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25 Cards in this Set
- Front
- Back
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Homocysteinurina
Pathway 5 3 forms: genetics? Tx? Result? 2 Findings? 7 |
Methionine + SAM ->
Homocysteine + cystathionine synthase + B6 -> cystathionine -> Cysteine Reversed by homocysteine methyltransferase + B12 + THF All auto R Cystathine synthase def; Tx: dec Met, Incr Cys, B12, folate Dec affinity for cystathionine synthase for B6; Tx: Incr B6 Homocyteine methylase def; Tx: cys Xs homocysteine; cysteine = essential Incr homocysteine in urine, MR, osteoporosis, tall stature, kyphosis, lens subluxation, atherosclerosis |
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Nucleotide structure:
1'C: 2'C: 3'C: 5'C: |
1: glycosolytic bond to base
2: decide if deoxy/ribose 3: necessary for chain elongation 5: attachment for phosphates |
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DNA organization:
7 levels DNA methylation: 2 Histone modification: 2 |
Histone -> octemeric nucleosome bead (2x H2A, H2B, H3, H4) -> 30 nm -> scaffold -> loops of 600 nm -> chromatids -> chromosome
cys -> 5-methylcytosine -> more compact CpG islands ATP-dependent complex -> loosen DNA Acetylation of lys residue on histone -> loosen DNA |
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DNA stats
Fidelity: Watson-Crick model Insertional fidelty of DNA polymerase Proofreading Mismatch repair # genes? # nucleotide pairs? # cell divisions b/t conception and sexual maturation? |
1x10^2
1x10^5 1x10^7 1x10^10 ~25,000 3.2 x 10^6 200 |
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DNA replication
Role of Mg ions? 2 How many ions? What do they do? DNA polymerase actions? 3 |
Drawing dNTP in; stabilizing phosphodiester bond formation
2 ions - one w/ 3'OH & other with dNTP O-helix slides into palm -> makes sure matches in size -> squishes hand |
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Reverse transcription steps 6
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1. tRNA bind PBS (primary binding site)
2. RT transcribe in 5' to 3' direction DNA from RNA 3. RNAseH remove hybridize DNA 4. Recombination/jump to 3' end 5. cDNA extended from 3' end 6. RNA & tRNA removed by RNAseH |
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Eukaryotic v. Prokaryotic DNA replication
# origins? Order? Nucleosomes? Speed? |
P: single origin, begins once, no nucleosomes, faster
E: multiple origins, loosely condensed regions first then tightly, nucleosomes need to dissemble and reform, slower |
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Recombination
Radding-Messelson Model: Found in? 1 Steps? 9 Double Strand Break Model: Found in? 3 Steps? 4 |
RM: Bacteria
1. Endoculease nick 2. RecA surround 3. Search homology 4. Strand exchange (D-loop) 5. Invading nick strand displaced w/ donor 6. Ligase 7. Holliday structure 8. Resolvase 9. Splice/patch DSB: yeast, bacteriophages, mammal cells 1. Homologue 1 ds break 2. Break widen to gap by exonuclease 3. Both 3' strands invade partner 4. DNA synth on 3' ends w/ II serving as template |
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Transposition
Target sequences? 2 Transposase actions? 2 Retrotransposons? 3 |
Preferred site of insertion
Duplicate upon insertion Recognize inverted terminal repeats Makes ds breaks Insert transposon into same chr but at different location Leaves original copy intact at old location If have inverted and direct repeats -> viral-like |
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DNA repairs
Base excision: Used for? Steps? 6 Nucleotide excision repair Used for? 3 Steps? 3 Direct removal Used for/patho? 2 Steps? 1 Mismatch repair Steps? 4 How know? 2 Ds DNA break repair Causes? 3 Repair by? 2 |
Small DNA distortions
Uracil glycosylase cuts out U -> apyramidine site -> endonuclease nicks 5' -> remove phosphate -> DNA polymerase -> ligase Cyclobutane dimers, adducts, cross-links 2 cuts: 3-4 nuc 3' to damage + 7 nuc 5' to damage -> DNA poly episilon/delta synth -> ligase Photoreactivation O6-guanine pairs w/ T instead of C O6-alkylguanine transferase transfer cys residue to itself & is deactivated Recognition via proteins -> exonuclease -> DNA polymerase -> ligase PCNA helps ID older strand and load mismatch repair complex on new strand Gamma rays, X-rays, collapse rep fork Single-strand annealing or non-homologous end joinging |
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Purine salvage pathway
HGPRT + PRPP catalyze? 2 APRT + PRPP catalyze? ADA catalyze? XO catayze? 2 ADA def: Patho & result Lesch-Nyhan syndrome: Patho? 2 Sx? 6 Mnemonic? |
Guanine -> GMP; hypoxanthine -> IMP
Adenine -> AMP Adenosine -> Inosine Hypoxathine -> xanthine; xanthine -> uric acid Build up ATP, dATP -> dec DNA synth -> dec lymphocyte count Cause SCID X-linked recessive; lack HGPRT -> xs uric acid Retardation, SELF-MUTILATION, aggression, hyperuricemia, gout, choreoathetosis He's Got Purine Recovery Trouble |
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RNA processing:
hnRNA v. mRNA Where occur? Post-transcriptional changes? Splicing steps? 3 Inh by? |
hnRNA = initial transcript; mRNA = capped & tailed
