biochem usmle rx Flashcards
(110 cards)
1
Q
deficiency of iduronate sulfate … accumulation of heparan sulfate
A
Hunter syndrome … XLR
2
Q
DD hunter vs hurler synd
A
Hunter NO corneal clouding
Hurler YES corneal clouding
3
Q
what happens to the potein in alpha 1 antutrypsin def
A
misfolded protein
4
Q
centriacinar emphysema
A
smoking
5
Q
paraacinar emphysema
A
alpha1 antitrypsin def
6
Q
lead poisoning (enzyme)
A
aminolavilunic acid dehydratase
7
Q
lead poisoning symptoms
A
stomach ache, vomitting, constitpation, loss of development milestones
8
Q
type 1 glycogen storage disease
A
glucose 6 phosphatase , final step of gluconeogensis
9
Q
MSUD deficiency of ….
A
alpha ketoacid dehydrogenase (B1)
10
Q
def of cystathione cynthase
A
homocystinuria …. thrombosis, marfan habitus, intellect disab
11
Q
increased Km means
A
lower affinity …. affected by competitive inhibitors
12
Q
vascular type ehlers danlos
most common cause of death
A
type 3 collagen
rupture of berry anneurysm
13
Q
aortic anneurysm
A
marfan synd (fibrillin 1) ch 15
14
Q
what step in gluconeogensis requires acetyl coA
A
pyruvate carboxylase —– this yields oxaloacetate
15
Q
which enzyme undergoes feedback inhibition by glucose 6 phosphate and which enzyme doesnt have feedback inhibition
A
hexokinase
glukokinase
16
Q
where is glucokinase found
A
liver and B pancreatic cells
17
Q
pyruvate kinase
A
converts phosphoenylpyruvate into pyruvate
18
Q
mechanism of fibrates
A
activate PPAR which increases lipoprotein TG lysis via lipoprotein lipase
19
Q
niacin mechanism
A
inhibits lipolysis via hormone sensitive lipase…. this reduces transp of free fatty acids to liver hence LOW TG
20
Q
lactic acid production under anaerobic conditions takes place in which part of the cell
A
cytoplasm
pyruvate converted into lactic acid by lactate dehydrogenase
21
Q
detox drugs and steroid synthesis takes place in
A
smooth endoplasmic reticulum
22
Q
21 hydroxylase def
A
hypotension, virilization, electrolyte abn
23
Q
retinoblastoma mechanism
A
point mutation inactivates RB tumor suppressor gene
24
Q
Rb on chrmosome 13 can develop into
A
osteosarcoma
25
VHL
angiomatosis of retina, renal malignancy
26
what symptms arise in a molar pregnancy
hyperthyroidism due to high level of BHCG
| triad of hyperemesis, hyperthyroidism and vaginal bleeding
27
PCR is used to amplify region of interest this could be usd to detect what disease
Cystic fibrosis
28
what is the cause of pellagra
tryptophan deficiency
| tryptophan is used to make niacin
29
intellectual disability and hypopigmentation
PKU
30
coarse facial features, agg behaviour, pearly skin lesions
hunter )iduronate sulfatase
31
mcArdle disease
def of myophosphorylase
32
def of phosphoglycerate kinase
similar to mcARDLE BUT ALSO HAVE hemolytic anemia and CNS dysf
33
acid alpha glucosidase def
pompe disease
34
Very Poor Carb Metabolism
```
von gierke ( glucose 6 phosphatase) impaired gluconeogenesis
Pompe ( acid alpha glucosidase)
Cori ( debranching ezyme) intact gluconeog... no lactate
```
35
Becker MD mode of transmission
XLR non frameshift
36
b3 def maybe seen in
hartnup and carcinoid
37
triad of eczema, pyogenic inf and thrombocytopenic purpura
wiskot aldrich ... elevated igA and igE BUT LOW igM
38
CATCH 22
cardiac abn, abn facies, thymic aplasia, cleft palat, hypoclacemia
39
What is involved in movement of vesicles down axons
Microtubules... made from tubulin
40
Dyenin
| Kinesin
Dyenin towards center minus end
| Kinesis away from center positive end
41
movement from golgi to lysosome
Clarithin
42
Ltb4 is a
Neutrophil Chemotactic agent
43
CVID
maturation defect of B lymphocytes, poor response to immunization
44
chediak higashi is a disorder of?
phagocyte function ... cannot empty lysosomes
45
what happens in carbomyl phosphatase synthase 1 def
build up of ammonia
46
def of adenosine deaminase
SCID -- inhibits purine salvage pathway
47
def of ATM kinase
ataxia telangectasia , susceptible to XRAY damage ---- later leukemia and lymphoma
48
MSH2 MLH 1 DNA mismatch repair
lynch syndrome
49
porphobilinogen demaniase
acute intermittent porphyria..... abd pain, red urine, neuropathy
50
which blotting technique is reflective of gene expression
northern blot --- RNA
51
6 month inf hypoglycemia, seizures, hepatomegaly
von gierkes glucose 6 phosphatase
52
galactose 1 phosphateUDT has smthn specific
infantile cataracts
53
pt has parasthesia, confusion, ataxia, convulsions wat drug is she taking ?
