How does DNA copy itself?
Ans:
DNA doesn’t copy itself. It needs an enzyme called DNA polymerase to do it. This, as the linked article describes it, unzips the double helix and then attaches a complementary set of bases to each half, thus creating two molecules where there was only one.
DNA is used only on relatively complex cells that have a lot of “machinery” that makes them function, and the DNA copying machine is one of those specialised mechanisms. Earlier cells probably used RNA, and some RNA can, in certain circumstances, catalyse its own copying, acting as its own polymerase.
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