DNA Replication

Chapter 6

template

DNA acts as a ____ for its own replication.

Base-pairing

enables smooth DNA replication

semi-conservative

DNA replication is considered to be _______.

DNA pol 1

Exonuclease activity removes RNA primer and replaces with with newly synthesized DNA

DNA pol 2

Main enzyme that adds nucleotides in the 5’ to 3’ direction

• required for DNA synthesis

OriC

bacterial chromosome have one origin of replication called ______.

Topoisomerase II

relaxes the supercoiled chromosome

helicase

breaks the hydrogen bonds between two strands

• using ATP

replication fork

• DNA becomes flat and open

• Y-shaped structure

-OH

DNA doesn’t have an -____ group, while RNA does.

RNA primase

initiates replication by replacing the first primer with a free 3’ -OH hang

DNA polymerase

start replication by adding nucleotide after nucleotide (complimentary) to the DNA.

Single-stranded binding proteins

stabilize the flat DNA so that it does not ”close” on itself or fold supercoils again

leading strand

• one half is a continous addition of DNA (5’ to 3’) without disruption

  • a continuous strand of replication

DNA polymerase I

removes primer RNA

adds correct DNA sequence to replace removed RNA

exonuclease activity

removes RNA molecules

DNA ligase

seals the gaps created between each Okazaki fragment

5’-3’

In which direction is DNA synthesized?

• adds nucleotides to 3’ -OH

topoisomerase IV

final genomes in bacteria are circular and intertwine. Which enzyme creates a nick between the two such that they are separated from one another and reseals them?

origin of replication

DNA double helix opens where?

replication forks

DNA synthesis occurs at Y-shaped junctions

opposite

Two strands of DNA are synthesized in ______ directions.

self-correcting

DNA Polymerase is _______-______.

DNA Polymerase

During DNA synthesis, which enzyme proofreads its own work?

Eukaryotes; Prokaryotes

________ have multiple origins of replication; ______ have only one origin of replication.

Telomere and Telomerase

prevent linear eukaryotic chromosomes from shortening with each cell division

DNA helicase

uses the energy of ATP hydrolysis to unwind the DNA double helix ahead of the replication fork

single-strand DNA-binding protein

binds to single-stranded DNA exposed by DNA helicase, preventing base pairs from re-forming before the lagging strand can be replicated

DNA topoisomerase

produces transient nicks in the DNA backbone to relieve the tension built up by the unwinding of DNA ahead of the DNA helicase

Sliding clamp

keeps DNA polymerase attached to the template, allowing the enzyme to move along without falling off as it synthesizes new DNA

Clamp loader

uses the energy of ATP hydrolysis to lock the sliding clamp onto DNA

Primase

synthesizes RNA primers along the lagging-strand template

DNA ligase

uses the energy of ATP hydrolysis to join Okazaki fragments made on the lagging-strand template