Does DNA replication only occur in one area of the DNA molecule?
cells; someone has calculated that our longest chromosomes would take about a fortnight to replicate, and we cannot wait that long! So replication begins at a number of sites along the length of the DNA molecule. At each replication site, as the DNA strands are separated there is a bulge in the molecule called a replication bubble. As replication proceeds these bubbles become longer, and eventually they merge into one another and the job is done.
