Question

multiple choice question
the approximate dimensions of fimbriae are ______.
3 to 10 μm in diameter and up to several mm long
3 to 10 μm in diameter and up to several μm long
3 to 10 μm in diameter and up to several nm long
3 to 10 nm in diameter and up to several μm long

Explanation:

Fimbriae are thin, hair - like appendages on some bacteria. Their diameter is typically in the range of 3 to 10 nanometers (nm), and their length can be up to several micrometers (μm). Let's analyze each option:

• Option 1: The length being up to several millimeters (mm) is incorrect as fimbriae are much shorter. Also, the diameter range here is wrong as it should be in nm, not μm.
• Option 2: The diameter range (3 - 10 μm) is incorrect for fimbriae; it should be in nm.
• Option 3: The length being up to several nanometers (nm) is incorrect. Fimbriae are longer than that, with length in the μm range.
• Option 4: This option has the correct diameter range (3 - 10 nm) and the correct length range (up to several μm long).

Answer:

D. 3 to 10 nm in diameter and up to several μm long