biochem usmle rx Flashcards
deficiency of iduronate sulfate … accumulation of heparan sulfate
Hunter syndrome … XLR
DD hunter vs hurler synd
Hunter NO corneal clouding
Hurler YES corneal clouding
what happens to the potein in alpha 1 antutrypsin def
misfolded protein
centriacinar emphysema
smoking
paraacinar emphysema
alpha1 antitrypsin def
lead poisoning (enzyme)
aminolavilunic acid dehydratase
lead poisoning symptoms
stomach ache, vomitting, constitpation, loss of development milestones
type 1 glycogen storage disease
glucose 6 phosphatase , final step of gluconeogensis
MSUD deficiency of ….
alpha ketoacid dehydrogenase (B1)
def of cystathione cynthase
homocystinuria …. thrombosis, marfan habitus, intellect disab
increased Km means
lower affinity …. affected by competitive inhibitors
vascular type ehlers danlos
most common cause of death
type 3 collagen
rupture of berry anneurysm
aortic anneurysm
marfan synd (fibrillin 1) ch 15
what step in gluconeogensis requires acetyl coA
pyruvate carboxylase —– this yields oxaloacetate
which enzyme undergoes feedback inhibition by glucose 6 phosphate and which enzyme doesnt have feedback inhibition
hexokinase
glukokinase
where is glucokinase found
liver and B pancreatic cells
pyruvate kinase
converts phosphoenylpyruvate into pyruvate
mechanism of fibrates
activate PPAR which increases lipoprotein TG lysis via lipoprotein lipase
niacin mechanism
inhibits lipolysis via hormone sensitive lipase…. this reduces transp of free fatty acids to liver hence LOW TG
lactic acid production under anaerobic conditions takes place in which part of the cell
cytoplasm
pyruvate converted into lactic acid by lactate dehydrogenase
detox drugs and steroid synthesis takes place in
smooth endoplasmic reticulum
21 hydroxylase def
hypotension, virilization, electrolyte abn
retinoblastoma mechanism
point mutation inactivates RB tumor suppressor gene
Rb on chrmosome 13 can develop into
osteosarcoma
VHL
angiomatosis of retina, renal malignancy
what symptms arise in a molar pregnancy
hyperthyroidism due to high level of BHCG
triad of hyperemesis, hyperthyroidism and vaginal bleeding
PCR is used to amplify region of interest this could be usd to detect what disease
Cystic fibrosis
what is the cause of pellagra
tryptophan deficiency
tryptophan is used to make niacin
intellectual disability and hypopigmentation
PKU
coarse facial features, agg behaviour, pearly skin lesions
hunter )iduronate sulfatase
mcArdle disease
def of myophosphorylase
def of phosphoglycerate kinase
similar to mcARDLE BUT ALSO HAVE hemolytic anemia and CNS dysf
acid alpha glucosidase def
pompe disease
Very Poor Carb Metabolism
von gierke ( glucose 6 phosphatase) impaired gluconeogenesis Pompe ( acid alpha glucosidase) Cori ( debranching ezyme) intact gluconeog... no lactate
Becker MD mode of transmission
XLR non frameshift
b3 def maybe seen in
hartnup and carcinoid
triad of eczema, pyogenic inf and thrombocytopenic purpura
wiskot aldrich … elevated igA and igE BUT LOW igM
CATCH 22
cardiac abn, abn facies, thymic aplasia, cleft palat, hypoclacemia
What is involved in movement of vesicles down axons
Microtubules… made from tubulin
Dyenin
Kinesin
Dyenin towards center minus end
Kinesis away from center positive end
movement from golgi to lysosome
Clarithin
Ltb4 is a
Neutrophil Chemotactic agent
CVID
maturation defect of B lymphocytes, poor response to immunization
chediak higashi is a disorder of?
phagocyte function … cannot empty lysosomes
what happens in carbomyl phosphatase synthase 1 def
build up of ammonia
def of adenosine deaminase
SCID – inhibits purine salvage pathway
def of ATM kinase
ataxia telangectasia , susceptible to XRAY damage —- later leukemia and lymphoma
MSH2 MLH 1 DNA mismatch repair
lynch syndrome
porphobilinogen demaniase
acute intermittent porphyria….. abd pain, red urine, neuropathy
which blotting technique is reflective of gene expression
northern blot — RNA
6 month inf hypoglycemia, seizures, hepatomegaly
von gierkes glucose 6 phosphatase
galactose 1 phosphateUDT has smthn specific
infantile cataracts
pt has parasthesia, confusion, ataxia, convulsions wat drug is she taking ?
