Continuous &
Discontinuous DNA synthesis
RNA primers are added to both strands of DNA
in the 5'
3' direction.
The Replication
Fork (RF) opens unidirectionally: in
this
diagram, it is shown as opening to the right. The RNA primers
are then
extended in the 5'
3'
direction on both strands as DNA synthesis proceeds. On the leading
strand, synthesis is continuous because the primer is extended
without
interruption into the replication fork as it continues to open to the
right. On
the lagging strand, synthesis is discontinuous, since
new RNA primers must be added as the opening
of the replication fork continues to expose new template.
All text material © 2004 by Steven M. Carr