Final answer:
A low copy origin of replication is a specific nucleotide sequence where DNA replication begins. It is approximately 245 base pairs long and rich in AT sequences. Replication forks are formed, and two replication forks extend in both directions as replication proceeds.
Step-by-step explanation:
A low copy origin of replication is a specific nucleotide sequence where DNA replication begins. In prokaryotes like E. coli, which have a single origin of replication, this sequence is approximately 245 base pairs long and rich in AT sequences. The origin of replication is recognized by proteins that bind to the site, and an enzyme called helicase unwinds the DNA at this site. Replication forks are formed, and two replication forks extend in both directions as replication proceeds. Single-strand binding proteins coat the single strands of DNA near the replication fork to prevent them from winding back into a double helix.