Lecture #21 Flashcards
____-_______: Each daughter duplex contains one strand from the parent structure
Semi-conservative
Replication starts at the ______ site
origin
Specific sequence called oriC where a number of proteins bind to _____ DNA replication
initiate
Replication proceeds ________
bidirectionally
__________ ____ are sites where:
- Parental ds DNA helix is unwinding.
- Nucleotides are being incorporated into the newly synthesized strands.
Replication forks
Topological constraints pose a problem for ______ replicated DNA
circular
DNA ______ (Type II topoisomerase) relieves the supercoiling. It travels in ______ of the replication fork, creating ds DNA breaks and sealing them and is an ____-dependent process.
gyrase, front, ATP
DNA _______ is responsible for synthesizing new DNA strands from a DNA _______
polymerase, template
DNA polymerase requires a ______; DNA strand synthesis occurs in the ___-to-___ direction.
primer, 5’, 3’
Both daughter strands are synthesized __________
simultaneously
DNA polymerase molecules move along a template only in a ___ → ___ direction
3′, 5′
The ________ strand is synthesized continuously.
The _______ strand is synthesized discontinuously.
leading, lagging
Polymerase ___ is the major replicative polymerase, functioning in the synthesis both of the leading strand of DNA and of Okazaki fragments by the extension of RNA ______
III, primers
Polymerase ___ then removes RNA primers and fills the gaps between Okazaki fragments
I
_______ – unwinds parental strands using ATP
Helicase
_____ is major helicase during replication in E. coli
DnaB
Single-stranded DNA-binding _______ (SSB) stabilize single stranded DNA
proteins
The _______ associated with the helicase synthesizes the RNA primers that begin each Okazaki fragment
primase
DNA polymerase ___ holoenzyme contains core polymerases, β-clamps maintaining the polymerase associated with DNA, and clamp loading Ɣ-complex) for the replication process.
III
DNA polymerase III molecules synthesize successive fragments of the ________ strand
lagging
DNA polymerase ___ is involved in DNA repair. It also removes RNA primers and replaces them with DNA.
I
_________ degrade nucleic acids by removing 5’ or 3’ terminal nucleotides
Exonucleases
___→___ exonuclease removes 90% of mismatched bases. Mismatch repair mechanisms reduce error rate to 10–9 overall.
3’, 5’
Eukaryotes replicate their genome in small portions called _______
replicons
Each replicon has its own ______ from which replication forks proceed outward in both directions
origin
______ points exist to ensure DNA is only replicated once per cell cycle
Control
DNA is synthesized in a _______ manner
semidiscontinuous
Five polymerases: α, β, γ, δ, ε
__ - replicates mtDNA
γ
Five polymerases: α, β, γ, δ, ε
__ - involved in DNA repair
β
Five polymerases: α, β, γ, δ, ε
__ - initiates Okazaki fragment synthesis
α
Five polymerases: α, β, γ, δ, ε
__ - lagging strand synthesis
δ
Five polymerases: α, β, γ, δ, ε
__ - leading strand synthesis
ε
