Replication begins
at a specific site in the DNA called the origin of replication. Unwinding
enzymes called DNA helicases cause the two parent DNA strands to unwind and
separate from one another in both directions at this site to form two "Y"-shaped
replication forks. These replication forks are the actual site of DNA copying.
During replication within the fork, helix destabilizing proteins (not shown
here) bind to the single-stranded regions preventing the strands from rejoining.
