Biochem Flashcards
Interfere with nucleotide synthesis: Leflunomide
qinhibits dihydroorotate dehydrogenase
Interfere with nucleotide synthesis:Mycophenolate and ribavirin
inhibit IMP dehydrogenase
Interfere with nucleotide synthesis:Hydroxyurea
inhibits ribonucleotide reductase
Interfere with nucleotide synthesis:6-Mercaptopurin(and prodrug azathioprine
inhibit de novo purine synthesis
Interfere with nucleotide synthesis:5-FU
inhibit thymidyalte synthase (decreases dTMP)
Interfere with nucleotide synthesis:Methotrexate, thrimethoprim, and pyrimethamine
inhibit dihydrofolate reductase in humans, bacteria, and protozoa
abnormal splicing variant disease example
beta-thalassemia
t-arm of tRNA
thymine psuedouridine cytosine
necessary for ribosome binding
d- arm of t RNA
dihydrouracil
recognition by aminoacyle trNA synthase
variable phase of cell cycle
G1 and G0
shortest phase of cell cycle
mitosis
Li Fraumeni syndrome
mutations in p53 and Rb =unrestrained cell division
N-linked oligosaccarhide addition
occurs in RER
adds to ASPARAGINE
O-linked oligosaccarhide addition
occurs in GA
adds to serine and threonine
I cell disease
inherited lysosomal storage disorder
GA fails to phophorylate mannose residues on glycoproteins
proteins excreted extracellularly
coarse facial features, clouded corneas, stiff joints, high plasma levels of lysosomal proteins
fatal in childhood
Drugs that act on microtubules
Mebendazole (anti-helminthic)
Griseofulvin (anti-fungal)
Colchicine (anti gout)
Vincristine and Vinblastine (anti cancer)
Paclitaxel (anti cancer)
(Microtubules Get Constructed Very Poorly)
cilia structure
9+2 arrangement of microtubules with axonemal dynein ATPase links
Kartagener syndrome (primary ciliary dyskinesia)
immotile cilia due to dynein arm defect
male and female infertility (sperm, fallopian tube)
increased risk of ectopic pregnancy, bronchiectasis, recurrent sinusitis etc
Ouabain
inhibits Na/K ATPase by binding to K site
digoxin and digitoxin
directly inhibit Na/K ATPase = indirect inhibition of Na/Ca exchange = increased intracellular Ca = increased cardiac contractility
Type three collagen defects
vascular type of Ehlers-Danlos
defect in cross linking of collagen;in osteogenesis imperfect T1 collagen and can’t form collagen triple helix
Type four collagen defects
Alport syndrome
targeted by autoantibodies in Goodpasture
Copper is a necessary cofactor for…
- lysyl oxidase
- deficiency in copper = kinky hair, growth retardation, and hypotonia
alpha antitrypsin deficiency
emphysema; due to excess elastase activity
confirmatory test for HIV
Western blot; after ELISA
codominance examples
A,B, O and alpha anti-trypsin
variable expressivity
variable phenotype with same genotype; NF1
incomplete penetrance
BRCA
pleiotropy
one gene produces multiple unrelated phenotypic effects; PKU = mental retardation, light skin, and musty odor
dominant negative mutation
nonfunctional protein produced from the mutant gene prevent the the normal protein product from working
locus heterogeneity
different loci produce the same phenotype; albinism
allelic heterogeneity
different mutation at the same locus produce the same phenotype; beta-thal
carrier frequency (autosomal recessive)
2pq
x linked recessive frequency males
q
x linked recessive frequency females
q^2
chromosome 15
Prader-Willi and angelman; both can also be caused by uniparental disomy instead of imprinting
Prader-Willi syndrome
maternal gene is noramlly silent and the paternal gene gets deleted
-hypogonadism, hypotonia, obesity, and hyperphagia
Angelman
paternal gene is normally silent and the maternal gene gets deleted
-inappropriate laughter and seizures
x-linked dominant example
hypophosphatemic rickets; affected father will always transmit to daughter and never transmit to son; affected mother can transmit to daughter or son at 50% risk
mitochondrial inheritance
mitochondrial myopathies= ragged red fiber, lactic acidosis and CNS disease
polycystic kidney disease
autosomal dominant, chrom 16, PKD1
always bilaters, massive enlargement due to multiple large cysts
familial adenomatous polyposis
autosomal D, chrom 5 , APC
progress to cancer unless resected
familial hypercholesterolemia
AD
absent LDL receptor
endon xanthomas
hereditary hemorrhagic telangiectasia
AD
telangiectasia, recurrent epistaxis, skin discolorations, GI bleeds, hematuria
hereditary sphereocytosis
AD
elevated MCHC
treatmetn splenectomy
Huntingtons
AD, chrom 4, CAG repeat disorder
caudate atrophy
decreased GABA and ACh in the brain
Marfan
AD,
pectus excavatum, hypermobile joints, long fingers, floppy mitral valve , subluxation of lenses
multiple endocrine neoplasias
AD, Men2A and B = ret gene
tumor of multiple different endocrine genes
Neurofibromatosis T1
AD, chrom 17, NF1
100% penetrance with variable expression
cafe au lait and cutaneous neurofibromas
Neurofibromatosis T2
AD, chrom22, Nf2
bilateral acoustic schwannomas, juvenile cataracts, memingiomas, and ependymomas
tuberous sclerosis
AD, incomplete penetrance, with variable expression
neurocutaneous disorder with multi organ system involvement
characterized by numerous benign hamartomas
von Hippel-Lindau
AD, chrom 3, deletion of VHL gene (tumor supressor gene)
numerous tumors both begin and malignant
cystic fibrosis
AR, defect CFTR, chrom 7 , commonly deletion of 508
x linked recessive disorders
Be Wise, Fools GOLD Heeds Sily H0pe
brutons agam, wiskott-ald, fabrys, G6PD, ocular albinism, Lesch-Nyhan, Duchhens and Beckes, Hunters , Hemophil A and B, and ornithine transcarbamylase
myotonic type 1 muscular dystrophy
CTG trinucleotide repeat expansion in the DMPK gene
myotonia, , muscle wasting, frontal balding, catarats, testicular atrophy, arrythmias
***think of the D in DMPK as degenerative = symptoms associated with old age
Trinucleotide repeat expansions
Huntingtons = CAG
Fragile X= CGG
Myotonic dystrophy= CTG
Friedrich axtaxia = GAA
Robertsonian translocation
commonly involves 13,114,15,21,22
Cri du chat
congential micro deletion of chromosome 5 (46XX/XY 5p-)
high pithed cry, microcephaly, intellectual disability, and epidcanthal folds, cardiac abnormalities
Williams syndrome
congential micro deletion of long arm of jchromosome 7 (deleted region inculdes elastin gene)
distinctive elfin facies, extreme friendliness with strangers, well developed verbal skills, intellectual disability, cardiovascular problems, hypercalcemia
