Practice question

Bacterial chromosomes possess single origin of replication oriC where DnaA-ATP binds DnaA boxes, unwinds DUE and recruits DnaB helicase with DnaC loader. Replication proceeds bidirectionally toward terminus region defined by Tus-Ter complexes. Because only one origin fires per chromosome per cell cycle, bacterial chromosome is monorepliconic. Some bacteria with secondary chromosomes or megaplasmids may appear multirepliconic but canonical E. coli remains model monoreplicon system. Regulation ensures initiation once per cycle via SeqA sequestration and DnaA inactivation, preventing over-replication and maintaining copy number control.