Question Detail
Question
Which of the following microorganisms are generally *not effectively removed* by the standard filtration process for sterilization, due to their extremely small size?
Correct Answer
Option D is the correct answer.
Detailed Explanation
Sterilizing filters typically have pore sizes ranging from 0.22 to 0.45 micrometers, which are sufficient to remove most bacteria, fungi (yeast and mold spores), and protozoa. However, viruses are significantly smaller, often in the nanometer range, and can frequently pass through these filters, making filtration generally ineffective for complete viral removal.
Hint
Think about the relative sizes of different microorganisms compared to filter pore sizes.