Sex pilus

Definition

A sex pilus is a hair-like appendage found on the surface of many bacteria that facilitates genetic exchange during conjugation. It connects a donor bacterium to a recipient bacterium, enabling the transfer of DNA.

5 Must Know Facts For Your Next Test

1. Sex pili are primarily involved in the process of bacterial conjugation, which is a type of horizontal gene transfer.
2. The sex pilus forms a physical connection between two bacterial cells, creating a conduit for DNA to be transferred from the donor to the recipient.
3. F+ cells (donor cells) produce the sex pilus, while F- cells (recipient cells) do not produce it but can receive DNA through it.
4. The genes responsible for the formation and function of the sex pilus are typically located on plasmids, such as the F plasmid (fertility plasmid).
5. Sex pili are generally longer and fewer in number compared to other types of pili or fimbriae present on bacterial surfaces.

Review Questions

Related terms

Conjugation:

A process by which one bacterium transfers genetic material to another through direct contact.

Plasmid:

A small, circular piece of DNA that is separate from chromosomal DNA and can replicate independently.

Fimbriae:

Short, hair-like structures on bacterial surfaces used primarily for attachment rather than genetic exchange.