Biochem :( Flashcards

1
Q

Elevated plasma porphyrins and photosensitivity

A

Deficiency in uroporphyrinogen decarboxylase

Photosensitivity means it is a late step problem

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2
Q

C-Jun

N-myc

A

Transcription factors that bind DNA

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3
Q

Northern Blot

A

RNA

uses ssDNA or ssRNA to probe

Used to assess gene expression

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4
Q

Southern blot

A

DNA

Paternity test

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5
Q

Western blot

A

Protein

Ab probe

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6
Q

Soutwestern blot

A

DNA-binding protein

Double stranded DNA probe

Transcription factors

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7
Q

Tumor Lysis syndrome

A

During chemo

Prevention: hydration and hypouricemic agents (allopurinol)

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8
Q

Heterochromatin

A

Methyl chromatin and non-acetylated histones

Condensed and transcriptionally inactive

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9
Q

Common reducing sugar in urine

A

Deficient fruktoinase

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10
Q

MAP kinase

A

GTP

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11
Q

Lynch syndrome

A
  1. NT mismatch repair defect

2. colon adenomatous polyps

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12
Q

Orotic acid in urine

A

Deficient ornithine transcarbamoylase

tx: uridine (inhibits CPS synthase II to prevent hyperammonia)

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13
Q

Deficiency in Dihydrobiopterin reductase

A

Atypical PKU

decreased levels of dopamine
Increased levels prolactin
Sx do not improved with restricted phenylalanine

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14
Q

Maple sugar odor in child

A

Alpha ketoacid dehydrogenase defect

Cannot break down branched chain amino acids (leucine, isoleucine, valine)

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15
Q

Glucose 6 phosphate dehydrogenase def (G6PD def)

A

X linked

hemolytic anemia during oxidative stress

common in africal and mediterranean

fava beans can induce hemolytic anemia

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16
Q

Alpha helix/beta sheets

A

Mediated via secondary structure (H bonds)

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17
Q

Hypoglycemia with fasting and low ketones

A

Impaired beta oxidation

commonly acetyl coA dehydrogenase def (catalyzes first step in beta oxidation)

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18
Q

Green bruise

A

Heme oxygenase turns heme into biliveriden

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19
Q

Primase

A

DNA dependent RNA polymerase that incorporates mall RNA primers into replicating DNA

Often with uracil

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20
Q

How much leptin is produced by adipocytes?

A

proportional to quantity of fat stored

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21
Q

Ketogenic AA

A
  1. Lysine
  2. Leucine

Would increase lactate in pts suffering from PDH deficiency

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22
Q

High levels arginine

A

Arginase deficiency (urea cycle)

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23
Q

Def of sphingomyelinase

A

Neimann pick disase

  1. AR
  2. mental retardation, splenomegaly, cherry red spot on macula
  3. foam cells in bone marrow
  4. death by 3

Sphingomyelin accumulates

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24
Q

Tay Sachs

A

Beta hexosaminidase def

GM2 accumulation

cherry red spot
ashkenazi jews

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25
Q

Dietary fructose

A
  1. fastest metabolized
  2. phosphorylated in liver to F-1-P
  3. rapidly metabolized because it bypasses PFK-1 (rate limiting step of glycoysis)
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26
Q

Rate limiting step of glycolysis

A

PFK-1

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27
Q

Streptomycin

A

inhibits the initiation of protein synthesis by binding to and distorting 30s ribosomal subunit of prokaryotes

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28
Q

Collagen production

A

hydroxylation of proline and lysin in RER (vit C cofactor)

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29
Q

Procollagen

A

glycosylation of pro alpha chain lysine residues (in RER)

triple helix with 3 alpha chains

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30
Q

Tropocollagen

A

c terminal pro peptide removal

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31
Q

collagen fibrils

A

cross linking bycovalent lysine-hydroxyl lysine cross links by lysyl oxidase (requires copper)

