Biochem: molecular/cellular bio, genetics Flashcards
uracil is made from deamination of
cytosine
cytosine deamination yields
uracil
leflunomide MOA
blocks dihydroorotate dehydrogenase to prevent conversion of carbamoyl phosphate to orotic acid
hydroxyurea MOA
inhibits ribonucleotide reductase to prevent conversion of UDP to dUDP
substances from glutamine + CO2 to synthesis of CTP
carbamoyl phosphate, orotic acid, UMP, UDP, CTP
substances from glutamine + CO2 to synthesis of dTMP
carbamoyl phosphate, orotic acid, UMP, UDP, dUDP, dUMP, dTMP
MTX, TMP, and pyrimethamine block
dihydrofolate reductase, which normally recycles DHF into THF
5FU blocks
thymidylate synthase, which normally converts dUMP to dTMP
Note: the active form of 5FU is 5FdUMP
azathioprine/6MP MOA
impairs purine synthesis by blocking formation of IMP from PRPP
Mycophenolate and ribavirin MOA
blocks IMP dehydrogenase to prevent conversion of IMP to GMP
probenecid MOA
stimulates conversionof uric acid to urine
Lesch-Nyhan (deficiency, symptoms)
HGPRT: hyperuicemia, gout, pissed off, retardation, dystonia
this sugar unbinds the repressor on lac operon
high lactose
XP is caused by a defect in
NER, which removes oligonucleotides e.g. pyrimidine dimers
Spontaneous deamination is repaired by
BER. AP endonuclease cleaves 5’ end, lyase cleaves 3’ end
Ataxia telangiectasia and Fanconi anemia have a defect in this DNA repair mechanism
NHEJ
function of eukaryotic RNA pol I
rRNA
function of eukaryotic RNA pol II
mRNA
function of eukaryotic RNA pol III
tRNA
what are the functions of the T arm and D arm of tRNA?
ribosome binding; aminoacyl-tRNA synthase recognition
Defect in I-cell disease
failure to add mannose-6-P (defect in n-acetylglucosaminyl-1-phosphotransferase)
Sx of I-cell disease
coarse facies, clouded corneas, restricted joint movement, high plasma level of lysosomal enzymes
this protein is involved in retrograde vesicular trafficking
COP I
this protein is involved in anterograde vesicular trafficking
COP II
this protein is involved in transport between Golgi and lysosomes, and in receptor mediated endocytosis
Clathrin
stain for mesenchymal intermediate filaments
vimentin
this microtuble motor protein does anterograde transport (toward positive end)
kinesin
this microtubule motor protein does retrograde transport (toward negative end)
dynein
ouabin MOA
inhibits Na/K ATPase by binding to K+ site