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21 Cards in this Set
- Front
- Back
What is the use of nucleotides
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Nitrogenous base + pentose monosaccharide + phosphate group, DNA, RNA, ATP, NAD, UDP-glucose
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What is the function of nucleotides in the GI?
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Mostly made denovo - only 5% taken in diet - used for synthesis of purines + pyrimidine's
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What molecule do purines build off of?
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PRPP -> built one atom at a time to make purines
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What is the rate of purine synthesis dependent upon?
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Dependent upon [PRPP] b/c PRPP concentrations are usually below Km
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What happen to purines if there is no Folate?
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U cant make purines b/c u are going to b missing 2 carbons -> thus cant make DNA
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What happens to pyrimidine's if there is no Folate?
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U cant convert U-> T thus u cant make DNA
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RR
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Ribonucleotide reductase - remove C2 on ribose ring -> converts to 2-deoxyribose -> necessary for synthesis of DNA
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Ribonucleotide reductase inhibitors = Anti-cancer drug
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Hydroxyurea = Stops DNA synthesis(slows cell growth)
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What molecule is a feed back inhibitor on ribonucleotide reductase?
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dATP - b/c u make enough nucleotides u don’t need to make more thus turn of Ribonucleotide reductoase (RR)
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Pt w/ 100x ↑ [dATP] but ↓ dTTP, ↓ dGTP, ↓ dCTP
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Adenosine deaminase deficiency = T + B cells affected - immununodeficiency(SCID)
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Pt w/ ↑ [dGTP] but blocked dCTP + dTTP
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Purine nucleoside phosphorylase deficiency = T -cells affected - immunodeficiency
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Elevated uric acid due to hypoxanthine-guanine phospho-ribosyl transferasae deficiency
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Lesch-nyhan syndrome - ↑ hypoxanthien + guanine concentrations -> ↑ uric acid b/c u cant recycle them thus the body tried to excrete them
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What drink elevates uric acid lvls?
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Beer
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What drug is used to treat elevated uric acid?
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Allopurinol - blocks xanthine oxidase -> synthesis of uric acid prevents conversion of hypoxanthine -> xanthine -> uric acid
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What are the treatments for gout?
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1. Colchicine (anti-inflammatory), 2. allopurinol (inhabits uric acid formation), 3. probenicid (inhibits kidney organic anion transporters -> blocks reabsorption of uric acid -> ↑ excretion of uric acid), 4. avoid meat, seafood, beer
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Pt w/lack of HGPRT gene
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Lesch-nyhan syndrome
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What are the problems in lesch-nyhan
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↑ PRPP -> ↑ de novo syntehsis of purines ->gout like damage to the brain -> chew on their fingers
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Treatment for lesch-nyhan
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Allopurinol
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Pt w/poorly coordinated, mentally retarted, extremely hostile, compulsive self-destructive tendencies: mutilate by biting off their fingers, toes, and lips
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Lesch-nyhan
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What bases are ↓ in orotic aciduria?
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↓ RNA bases C + U, ↓ DNA bases C + T, also causes immunodeficiency
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New born, macrocytic hypochromic megaloblastic anemia, failure to thrive, sparse hair, cardiac malforamtions, bilatreal strabismus, inability to sit unaided, Crystal urea -> kidney stones, immunodeficiency's,
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Orotic aciduria
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