Which plasmid feature enables replication in the bacterial host?

Which plasmid feature enables replication in the bacterial host?

• A. Promoter
• B. Ori
• C. Antibiotic resistance gene
• D. Multiple origins

Answer: (B)

Replication in a bacterial host starts at a specific DNA sequence on the plasmid called the origin of replication. This Ori is recognized by the host’s replication machinery and marks where copying begins, ensuring the plasmid is duplicated as the cell divides. Without this sequence, the plasmid cannot replicate and would be lost over generations. A promoter drives transcription of genes, not the copying of DNA. An antibiotic resistance gene helps identify cells that carry the plasmid but doesn’t enable replication. Some plasmids can have more than one origin, but the essential feature that makes replication possible is the origin of replication. So, the origin of replication, often abbreviated Ori, is the correct feature.

Replication in a bacterial host starts at a specific DNA sequence on the plasmid called the origin of replication. This Ori is recognized by the host’s replication machinery and marks where copying begins, ensuring the plasmid is duplicated as the cell divides. Without this sequence, the plasmid cannot replicate and would be lost over generations. A promoter drives transcription of genes, not the copying of DNA. An antibiotic resistance gene helps identify cells that carry the plasmid but doesn’t enable replication. Some plasmids can have more than one origin, but the essential feature that makes replication possible is the origin of replication. So, the origin of replication, often abbreviated Ori, is the correct feature.