Week 5 Nucleic Acid Metabolism Flashcards Preview

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Flashcards in Week 5 Nucleic Acid Metabolism Deck (17)
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what is the function of the PP pathway 2

produce NADPH (anti-oxidant, reductive biosynthesis) and ribose-5-phophate (nucleic acid synthesis)


how does G6PD deficiency lead to hemolytic anemia?

the first (and commitment) rxn in PP pathway. converts G-6-P to 6-phosphogluterate and generates NADPH. w/o NADPH the glutathione pathway cant fxn and H2O2 accumulates (forms ROS). ROS accumulation causes RBCs to hemolyze


briefly describe the glutathione pathway

uses NADPH to reduce GSSG to GSH. GSH is then used to reduce H2O2 to H2O


In purine metabolism, what is the first nucleic acid produced?

IMP: IMP then branches into two pathways to form ATP or GTP


what is PRPP

produced in first rxn of purine synthesis: required for purine and pyrimidine de novo salvage pathways


in purine nucleotide synthesis, the ____ is built onto the ____

base built onto sugar (ribose)


what is the product of purine catbolism (purines are just the bases!)

uric acid


what is the role of the purine salvage pathway

convert bases (broken down or dietary) to nucleotides


what is ADA deficiency? cause?

lack of ADA which normally converts adenosine to inosine. results in high levels of dATP which inhibits dNTP production essential for DNA synthesis. A lack of immune cells results (immunodeficiency)


what is the Gout? cause?

an increase in purine bases due to increased production or a blocked salvage pathway casues excessive formation of uric acid via Xanthine Oxidase. Uric acid crystals from in extremities


what is the treatment for gout? how does this work?

Allopurionol; as suicide inhibitor of XO that irreversibly binds XO and prevents uric acid formation


what is Lesch-Nyhan Syndrome? cause?

HGPRT deficiency in which the salvage pathway is absent. This causes an increase in PRPP and drastic increase in bases. the increase in base increases uric acid and presents with Gout-like symptoms and aggressiveness/self-mutilaiton


in pyrimidine nucleotide synthesis the ____ is formed prior to the _____

base prior to the sugar


how are thymine nucleotides (dTMP) produced?

ONLY through dUMP.


what is hydroxyurea? how does it fxn?

anti-cancer drug (prevents nucleotide synthesis) through inhibition of ribonucleotide reductase(NDP-->dNDP)


what is fluorouracil? how does it fxn?

anti-cancer; inhibits thymidylate synthase (dUMP-->dTMP)


what is methotrexate? how does it fxn?

anti-cancer; inhibits dihydrofolate reductase (DHF-->THF, essential for dTMP production)

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