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Flashcards in Biochem Deck (151)
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1
Q

histone methylation / acetylation

A

methylation - inactivates transcription

acetylation - relaxes coiling allowing for transcription

2
Q

orotic aciduria

A

cant convert orotic acid into UMP (pyrimidine synth) due to defect in UMP synthase. AR inheritance

orotic acid in urine, megaloblastic anemia, failure to thrive

tx w/ oral uridine

3
Q

adenosine deaminase def

A

excess ATP / dATP > feedback inhibition > dec DNA synth > dec lymphocyte count
Major cause of SCID **
AR inheritance

4
Q

Lesch-Nyhan syndrome

A

absence of HGPRT (purine salvage) > excess uric acid production and de novo purine synth
x linked recessive

retardation, self mutilation, aggression, hyperuricemia, gout, choreoathetosis

5
Q

direction of DNA synth, RNA synth, mRNA reading, protein synth

A

DNA synth: 5’ > 3’
RNA synth: 5’ > 3’
mRNA reading: 5’ > 3’
protein synth: N > C terminus

6
Q

start codon

A

AUG

7
Q

ribosomal subunits for eukaryotes and prokaryotes

A

eu: 40S + 60S > 80S (even)
pro: 30S + 50S > 70S (odd)

8
Q

abx that block protein synth by binding to ribosomal subunits

A

aminoglycosides - 30s
tetracyclines - 30s
chloramphenicol - 50s
macrolides - 50s

9
Q

p53 and hypophosphorlyated Rb usually do what in cell cycle?

A

inhibit G1 to S progression

10
Q

mannose 6 phosphate is signal for transport to

A

lysosome

11
Q

inclusion cell disease

A

inherited lysosomal storage disorder, failure to add mannose 6 phosphate to lysosomal proteins
coarse facial features, cloudy corneas, restricted joint mvmt, high plasma levels of lysosomal enzymes. often fatal in childhood

12
Q

what kind of transport are COPI, COPII and clathrin used in, respectively?

A

COPI - retrograde
COPII - anterograde
clathrin - golgi > lysosome and PM > endosome

13
Q

Chediak Higashi syndrome

A

mutation in LYST (lysosomal trafficking regulator gene) > can’t do MT assisted sorting of endosomal proteins into late endosomes

recurrent pyogenic infections + partial albinism + peripheral neuropathy

14
Q

Kartagener’s syndrome

A

immotile cilia due to dynein arm defect

male infertility, female dec fertility, bronchiectasis, recurrent sinusitis, assoc w/ situs inversus

15
Q

defect in type I collagen is what disease?

A

osteogenesis imperfecta

16
Q

defect in type IV collagen is what disease?

A

alport syndrome

17
Q

scurvy happens b/c vitamin C is needed for what process?

A

synth of collagen (hydroxylation of proline and lysine)

18
Q

Ehlers Danlos is due to a defect in what step of collagen synthesis?

A

cross linking (extracellular)

19
Q

osteogenesis imperfecta

A

abnormal type I collagen (usually AD)

multiple fractures w/ minimal trauma, blue sclera, hearing loss, dental imperfections

20
Q

alport syndrome

A

abnormal type 4 collagen (XLR)

progressive nephritis and hearing loss, ocular disturbances

21
Q

alpha 1 antitrypsin

A

blocks elastase from breaking down elastin

deficiency can result in emphysema

22
Q

Southwestern blot

A

identifies DNA binding proteins

23
Q

imprinting

A

differences in gene expression depend on whether mutation is of maternal or paternal origin
ex - prader-willi and angelman’s syndromes

24
Q

dominant negative mutation

A

heterozygote produces nonfunctional protein that also prevents normal gene product from functioning

25
Q

heteroplasmy

A

presence of both normal and mutated mtDNA resulting in variable expression in mitochondrial inherited disease

26
Q

Hardy Weinberg eqn

A

p^2 + 2pq + q^2 = 1

27
Q

in Prader-Willi and Angelman’s syndromes, which parent’s allele is not expressed, respectively?