isoniazid b6 def
54
bruton agammaglobulinemia has a mutation in
tyrosine kinase
55
thromboxane A2 role in DVT
causes platelet agg and vasoconstriction
56
which 3 processes take place in mitochondria
FA oxidation, acetyl coa production and krebs cycle
57
BRCA1 BRCA2 tumor suppressive or oncogene
tumor suppressive
58
MYC gene
oncogene
59
MEN2A
medullary thyroid carcinoma, pheo, parathyroid
60
wasting of lysine, arginine, cysteine and ornithine
amino acid reabsp disorder, risk of kidney stones
61
pt has a depigmented nevus, angiofibroma, epilepsy,cardiac rhabdomyoma in childhood and MRI shows multiple glial nodules
skin findings also include ash green spot and shagreen patch
Tuberous sclerosis, ch 9,16
62
VHL most common finding
hemangioblastoma in retina brain and spinal cord
63
alpha amanitin
inhibits rna pol 2 .... wch mkes mrna
64
mechanism of fluoroquinolones
DNA gyrase (toposioneras2)
65
irinotectan/topotectan
topoisomeras 1
66
etoposide tenoposide
topoisomerase 2
67
discoloration of teeth , injuries from minor trauma
osteogenesis imperfecta , lead to hearing loss
68
how to treat choreiform movements in VHL
tetrabenazine (VMAT inhibotr) to reduce dopamine levels
69
protein malnutrition is ...
kawashiorkor
70
marasmus
muscle wasting, anemia, growth retardation
71
GLUT 4 is insulin dependent or independent
DEPENDENT
72
malignant prolif of neuroectodermal cells is seen in
Ewings sarcoma
73
NF 1 clinical mannifestation
skin changes, scoliosis, iris hamartomas (lisch nodules), risk of early bone fracture
74
mutation of CD40 L
hyper igM syndrome ---- prevent isotype class switching
75
candida infection or pneumocystis jorveci , rash baby boy ... decreased B and T cell count
SCID
76
incorrect protein splicing seen in
B thalassemia
77
truncate protein seen in
duchenne muscular dystrophy
78
high foot arch, gait instability in a child whose uncle had similar condition
GAA ... freidrich ataxia
79
pt has svt.. after treatment complains of weight loss and feeling hot ... what drug is this?
amiodarone, potassium blockers... prolong phase 3 ..... SE include- hyperthyroidism, pulm fibrosis, neurological effects, constipation
80
what confirms immunity against hepatitis B
antibody against surface
81
5 yr old boy has orange granules in diaper and bites his nails and lips
lesch nyhan ..... problem HGPRT of the purine salvage pathway .... this puts strain on denove purine synthesis and uses up all folate and b12 ----- HYPERSEGMENTED neutrophils can be seen on smear
82
wch antibiotic forms free radical toxic metabolites that damage cell wall
metronidazole rmmber its disulfram reaction with alcohol consmp
83
inhibit DNA dependent RNA polymerase
rifampin
84
inability to repair thymidine dimers leads to
xeroderma pigmentosa
85
17 alpha hydroxylase def
hypokalemia .... this enzyme is used to make corticosteroids in zona fasiculata and androgens in zona reticularis
86
folate deficiency describe what happens to homocysteine and methymalonic acid
homo is high but methyl is not
87
def of lysosomal alpha 1,4 glucosidase
pompe
88
fructose intolerance presents with hypoglycemia or hyperglycemia and why
hypo ... aldolase b def .... fructose 1 phosphate accumulates means low levels of phosphate hence loe gluconeogenesis and glycogenolysis
89
homeless man ... got into a fight... bleeding gums recently ... but aptt and bleeding time all normal
vitamin c deficiency .... problem with hydroxylation of proline residues ... no proper collagen
90
painless bump on penis
think syphilis
91
anticardiolipin antibodies
detected in syphilis, phopholipid found in the inner mitochondrial membrane ....
92
diagnose diabetes typ1
glucose>200, ph<7.4, bicarb, 15
93
histology of the organ involved in diabetes typ1
lymphocytes can be seen (T cell mediated)
94
histology of type 2 diabetes
amyloidosis
95
GLUT 2 expressed on?
liver cells (bidirectional) , pancreatic b cells and renal tubular cells
96
glitazones mechanism and SE
increase insulin senstivity ... bind to PPAR gamma nuclear transcription regulator .....
weight gain edema and risk of fractures
SAFE IN RENAL IMPAIRMENT
97
Meglitinides ( repaglinide) normally combined with metformin
different site from sulfanylureas but same effect --> increase post prandial insulin
SE.. hypoglycemia specially in renal imp
98
GLP analog ( Exenatide)
inc glucose dependent insulin releae, dec glucagon, inc statiety and dec gastric emptying
SE ---- rmmber pancreatitis
99
DDP4 inhibitors (LIPTINS)
ddp4 breaks down GLP normally --- they block this enzyme
| SE ---- urinary and resp infection
100
pt given nitroprusside ... can lead to what toxicity?
cyanide
101
symp of cyanide toxicity
headache, cherry red lips, seizures and vomiting
102
txt of cyanide tox
poisoning inhibits mitochondrial cytochrome oxidase which is last enzyme in ETC
103
arsenic toxicity due to inhibition of
lipoic acid (neede in PDH complex)
104
kid intellectual disability, spasticity, painful joints
HGPRT lesch nyhan ..... URIC acid causes pain in joints
105
left shif in Hb curve means?
increase in affinityh for oxygen
106
tumor suppressor gene p53 is located on wch chromosome
17
107
steroid hormones from what complex
hormone receptor complex
108
which electron carrier is used to make steroids
NADPH
109
NADPH is a prodict of
HMP shunt
110
NADPH can be used in
anabolic process
| Resp burst
