Which process involves transfer of DNA between bacteria via a pilus?

Which process involves transfer of DNA between bacteria via a pilus?

• A. Transformation
• B. Transduction
• C. Binary Fission
• D. Conjugation

Answer: (D)

Conjugation is the process where DNA moves from one bacterium to another through direct cell-to-cell contact using a pilus. The pilus, often encoded by the F plasmid in the donor cell, forms a mating bridge to the recipient. Through this bridge, DNA—usually a copy of the F plasmid, and in some cases a portion of the chromosome in special donor strains—is transferred. This direct transfer requires physical contact, which is the hallmark of conjugation. This sets it apart from transformation, where bacteria pick up free DNA from the environment, and transduction, where DNA is moved by a bacteriophage. Binary fission is simply asexual reproduction that copies DNA but does not involve transfer between cells. The pilus-mediated contact and plasmid-based transfer are the defining features that point to conjugation.

Conjugation is the process where DNA moves from one bacterium to another through direct cell-to-cell contact using a pilus. The pilus, often encoded by the F plasmid in the donor cell, forms a mating bridge to the recipient. Through this bridge, DNA—usually a copy of the F plasmid, and in some cases a portion of the chromosome in special donor strains—is transferred. This direct transfer requires physical contact, which is the hallmark of conjugation.

This sets it apart from transformation, where bacteria pick up free DNA from the environment, and transduction, where DNA is moved by a bacteriophage. Binary fission is simply asexual reproduction that copies DNA but does not involve transfer between cells. The pilus-mediated contact and plasmid-based transfer are the defining features that point to conjugation.