isoniazid b6 def
bruton agammaglobulinemia has a mutation in
tyrosine kinase
thromboxane A2 role in DVT
causes platelet agg and vasoconstriction
which 3 processes take place in mitochondria
FA oxidation, acetyl coa production and krebs cycle
BRCA1 BRCA2 tumor suppressive or oncogene
tumor suppressive
MYC gene
oncogene
MEN2A
medullary thyroid carcinoma, pheo, parathyroid
wasting of lysine, arginine, cysteine and ornithine
amino acid reabsp disorder, risk of kidney stones
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
VHL most common finding
hemangioblastoma in retina brain and spinal cord
alpha amanitin
inhibits rna pol 2 …. wch mkes mrna
mechanism of fluoroquinolones
DNA gyrase (toposioneras2)
irinotectan/topotectan
topoisomeras 1
etoposide tenoposide
topoisomerase 2
discoloration of teeth , injuries from minor trauma
osteogenesis imperfecta , lead to hearing loss
how to treat choreiform movements in VHL
tetrabenazine (VMAT inhibotr) to reduce dopamine levels
protein malnutrition is …
kawashiorkor
marasmus
muscle wasting, anemia, growth retardation
GLUT 4 is insulin dependent or independent
DEPENDENT
malignant prolif of neuroectodermal cells is seen in
Ewings sarcoma
NF 1 clinical mannifestation
skin changes, scoliosis, iris hamartomas (lisch nodules), risk of early bone fracture
mutation of CD40 L
hyper igM syndrome —- prevent isotype class switching
candida infection or pneumocystis jorveci , rash baby boy … decreased B and T cell count
SCID
incorrect protein splicing seen in
B thalassemia
truncate protein seen in
duchenne muscular dystrophy
high foot arch, gait instability in a child whose uncle had similar condition
GAA … freidrich ataxia
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
what confirms immunity against hepatitis B
antibody against surface
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
wch antibiotic forms free radical toxic metabolites that damage cell wall
metronidazole rmmber its disulfram reaction with alcohol consmp
inhibit DNA dependent RNA polymerase
rifampin
inability to repair thymidine dimers leads to
xeroderma pigmentosa
17 alpha hydroxylase def
hypokalemia …. this enzyme is used to make corticosteroids in zona fasiculata and androgens in zona reticularis
folate deficiency describe what happens to homocysteine and methymalonic acid
homo is high but methyl is not
def of lysosomal alpha 1,4 glucosidase
pompe
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
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
painless bump on penis
think syphilis
anticardiolipin antibodies
detected in syphilis, phopholipid found in the inner mitochondrial membrane ….
diagnose diabetes typ1
glucose>200, ph<7.4, bicarb, 15
histology of the organ involved in diabetes typ1
lymphocytes can be seen (T cell mediated)
histology of type 2 diabetes
amyloidosis
GLUT 2 expressed on?
liver cells (bidirectional) , pancreatic b cells and renal tubular cells
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
Meglitinides ( repaglinide) normally combined with metformin
different site from sulfanylureas but same effect –> increase post prandial insulin
SE.. hypoglycemia specially in renal imp
GLP analog ( Exenatide)
inc glucose dependent insulin releae, dec glucagon, inc statiety and dec gastric emptying
SE —- rmmber pancreatitis
DDP4 inhibitors (LIPTINS)
ddp4 breaks down GLP normally — they block this enzyme
SE —- urinary and resp infection
pt given nitroprusside … can lead to what toxicity?
cyanide
symp of cyanide toxicity
headache, cherry red lips, seizures and vomiting
txt of cyanide tox
poisoning inhibits mitochondrial cytochrome oxidase which is last enzyme in ETC
arsenic toxicity due to inhibition of
lipoic acid (neede in PDH complex)
kid intellectual disability, spasticity, painful joints
HGPRT lesch nyhan ….. URIC acid causes pain in joints
left shif in Hb curve means?
increase in affinityh for oxygen
tumor suppressor gene p53 is located on wch chromosome
17
steroid hormones from what complex
hormone receptor complex
which electron carrier is used to make steroids
NADPH
NADPH is a prodict of
HMP shunt
NADPH can be used in
anabolic process
Resp burst
