Biochem :( Flashcards
(130 cards)
1
Q
Elevated plasma porphyrins and photosensitivity
A
Deficiency in uroporphyrinogen decarboxylase
Photosensitivity means it is a late step problem
2
Q
C-Jun
N-myc
A
Transcription factors that bind DNA
3
Q
Northern Blot
A
RNA
uses ssDNA or ssRNA to probe
Used to assess gene expression
4
Q
Southern blot
A
DNA
Paternity test
5
Q
Western blot
A
Protein
Ab probe
6
Q
Soutwestern blot
A
DNA-binding protein
Double stranded DNA probe
Transcription factors
7
Q
Tumor Lysis syndrome
A
During chemo
Prevention: hydration and hypouricemic agents (allopurinol)
8
Q
Heterochromatin
A
Methyl chromatin and non-acetylated histones
Condensed and transcriptionally inactive
9
Q
Common reducing sugar in urine
A
Deficient fruktoinase
10
Q
MAP kinase
A
GTP
11
Q
Lynch syndrome
A
- NT mismatch repair defect
2. colon adenomatous polyps
12
Q
Orotic acid in urine
A
Deficient ornithine transcarbamoylase
tx: uridine (inhibits CPS synthase II to prevent hyperammonia)
13
Q
Deficiency in Dihydrobiopterin reductase
A
Atypical PKU
decreased levels of dopamine
Increased levels prolactin
Sx do not improved with restricted phenylalanine
14
Q
Maple sugar odor in child
A
Alpha ketoacid dehydrogenase defect
Cannot break down branched chain amino acids (leucine, isoleucine, valine)
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
16
Q
Alpha helix/beta sheets
A
Mediated via secondary structure (H bonds)
17
Q
Hypoglycemia with fasting and low ketones
A
Impaired beta oxidation
commonly acetyl coA dehydrogenase def (catalyzes first step in beta oxidation)
18
Q
Green bruise
A
Heme oxygenase turns heme into biliveriden
19
Q
Primase
A
DNA dependent RNA polymerase that incorporates mall RNA primers into replicating DNA
Often with uracil
20
Q
How much leptin is produced by adipocytes?
A
proportional to quantity of fat stored
21
Q
Ketogenic AA
A
- Lysine
- Leucine
Would increase lactate in pts suffering from PDH deficiency
22
Q
High levels arginine
A
Arginase deficiency (urea cycle)
23
Q
Def of sphingomyelinase
A
Neimann pick disase
- AR
- mental retardation, splenomegaly, cherry red spot on macula
- foam cells in bone marrow
- death by 3
Sphingomyelin accumulates
24
Q
Tay Sachs
A
Beta hexosaminidase def
GM2 accumulation
cherry red spot
ashkenazi jews
25
Dietary fructose
1. fastest metabolized
2. phosphorylated in liver to F-1-P
3. rapidly metabolized because it bypasses PFK-1 (rate limiting step of glycoysis)
26
Rate limiting step of glycolysis
PFK-1
27
Streptomycin
inhibits the initiation of protein synthesis by binding to and distorting 30s ribosomal subunit of prokaryotes
28
Collagen production
hydroxylation of proline and lysin in RER (vit C cofactor)
29
Procollagen
glycosylation of pro alpha chain lysine residues (in RER)
triple helix with 3 alpha chains
30
Tropocollagen
c terminal pro peptide removal
31
collagen fibrils
cross linking bycovalent lysine-hydroxyl lysine cross links by lysyl oxidase (requires copper)
32
Immediate source of nitrogen for urea
aspartate
33
G6PDH deficiency
Similar to deficiency in glutathione reductase
Increase RBC oxidation damage leading to hemolytic anemia
34
Precursor to NAD+ coenzyme
tryptophan
35
Niacin def
Pellagra
dermatitis, dementia, diarrhea
36
Gene Enhancers are located
variable location
37
Promoters are located
25-7 bases upstream
38
TATA box
promoter
bings TF and RNA pol II during initiation
39
Poly AAA
3' tail NOT transcribed by DNA template
40
HOMEOBOX gene
code for proteins such as transcription regulators
41
DNA pol I
5'-3' exonuclease can remove RNA primer
5'-3' polymerase
3'-5' exonuclease
42
Lupus antibodies
Splicesomal snRNPs
43
Aminoglycosides
bind 30s subunit and inhibit formation of initiation complex and mixread RNA
44
