Which feature enables a plasmid to be replicated and propagated in bacterial cells?

• A. Origin of replication enables antibiotic resistance.
• B. Origin of replication allows genetic material to integrate into host genome.
• C. Origin of replication allows plasmid DNA to be copied and propagated in bacteria.
• D. Origin of replication is a promoter for gene expression.

Answer: (C)

The feature being tested is the origin of replication. This sequence is recognized by the bacterial replication machinery and starts the copying process for the plasmid, so new copies are made and can be passed to daughter cells during division. That’s how the plasmid is propagated and maintained in the bacterial population. Antibiotic resistance genes can ride on plasmids, but resistance itself doesn’t enable replication—that’s the role of the origin. Integration into the host genome would require recombination, not the plasmid’s replication origin, and a promoter drives gene expression, not DNA copying. Different origins also set the plasmid’s copy number and host range, influencing how many copies are present in each cell.