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Ch. 13 - Characterizing and Classifying Viruses, Viroids, and Prions
Bauman - Microbiology with Diseases by Taxonomy 6th Edition
Bauman6th EditionMicrobiology with Diseases by TaxonomyISBN: 9780134832302Not the one you use?Change textbook
Chapter 13, Problem 10

A clear zone of phage infection in a bacterial lawn is __________ .
a. A prophage
b. A plaque
c. Naked
d. A zone of inhibition

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1
Understand the context: The problem is asking about a clear zone formed on a bacterial lawn due to phage infection. This relates to how bacteriophages (viruses that infect bacteria) affect bacterial cultures.
Recall the definition of each option: A prophage is viral DNA integrated into the bacterial genome; a plaque is a clear area on a bacterial lawn where phages have lysed bacteria; naked refers to viruses without an envelope; a zone of inhibition is a clear area caused by antibiotics, not phages.
Identify the phenomenon: When bacteriophages infect bacteria on a solid medium, they lyse the bacterial cells, creating clear spots called plaques.
Match the term to the description: Since the question describes a clear zone caused by phage infection, the correct term is 'plaque'.
Conclude that the clear zone of phage infection in a bacterial lawn is called a plaque.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Bacteriophage Infection

Bacteriophages are viruses that infect bacteria by attaching to the bacterial cell, injecting their genetic material, and replicating inside. This process often leads to the lysis (destruction) of the bacterial cell, which is visible as clear zones on a bacterial lawn.
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Map of Lesson on Bacteriophage Infections

Plaque Formation

A plaque is a clear, circular area on a bacterial lawn where phages have lysed bacterial cells. Each plaque originates from a single phage particle infecting and killing bacteria, creating a visible zone of clearing that indicates phage activity.
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Bacterial Lawn and Zones of Inhibition

A bacterial lawn is a uniform layer of bacteria grown on an agar plate. Zones of inhibition are clear areas around antibiotic discs where bacterial growth is prevented, differing from plaques which result from viral lysis rather than chemical inhibition.
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