Vol. I - Biochem Flashcards
1
Q
name the pyrimidines
A
Cytosine, uracil, thymine
2
Q
Vitamin E deficiency
A
hemolytic anemia, acanthocytosis, weakness, posterior column demyelination (like B12)
3
Q
B12 deficiency labs
A
high homocysteine AND high MMA levels
4
Q
p53 –> Rb hypophosphorylation (activation) blocks
A
G1 to S transition
5
Q
Deficiency in homologous recombination is found in:
A
BRCA1 mutation and Fanconi anemia
6
Q
PKA is activated by
A
glucagon –> cAMP (in a fasting state)
7
Q
Vitamin A (retinoic acid et al) deficiency
A
Night blindness, dryness, corneal degeneration, immunosupression
8
Q
Lysosomal acid alpha 1,4 glucosidase (aka acid maltase) deficiency
A
Pompe disease
9
Q
Homocystinuria presentation
A
HOMOCYstiene: high Homocysteine, Osteoporosis, Marfanoid habitus, Occular changes (down and in), Cardiovascular effects, kYphosis
10
Q
Angelman syndrome mechanism
A
Paternal genes are silenced, disease occurs when maternal allele is lost
11
Q
Rate limiting enzyme of de novo pyrimidine synthesis
A
Carbamoyl phosphate synthetase II
12
Q
Function of 1,25 D3
A
increased intestinal absorption of Ca and PO4
increased bone mineralization (low levels)
increased bone resorption (high levels)
13
Q
Most common lysosomal storage disease
A
Gaucher disease
14
Q
Metachromatic leukodystrophy presentation
A
Central and peripheral demyelination –> ataxia and dementia
15
Q
glycine is a precursor for
A
porphyrin –> heme
16
Q
Rate limiting enzyme of fatty acid synthesis
A
Acetyl-CoA carboxylase
17
Q
vitamin K dependent clotting factors
A
II, VII, IX, X, protein C and S
18
Q
Is euchromatin expressed?
A
Yes - E is for expressed
19
Q
citrate shuttle is required for
A
Fatty acid synthesis
20
Q
VLDL apolipoproteins
A
Apo-E, C II, and B 100
21
Q
Cause of Lesch-Nyhan syndrome
A
lack of HGPRT
22
Q
Rate limiting enzyme of cholesterol synthesis
A
HMG-CoA reductase
23
Q
Pyruvate dehydrogenase complex deficiency
A
x linked
pyruvate is shunted to lactate, high serum alanine
treat with ketogenic diet
24
Q
Pathophysiology of Glucose-6-phosphate dehydrogenase deficiency
A
Reduced NADPH production –> not enough NADPH to reduce glutathione in RBCs –> vulnerable to oxidative damage (fava beans, sulfa drugs, nitrogen drugs) –> hemolytic anemia
25
Vitamin D deficiency
rickets in children, osteomalacia in adults
26
Purely glucogenic amino acids
Methionine, histidine, valine
27
Classic galactosemia is caused by
deficiency of galactose-1-phosphate uridyltransferase
28
Presentation of Lesch Nyhan syndrome
HGPRT: Hyperuricemia, Gout, Pissed off, Red/orange crystals in urine, Tense muscles
29
Fasting hypoglycemia, increased glycogen in liver, increased lactate, triglyceride, uric acid, hepatomegally
Von Gierke disease
30
Drugs that block pyrimidine synthesis:
Leflunomide and 5-FU/Capecitabine
31
Refsum disease defect
AR disorder of alpha-oxidation --> buildup of phytanic acid
32
Apo-C II function
lipoprotein lipase cofactor
33
hexokinase is found in
most tissues, not liver or beta cells
34
adrenoleukodistrophy defect
beta-oxidation (mutation in ABCD1)
35
Drugs the block all nucleotide synthesis:
Hydroxyurea, methotrexate, trimethoprim, pyrimethamine
36
Actinomycin D mechanism of action
inhibits RNA pol
37
Cause of beriberi
B1 deficiency
38
Pathogenesis of I-cell disease
defective enzyme in golgi --> can't phosphorylate mannose --> low mannose-6-P --> enzymes are secreted instead of trafficked to lysosome --> build up of debris in lysosomes
39
Rate limiting enzyme of TCA cycle
isocitrate dehydrogenase
40
Vitamin B9
folate
41
RNA pol III makes
tRNA
42
Antimycin A target
ETC complex III
43
Digoxin mechanism
blocking Na-K-ATPase --> decreased Na/Ca exchange --> increased intracellular Ca --> increased contractility
44
Lack of tyrosinase causes
albinism
45
Gowers sign
Use of upper extremities to help stand up (common in muscular dystrophies)
46
Rate limiting enzyme of urea cycle
Carbamoyl phosphate synthetase I
47
Rett syndrome
