Question

What are the filaments called that help some bacteria stick to surfaces and exchange plasmids through conjugation?

Answer 1

Pili `to` Conjugation.
Fimbriae(short pili) `to` Attachment.

Explanation:

• Pilli (Singular = Pilus):
  Pili are hollow, non-helical, filamentous appendages and are smaller than flagella.These are made of special protein called pilin. These are used by bacteria to exchange their genetic materials in process of conjugation.

• Fimbriae(Singular = Fimbria):
  These are shorter pili which function as a mean of attachment of bacteria to various surfaces e.g host. So, their basic function is adherence.
  
  http://www.easybiologyclass.com/bacterial-cell-surface-structures-and-appendages-flagella-fimbriae-and-pili/