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    Ok so in my book in the spread about PCR it says that 'the sequencing reaction relies on the fact that DNA growns only from the 3' end', but on wikipedia it says that 'nucleic acids can only be synthesized in vivo in the 5′-to-3′ direction, as the polymerase that assembles new strands only attaches new nucleotides to the 3′-hydroxyl (-OH) group'.

    http://en.wikipedia.org/wiki/Directi...cular_biology)

    So which one's right, or have I misinterpreted?
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    (Original post by tazmaniac97)
    Ok so in my book in the spread about PCR it says that 'the sequencing reaction relies on the fact that DNA growns only from the 3' end', but on wikipedia it says that 'nucleic acids can only be synthesized in vivo in the 5′-to-3′ direction, as the polymerase that assembles new strands only attaches new nucleotides to the 3′-hydroxyl (-OH) group'.

    http://en.wikipedia.org/wiki/Directi...cular_biology)

    So which one's right, or have I misinterpreted?
    Your book's description of growing "from the 3' end" is ambiguous, and could be taken in one of two ways. I suspect you're thinking of the way they don't mean-not your fault, just the sloppy wording of the book. What they mean is this:

    If I have a growing strand of DNA bases (B):

    5'.........3'
    BBBBBB

    And I add new bases (N) to it:

    5'.........3'
    BBBBBBNNNN

    The new bases get added to the 3' end, or to put it another way, the strand grows from the three prime end. It's also growing in the 5' to 3' direction.
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    (Original post by schtim)
    Your book's description of growing "from the 3' end" is ambiguous, and could be taken in one of two ways. I suspect you're thinking of the way they don't mean-not your fault, just the sloppy wording of the book. What they mean is this:

    If I have a growing strand of DNA bases (B):

    5'.........3'
    BBBBBB

    And I add new bases (N) to it:

    5'.........3'
    BBBBBBNNNN

    The new bases get added to the 3' end, or to put it another way, the strand grows from the three prime end. It's also growing in the 5' to 3' direction.
    Thank you
 
 
 
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