Betty asked in Science & MathematicsBiology · 1 decade ago

Why are okazaki fragments formed?

Why are okazaki fragments formed on the lagging strand during DNA replication?

2 Answers

  • Robert
    Lv 4
    1 decade ago
    Best Answer

    When DNA is being replicated, it can only be replicated from the 5' end to the 3' end. Each strand is anti-parallel, meaning while one goes 5' to 3' in one direction, the other goes 3' to 5' in that same direction. As the strand unwinds, DNA polymerases catalyze the attachment of bases on the non-lagging strand continuously, in a 5' to 3' direction. However, going the other direction, you would have to leave the whole strand unwound or unwind it a second time in order to perform that continuously. Instead, small okazaki fragments are formed in the 5' to 3' direction, opposite the direction of unwinding (but continuing in the direction that the unwinding is occurring).

    Source(s): My professor discovered DNA Polymerase II... I guess that's more of a fact that a source, but I did learn this from him.
  • 1 decade ago

    The double helix unzips in one direction, and DNA polymerase only works in one direction along the DNA strand, but the two DNA strands in the double helix run in opposite direction.

    As an analogy, imagine you are paving a highway that runs in two directions. You have machines that will pave the highway, but can only run in the direction of normal traffic flow. The two machines have to stay near each other. By running one constantly and having the other pave in the opposite direction, then moving the machine farther back and going until it meets the part it just paved, you get the same effect.

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