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32
Q

Immediate source of nitrogen for urea

A

aspartate

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33
Q

G6PDH deficiency

A

Similar to deficiency in glutathione reductase

Increase RBC oxidation damage leading to hemolytic anemia

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34
Q

Precursor to NAD+ coenzyme

A

tryptophan

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35
Q

Niacin def

A

Pellagra

dermatitis, dementia, diarrhea

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36
Q

Gene Enhancers are located

A

variable location

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37
Q

Promoters are located

A

25-7 bases upstream

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38
Q

TATA box

A

promoter

bings TF and RNA pol II during initiation

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39
Q

Poly AAA

A

3’ tail NOT transcribed by DNA template

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40
Q

HOMEOBOX gene

A

code for proteins such as transcription regulators

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41
Q

DNA pol I

A

5’-3’ exonuclease can remove RNA primer

5’-3’ polymerase

3’-5’ exonuclease

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42
Q

Lupus antibodies

A

Splicesomal snRNPs

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43
Q

Aminoglycosides

A

bind 30s subunit and inhibit formation of initiation complex and mixread RNA

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44
Q

Chloramphenicol

A

binds 50s

inhibits peptidyl transferase

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45
Q

Macrolides

A

bind 50s

prevent release of uncharge RNA

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46
Q

Tetracyclines

A

binds 30s

blocks aminoactyl tRNA attachment at A site

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47
Q

Stop codon is recognized by

A

releasing factor

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48
Q

Mischarged tRNA

A

reads correct codon but inserts wrong AA

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49
Q

Fetal Hb

A

2alpha 2gamma

poor interaction with 2,3-BPG

Binds oxygen with higher affinity

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50
Q

Galactosemia

A
  1. galactose 1-phosphage uridyl transferased deficiency

2. galactose kinase deficiency

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51
Q

galactose-1-phosphate uridyl transferase

A
  1. vomit
  2. mental retardation
  3. lethargy
  4. failure to thrive
  5. cataracts

AR
die within first few months of life

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52
Q

Galactose kinase deficiency

A
  1. mild galactosemia
  2. cataracts early in life (aldose reductase)
  3. mild form of galactosemia (does not cause death)
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53
Q

Thiamine cofactor

A
  1. transketolase
  2. AKGDH
  3. PDH

Alcoholics impair these

54
Q

Wernicke encephalopathy

A
  1. confusion, ophthalmoplegia, ataxia, persistent memory loss
  2. horizontal nystagmus and b/l abducens weakness
    dg: erythrocyte transketolase activity
55
Q

Von Gierke

A

Glucose 6 phophatase deficiency

hypoglycermia
lactic acidosis
hyperlipidemia 
hyperuricemia 
hepatomegaly (steatosis)
56
Q

McArdle disease

A

glycogen phosphorylase deficiency in muscles

exercise tolerance, muscle pain, cramping
myoglobinuria
blood lactate low after exercise

excess glycogen in muscles

57
Q

pyruvate kinase deficiency

A

hemolytic anemia

58
Q

Pantothenic acid

A

needed for conversion of oxaloacetate to citrate

bioactive form: coenzyme A (binds oxaloacetate in first step of CAC to form citrate)

59
Q

CO

A

car exhaust

competitively binds heme with 200X affinity of oxygen

60
Q

Nitrite poisoning

A

heme to ferric state (oxidized)

PpO2 will not changee

tx of cyanide poisoning

61
Q

Fructose 2,6-bisphosphanate

A

activates glycolysis by inducing PFK-1 and inhibits gluconeogenesis by inhibiting F1,6BP

62
Q

Rate limiting step of glycolysis

A
  1. Hexokinase
  2. phosphofructokinase
  3. pyruvate kinase
63
Q

SnRNP

A

Spliceosomes

remove introns

64
Q

Lesch Nyhan

A

HGPRT def

Normal converts hypoxanthine to IMP

Increased XO activity

65
Q

Lead inactivates

A

Aminolevulinate dehydrogenase

Accumulates
G ALA
protoporphyrin IX

66
Q

Pentose phosphate shunt occurs in the

A

cytosol (transketolase)