MECP2 mutations, only seen in females, "regression"
48
Menkes disease pathophysiology
Impaired copper absorption due to defective ATP7A --> defective collagen cross-linking --> brittle hair, dev delay, increased risk of aneurysms
49
Mutation in Li-Fraumeni syndrome
p53
50
Rate limiting enzyme of glycolysis
PFK-1
51
Krabbe disease presentation
peripheral neuropathy, destruction of oligodendrocytes, developmental delay, optic atrophy, globoid cells
52
Collagen hydroxylation requires
Vitamin C
53
Urea cycle
Ordinarily Careless Crappers Are Also Frivolous About Urination
Ornithine + Carbamoyl Phosphate --> Citruline + Aspartate --> Arginosuccinate --> Funarate and Arginine --> Urea and Ornithine
54
Tryptophan is a precursor for
serotonin and niacin
55
RNA pol II makes
mRNA
56
Symptoms of Pellagra
3Ds: diarrhea, dementia, and dermatitis
57
Tay-Sachs presentation
Cherry red spot on macula, NO hepatosplenomegally, progressive neurodegeneration
58
Becker's muscular dystrophy
less severe than Duchenne, cause by a non-frameshift deletion --> partially functional
59
skeletal muscle glycogen phosphorylase deficiency
McArdle disease
60
Cori Cycle
Glucose from liver to muscle
| Lactate from muscle to liver
61
Tay-Sachs disease
Hexoamidase A loss --> GM2 ganglioside accumulation
62
Zellweger syndrome presentation
hypotonia, seizures, hepatomegaly, early death
63
Rate limiting enzyme of ketogensis
HMG-CoA synthase
64
Signal recognition particle
traffics proteins to rough ER
65
LDL apolipoproteins
Apo-B 100
66
Presentation of I-cell disease
coarse facial features, gingival hyperplasia, corneal clouding, restricted hand movements, claw hand, kyphoscoliosis
often fatal in childhood
67
Vitamin B7
biotine
68
Duchenne Muscular Dystrophy presentation
progressive weakness beginning in pelvic girdle, calf pseudohypertrophy, waddling gait
69
Drugs that target ETC complex IV
Azide, cyanide, CO
70
Debranching enzyme deficency
Cori disease
71
Is heterochromatin expressed?
No - HC is for highly condensed
72
Test for lactase deficiency
low pH in stool and H+ on breath
73
Edward syndrome cause
trisomy 18
74
Effects of PTH
increased 1,25 D3 production
increased Ca reabsorption in kidney
decreased PO4 reabsorption in kidney
75
Vitamin B5
Pantothenic acid --> CoA
76
Folate deficiency labs
high homocysteine, normal MMA levels
77
Defined Lyonization
Spontaneous X inactivation by methylation
78
Cri-du chat syndrome cause
chromosome 5 short arm deletion
79
PKU findings
intellectual disability, microcephaly, seizures, hypopigmented skin, eczema, musty body odor
80
Down syndrome findings
Intellectual disability, flat facies, single palmar crease, duodenal atresia, Hirschsprung disease, congenital heart disease, early onset alzheimers
81
Glycogen storage diseases in order I-V:
Vice Presidents Can't Accept Money: Von Gierke, Pompe, Cori, Andersen, McArdle
82
Cystinuria pathophysiology
PCT and intestinal deffect preventing reabsorption of COLA: cystine, ornithine, lysine, and arginine
83
phenylalanine and tyrosine are precursors for
catecholamines
84
Niemann-Pick disease presentation
progressive neurodegeneration, hepatosplenomegally, cherry red spot on macular, foam cells
85
Rate limiting enzyme of de novo purine synthesis
glutamine-PRPP amidotransferase
86
Refsum disease treatment
diet
87
sorbitol can accumulate in
Lens, Retina, Kidney, Schwann cells ( all lack sorbitol dehydrogenase)
88
deficient enzyme in Bloom Syndrome
DNA helicase (BLM gene)
89
F-1,6-BP regulation
activates PFK 1
produced in fed state by PFK 2
converted back to F6P by FBPase2 in fasting state
90
fragile X presentation (>200 repeats)
macroorchidism, long face, large jaw and ears, autism, mitral valve prolapse, hypermobile joints
91
Fragile X-syndrome cause
trinucleotide CGC repeat expansion in FMR1 --> decreased expression
92
tRNA structure
ACC attachment site at 3'
T arm Tethers to ribosome
Anticodon loop
D arm binds synthetase for charging
93
Niemann-Pick disease
