Question

What is the typical pore size of a membrane filter used to sterilize heat-sensitive liquids?

• A. 1.0 µm
• B. 0.45 µm
• C. 0.22 µm
• D. 5.0 µm

Hint:

Membrane sterilization → 0.22 µm filter → Removes bacteria effectively.

Answer 1

The Correct Option is C

Concept: Membrane filtration is a method used to sterilize heat-sensitive liquids such as vaccines, enzymes, and culture media by physically removing microorganisms.
Step 1: Understanding membrane filtration.
It involves passing liquid through a filter with very small pore sizes to retain microorganisms.
Step 2: Typical pore size.
A pore size of 0.22 µm is commonly used to remove bacteria and achieve sterilization.
Step 3: Why this size is effective.

• Most bacteria are larger than 0.22 µm
• Ensures removal of microbial contaminants

Step 4: Eliminating other options.

• 1.0 µm and 0.45 µm: May allow some bacteria to pass
• 5.0 µm: Too large, ineffective for sterilization

Step 5: Conclusion.
Thus, 0.22 µm is the standard pore size used for sterilizing heat-sensitive liquids.