Which of the following is false about fimbriae?
a. They are composed of protein.
b. They may be used for attachment.
c. They are found on gram-negative cells.
d. They are composed of pilin.
e. They may be used for motility.

Verified step by step guidance

1. Step 1: Understand what fimbriae are. Fimbriae are hair-like appendages found on the surface of many bacteria, primarily involved in attachment to surfaces or other cells.
2. Step 2: Analyze each statement about fimbriae: (a) They are composed of protein. This is true because fimbriae are made of protein subunits.
3. Step 3: (b) They may be used for attachment. This is true since fimbriae help bacteria adhere to host cells or surfaces.
4. Step 4: (c) They are found on gram-negative cells. This is generally true as fimbriae are commonly found on gram-negative bacteria.
5. Step 5: (d) They are composed of pilin. This is true because pilin is the protein subunit that makes up fimbriae. (e) They may be used for motility. This is false because fimbriae are not involved in motility; that function is typically associated with flagella.

Key Concepts

Structure and Composition of Fimbriae

Fimbriae are thin, hair-like appendages on the surface of many bacteria, primarily composed of the protein pilin. They differ from flagella in size and function, being shorter and more numerous, and their protein composition allows them to mediate specific interactions with surfaces or host cells.

Function of Fimbriae in Attachment

Fimbriae primarily function to help bacteria adhere to surfaces, including host tissues, which is crucial for colonization and infection. This attachment ability distinguishes fimbriae from other appendages like flagella, which are mainly involved in movement.

Distribution of Fimbriae in Bacteria

Fimbriae are commonly found on gram-negative bacteria, where they play a key role in pathogenicity. While some gram-positive bacteria may have similar structures, fimbriae are most characteristic and well-studied in gram-negative species.