Pili

Definition

Pili are hair-like appendages found on the surface of many bacteria that facilitate attachment to surfaces and genetic exchange. They are essential for processes like conjugation and biofilm formation.

5 Must Know Facts For Your Next Test

1. Pili are primarily composed of a protein called pilin.
2. There are different types of pili, including fimbriae (shorter) and conjugative pili (longer).
3. Conjugative pili play a crucial role in bacterial conjugation, allowing DNA transfer between cells.
4. Pili can help bacteria adhere to host tissues, contributing to pathogenicity.
5. Some pili are involved in motility, aiding in twitching or gliding movements.

Review Questions

• What is the primary component of pili?
• How do conjugative pili differ from fimbriae?
• What role do pili play in bacterial pathogenicity?

Related terms

Fimbriae:

Shorter, more numerous structures similar to pili that aid in adhesion.

Bacterial Conjugation:

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

Biofilm:

Complex communities of microorganisms adhering to surfaces, often facilitated by structures like pili.