67
Q

Vitamin K

A

Carboxylation of glutamic residuces

68
Q

Riboflavin

A

succinate dehydrogenase

69
Q

Biotin

A

Carrier of CO2

needed for pyruvate oxaloacetate

Ingest avidin (egg whites) -> deficiency

70
Q

B 12 def

A

Increased levels of methylmalonic acid

71
Q

Sun burn

A

pyrimidine dimers and endonuclease initiates the repair process nicking the strand with thymine dimer

72
Q

Amatoxins

A

wild mushrooms

potent inhibitors of RNA pol II (halt mRNA synthesis)

73
Q

12-18 hours of fasting

A

gluconeogenesis principle source of blood glucose

oxalo-> pep

74
Q

Gouty arthritis pain associated with

A

Neutrophils

colchicine inhibits chemotaxis by preventing microtubule fromation

75
Q

gestational diabetes

A

decreased activity of glucokinase

76
Q

Aging/wrinkles

A

collagen fibril production decreases

77
Q

Xeroderma pigmentosum

A

UV specific endonuclease deficiency

AR

78
Q

ACTH made in the

A

SER

79
Q

Alcoholics

A

Increase NADH:NAD and inhibits gluconeogenesis

80
Q

Alkaprotonuria

A

def in homogetisic acid oxidase (breakdown of tyrosin)

Pigment deposits in CT and black urine

Cannot convert tyrosine to fumarate

81
Q

Homocystinuria

A
  1. cystathione synthase deficiency
  2. vitamin b6 def
  3. vit b12 def

Excess homocysteine
Cysteine becomes essential

Lense sublexation, atherosclerosis, fine hair, marfanoid habitus

82
Q

Peroxisomes

A

breakdown long chain and odd chain fatty acids

83
Q

Energy in erythrocytes

A

bisphosphoglyerate to 2,3-BPG

84
Q

JaK 2 mut

A

chronic myeloproliferative disorders (poly vera, thrombocytosis, mylofibrosis)

Constitutive tyrosine kinase activity

85
Q

Vitamin A overdose

A

headache, vomiting, eccentric dietary habits, papilledema, dry skin, hepatomegaly

86
Q

Aldolase B deficiency

A
  1. fructose intolerance
  2. vomit and hypoglycermia with fruit introduction
  3. failure to thrive, jaundice, hepatomegaly
87
Q

RNA facts
rRNA most ____
tRNA ____
mRNA ____

A

rRNA is most abundant
tRNA is smallest
mRNA is longest

88
Q

RNA pol I

A

rRNA

89
Q

RNA pol II

A

mRNA

90
Q

RNA pol III

A

tRNA

91
Q

Nucleotide excision repair mutation

A

Xeroderma pigmentosum

cannot repair UV TT dimers

92
Q

Base excision repair

A

demaination

93
Q

Mismatch repair defect

A

HNPCC

94
Q

NHEJ defct

A

Ataxia telangiectasia

95
Q

elastin plasticity

A

unique form of desmosine crosslinking between 4 different lysine residues

via extracellular lysyl hydroxylase

Interchain crosslinks with lysine

96
Q

Carnitine deficiency

A

cannot transport fat across mitochondrial membrane to create acetyl-CoA a precursor for acetoacetate

97
Q

Individual beta hemoglobin

A

act like myoglobin shape curve

98
Q

Orotic adicuria

A
  1. Increased orotic acid (cannot convert to UMP)
  2. defect in UMP synthase
  3. No hyperammonia (only in OTCarboxylase deficiency)
  4. impaired de novo pyrimidine synthesis
  5. Hypochromic megaloblastic anemia
  6. neurologic abnormalities, and growth retardation
  7. tx: uridine supplementation improves symptoms by inhibitin carbamoyl phosphate synthetase II
99
Q

Ehler’s danlos

A

mut in collagen

Lysyl hydroxylase or procollagen peptidase

100
Q

tRNA

A
  1. dihydrouracil
  2. CCA at 3’
  3. 5’ phosphate
101
Q

Ab in RA

A

Citrullinated protein

102
Q

HMP shunt oxidation rxn

A

necessary for anabolic reactions that use NADPH as a donor like cholesterol and fatty acid synthesis

