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Okazaki fragment

Definition

noun, plural: Okazaki fragments

Relatively short fragment of DNA synthesized on the lagging strand during DNA replication.


Supplement

At the start of DNA replication, DNA unwinds and the two strands splits in two, forming two "prongs" which resemble a fork (thus, called replication fork). One of the strands goes from 5’ to 3’ and is called the leading strand; the other strand goes from a 3' to 5' and is called the lagging strand. Unlike the leading strand where DNA can be synthesized continuously the lagging strand is synthesized discontinuously in the form of short fragments called Okazaki fragments that are later connected covalently to form a continuous strand. This is because DNA synthesis can proceed only in one direction -- the 5' to 3' direction.

Okazaki fragments are originally discovered by Reiji Okazaki, Tsuneko Okazaki, and their colleagues while studying replication of bacteriophage DNA in Escherichia coli in 1968.


Word origin: named after its discoverers, Reiji Okazaki and his wife, Tsuneko Okazaki, while studying replication of bacteriophage DNA in Escherichia coli in 1968.

See also: DNA, replication, lagging strand.


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No "beginning-replication problem" on leading strand?

... from another direction or end of the strand. The primer is removed by Okazaki fragment going in the other direction.

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by JackBean
Tue May 13, 2014 4:55 pm
 
Forum: Molecular Biology
Topic: No "beginning-replication problem" on leading strand?
Replies: 1
Views: 897

No "beginning-replication problem" on leading strand?

... This is because the extreme end have a RNA primer to make the last Okazaki fragment, and after the removal of this primer it needs to somehow be replaced with DNA. I ...

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by poobear
Fri Apr 11, 2014 9:40 pm
 
Forum: Molecular Biology
Topic: No "beginning-replication problem" on leading strand?
Replies: 1
Views: 897

Okazaki Fragment and RNA Primer

Hi, I have a simple semantics question. I have been reading some literature that seems to consider RNA Primers as part of Okazaki fragments, but this should not be so because Okazaki Fragments by definition are just the DNA portions synthesized on the lagging strand. Any opinions/clarifications ...

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by ahyaa
Sun Nov 17, 2013 10:01 am
 
Forum: Molecular Biology
Topic: Okazaki Fragment and RNA Primer
Replies: 1
Views: 1402

Topoisomerase DNA Replication :D

... "Topoisomerase DNA replication"? :roll: Where else should the Okazaki fragment be than just after the primer?

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by JackBean
Wed Mar 28, 2012 11:22 pm
 
Forum: Cell Biology
Topic: Topoisomerase DNA Replication :D
Replies: 2
Views: 2395

Topoisomerase DNA Replication :D

Will the Okazaki fragment in Topoisomerase DNA replication always be between the primase and the ligase protein complexes on the ...

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by billyfisher100
Wed Mar 28, 2012 6:37 pm
 
Forum: Cell Biology
Topic: Topoisomerase DNA Replication :D
Replies: 2
Views: 2395
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