Biochemistry 2/2, First Aid for the USMLE Step 1 Flashcards
1
Q
Vitamin B1
A
Thiamine
2
Q
Vitamin B2
A
Riboflavin
3
Q
Vitamin B3
A
Niacin
4
Q
Vitamin B5
A
Pantothenic acid
5
Q
Vitamin B6
A
Pyridoxine
6
Q
Vitamin B7
A
Biotin
7
Q
Vitamin B9
A
Folate
8
Q
Vitamin B12
A
Cobalamin
9
Q
Vitamin that reguates Cl- channel in nerve conduction
A
B1
10
Q
Vitamin essential for normal differentiation of epithelial cells into specialized tissue
A
Vitamin A
11
Q
Vitamin A is found in what food stuff
A
Liver and leafy vegetables
12
Q
Vitamin A prevents what cellular adaptation
A
Squamous metaplasia
13
Q
Vitamin A is used to treat what CA
A
AML M3
14
Q
Seen in conjunctiva of patients with Vitamin A deficiency
A
Bitot spots
15
Q
T/F Vitamin A is teratogenic
A
T
16
Q
Drug which is a vitamin A derivative that is contraindicated in pregnancy
A
Isotretinoin
17
Q
Deficient in beriberi
A
B1
18
Q
Deficient in Wernicke-Korsakoff syndrome
A
B1
19
Q
Classic triad of Wernicke Korsakoff syndrome
A
1) Confusion 2) Ophthalmoplegia 3) Ataxia
20
Q
Dry vs wet beriberi: Polyneuritis, symmetrical muscle wasting
A
Dry beriberi
21
Q
Dry vs wet beriberi: High-output cardiac failure (dilated cardiomyopathy), edema
A
Wet beriberi
22
Q
Vitamin component of FAD and FMN, used as cofactors in redox reactions
A
B2
23
Q
ATP per B2
A
2
24
Q
2 Cs of B2
A
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