103
Q

Telomerase

A

RT adds TTAGGG repeats to 3’ end of DNA

found in epidermal BASAL

104
Q

Amino charges

A
  1. alanine give amino group to AKG to form glutamate
  2. Glutamate give amino group to oxaloacetate to form aspartate
  3. thymidine helps folic acid deprived RBC undering megaloblastic anemia
105
Q

Nuclear receptors

A

thyroid hormone
steroid hormones
Glucocorticoids
minteraocorticoids

106
Q

Shine delgarno

A

16s rRNA complementary sequence to mRNa

107
Q

Lac operon

A

glucose -> low cAMP

stop fermenting lactose

108
Q

Lead poisoning

A

PB binds sulhydril groups and lowers Hb

109
Q

Proteins targeted for lysosomes

A

mannose-6 phosphate

110
Q

DNA pol 1 deficiency

A

many short fragments of DNa with RNA sequence at 5’ end

111
Q

Thymine

A

marker for rate of DNa synthesis

112
Q

Biopterin

A

coenzyme for phenylalanine hydroxylase

def -> increased phenylalanine in blood

113
Q

Von Gierke

A

Glucose 6 phosphate deficiency

Most common glycogen storage disease
Prevents release of glucose from glycogen

G6p trapped in liver and degraded to lactate and pyruvate

114
Q

Succinyl CoA

A

precursor to Heme in reticulocytes

115
Q

Heme synthesis

A

first step catalyzed by aminolevulinate synthase

Needs vit B6 pyridoxine)

116
Q

Homocysteine methyl transferase

A

requires vB12 and folate

def: megaloblastic anemia and neuropathy

117
Q

Edwards syndrome

A

Trisomy 19

  1. rocker bottom feet
  2. low set ears
  3. micrognathia
  4. VSD
  5. mental retardation
  6. clenched hand with overriding middle finger and 5th finger over 4th
118
Q

Turner syndrome

A

45 XO
1. short, ovarian dysgenesis, webbed neck, hypogonadism

  1. lymphedema
  2. cystic hygroma
119
Q

Patau syndrome

A

Trisomy 13

  1. mental retardation, NS issues, umbilical hernia, polydactyly, clef lip-palate
120
Q

Propionic aciduria

A
  1. biotin def (cofactor of propionyl CoA Carboxyase)

2. Val, isoleucine, methionine

121
Q

Galactoremia

A
  1. def of galactose 1-phosphate uridytyltransferae (death in infancy)
  2. Def of galactokinase (benign disease except for cataract formation)
122
Q

Gaucher

A

def of beta glucocerebrosidasse

AR

splenomegaly, neuro deficits, mental retardation

123
Q

Tay Sachs

A

Hexosamine A Deficiency
GM2 accumulation in gangliosides

Blind, muscular weakness, cherry spot on macula

Death by 3

124
Q

PKU

A

phenylalanine hydroxylase def

musty/mousy odor
mental retardation
fair skin
cannot produce tyrosine

125
Q

Homocystinuria

A

Cystathione synthase def

failure to thrive, vision problems

Can also be cause by: def in methionine synthase, def in pyridoxine, folate, b12

126
Q

Vit K in infants

A

Coenzyme for gamma glutamyl carboxylase (II, VII, IX, X)

makes prothrombin in hepatocytes

without it: GI bleed, intracranial hemorrhage, prolonged PT and PTT

127
Q

VB12 def

A

co factor in conversion of methylmalonyl coA to succinyl CoA

Meth-MCoA accumulation in urine

128
Q

Cystinuria

A

AR

Defect in transport protein for lysine

Arg, cysteine, ornithine in urine

129
Q

Vitamine A

A

Hyperkeratosis
high fever, confusion, skin rash

Asia, africa, south america

130
Q

SCID

A

adenosine deaminase def