A

Prader Willi - paternal not expressed

Angelman’s - maternal not expressed

28
Q

example of x linked dominant disease

A

Hypophosphatemic rickets

29
Q

hypophosphatemic rickets

A

x linked dominant disorder

inc phosphate wasting in proximal tubule > rickets like presentation that does not respond to vit D

30
Q

“ragged red fibers” on muscle biopsy

A

mitochondrial myopathy usually

31
Q

achondroplasia mutated protein

A

FGF receptor 3

32
Q

familial adenomatous polyposis mutated gene

A

APC gene

33
Q

Osler Weber Rendu syndrome is also known as

A

hereditary hemorrhagic telangiectasia

34
Q

NT changes in huntington’s

A

dec GABA and ACh in brain

35
Q

marfan’s syndrome mutated gene

A

fibrillin-1

36
Q

von Recklinhausen’s dz aka…

A

NF type 1

37
Q

Lisch nodules

A

pigmented iris hamartomas seen in NF type 1

38
Q

NF type 2 findings

A

bilateral acoustic schwannomas, juvenile cataracts

39
Q

Tuberous sclerosis findings and inheritance type

A
AD (incomplete penetrance)
facial lesions (adenoma sebaceum), ash leaf spots on skin, cortical and retinal hamartomas, seizures, mental retardation, renal cysts and angiomyolipomas, cardiac rhabdomyomas, astrocytomas
40
Q

von hippel lindau findings

A

hemangioblastomas of retina/cerebellum/medulla, mult bilat renal cell carcinomas, other tumors

41
Q

CF gene mutated

A

CFTR

42
Q

mutated gene in duchenne’s and becker’s

A

dystrophin

43
Q

Gower’s maneuver assoc w/

A

Duchenne’s muscular dystrophy

44
Q

lab test to dx muscular dystrophies

A

inc CPK

45
Q

fragile x mutated gene

A

FMR1 gene

46
Q

top 2 MCC genetic mental retardation

A

Down syndrome

Fragile X

47
Q

genetic disorder assoc w/ macroorchidism

A

fragile x

48
Q

4 trinucleotide repeat disease

A

huntington’s - CAG
myotonic dystrophy - CTG
friedreich’s ataxia - GAA
fragile x syndrome - CGG

49
Q

congenital heart dz in Down syndrome

A

ostium primum ASD

50
Q

pregnancy screening for Down syndrome

A

dec alpha fetoprotein, inc beta HCG, dec estriol, inc inhibin A
ultrasound - inc nuchal translucency in 1st TM

51
Q

Edward’s syndrome - genetic cause

A

trisomy 18

52
Q

Edward’s syndrome findings

A

mental retardation, rocker bottom feet, micrognathia, low set ears, clenched hands, prominent occiput, congenital heart dz
death within first year of life usually

53
Q

pregnancy screening for Edward’s syndrome

A

dec alpha fetoprotein, dec beta HCG, dec estriol, nl inhibin A

54
Q

Patau’s syndrome - genetic cause

A

trisomy 13

55
Q

Patau’s syndrome findings

A

severe mental retardation, rocker bottom feet, microphthalmia, microcephaly, cleft palate/lip, holoprosencephaly, polydactyly, congenital heart dz
death w/in first year of life usually

56
Q

pregnancy screening for Patau’s syndrome

A

dec beta HCG, dec PAPP-A, inc nuchal translucency

57
Q

Cri du chat syndrome genetic cause

A

microdeletion of short arm of chromosome 5

58
Q

Cri du chat syndrome findings

A

microcephaly, mental retardation, high pitched crying/mewing, epicanthal folds, ventricular septal defect

59
Q

Williams syndrome genetic cause

A

microdeletion of long arm of chromosome 7

60
Q

Williams syndrome findings

A

elfin facies, intellectual disability, hypercalcemia, good verbal skills, friendly w/ strangers, CV problems

