Question

which of the following statements regarding archaeal pili is false?
adhesion to surfaces is one function of pili.
pili are not involved in cellular motility.
a cell can have only one type of pilus.
uv light can trigger the synthesis of a pilus.

Explanation:

• For "Adhesion to surfaces is one function of pili": Archaeal pili do help in adhering to surfaces, so this is true.
• For "Pili are not involved in cellular motility": Some archaeal pili are involved in motility (like twitching motility), but the statement says they are NOT involved. Wait, no—actually, many archaeal pili have roles other than motility, but some can be involved. Wait, no, let's recall: Archaeal pili functions include adhesion, and some (like type IV pili - like structures) can be involved in motility. But the option says "Pili are not involved in cellular motility"—is this false? Wait, no, let's check the other options.
• For "A cell can have only one type of pilus": Archaeal cells can have multiple types of pili, each with different functions (adhesion, DNA transfer, response to stress like UV). So a cell having only one type is false.
• For "UV light can trigger the synthesis of a pilus": UV stress can induce pilus synthesis in archaea as a response (e.g., for DNA uptake or repair - related functions), so this is true.

So the false statement is "A cell can have only one type of pilus".

Answer:

C. A cell can have only one type of pilus