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Ch. 9 - Controlling Microbial Growth in the Environment
Bauman - Microbiology with Diseases by Taxonomy 6th Edition
Bauman6th EditionMicrobiology with Diseases by TaxonomyISBN: 9780134832302Not the one you use?Change textbook
Chapter 9, Problem 11

Which of the following substances would most effectively inhibit anaerobes?
a. Phenol
b. Silver
c. Ethanol
d. Hydrogen peroxide

Verified step by step guidance
1
Step 1: Understand the nature of anaerobes. Anaerobic microorganisms thrive in environments without oxygen and are often sensitive to substances that generate reactive oxygen species or disrupt their metabolic processes.
Step 2: Review the mode of action of each substance: Phenol disrupts cell membranes and denatures proteins; Silver ions interfere with microbial enzymes and DNA; Ethanol denatures proteins and dissolves lipids; Hydrogen peroxide produces reactive oxygen species that damage cellular components.
Step 3: Consider that anaerobes lack certain enzymes like catalase and superoxide dismutase, which protect against oxidative damage, making them particularly vulnerable to oxidative agents.
Step 4: Analyze which substance generates oxidative stress. Hydrogen peroxide decomposes to form reactive oxygen species, which are highly toxic to anaerobes due to their inability to neutralize these compounds effectively.
Step 5: Conclude that the substance producing reactive oxygen species (hydrogen peroxide) would most effectively inhibit anaerobic bacteria compared to the other options.

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Key Concepts

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

Anaerobic Microorganisms

Anaerobes are microorganisms that do not require oxygen for growth and may even be harmed by it. They thrive in oxygen-free environments and have unique metabolic pathways that differ from aerobic organisms. Understanding their oxygen sensitivity is key to targeting them effectively.
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Mechanism of Action of Antimicrobial Agents

Different antimicrobial substances inhibit microbes through various mechanisms, such as disrupting cell walls, denaturing proteins, or generating reactive oxygen species. Knowing how each agent works helps predict its effectiveness against specific types of microbes, including anaerobes.
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Effect of Oxidative Agents on Anaerobes

Oxidative agents like hydrogen peroxide produce reactive oxygen species that damage cellular components. Anaerobes, lacking protective enzymes against oxidative stress, are particularly susceptible to these agents, making oxidative substances effective inhibitors of anaerobic bacteria.
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