DNA replication requires several key enzymes to unwind, unwind, and synthesize a new double strand of DNA. Helicase unwinds the double helix by breaking hydrogen bonds. Topoisomerase breaks phosphodiester bonds ahead of the replication fork to prevent overwinding of DNA. Primase synthesizes RNA primers providing a 3' end for DNA polymerase to bind and add new nucleotides, forming new phosphodiester bonds through dehydration synthesis and replacing RNA primers with DNA. Ligase seals together the breaks in DNA between Okazaki fragments.

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originof
replication
EnzymesforReplication
0Helicaseunwindsthedouble
helixbreaksHbonds
0Topoisomerase breaksphosphodiesterbonds
aheadofthereplicationforkprevents
over
winding
ofDNA
Prima
sesynthesizesRNA
primers
providing
asite 3end for
DNA
polymerase
to
bindto start
working
0DNApolymerase addsnewnucleotidesto anavailable3endofanothernucleotideforming anew
phosphodiester
bond
bydehydrationsynthesis
replacesRNA
primers
with
DNA
0Ligaseseals
together
breaksinthe
DNAfrom
primessbetween
Okazakifragments