Chloramphenicol
binds 50s
inhibits peptidyl transferase
45
Macrolides
bind 50s
prevent release of uncharge RNA
46
Tetracyclines
binds 30s
blocks aminoactyl tRNA attachment at A site
47
Stop codon is recognized by
releasing factor
48
Mischarged tRNA
reads correct codon but inserts wrong AA
49
Fetal Hb
2alpha 2gamma
poor interaction with 2,3-BPG
Binds oxygen with higher affinity
50
Galactosemia
1. galactose 1-phosphage uridyl transferased deficiency
| 2. galactose kinase deficiency
51
galactose-1-phosphate uridyl transferase
1. vomit
2. mental retardation
3. lethargy
4. failure to thrive
5. cataracts
AR
die within first few months of life
52
Galactose kinase deficiency
1. mild galactosemia
2. cataracts early in life (aldose reductase)
3. mild form of galactosemia (does not cause death)
53
Thiamine cofactor
1. transketolase
2. AKGDH
3. PDH
Alcoholics impair these
54
Wernicke encephalopathy
1. confusion, ophthalmoplegia, ataxia, persistent memory loss
2. horizontal nystagmus and b/l abducens weakness
dg: erythrocyte transketolase activity
55
Von Gierke
Glucose 6 phophatase deficiency
```
hypoglycermia
lactic acidosis
hyperlipidemia
hyperuricemia
hepatomegaly (steatosis)
```
56
McArdle disease
glycogen phosphorylase deficiency in muscles
exercise tolerance, muscle pain, cramping
myoglobinuria
blood lactate low after exercise
excess glycogen in muscles
57
pyruvate kinase deficiency
hemolytic anemia
58
Pantothenic acid
needed for conversion of oxaloacetate to citrate
bioactive form: coenzyme A (binds oxaloacetate in first step of CAC to form citrate)
59
CO
car exhaust
competitively binds heme with 200X affinity of oxygen
60
Nitrite poisoning
heme to ferric state (oxidized)
PpO2 will not changee
tx of cyanide poisoning
61
Fructose 2,6-bisphosphanate
activates glycolysis by inducing PFK-1 and inhibits gluconeogenesis by inhibiting F1,6BP
62
Rate limiting step of glycolysis
1. Hexokinase
2. phosphofructokinase
3. pyruvate kinase
63
SnRNP
Spliceosomes
remove introns
64
Lesch Nyhan
HGPRT def
Normal converts hypoxanthine to IMP
Increased XO activity
65
Lead inactivates
Aminolevulinate dehydrogenase
Accumulates
G ALA
protoporphyrin IX
66
Pentose phosphate shunt occurs in the
cytosol (transketolase)
67
Vitamin K
Carboxylation of glutamic residuces
68
Riboflavin
succinate dehydrogenase
69
Biotin
Carrier of CO2
needed for pyruvate oxaloacetate
Ingest avidin (egg whites) -> deficiency
70
B 12 def
Increased levels of methylmalonic acid
71
Sun burn
pyrimidine dimers and endonuclease initiates the repair process nicking the strand with thymine dimer
72
Amatoxins
wild mushrooms
potent inhibitors of RNA pol II (halt mRNA synthesis)
73
12-18 hours of fasting
gluconeogenesis principle source of blood glucose
oxalo-> pep
74
Gouty arthritis pain associated with
Neutrophils
colchicine inhibits chemotaxis by preventing microtubule fromation
75
gestational diabetes
decreased activity of glucokinase
76
Aging/wrinkles
collagen fibril production decreases
77
Xeroderma pigmentosum
UV specific endonuclease deficiency
AR
78
ACTH made in the
SER
79
Alcoholics
Increase NADH:NAD and inhibits gluconeogenesis
80
Alkaprotonuria
def in homogetisic acid oxidase (breakdown of tyrosin)
Pigment deposits in CT and black urine
Cannot convert tyrosine to fumarate
81
Homocystinuria
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
Peroxisomes
breakdown long chain and odd chain fatty acids
83
Energy in erythrocytes
bisphosphoglyerate to 2,3-BPG
84
JaK 2 mut
chronic myeloproliferative disorders (poly vera, thrombocytosis, mylofibrosis)
Constitutive tyrosine kinase activity
85
Vitamin A overdose
headache, vomiting, eccentric dietary habits, papilledema, dry skin, hepatomegaly
86
Aldolase B deficiency
1. fructose intolerance
