Hartnup disease

30

Facial flushing in niacin excess is due to

Prostaglandin release, NOT HISTAMINE!

31

How can facial flushing from niacin be avoided

Take aspirin with niacin

32

Vitamin that is an essential component of coenzyme A (CoA, a cofactor for acyl transfers) and fatty acid synthase

B5

33

Deficiency of this vitamin causes sideroblastic anemias due to impaired hemoglobin synthesis and iron excess

B6

34

Deficiency of this vitamin causes peripheral neuropathy

B6

35

Vitamin which is a cofactor for carboxylation enzymes (which add a 1-carbon group)

B8

36

Food stuff that avidly binds biotin

Egg whites (avidin; excessive ingestion of raw egg whites can cause deficiency of biotin)

37

Vitamin that is important for the synthesis of nitrogenous bases in DNA and RNA

B9

38

B9 is found in what foodstuff

Green leafy vegetables [FOLate from FOLiage]

39

B9 is absorbed in

Jejunum

40

Vitamin deficiencies that can cause macrocytic, megaloblastic anemia; hypersegmented polymorphonuclear cells (PMNs)

B9, B12

41

Symptom that distinguishes folate from B12 deficiency

No neurologic symptoms in folate defciency, present in B12

42

Vitamin that serves as cofactor for homocysteine methyltransferase (transfers CH3 groups) and methylmalonyl-CoA mutase

B12

43

Foodstuff that contain vitamin B12

Animal products

44

Vitamin which is an antioxidant and facilitates iron absorption

Vitamin C

45

Vitamin which is necessary for hydroxylation of proline and lysine in collagen synthesis

Vitamin C

46

Vitamin which is necessary for dopamine β-hydroxylase, which converts dopamine to norepinephrine

Vitamin C

47

Vitamin that can be used as ancillary treatment for methemoglobinemia by reducing iron to the ferrous form

Vitamin C

48

Corkscrew hair

Vitamin C deficiency

49

Form of vitamin D ingested from plants

D2/ergocalciferol

50

Form of vitamin D consumed in milk

D3/cholecalciferol

51

Vitamin D formed in sun-exposed skin

D3/cholecalciferol

52

Vitamin D is formed in what layer of the skin

Stratum basale

53

Storage form of vitamin D

25-OH D3

54

Active form of vitamin D

1,25-(OH)2 D3/calcitriol

55

Deficiency of vitamin D in children

Rickets

56

Deficiency of vitamin D in adults

Osteomalacia

57

Why is there vitamin D excess in granulomatous disease

Increased activation of vitamin D by epithelioid macrophages

58

Rickets, genu varum vs valgum

Varum

59

Vitamin that can enhance anticoagulant effects of warfarin

Vitamin E

60

Deficiency of this vitamin may have neurologic presentation that appear similar to vitamin B12 deficiency, but without megaloblastic anemia, hypersegmented neutrophils, or serum methylmalonic acid levels.

Vitamin E

61

Cofactor for the γ-carboxylation of glutamic acid residues on various proteins required for blood clotting

Vitamin K

62

Vitamin K dependent clotting factors

IX, X, VII, II, protein C, protein S

63

Vitamin K antagonist

Warfarin

64

T/F Vitamin K is supplied by breast milk

F

65

Mineral essential for the activity of 100+ enzymes

Zinc

66

Vitamin important in formation of transcription factor motif

Zinc (transcription factor motif is aka zinc fingers)

67

Deficiency of this vitamin results in delayed wound healing

Zinc

68

Acrodermatitis enteropathica is due to deficiency of what enzyme

Zinc

69

Vitamin deficiency that may predispose to alcoholic cirrhosis

Zinc

70

Inhibits alcohol dehydrogenase and is an antidote for methanol or ethylene glycol poisoning

Fomepizole

71

Inhibits acetaldehyde dehydrogenase (acetaldehyde accumulates, contributing to hangover symptoms)

Disulfiram

72

Limiting reagent in ethanol metabolism

NAD+

73

Ethanol metabolism NADH/NAD+ ratio in liver, causing

1) Pyruvate > lactate (lactic acidosis) 2) Oxaloacetate > malate (prevents gluconeogenesis > fasting hypoglycemia) 3) Dihydroxyacetone phosphate > glycerol- 3-phosphate (combines with fatty acids to make triglycerides > hepatosteatosis)

74

Pathways that take place in the mitochondria

1) Fatty acid oxidation (β-hydroxylase) 2) acetyl- CoA production 3) TCA cycle 4) oxidative phosphorylation 5) ketogenesis

