Here's how it works:

* Pilus: A pilus is a hair-like appendage on the surface of a bacterium.

* Bridge: A pilus can act as a bridge between two bacteria, allowing them to transfer genetic material.

* Conjugation: The transfer of genetic material from one bacterium to another through a pilus is known as conjugation.

During conjugation, one bacterium (the donor) replicates its DNA and sends a copy through the pilus to the other bacterium (the recipient). This transfer can include plasmids (small, circular DNA molecules) or even fragments of the bacterial chromosome.

Conjugation is a key mechanism for horizontal gene transfer in bacteria, which allows them to share traits like antibiotic resistance.