61
Q

2 22q11 deletion syndromes

A

Digeorge syndrome and velocardiofacial syndrome

62
Q

22q11 deletion syndrome findings

A

cleft palate, abnl facies, thymic aplasia, cardiac defects, hypocalcema 2/2 PTH aplasia

63
Q

vit A def

A

night blindness and dry skin

64
Q

vit A excess

A

arthralgia, fatigue, HA, skin changes, sore throat, alopecia, teratogenic

65
Q

3 syndromes assoc w/ B1 def

A

Wernicke-Korsakoff
wet beriberi
dry beriberi

66
Q

vit B1 is needed for…

A

breakdown of glucose / production of ATP

67
Q

classic triad of Wernicke-Korsakoff syndrome

A

confusion, ophthalmoplegia, ataxia

68
Q

dry beriberi

A

b1 def

polyneuritis, symmetrical muscle wasting

69
Q

wet beriberi

A

high output cardiac failure, edema

70
Q

vit b2 function

A

oxidation and reduction

71
Q

vit B2 def

A

cheilitis and corneal vascularization

72
Q

vit B3 is a constituent of what important metab molecule?

A

NAD (NAD derived from Niacin)

73
Q

vit b3 def

A

pellagra: 3 D’s of B3

diarrhea, dermatitis, dementia

74
Q

vit B5 is component of what metab molecule?

A

CoA

75
Q

vit b5 def

A

dermatitis, enteritis, alopecia, adrenal insufficiency

76
Q

fn of vit b6

A

transamination and decarboxylation rxns

synth of heme, histamine, NTs

77
Q

vit b6 def

A

peripheral neuropathy and siderblastic anemia

78
Q

vit b9 is aka

A

folate!!

79
Q

folate is vit…

A

b9

80
Q

folate fn

A

synth of nitrogenous bases for DNA and RNA

81
Q

folate def

A

macrocytic, megaloblastic anemia, neural tube defects in first TM

82
Q

most common vit def in US

A

b9 (folate)

83
Q

vit b12 def

A

macrocytic megaloblastic anemia, hypersegmented PMNs, neuro sx - paresthesia, subacute combined systems degeneration

84
Q

s-adenosyl-methionine (SAM) is required for

A

converting NE to epi by donating methyl group

85
Q

fns of vit C

A

antioxidant
keeps Fe in reduced state for absorption
hydroxylation of proline and lysine in collagen synth
cofactor for conversion of DA to NE

86
Q

fn of vit D

A

inc intestinal abs of Ca and PO4, inc bone mineralization

87
Q

vit D deficiency

A

Rickets in kids, osteomalacia in adults

hypocalcemic tetany

88
Q

vit E function

A

antioxidant that protects Erythrocytes

89
Q

zinc def

A

delayed wound healing, hypogonadism, dec adult hair, dysgeusia, anosmia

90
Q

limiting reagent in alcohol metabolism

A

NAD+

91
Q

fomepizole

A

inhib alcohol dehydrogenase to protect from methanol or ethylene glycol poisoning

92
Q

kwashiorkor

A

protein malnutrition > skin lesions, edema, fatty change in liver

93
Q

marasmus

A

energy malnutrition > muscle wasting, loss of subq fat, variable edema

94
Q

3 metab processes that occur in both cytoplasm and mitochondria

A

heme synth
urea cycle
gluconeogenesis

95
Q

biotin (b7) is needed for

A

carboxylase enzymes to work

96
Q

net ATP from aerobic vs anaerobic metab of glucose

A

aerobic - 32

anaerobic - 2

97
Q

NADPH is product of

A

HMP shunt

98
Q

NADPH used in (4)

A

anabolic processes
respiratory burst
P450
glutathione reductase

99
Q

hexokinase vs glucokinase

A

both start glycolysis (or glycogen synth in liver)

hexo - in most tissues, high affinity, low capacity, no change w/ insulin

gluco - in liver and beta cells of pancreas, low affinity, high capacity, induced by insulin

