dna biochem

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  1. topoisomerase
    prevents DNA helix overwinding ('supercoiling')

    • type 1- cuts one strand on dna to relax
    • type 2- cuts both strands to unwind
  2. SSB single stranded binding proteins
    prevent double helix from reforming temporarily
  3. Etoposide
    topoisomerase 2 inhibitor
  4. camptothecin
    topoisomerase 1 inhibitor
  5. DPol alpha
    combo of DPol and RPol that builds RNA primer from 5' end of DNA to be copied
  6. DPol epsilon
    synthesizes leading strand and held on DNA by PCNA
  7. DPol delta
    synthesizes lagging strand, held in place by PCNA
  8. 5' C of DNA strand
    has PO4 attached
  9. 3' C of DNA strand
    has OH attached
  10. ligase
    forms a phosphodiester bond to connect Okazaki fragments and close DNA knicks
  11. telomerase
    a RdDP that adds specific repeats to cap the end of a newly copied DNA strand
  12. alpha- amantin
    • RPol2 inhibitor derived from death cap mushroom
    • -RPol2, 3, 1 decreasing sensitivity
  13. chromosomes with ribosomal notches
    13,14,15,21 and 22
  14. ricin
    • depurinate(a single A) from the 28s subunit, deactivating the 60s large subunit of the ribosome
    • this prevents the amino-acyl tRNA from entering the A site because eEF1 and eEF2 cannot bind
  15. 3' end of tRNA
    has a CCA(adenosine) sequence that the amino acids attach to
  16. this RNA contains T (thymine)
    only tRNA
  17. some tRNA associated pathologies
    • MIDD- maternally inherited diabetes and deafness= complex 1 defeciency= dec ATP synth
    • MELAS- mitochondrial encephalopathy, lactic acidosis, stroke-like episodes
    • tRNA(leu)
  18. enhancers
    sequences of DNA that bind enhance bind TF which bind activated TF to increase the activity of RPol and can be upstream or downstream from the gene being transcribed and forward of backward orientation (ie, actgta or tacagt)
  19. promoters
    sequences of DNA that bind TF and RPol, and tell RPol where to start
  20. LCR
    locus control region- controls gene expression by causing chromatin to loosen by removing histones and L1
  21. CTD
    • c terminal domain of RPol
    • required for modifying mRNA, processing proteins bind to the CTD and wait for the particular sequence they are looking for then hop of and do their job, ie splice, cap, polyA
    • Ser5PO4
  22. splicing sequences
    • GU at 5' splice site (donor)
    • A at branch site
    • AG at 3' splice site (acceptor)
  23. RAT1
    binds CTD after polyA factors release and chew up leftover RNA untill it catches up to RPol and kicks it off DNA, effectively ending transcription
  24. eIF-1
    binds met-tRNA (initiator) to AUG on mRNA
  25. aminoacyl-tRNA sythetase
    • attach aa to tRNAs
    • reguires 2 high E bonds
  26. Energy requirements for protein sytnesis
    • ATP- to hook tRNA and aa
    • GTP- to translate mRNA
    • ** though the formation of the peptide bond requires no additional E, the E needed is stored in the AA before it enters the ribosome
  27. inosine
    • base that when in the wobble position can bind the A,U and C
    • -is deaminated G
  28. binary complex
    • eIF-2 and GTP
    • GTP is hydrolyzed when start codon is recognized to initiate translation. one GTP is hydrolyzed the large subunit will bind
  29. eIF4
    complexes with the 5' cap, which then binds PBP(polyA binding protein) which acts as an activator of translation
  30. eEF1
    guides aminoacyl tRNA to bind to A site on ribosome
  31. eEF2
    • "translocase"
    • aids mRNA to move 3 nucleotides down in ribosome as elongation occurs
    • **GTP required**
  32. 28s
    • has peptidyle transferase that forms the peptide bond on a growing peptide chain
    • **on large subunit**
  33. cyclohexamide
    inhibits peptidyl transferase by binding the 28s rRNA on the 60S subunit
  34. eIF2B
    • exchanges GDP for GTP on eIF2, which is necessary to guide tRNA to the P site during translation
    • **phosphorylation of eIF2B inactivates it**
    • **PO4 seen as a response to interferon as response to viral infection**
  35. aconitase
    • controls ferratin and transferrin translation
    • **controlled by Fe levels**
    • -3' end of transferrin - on during Fe def
    • -5' end of ferratin - off during Fe def
  36. poliovirus
    cleaves eIF-4G(CBP) so translation stops in infected cell, leaves 5'binding cap and hijacks (CBP) the with its own ribosomal entry site to induse its own translation
  37. diphtheria toxin
    inactivates eEF-2, disrupting elongation
  38. weakest point on a DNA strand
    point between a purine and deoxyribose
  39. interferon
    blocks eIF2
  40. exonuclease
    • - stops transcription after addition of polyA tail by bumping RPol off
    • - proofreading
  41. adenine
    catalyzes peptide bond formation
  42. eIF2
    brings first tRNA to A site
Card Set:
dna biochem
2011-12-08 18:47:57

sands biochem for mini 1
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