sphingomyelinase loss
94
Relationship b/w Vitamin C and Fe
C reduces iron to 2+ state --> aids absorption and is ancillary treatment for methemoglobinemia
95
Prader-Willi presentation
Hyperphagia, obesity, intellectual disability, hypogonadism, hypotonia
96
Apo-A I function
activates LCAT, is found only on HDL
97
Friedreich ataxia cause
AR trinucleotide expansion of GAA
98
Hunters see clearly and aim for the X
Hunters syndrome has no corneal clouding and is X linked
99
RNA pol I makes
rRNA
100
Excess vitamin A (chronic)
alopecia, dry skin, liver toxicity, increased ICP
101
alpha1-antitrypsin deficiency pathophysiology
decreased alpha1-AT --> unopposed elastase activity --> breakdown of elastic structures --> COPD
102
Pyruvate dehydrogenase complex is activated by
High NAD/NADH, high ADP, high Ca
103
Vitamin B6
pyridoxine
104
Purely ketogenic amino acids
Leucine, lysine
105
Prader-Willi syndrome mechanism
Maternal genes are silenced, disease when paternal copy is lost
106
Cahill Cycle
Alanine from muscle to liver
| Glucose from liver to muscle
107
Glucose-6-phosphate deficiency
Von Gierke disease
108
Defective in Alport syndrome
Collagen type IV --> BM
109
Branching enzyme deficiency
Andersen disease
110
B12 deficiency causes
megaloblastic anemia and subacute combined degeneration (all 3 spinal tracts)
111
Chylomicron apolipoproteins
Apo-E, C II, and B 48
112
Essential amino acids
PVT TIM HaLL: phenylalanine, valine, tryptophan, threonine, isoleucine, methionine, histidine, leucine, lysine
113
Patau syndrome cause
trisomy 13
114
Osteogenesis Imperfecta presentation
BITE: Bones, I(eye - blue sclera), teeth, ear
115
Hurler and Hunter syndrome
Mucopolysaccharidoses
116
Kartegener syndrome findings
situs inversus, hearing loss, recurrent infections, infertility
decreased nasal NO is used to screen
117
Edward syndrome finidngs
PRINCE: Prominent occiput, rocker-bottom feet, Intellectual disability, non-disjunction, ears are low set
death by age 1
118
Muscular dystrophy inheritance
X-linked
119
most common urea cycle disorder
Ornithine transcarbamylase deficiency
120
Cause of Wernicke-Korsakoff syndrome
B1 deficiency --> glucose infusion --> damage to medial dorsal nucleus of thalamus and mamillary bodies
121
Oligomycin target
ETC complex V
122
B2 (riboflavin) deficiency
Chielosis, "magenta" tongue, corneal vascularization
123
Treatment of acute promyelocytic leukemia
all-trans retinoic acid
124
Williams syndrome cause
microdeletion on chromosome 7 --> "elfin" facies
125
Fabry disease presentation
triad of episodic peripheral neuropathy, angiokeratomas, and hypohidrosis
126
Name the purines
Adenine and guanine
127
Myotonic dystrophy pathophysiology
CTG repeat expansion in DMPK gene --> onset 20-30 years --> CTG: cataracts, toupees, gonadal atrophy
128
Rate limiting enzyme of glycogenolysis
glycogen phosphorylase
129
Vitamin B1 (thiamine) deficiency
impaired glucose breakdown --> glucose infusion worsens ATP depletion
130
Cardiomyopathy, hypotonia, exercise intolerance
Pompe disease - Pompe trashes the pump
131
Vitamin B3
niacin --> NAD+
132
Colchicine use
karyotyping - arrests cells in metaphase
133
glucokinase is found in
liver, beta cells
134
Kinesin transport direction
anterograde
135
Gaucher disease
Glucocerebrosidase loss
136
Hartnup Disease
AR deficiency of neutral AA transport --> decreased niacin production --> Pellagra like symptoms
137
Apo-E function
mediates remnant uptake
138
Fabry disease
alpha-galactosidase loss --> ceramide trihexoside accumulation
139
Location of glucose-6-phosphotase
smooth ER
140
Apo-B 100
originates in liver, binds LDL receptor
141
Kartegener syndrome defect
AR dynein arm defect --> immotile cilia
142
Nissl bodies
rough ER in neurons
143
Defective in Xeroderma Pigmentostum
Nucleotide Excision Repair
144
Deficiency in Ataxia-Telangiectasia
Non-homologous end joining
145
Vitamin B2
Riboflavin --> FAD
146
Which amino acids are necessary for purine synthesis?