100
Q

rate limiting enzyme of glycolysis

A

phosphofructokinase 1

101
Q

2 enzyme/steps that req ATP and 2 that produce in glycolysis

A

require atp: hexokinase/glucokinase, phosphofructokinase 1

produce: phosphoglycerate kinase, pyruvate kinase

102
Q

fasting and fed state regulation of glucose handling by F2,6BP

A

fasting: inc glucagon > inc cAMP > inc PKA > inc FBPase2, dec PFK2, dec glycolysis
fed: inc insulin > dec cAMP > dec PKA > dec FBPase2, inc PFK2, more glycolysis

103
Q

2 purely ketogenic AAs

A

lysine and leucine

104
Q

pyruvate dehydrogenase complex deficiency - most common inheritance pattern, main sx, tx

A

x linked
neuro deficits
inc intake of ketogenic nutrients

105
Q

4 different metab paths that pyruvate can take

A

to alanine via ALT
to oxaloacetate to replenish TCA cycle
to acetyl CoA to enter TCA cycle
to lactate to finish anaerobic glycolysis

106
Q

which makes more ATP - 1 NADH or 1 FADH2?

A

NADH (3 vs 2)

107
Q

rotenone, CN, antimycin A, and CO have what effect (all same) on metabolism?

A

electron transport inhibitors

108
Q

ATP synthase inhibitor

A

oligomycin

109
Q

why can’t muscle do gluconeogenesis?

A

lacks glucose 6 phosphatase

110
Q

3 products of HMP shunt

A

NADPH, ribose, glycolytic intermediates

111
Q

where is the HMP shunt used?

A

lactating mammary glands, liver, adrenal cortex, RBCs

112
Q

chronic granulomatous dz has a deficiency of what enzyme?

A

NADPH oxidase - needed to initiate respiratory burst

113
Q

G6PD def pathophys

A

less G6PD > less NADPH > less protection from oxidation, esp in RBCs > hemolyitc anemia when exposed to oxidizing agents (fava beans, etc) or infections

114
Q

G6PD def inheritanced

A

XLR

115
Q

2 PBS findings in G6PD def

A
Heinz bodies (oxidized Hgb)
Bite cells (phagocytosed Heinz bodies in spleen leave "bite" in cell)
116
Q

essential fructosuria

A

defect in fructokinase, AR, asymptomatic, fructose in blood and urine

117
Q

fructose intolerance

A

def in aldolase B, AR
accum of fructose 1 phosphate > dec available PO4 > inhib glycogenolysis/gluconeogenesis
sx - hypoglycemia, jaundice, cirrhosis, vomiting
tx - dec intake of fructose and sucrose

118
Q

galactokinase def

A

mild, AR

galactose in blood/urine. infantile cataracts. may not track objects or develop social smile

119
Q

classic galactosemia

A

no galactose-1-phosphate uridyltransferase > accum of toxic substances
failure to thrive, jaundice, hepatomegaly, infantile cataracts, mental retardation
tx - dont eat galactose/lactose

120
Q

cells at risk for sorbitol accumulation

A

schwann cells, retina, kidney

121
Q

essential AAs

A

Met Val His
Ile Phe Thre Trp
Leu Lys

122
Q

Cori cycle

A

muscle uses glucose and makes lactate, shuttle to liver, where it is turned back into glucose and reenters bloodstream

123
Q

hyperammonemia

A

can be congenital or acquired. excess NH4 > inhib TCA cycle

124
Q

signs of ammonia intox

A

asterixis, slurring, somnolence, vomiting, cerebral edema, blurry vision

125
Q

ornithine transcarbamoylase deficiency

A

MC urea cycle disorder - XLR
can’t eliminate ammonia properly, buildup of orotic acid
inc orotic acid, dec BUN, hyperammonemia sx