2. vomit and hypoglycermia with fruit introduction
3. failure to thrive, jaundice, hepatomegaly
87
RNA facts
rRNA most ____
tRNA ____
mRNA ____
rRNA is most abundant
tRNA is smallest
mRNA is longest
88
RNA pol I
rRNA
89
RNA pol II
mRNA
90
RNA pol III
tRNA
91
Nucleotide excision repair mutation
Xeroderma pigmentosum
cannot repair UV TT dimers
92
Base excision repair
demaination
93
Mismatch repair defect
HNPCC
94
NHEJ defct
Ataxia telangiectasia
95
elastin plasticity
unique form of desmosine crosslinking between 4 different lysine residues
via extracellular lysyl hydroxylase
Interchain crosslinks with lysine
96
Carnitine deficiency
cannot transport fat across mitochondrial membrane to create acetyl-CoA a precursor for acetoacetate
97
Individual beta hemoglobin
act like myoglobin shape curve
98
Orotic adicuria
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
Ehler's danlos
mut in collagen
Lysyl hydroxylase or procollagen peptidase
100
tRNA
1. dihydrouracil
2. CCA at 3'
3. 5' phosphate
101
Ab in RA
Citrullinated protein
102
HMP shunt oxidation rxn
necessary for anabolic reactions that use NADPH as a donor like cholesterol and fatty acid synthesis
103
Telomerase
RT adds TTAGGG repeats to 3' end of DNA
found in epidermal BASAL
104
Amino charges
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
Nuclear receptors
thyroid hormone
steroid hormones
Glucocorticoids
minteraocorticoids
106
Shine delgarno
16s rRNA complementary sequence to mRNa
107
Lac operon
glucose -> low cAMP
stop fermenting lactose
108
Lead poisoning
PB binds sulhydril groups and lowers Hb
109
Proteins targeted for lysosomes
mannose-6 phosphate
110
DNA pol 1 deficiency
many short fragments of DNa with RNA sequence at 5' end
111
Thymine
marker for rate of DNa synthesis
112
Biopterin
coenzyme for phenylalanine hydroxylase
def -> increased phenylalanine in blood
113
Von Gierke
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
Succinyl CoA
precursor to Heme in reticulocytes
115
Heme synthesis
first step catalyzed by aminolevulinate synthase
Needs vit B6 pyridoxine)
116
Homocysteine methyl transferase
requires vB12 and folate
def: megaloblastic anemia and neuropathy
117
Edwards syndrome
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
Turner syndrome
45 XO
1. short, ovarian dysgenesis, webbed neck, hypogonadism
2. lymphedema
3. cystic hygroma
119
Patau syndrome
Trisomy 13
1. mental retardation, NS issues, umbilical hernia, polydactyly, clef lip-palate
120
Propionic aciduria
1. biotin def (cofactor of propionyl CoA Carboxyase)
| 2. Val, isoleucine, methionine
121
Galactoremia
1. def of galactose 1-phosphate uridytyltransferae (death in infancy)
2. Def of galactokinase (benign disease except for cataract formation)
122
Gaucher
def of beta glucocerebrosidasse
AR
splenomegaly, neuro deficits, mental retardation
123
Tay Sachs
Hexosamine A Deficiency
GM2 accumulation in gangliosides
Blind, muscular weakness, cherry spot on macula
Death by 3
124
PKU
phenylalanine hydroxylase def
musty/mousy odor
mental retardation
fair skin
cannot produce tyrosine
125
Homocystinuria
Cystathione synthase def
failure to thrive, vision problems
Can also be cause by: def in methionine synthase, def in pyridoxine, folate, b12
126
Vit K in infants
Coenzyme for gamma glutamyl carboxylase (II, VII, IX, X)
makes prothrombin in hepatocytes
without it: GI bleed, intracranial hemorrhage, prolonged PT and PTT
127
VB12 def
co factor in conversion of methylmalonyl coA to succinyl CoA
Meth-MCoA accumulation in urine
128
Cystinuria
AR
Defect in transport protein for lysine
Arg, cysteine, ornithine in urine
129
Vitamine A
Hyperkeratosis
high fever, confusion, skin rash
Asia, africa, south america
130
SCID
adenosine deaminase def
