BIOL340 DAZZA EXAM QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS GRADED A++ LATEST UPDATE
meselson-stahl experiment
grew bacteria in 15N, washed and put in 14N, 2nd gen 1/2 way band, 3rd gen just 14N
(not disp as 1/2 way band, not cons as new band)
prokaryote dna replication
topisomerase cuts and loosens dna, initiator proteins bind to OriC, helicase binds and
unwinds using atp, primase binds, dna pol 3 synthesises, pol 1 removes primer using
nick translation and ligase seals okazaki fragments
3' to 5' exonuclease activity prok
all dna pols stall when incorrect nucleotide is inserted, cuts it out and replaces
5' to 3' exonuclease activity prok/nick translation
pol 1 encounters nick in dna, cleaves base in front, fills in and sealsl, continues
how did they find out pol 1 vs 3 function prok
temp sensitive pol 1 in pcr = pcr still worked so couldnt be main pol, mutated pol in
exonuclease domain = lethal!
dna pol 3 prok
core pol distributive, made processive by beta subunit that clamps pol to dna
okazaki experiment
pulse labelled = short fragments immediately post dna rep, pulse chase = long a little bit
after,, so meant discontinuous replication (uracil dissociated in leading strand)
, prokaryote proofreading
3' to 5' exonucleases, mismatch repair
eukaryotic dna replication
topoisomerase relaxation, helicase, ssb protein, primosome, dna polymerase a (1)
initiates synthesis then pol d (2) loaded by rfc with pcna processive subunit, joining
okazaki with ligase, nucleases fen-1 and rnase h1 remove primer, pol d fills gap
euk dna rep link to cell cycle
cdk and ddk activated helicase precursors such as cdc6 to form active helicase and
initiate rep
how replication is controlled
rate is by number of replicon sites, chromatid structure, intact nucleus required for euks
why is nuclear structure important in replication
regulates conc of initiation proteins in region, facilitates assembly of replication fork,
determines where initiation will occur
mt dna basic facts
circular genome, encodes 13 proteins mostly on outer heavy strand, one OriC on each
strand, heavy started first then light, lots of mut = oxiphos, maternal, cell cycle
independent, lots of expression
mtdna replication
mtrna pol and mt tf a make primer, displaces heavy strand and forms a d loop at oriC,
twinkle unwinds dna, mtssb stabilises, polg synthesises dna, rnase h1 and mgmt
remove primer. starts at H OriC then once that passes L oriC L starts
holliday model of recombination
COMPLETE SOLUTIONS GRADED A++ LATEST UPDATE
meselson-stahl experiment
grew bacteria in 15N, washed and put in 14N, 2nd gen 1/2 way band, 3rd gen just 14N
(not disp as 1/2 way band, not cons as new band)
prokaryote dna replication
topisomerase cuts and loosens dna, initiator proteins bind to OriC, helicase binds and
unwinds using atp, primase binds, dna pol 3 synthesises, pol 1 removes primer using
nick translation and ligase seals okazaki fragments
3' to 5' exonuclease activity prok
all dna pols stall when incorrect nucleotide is inserted, cuts it out and replaces
5' to 3' exonuclease activity prok/nick translation
pol 1 encounters nick in dna, cleaves base in front, fills in and sealsl, continues
how did they find out pol 1 vs 3 function prok
temp sensitive pol 1 in pcr = pcr still worked so couldnt be main pol, mutated pol in
exonuclease domain = lethal!
dna pol 3 prok
core pol distributive, made processive by beta subunit that clamps pol to dna
okazaki experiment
pulse labelled = short fragments immediately post dna rep, pulse chase = long a little bit
after,, so meant discontinuous replication (uracil dissociated in leading strand)
, prokaryote proofreading
3' to 5' exonucleases, mismatch repair
eukaryotic dna replication
topoisomerase relaxation, helicase, ssb protein, primosome, dna polymerase a (1)
initiates synthesis then pol d (2) loaded by rfc with pcna processive subunit, joining
okazaki with ligase, nucleases fen-1 and rnase h1 remove primer, pol d fills gap
euk dna rep link to cell cycle
cdk and ddk activated helicase precursors such as cdc6 to form active helicase and
initiate rep
how replication is controlled
rate is by number of replicon sites, chromatid structure, intact nucleus required for euks
why is nuclear structure important in replication
regulates conc of initiation proteins in region, facilitates assembly of replication fork,
determines where initiation will occur
mt dna basic facts
circular genome, encodes 13 proteins mostly on outer heavy strand, one OriC on each
strand, heavy started first then light, lots of mut = oxiphos, maternal, cell cycle
independent, lots of expression
mtdna replication
mtrna pol and mt tf a make primer, displaces heavy strand and forms a d loop at oriC,
twinkle unwinds dna, mtssb stabilises, polg synthesises dna, rnase h1 and mgmt
remove primer. starts at H OriC then once that passes L oriC L starts
holliday model of recombination