75

Pathways that take place in the cytoplasm

1) Glycolysis 2) fatty acid synthesis 3) HMP shunt 4) protein synthesis (RER) 5) steroid synthesis (SER) 6) cholesterol synthesis

76

Enzyme deficient in PKU

Phenylalanine hydroxylase or THB4 cofactor (malignant PKU)

77

T/F Screening for PKU should be done immediately after birth

F, 2-3 days after birth because baby is normal at birth due to maternal enzyme

78

Disorder of aromatic amino acid metabolism

PKU

79

What food stuff must patients with PKU avoid

Aspartame (artificial sweetener that contains phenylalanine)

80

Enzyme deficient in albinism

Tyrosinase

81

Enzyme deficient in alkaptonuria

Homogentisate oxidase

82

Enzyme inhibited by Carbidopa in catecholamine synthesis

DOPA decarboxylase

83

Enzyme stimulated by cortisol in catecholamine synthesis

Phenylethanolamine-N-methyltransferase

84

Enzyme deficient in MSUD

α-ketoacid dehydrogenase

85

Most abundant α-ketoacid in the blood of patients with MSUD

Leucine

86

Supplemented in patients with MSUD

Thiamine

87

Congenital deficiency of homogentisate oxidase in the degradative pathway of tyrosine to fumarate

Alkaptonuria

88

Alkaptonuria is aka

Ochronosis

89

Direction of lens subluxation in homocystinuria

Downward and inward

90

Hereditary defect of renal PCT and intestinal amino acid transporter that prevents reabsorption of Cysteine, Ornithine, Lysine, and Arginine (COLA)

Cystinuria

91

Test to diagnose cystinuria

Urinary cyanide-nitroprusside test

92

Microscopic shape of cystine crystals

Hexagonal

93

Treatment for cystinuria

1) Urinary alkalinization (potassium citrate or acetazolamide) 2) Chelating agents (penicillamine)

94

Refers to the one to four residues remaining on a branch after glycogen phosphorylase has already shortened glycogen

Limit dextrin

95

Debranching enzymes in glycogenolysis

1) 4-α-D-glucanotransferase 2) α-1,6-glucosidase

96

Glycogen storage disease: Severe fasting hypoglycemia

Von Gierke

97

Glycogen storage disease: Cardiomegaly, hypertrophic cardiomyopathy, exercise intolerance

Pompe

98

Glycogen storage disease: Milder form of type I with normal blood lactate levels

Cori

99

Glycogen storage disease: Increased glycogen in muscle, but muscle cannot break it down

McArdle

100

Enzyme deficient: Von Gierke

Glucose-6-phosphatase

101

Enzyme deficient: Pompe

Lysosomal α-1,4-glucosidase (acid maltase)

102

Enzyme deficient: Cori

Debranching enzyme ( α-1,6-glucosidase)

103

Enzyme deficient: McArdle

Skeletal muscle glycogen phosphorylase (myophosphorylase)

104

Treatment for McArdle

Vitamin B6 (cofactor)

105

MC sphingolipidosis

Gaucher

106

Sphingolipidosis: Aseptic necrosis of femur

Gaucher

107

Sphingolipidosis: Lysosomes with onion skin

Tay-Sachs

108

Enzyme deficient and substance that accumulates: Fabry

α-galactosidase A; Ceramide trihexoside

109

Enzyme deficient: Gaucher disease

Glucocerebrosidase (β-glucosidase); Glucocerebroside

110

Enzyme deficient: Niemann-Pick disease

Sphingomyelinase; Sphingomyelin

111

Enzyme deficient: Tay-Sachs disease

Hexosaminidase A; GM2 ganglioside

112

Enzyme deficient: Krabbe disease

Galactocerebrosidase; Galactocerebroside, psychosine

113

Enzyme deficient: Metachromatic leukodystrophy

Arylsulfatase A; Cerebroside sulfate

114

Gargoylism

Hurler

115

Mild Hurler + aggressive behavior

Hunter

116

Corneal clouding

Hurler, NOT hunter

117

Hurler vs hunter: X-linked recessive

Hunter

118

Enzyme deficienct: Hurler

α-l-iduronidase

119

Enzyme deficient: Hunter

Iduronate sulfatase

120

Lysosomal storage diseases with increased incidence in Ashkenazi Jews

Tay-Sachs, Niemann-Pick, and some forms of Gaucher disease

121

Long-chain fatty acid (LCFA) degradation requires

Carnitine-dependent transport into the mitochondrial matrix

122

Inherited defect in transport of long chain fatty acids into the mitochondria toxic accumulation

