DNA replication, repair and recombination 1 (lecture 3) Flashcards
their are approximately ___ new single-nucleotide mutations in the offspring’s grem-line when compared to parental germ-line
70
Mutation rate of one nucleotide change per ______ nucleotides per generation
10^8
The human mutation rate is very to the E. coli rate of one change per ____ nucleotides per cell generation
10^10
Most DNA mutations are corrected by ____ and _____
proofreading and DNA repair
besides from proofreading and DNA repair errors can be further corrected by _______
post-replication repair mechanisms
Multicellular organisms need _______ _____ replication
high fidelity
Germ cells have to have low mutation rates to
Maintain species
Somatic cells need low mutation rates to
avoid uncontrolled proliferation/cancer
DNA duplication rates are as high as ______ nucleotides per second
1000
DNA polymerase synthesizes DNA by catalyzing what reaction
(DNA)n residues + dNTP (deoxyribonucleoside triphosphate aka primer strand) —-> (DNA) n+residues + P2O7^4-
DNA replication requires separation of
the two parental strands
DNA replication requires
dATP, dGTP, dCTP, and dTTP
DNA polymerase requires a primer with a ____ to begin
free 3’ -OH (hydroxyl end)
The newly synthesized DNA strand polymerizes in the _____ direction
5’ to 3’
DNA synthesis is catalyzed by DNA polymerase and the reaction is driven by
a large, favorable fee-energy change, caused by the release of pyrophosphate and its subsequent hydrolysis to two molecules of inorganic phosphate
The proper base-pair geometry of a correct incoming deoxyribonucleoside triphosphate causes the polymerase to ____ around the base pair, thereby initiating the
Tighten around the base pair, thereby initiating the nucleotide addition reaction
During synthesis of DNA the dissociation of pyrophosphate ______ the polymerase, allowing
loosens the polymerase, allowing translocation of the DNA by one nucleotide so the active site of the polymerase is ready to receive the next deoxyribonucleoside triphosphate
Is the replication fork asymmetric
yes
Both strands are _____ replicated
simultaneously
DNA polymerase can only synthesize DNA in the _______ direction
5’-to-3’
The ___ strand is synthesized continuously
leading
The ____ strand is synthesized in segments
laggins
Okazaki fragment are polymerized only in the _____ direction
5’-to-3’
DNA polymerase makes a mistake out of every ____ nucleotides copied
10^9