DNA Structure and Replication

ID #1702

Why can't synthesis of DNA occur either 5' to 3' or 3' to 5'? I thought that in lecture you said that it can either be in the form of 5' to 3' exonuclease activity or 3' to 5' exonuclease activity? Or does the exonuclease activity not have to do with synthesis of DNA?

Exonuclease activity is separate from synthesis activity -- in fact they are opposites of each other -- and would be catalyzed in different active sites of the enzyme. Exonuclease activity can occur in either the 5'-3' direction or the 3'-5' direction, but synthesis activity...ONLY...EVER...occurs in the 5'-3' direction.


Print this record Print this record
Send to a friend Send to a friend
Show this as PDF file Show this as PDF file
Export as XML-File Export as XML-File