Nucleus 5' cap, poly(A) tail, intron splicing Primary transcript combine w/ snRNPs & proteins -> form spliceosome Lariat-shaped (loop) intermediate Lariat released to remove intron & 2 exons joined Lupus Ab to splicesomal snRNPs |
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Imprinting disorders
Prader-Willi: Allele deleted? Chr? Sx? 5 Angelman: Allele deleted? Chr? Sx? 4 |
Paternal Chr 15
MR, hyperphagia, obesity, hypogonadism, hypotonia Maternal Chr 15 MR, seizures, ataxia, inappropriate laughter (happy puppet) |
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Hardy-Weinberg
Disease prevalence eqn Allele prevalence eqn X-linked recessive prevalence M v. F Law assumptions? 4 |
p^2 +2pq + q^2 = 1
p + q = 1 M: q; F: q^2 No mutations, no selection, nno migration, random mating |
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Modes of inheritance: features
Auto dom: 3 Auto R: 4 X-linked R: 2 X-linked dom: 1 Mitochondrial: 2 |
Both M & F; Usu pleiotropic, after puberty; affect many generations
25% of 2 carrier parents; usu skip generation; usu more severe than dom, present in childhood No male-male transmission; more severe in M All female offspring of affected father have dz Ends with male; may affect all children of diseased mother |
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Cru du chat
Microdeletion of? Findings? 5 |
Chr 5p
Microcephaly, mod-server MR, high-pitched crying, epicanthal folds, cardio abnorm |
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Sanger method
Uses? Read gel? Gel code represents? |
ddNTPs
Bottom to top = 5' -> 3' Complementary, not template sequence |
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PCR steps? 5
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1. Short oligonucleotide primers hybridize with complementary strand of ds DNA
2. high temp denaturation 3. low temp so primers can anneal 4. DNA polymerase 5. Raise temp |
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Transcription regulation
RLS - prokaryote v. eukaryote Role of: repressor? inducer? corepressor? activator? effector? |
Prok: how many RNA poly bind promoter
Euk: formation of pre-initiation complex Repressor halt transcription Inducer inhibits repressor Corepressor helps repressor Activator promotes transcription Effector helps activator |
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Lac operon
Order: Repressor regulated by? Mechanism? 3 steps Requires? 2 |
LacI, CAP, LacP, LacO, LacZ, LacY. LacA
Inducer = allolactose Glucose low -> incr cAMP -> CAP binds activator sequence CAP bound No repressor |
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Trp operon
Regulated by? 2 Mechanisms? |
Attenuation:
Leader peptide contain trp Low trp -> slow ribosome -> stalled at part 1 -> 2 & 3 from stem loop -> RNA can keep going Repression: trp activates repressor to trpR |
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Retinoblastoma
Sporadic: 3 Familial: 2 hit hypothesis Genetics? |
single, u/l, later age
b/l, multifoal, during development Knudson model Sporadic = 2 hits Familial = 1 inherited, 1 somatic hit Delection in Chr 13 |
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Nucleotide metab
Purine synth: Aa involved? RLS: Req? 4 1st nuc synth? How get to AMP? GMP? How make dNDP? 2 1st real purine synth? Purine salvage: -> uric acid? 3 Adenosine deaminase def: patho? Lesch-Nyhan syndrome: patho? Sx? 6 Pyrimidine synth 1st real pyrim made? Key enzyme? Reg by? dCMP from? dUMP? dTMP? Orotic aciduria: genetics? Sx? 4 Tx? |
Asp, FH4, Gln, gly
Ribose-5-P -> PRPP via PRPP synthetase Req: gly, asp, glu, THF IMP IMP -> AMP IMP -> XMP -> GMP NDP -> dNDP by ribonucleotide reductase Uses NADPH Orotic acid GMP -> guanosine -> G -> xanthine AMP -> IMP -> inosine -> hypoxanthine -> xanthine Xanthine -> Uric acid via XO xs ATP & dATP -> feedback inh of ribonucleotide reductase -> low lymphocyte count -> SCID X-linked R; absent HGPRT --> xs uric acid production Retardation, aggression, self-mutiliation, hyperuricemia, gout, choreoathetosis UMP CPS II: UTP (-), PRPP (+) UMP -> UDP -> UTP -> CTP -> CDP -> dCDP -> dCMP -> dUMP -> dTMP Auto R Incr ortoic acid in urine, megaloblastic anemia, failure to thrive, no hyperammonemia (DDx for NH3) Oral uridine admin |
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Trisomy d/o: Chr, Sx, mnemonic
Down syndrome: 7 Edwards syndrome: 8 Patau's syndrome: 8 |
Drinking age - 21
Flat facies, epicanthal folds, simian crease Septum primum type ASD Incr risk ALL, Alzheimer's Election age - 18 Severe MR, ROCKER-BOTTOM FEET, MICROGNATHIA, low-set ears, CLENCHED HANDS, congenital heart dz Death w/in 1 yr Puberty age - 13 Cleft lip/Palate, holoProsencephaly, Polydactyly, severe MR, ROCKER-BOTTOM FEET, congenital heart dz Death w/in 1 yr |
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Chromosome assoc d/o:
4: 5: 7: 13: 15: 16: 17: 18: 21: 22: X: |
4: Huntington's
5: FAP, Cri du chat 7: CF, William's 11: DiGeorge 13: Patau 15: Prader-Willi, Angelman 16: ADPKD 17: NF-1 18: Edwards, 21: Down's 22: NF-2, DiGeorge X: Bruton's agammaglobinemia, Wiskott-Aldrich, Fabry's, G6PDH, Lesch-Nyhan, Duchenne's/Becker's, Hunter's syndrome, Hemophilia, Fragile X |
