Question

The acronym HEPA stands for-

• A. High Evaluation Protection
• B. High-Efficiency Particulate Air
• C. High-Energy Particles in Air
• D. Hepatitis A

Hint:

In the lab, always remember that HEPA filters do not kill microbes; they physically remove them from the air stream.
Regularly checking the pre-filters in a Laminar Air Flow hood helps extend the life of the expensive HEPA filter.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks for the full form of the acronym HEPA, which is a term frequently encountered in plant biotechnology laboratories, specifically in relation to sterilization and sterile working environments.
Detailed Explanation:

• Definition and Standards:
HEPA stands for High-Efficiency Particulate Air.
It is an efficiency standard for air filters.
To be classified as a true HEPA filter by government standards, the filter must remove at least \( 99.97\% \) of any airborne particles with a size of \( 0.3 \mu m \) (micrometers).

• Importance in Biotechnology:
In plant tissue culture and microbiology, maintaining an aseptic (sterile) environment is critical.
HEPA filters are the core component of Laminar Air Flow (LAF) hoods and biosafety cabinets.
The air is forced through these filters, which trap fungal spores, bacteria, and dust particles, providing a sterile workspace for subculturing plants or inoculating microbes.

• Mechanism of Action:
Unlike simple membrane filters, HEPA filters use a dense mat of randomly arranged fibers (usually fiberglass).
They trap particles through three primary mechanisms: Interception (particles following a line of flow come within one radius of a fiber), Impaction (larger particles cannot avoid fibers due to inertia), and Diffusion (very small particles move erratically and collide with fibers).

Step 3: Final Answer:
The acronym HEPA stands for High-Efficiency Particulate Air.