Plaque terminology: On a lawn culture of bacteria, the clear area produced by phage-mediated lysis is called a what?

Introduction / Context:
When bacteriophages infect and lyse bacteria growing as a uniform lawn on agar, they produce localized clearings. These cleared zones are central to quantifying phage titers (plaque-forming units, PFU) and studying phage biology.

Given Data / Assumptions:

• Bacterial lawn provides uniform host distribution.
• Each clearing arises from one infectious phage particle (assuming proper dilution).
• Standard virology terminology is required.

Concept / Approach:
The correct term is “plaque.” Counting plaques at suitable dilutions yields PFU per mL. Morphology (clear vs. turbid, size, halo) can inform phage traits such as lytic strength or depolymerase activity.

Step-by-Step Solution:
Plate host with soft agar and phage dilutions. After incubation, identify discrete clearings. Apply standard term: plaque. Use counts to calculate PFU/mL if needed.

Verification / Alternative check:
Virology manuals define PFU based on plaque counts; antibiotic susceptibility tests use “zones of inhibition,” a different concept.

Why Other Options Are Wrong:
“Pock” and “pox” are historical/animal virus terms in different contexts; “all of these” is inaccurate; zones of inhibition arise from antibiotics, not phages.

Common Pitfalls:
Confusing plaques with bacterial colony morphology or antibiotic halos; plaques reflect viral lysis and spread.

Final Answer:
Plaque.