126
Q

catecholamine synth pathway

A

phenylalanine > tyrosine > dihydroxyphenylalanine (dopa) > dopamine > norepinephrine > epinephrine

127
Q

dietary reqs of PKU

A

tyrosine becomes essential, strict phenylalanine restriction

128
Q

sx of PKU

A

mental and growth retardation, seizures, fair skin, eczema, musty body odor

129
Q

deficiency in PKU

A

phenylalanine hydroxylase or tetrahydrobiopterin cofactor

130
Q

alkaptonuria

A
def in degradative pathway of tyrosine
AR, benign
dark connective tissue, brown sclera, urine turns black on prolonged exposure to air, debilatating arthralgias
131
Q

3 causes of albinism

A

tyrosinase def
defective tyrosine transporters
lack of migration of neural crest cells

132
Q

nutritition req in homocystinuria

A

cysteine becomes essential

133
Q

3 forms of homocystinuria etiology

A
def cystathionine synthase
dec affinity of cystathionine synthase
homocysteine methyltransferase def
134
Q

sx of homocystinuria

A

mental retardation, osteoporosis, tall stature, kyphosis, lens subluxation, atherosclerosis

135
Q

cystinuria

A

defect in one of the AA transporters in PCT of kidney
> precipitation of hexagonal crystals and renal staghorn calculi
AR
tx w/ good hydration and urinary alkalinization`

136
Q

maple syrup urine dz

A

AR
blocked degradation of branched AAs due to dec alpha ketoacid dehydrogenase > inc alpha ketoacids in blood
CNS defects, mental retardation, death
urine smells like maple syrup

137
Q

hartnup dz

A

AR
defective neutral AA transporter in kidney and intestines
tryptophan excretion in urine and dec absorption in gut > pellagra

138
Q

intracellular messenger that glucagon/epi increases

A

cAMP

139
Q

4 glycogen storage diseases

A

Von Gierke’s (type 1)
Pompe’s (type 2)
Cori’s (type 3)
McArdle’s (type 4)

140
Q

general sx of lysosomal storage disorders

A

peripheral neuropathy / demyelination, neurodegeneration, hepatosplenomegaly, cherry red spot in macula

141
Q

Fabry’s, Gaucher’s, Niemann-Pick, Tay-Sachs, Krabbe’s, Metachromatic leukodystrophy are examples of what kind of disorder?

A

lysosomal storage disease - sphingolipidoses

142
Q

Hurler’s and Hunter’s diseases are what kind of disorders?

A

lysosomal storage disease - mucopolysaccharidoses

143
Q

where does fatty acid degradation take place?

A

mitochondrion

144
Q

carnitine deficiency

A

inability to transport LCFAs into mito > toxic accumulation

weakness, hypotonia, hypoketotic hypoglycemia

145
Q

which ketone is not detected by urine dipstick?

A

beta hydroxybutyrate

146
Q

rate limiting step of cholesterol synth

A

HMG CoA reductase

147
Q
which way do these lipid particles go (liver > periphery or vice versa)?
VLDL
IDL
LDL
HDL
A

VLDL - TGs to peripheral tissue
IDL - TGs and cholesterol to liver
LDL - cholesterol to tissues
HDL - cholesterol to liver

148
Q

familial dyslipidemias - type 1 hyperchylomicronemia

A

AR

pancreatitis, xanthomas, NO INC RISK FOR ATHEROSCLEROSIS

149
Q

familial dyslipidemias - type 2a familial hypercholesterolemia

A

AD, absent or dec LDL receptor

accelerated atherosclerosis

150
Q

familial dyslipidemias - type 4 hypertriglyceridemia

A

AD, hepatic overproduction of VLDL

pancreatitis

151
Q

abetalipoproteinemia

A

AR
mutation in microsomal TG transfer protein (MTP) gene
dec chylomicron and VLDL synth > lipid accumulation in enterocytes
failure to thrive, steatorrhea, acanthocytosis, ataxia, night blindness