Under physiological conditions, double-stranded DNA is thermodynamically much more stable than the separated strands and that explains why the double-stranded form predominates in vivo. However, the structure of localized regions of the double helix can sometimes be disrupted by unwinding. Such disruption occurs during DNA replication, repair, recombination, and transcription.Having trouble seeing where I went wrong, according to some people? Check out this and this.
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