GAG - glycine, aspartate, and glutamine
147
Dynein transport direction
retrograde
148
Glugenic and ketogenic amino acids
Isoleucine, phenylalanine, tryptophan, threonine
149
Ehlers-Danlos syndrome mechanism
faulty collagen synthesis
150
Vitamin B12
cobalamin
151
Apo-B 48
originates in intestines, mediates chylomicron secretion
152
Cardiac glycoside (digoxin) target
Na-K-ATPase
153
Marasmus
Malnutrition not causing edema
154
Osteogenesis Imperfecta defect
Collagen glycosylation (usually AD)
155
G6PD deficiency clinical features
x linked, bite cells and heinz bodies
156
HDL apoliproteins
Apo-E, A I, C II
157
Drugs that block purine synthesis:
G-MP, mycophenylate, and ribavirin
158
B6 (pyroxidine) deficiency
convulsions, hyper-irritability, peripheral neuropathy, sideroblastic anemia
159
When does nucleotide excision repair occur
G1
160
Aspiring overdose
disrupts mithocondrial membrane --> no electron transport
161
Hyperammonemia presentation
flapping tremor, slurring speech, vomiting, cerebral edema, blurred vision
162
substances that metabolize to propionyl-CoA
VOMIT: valine, odd chain fatty acids, methionine, isoleucine, threonine
163
Cause of Maple Syrup Urine disease
blocked degradation of Isoleucine, leucine, and valine (B1 loss) --> increased alpha-keto acids in blood.
164
Vitamin B1
thiamine
165
Ornithine transcarbamylase deficiency presentation
increased orotic acid, symtpoms of hyperammonemia
166
Rate limiting enzyme of gluconeogenesis
F-1,6-BP1
167
Andersen disease presentation
hepatosplenomegaly and failure to thrive
168
Rate limiting enzyme of HMP shunt
G6PD
169
Gaucher disease presentation
hepatosplenomegally, pancytopenia, osteoporosis, avascular necrosis of femur head, Gaucher cells
170
Krabbe disease
Glacatocerebrosidase loss
171
Angelman syndrome presenation
SAIL: seizures, ataxia, Intellectual disability, (inappropriate) laughter
172
Zellweger syndrome defect
AR disorder of peroxisomes
173
Fragile X presentation (<200 repeats)
tremor, ataxia, primary ovarian insufficency
174
Hyperammonemia treatment
- Lactulose to acidify GI and trap NH4
- Abx if bacterial cause
- Benzoate, phenylacetate or phenylbutyrate to increase glycine and glutamine excretion
175
Increased glycogen in muscle that can't be broken down causing painful cramps and myoglobinuria (red urine)
McArdle disease
176
Excess vitamin A (acute)
nausea, vomiting, increased ICP
177
Metachromatic leukodystrophy
Arylsulfatase A loss --> cerebroside sulfate accumulation
178
Rate limiting enzyme of glycogenesis
glycogen synthase
179
three ketone bodies
acetone, acetoacetate, beta-hydroxybutyrate
180
Rate limiting enzyme of fatty acid oxidation
Carnitine acyl transferase
181
Ragged red muscle fibers
mitochondrial myopathy
182
Kwashiorkor presentation
MEALS: malnutrition, edema, anemia, liver is fatty, skin lesions
183
Weird cause of B7 (biotin) deficiency
excessive consumption of egg white
184
Cori disease presentation
like Von Gierke, but mild and normal blood lactate. Gluconeogenesis is intact.
185
PKU is caused by
lack of phenylalanine hydroxylase
186
McCune-Albright syndrome defect
G_s-protein activating mutation, lethal unless mosaic
187
Marfan defect
Fibrillin 1
188
Down syndrome cause
trisomy 21
189
alkaptonuria is caused by
lack of homogentisate oxidase
190
Na-K-ATPase function
2 K in, 3 Na out
191
Alkaptonuria findings
pigment forming homogentisic acid builds up in tissues --> blue-black CT, ears, sclera; urine oxidizes black
192
McCune-Albright syndrome presentation
unilateral cafe-au-lait spots with ragged edges, bone is replaced by collagen and fibroblasts, endocrinopathy
193
Hereditary fructose intolerance is caused by
deficiency of Aldolase B
194
Drugs that inhibit ETC complex I
Rotenone, metformin
195
Defective in Lynch Syndrome (HNPCC)
Mismatch repair
196
Hardy-Weinberg equation
p^2 + 2pq + q^2 = 1
