Genetics Chapter 9 DNA replication

dNTPs

nucleotide units that are linked together by DNA polymerases

single strand binding proteins

keep DNA single stranded

DNA gyrase

a kind of topoisomerase, keeps DNA from becoming positively supercoiled while its being unwound

DNA polymerase 3

the main replication enzyme in E. coli to synthesize DNA

primase

type of RNA polymerase that makes RNA primers

primers

starting point for DNA synthesis, short structures of nucleotides

termination of replication

when 2 replication forks meet or by termination protein

semiconservative replication

one old strand and one new strand of DNA

replicons

units of replication, replication origin

prokaryotic replication

circular DNA, one replicon

eukaryotic DNA

linear DNA, thousands of origins, many replicons

minimum requirements of replication

template stand, raw material, DNA polymerases, primer

leading strand

undergoes continuous replication

lagging stand

undergoes discontinuous replication

okazaki fragments

the discontinuously synthesized short DNA fragments forming the lagging strand

DNA helicase

unwinds the double helix

DNA ligase

enzyme that chemically links DNA fragments together

DNA polymerase I

removes the RNA primer and replaces it with DNA

initiator proteins

bind to origin and separate strands of DNA to initiate replication

exonuclease activity

removes incorrectly paired base pairs

mismatch repair

corrects errors after replication is complete, original strand is marked