DNA Question

[gsrt=r]

DNA Question

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Post by gsrt=r » Thu Nov 25, 2004 11:40 pm

If an incorrect nucleotide is incorporated into a forming strand of DNA, will this mistake be transmitted to the next generation of DNA molecules that forms from this strand?

[biostudent84]

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Post by biostudent84 » Mon Nov 29, 2004 9:06 pm

Maybe..

There are three different proof-reading activities that occur during and after DNA replication. If the mistake is not found after all three proof-readers check, then yes, the mistake will be transmitted to the next DNA generation.

[Inuyasha]

reply

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Post by Inuyasha » Tue Dec 14, 2004 1:08 pm

Normally the excision process of the DNA checking mechanism should be able to cut and normalize the DNA. However in rare cases the excision mechanism may not work because of the close structure.

[biostudent84]

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Post by biostudent84 » Tue Dec 14, 2004 8:05 pm

The PCNA/Rfc/Pol Delta complex is the initial proof-reader. However, when a mistake is made, the DNA strand is transferred to an Exonuclease site, where the incorrect base is removed. The DNA strand is then transferred back to the PCNA/Rfc/Pol Delta, where replication is continued.

[sachin]

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Post by sachin » Sat Jan 13, 2007 4:32 pm

Mutation Discussion long Ago.......

end up in Mods....

[victor]

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Post by victor » Wed Jan 24, 2007 9:00 am

there are 2 exonuclease activities which is 3'->5' and 5'->3'.
3'->5' = cuts the incorrect base before getting integrated along with the DNA backbone.

5'->3' = cuts the incorrect base after getting integrated along with the DNA backbone. example, the base changing activities by polymerase I in DNA lagging strand after attached one fragment to another by ligase enzyme.