What is the process called when bacteria transfer plasmids to another cell?

• A. Conjugation
• B. Transduction
• C. Transformation
• D. Replication

Answer: (A)

Conjugation is the process by which bacteria transfer plasmids to a neighboring cell. This requires direct cell-to-cell contact, typically via a sex pilus that forms a mating bridge between donor and recipient. The donor carries a conjugative plasmid (often with tra genes) that enables DNA transfer. The plasmid DNA is nicked at the origin of transfer, and a single strand moves into the recipient; both cells then synthesize the complementary strand, restoring double-stranded plasmids in each. This mechanism is a major way bacteria share genetic traits, including antibiotic resistance.

Transduction uses a bacteriophage to move DNA between cells, transformation is uptake of naked DNA from the environment, and replication is just copying DNA within a cell—none of these describe direct plasmid transfer between bacterial cells.