The flashcards below were created by user xijunzhu on FreezingBlue Flashcards.

  1. degenerate
    more than one codon for some amino acids
  2. stop codons
  3. short range frameshift
    indertion of three nucleotides
  4. proteins are encoded by
  5. weight of aa
    number of aa*110daltons
  6. how are tRNAs charged with amino acids?
    aminoacyl tRNA synthetase
  7. nonsense mutation aa
    generates stop codon
  8. missense mutation
    different aa
  9. sickle cell anemia
    beta chains of hemoglobin are altered due to a single amino acid change.
  10. Creutzfeldt-Jakob disease
    alters folding of the protein, forms prions
  11. imprinting
    the phenomenon whereby the phenotypic expression of a gene is determined by the sex of the parent from whom it is inherited. This situation is not like a normal mutation, because it can be reversed when passed through the opposite parent.
  12. conservative (missense) mutation
    change codon and change amino acid, but that amino acid has similar biochemical functions.
  13. Transition
    one purine replaced by another, or one pyrimidine replaced by another.
  14. Transversion
    one purine changed to a pyrimidine
  15. mutagenesis experiments
    use radiation, chemicals, and such to induce new mutation.
  16. What is the role of DNA pol I
    DNA 5' to 3' proofreading (exonuclease activity) removes RNA primers
  17. what is the role of 3' to 5' exonuclease activity?
    proofreads the most recently added deoxynucleotide and excises it if it is incorrect
  18. what is the shifting of protons and electrons of a given base called leading to mispairing (anomalous)
    tautomeric shift
  19. what does reactive oxygen species alter?
    covalent structure of bases, leading to replication errors
  20. Which bases are purines? pyrimidines?
    • purines: G or A
    • Pyrimidines: C and T
  21. what are transposons
    insertion of DNA into or between genes that alter gene structure, coding capacity, transcription and regulation
  22. what is replication slippage
    looping out the leading or lagging strand during replication or slippage of the DNA polymerase, which can cause insertion or deletion of extra bases, more frequent with repetitive gene sequences called microsatelite regions
  23. what are three trinucleotide repeat diseases?
    • -Fragile X syndrome
    • -Myotonic dystrophy
    • -Huntington's disease
  24. what is fragile x syndrome
    contains thousands of CGG repeats in 5' UTR (untranslated). Array too long may impede expression of FMRP protein
  25. what is myotonic dystrophy
    tens of thousands of CTG repeat in 3'. increased copies mean earlier onset and more severe
  26. what is huntington's disease
    10-120 CAG repeats in coding sequence, increased number equals earlier onset.
  27. what is the result of incorporation of 5-BU
    increases probability of tautomeric shift with mispairing and altering
  28. what groups does alkylating agents in nucleotides?
    methyl or ethyl groups to amino or keto groups in nucleotide; this leads to point mutations during replication
  29. ethylmethane sulfonate
    used as chemical mutagen to perform screens for new mutants
  30. what does aridine dye mutate cells?
    intercalate with DNA helix, distorting its structure, lead to deletion or insertions of basepairs.
  31. UV radiation, how does it mutate cells?
    -damage DNA directly or create free radicals that covalently modify and damage DNA.

    -Radiation can break phosphodiester bonds and chromosomal breaks.

    -UV can create pyrimidine dimers (distort DNA helix)/crosslinking leading to replication errors
  32. how does ionization induce mutations?
    free radicals which can cause damage to DNA bases and backbone
  33. what is the aim of the Ames test?
    reveal the ability of chemicals to induce different types of mutations
  34. what are the strains used in the ames test?
    histidine auxotrophs with mutation that does not allow them to synthesize histidine
  35. what is the error rate of bacteria pol iii
  36. how much can proofreading correct the 10^-5 error rate?
    99%, so 10^-7
  37. what is mismatch repair?
    when error persists after proofreading, excise the incorrect nucleotide and adds the correct nucleotide via DNA synthesis (MutL, MutS)
  38. how does DNA recognize the correct sequence for mismatch repair?
    mismatch repair is mediated by MutL/s/h that recognizes the template strand and the correct nucleotide based on the methylation on the parental strand
  39. what is photoreactivation repair?
    exposure to blue light following exposure to UV enables action of photoreactivation enzyme (PRE) not in humans but repairs thymine dimers
Card Set
Show Answers