11.05.2013 Molecular Biology 4 Flashcards
Accurate mechanism for replication
- repair of accidental lesion
- -is required for genetic (instability/stability)
stability
(transition/transversions)substitution of a pyrimidine with a purine or vice versa.
tranversion
(transition/transversions)substitution of a pyrimidine with another pyrimidine or a purine with another purine.
transition
First level of repair during replication is ?
3’ to 5’ exonuclease activty of DNA polymerase
T/F Distortion in the DNA helix is recognized and repaired by strand-directed mismatch repair
T
Single strand breaks or nicks provide the repair signal.
-mechansims for recognizing mismatch in (e.coli/mammalian cells)
mammalian cells
Both strands are methylated (dam methylase) at A in the sequence GATC.
There is a lag in the methylation of GATC sequence in the newly synthesized strand
(e.coli/mammalian cells)
e.coli
(MutS/MutL) recognizes mismatched bases
Mut S
(MutS/MutL)scans the DNA
for a nick to determine
the newly replicated
DNA.
MutL
T/F Colon cancer phenotype has FAP stands for familial adenomatous polyposis and HNPCC stands for hereditary non-polyposis
T
(transversions/frameshift) due to addition/deletion of bases
frameshift
Cellular metabolic activity Heat Extreme pH Radiations Substances in environment --- can all case what?
structural alteration in DNA bases
(spontaneous changed/UV damage) sepurination, deamination
spontaneous changed
(spontaneous changed/UV damage) pyrimidine dimers
UV damage
(Depurination/deamination) converst C to U
damination
(Depurination/deamination) removes a purine from the nucleotide
depurination
which one of the DNA bases would not undergo deamination?
guanin/cytosine/thymine
thymine has no amino group
T/F mehtylated cytosine is commonly found in DNA
T
Uv induces pyrimidne (A or G/ Cor T) dimers
C or T
(deamination/depurination) changes the base
deamination
(deamination/depurination) leads to deletion
depurination
(Base excision repair/Nucleotide excision repair)Specific base is removed and repaired
Base excision repair
(Base excision repair/Nucleotide excision repair)A stretch of DNA strand is removed and new strand with correct base is synthesized
Nucleotide excision repair
(T/U) is an unusual base for DNA
U
(RAD3/RAD6/RAD52)excision repair
RAD 3
(RAD3/RAD6/RAD52) recombination-mediated repair
rad6
(RAD3/RAD6/RAD52) post replication repair
rad 52
yeast is best model system characterized for (prokaryote/eukaryotic) repari
eukaryotic
T/F active genese are preferentially repaired
T
(RAD3/RAd6) a helicase is required for repair is componenet of transcription factore associated with (DNA/RNA) polymerase
Rad3, RNA
recombination , ionizing radiation
-double stand breaks are(repaired/occur)
occur
Homologous end-joining (HEJ)
Non-homologous end-joining (NHEJ)
double strands breaks are (repaired/occur)
repaired
(nonhomologous/homologous) end-joining results in loss of original sequence
non-homologous
(nonhomologous/homologous) repair of double stranded breaks has no loss of sequences
homologous
T/F BRCA1 and BRCA2 predispose women to breast and ovarian cancer
T
(BRCA1/BRCA2) 1863 amino acids
BRCA1
(BRCA1/BRCA2) 3418 amino acids
BRCA2
(BRCA1/BRCA2)also involved in transcriptional regulation of genes activated in response to DNA damage.
BRCA1
(BRCA1/BRCA2)Initial studies indicated involvement of BRCA1 in repairing DNA damage.
BRCA1
BRCA1 and BRCA2 interact with other proteins that activate repair of double strand breaks and initiate (homologous/nonhomologous) recombination.
homologous
Werner syndrome is autosomal recessive what type of manifest in the eye does it have?
cataracts
Autosomal recessive: stunted growth sunlight sensitivity chromosome breakage immunologic deficiency infertility increased risk for neoplasia --describes (bloom syndrome/werner syndrome)
bloom syndrome
Autosomal recessive
cataracts
changing of skin conditions
atypical short stature
premature graying or thinning of the hair.
Patients also often develop hypogonadism, osteoporosis, diabetes mellitus, atherosclerosis and cancers (sarcomas)
–describes (bloom syndrome/werner syndrome)
werner syndrome
both werner syndrome and bloom syndrome mutations in the helicase of Rec Q family
T
