DNA Structure and Replication

ID #2079

I have a question regarding the replication of bacterial chromosomes. The actual process of two replication forks on either side of the ori and moving around the circle till they meet and separate makes sense. The part I'm confused about is the fact that the template bacterial chromosome is double stranded. Is the newly synthesized bacteria in ds form or ss? And how is it getting replicated if the template is double stranded?


When DNA replication starts, whether it's in a prokaryote or a eukaryote, a replication fork heads out away from the ori in each direction. When we say the fork is moving, what we're really indicating is that more ds-DNA is being denatured into 2 parental strands of ss-DNA. Each of these parental strands is being used as template, one in continuous synthesis and the other in discontinuous synthesis, and the newly-synthesized DNA stays hybridized to the parental template. So you "build" ds-DNA and leave it that way. The region of the DNA that the fork has passed is now two identical helices of ds-DNA, and the part that the fork hasn't reached yet is one helix of ds-DNA.

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