F pilus

Definition

An F pilus, or sex pilus, is a hair-like appendage found on the surface of many bacteria that facilitates the transfer of DNA between cells during bacterial conjugation. It is primarily composed of the protein pilin and encoded by the F (fertility) plasmid.

5 Must Know Facts For Your Next Test

1. The F pilus mediates the process of bacterial conjugation by connecting a donor cell to a recipient cell.
2. It is encoded by genes located on the F plasmid (fertility factor).
3. Bacteria possessing an F pilus are termed F+ (donor) cells, while those without it are termed F- (recipient) cells.
4. During conjugation, an F+ cell transfers a copy of its F plasmid to an F- cell, converting it into an F+ cell.
5. The formation and function of the F pilus are crucial for horizontal gene transfer among bacteria, contributing to genetic diversity.

Review Questions

• What role does the F pilus play in bacterial conjugation?
• How do bacteria with and without an F pilus differ in terms of their ability to donate DNA?
• What genetic element encodes the proteins required for forming an F pilus?

Related terms

Conjugation:

A process where genetic material is transferred between bacterial cells through direct contact.

F Plasmid:

A type of plasmid that carries genes responsible for the formation of the sex pilus and initiation of conjugation.

Horizontal Gene Transfer:

The movement of genetic material between organisms other than by transmission from parent to offspring.