Systemic 1° carnitine deficiency

123

Autosomal recessive disorder of fatty acid oxidation characterized by decreased ability to break down fatty acids into acetyl-CoA > accumulation of 8- to 10-carbon fatty acyl carnitines in the blood and hypoketotic hypoglycemia

Medium-chain acyl-CoA dehydrogenase deficiency

124

Shunts glucose and FFA toward the production of ketone bodies

Buildup of acetyl-CoA

125

Breath smells like acetone (fruity odor)

Ketoacidosis

126

Urine test for ketones does not detect

_-hydroxybutyrate

127

1g protein = how many kcal

4

128

1g CHO = how many kcal

4

129

1g fat = how many kcal

9

130

1g alcohol = how many kcal

7

131

Glycogen reserves are depleted after how many hours of starvation

24/1 day

132

Rate-limiting enzyme in cholesterol synthesis

HMG-CoA reductase

133

Hormone that induces HMG-CoA reductase

Insulin

134

HMG-CoA reductase converts HMG-CoA to

Mevalonate

135

2⁄3 of plasma cholesterol esterified by ___

Lecithin-cholesterol acyltransferase (LCAT)

136

Competitively and reversibly inhibit HMG-CoA reductase

Statins

137

Enzyme: Degradation of dietary triglycerides (TGs) in small intestine

Pancreatic lipase

138

Enzyme: Degradation of TGs circulating in chylomicrons and VLDLs

Lipoprotein lipase (LPL)

139

Enzyme: Found on vascular endothelial surface; degrade circulating TGs

Lipoprotein lipase (LPL)

140

Enzyme: Degradation of TGs remaining in IDL

Hepatic TG lipase (HL)

141

Enzyme: Degradation of TGs stored in adipocytes

Hormone-sensitive lipase

142

Enzyme: Catalyzes esterification of cholesterol

LCAT

143

Mediates transfer of cholesterol esters to other lipoprotein particles

Cholesterol ester transfer protein (CETP)

144

Apolipoprotein: Mediates remnant uptake

E

145

Apolipoprotein: Activates LCAT

A-I

146

Apolipoprotein: Lipoprotein lipase cofactor

C-II

147

Apolipoprotein: Mediates chylomicron secretion

B-48

148

Apolipoprotein: Binds LDL receptor

B-100

149

Lipoprotein: Transports cholesterol from liver to tissues

LDL

150

Lipoprotein: Transports cholesterol from periphery to liver

HDL

151

Lipoprotein: Delivers dietary TGs to peripheral tissue

Chylomicron

152

Lipoprotein: Delivers cholesterol to liver in the form of chylomicron remnants, which are mostly depleted of their TGs

Chylomicron

153

Lipoprotein: Secreted by intestinal epithelial cells

Chylomicron

154

Lipoprotein: Delivers hepatic TGs to peripheral tissue

VLDL

155

Lipoprotein: Secreted by liver

VLDL

156

Lipoprotein: Formed in the degradation of VLDL. Delivers TGs and cholesterol to liver.

IDL

157

Lipoprotein: Formed by hepatic lipase modification of IDL in the peripheral tissue. Taken up by target cells via receptor-mediated endocytosis.

LDL

158

Lipoprotein: Mediates reverse cholesterol transport

HDL

159

Lipoprotein: Acts as a repository for apolipoproteins C and E (which are needed for chylomicron and VLDL metabolism).

HDL

160

Lipoprotein: Secreted from both liver and intestine.

HDL

161

Type I dyslpidemia

Hyperchylomicronemia

162

Type IIa dyslipidemia

Familial hypercholesterolemia

163

Type IV dyslipidemia

Hypertriglyceridemia

164

Familial dyslipidemia: Lipoprotein lipase deficiency or altered apolipoprotein C-II.

Type I

165

Familial dyslipidemia: Absent or defective LDL receptors.

Type IIa

166

Familial dyslipidemia: Causes accelerated atherosclerosis (may have MI before age 20), tendon (Achilles) xanthomas, and corneal arcus

Type IIa

167

Familial dyslipidemia: Hepatic overproduction of VLDL.

Type IV

168

T/F In hyperchylomicronemia, there is an increased risk for atherosclerosis

F

169

Triglyceride level in hypertriglyceridemia that can cause acute pancreatitis

> 1000 mg/dL

170

Elevated in the blood: Hyperchylomicronemia

Chylomicrons, TG, cholesterol

171

Elevated in the blood: Familial hypercholesterolemia

LDL, cholesterol

172

Elevated in the blood: Hypertriglyceridemia

VLDL, TG

173

Hydroxylation of proline and lysine takes place in the

RER

174

Collagen has what amino acid in every 3rd position

Proline