Textbook Question
Why is the phosphorus cycle important?
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Ch. 27 - Environmental Microbiology
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398
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Table of contents
- Ch. 1 - The Microbial World and You18
- Ch. 2 - Chemical Principles20
- Ch. 3 - Observing Microorganisms Through a Microscope18
- Ch. 4 - Functional Anatomy of Prokaryotic and Eukaryotic Cells21
- Ch. 5 - Microbial Metabolism20
- Ch. 6 - Microbial Growth20
- Ch. 7 - The Control of Microbial Growth20
- Ch. 8 - Microbial Genetics19
- Ch. 9 - Biotechnology & DNA Technology20
- Ch. 10 - Classification of Microorganisms15
- Ch. 11 - The Prokaryotes: Domains Bacteria and Archaea14
- Ch. 12 - The Eukaryotes: Fungi, Algae, Protozoa, and Helminths17
- Ch. 13 - Viruses, Viroids, and Prions20
- Ch. 14 - Principles of Disease and Epidemiology21
- Ch. 15 - Microbial Mechanisms of Pathogenicity19
- Ch. 16 - Innate Immunity: Nonspecific Defenses of the Host20
- Ch. 17 - Adaptive Immunity: Specific Defenses of the Host20
- Ch. 18 - Practical Applications of Immunology20
- Ch. 19 - Disorders Associated with the Immune System19
- Ch. 20 - Antimicrobial Drugs19
- Ch. 21 - Microbial Diseases of the Skin and Eyes21
- Ch. 22 - Microbial Diseases of the Nervous System19
- Ch. 23 - Microbial Diseases of the Cardiovascular and Lymphatic Systems20
- Ch. 24 - Microbial Diseases of the Respiratory System20
- Ch. 25 - Microbial Diseases of the Digestive System20
- Ch. 26 - Microbial Diseases of the Urinary and Reproductive Systems19
- Ch. 27 - Environmental Microbiology20
- Ch. 28 - Applied and Industrial Microbiology19
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398Not the one you use?Change textbook
Chapter 27, Problem 3
For the following question, answer whether
a. The process takes place under aerobic conditions.
b. The process takes place under anaerobic conditions.
c. The amount of oxygen doesn’t make any difference.
Nitrogen fixation
Verified step by step guidance1
Step 1: Understand the process of nitrogen fixation. Nitrogen fixation is the conversion of atmospheric nitrogen (N\_2) into ammonia (NH\_3), which can be used by plants and other organisms.
Step 2: Recall that nitrogenase, the enzyme complex responsible for nitrogen fixation, is highly sensitive to oxygen and is inactivated by it.
Step 3: Recognize that because nitrogenase is oxygen-sensitive, nitrogen fixation typically occurs under anaerobic or low-oxygen conditions to protect the enzyme from inactivation.
Step 4: Consider that some nitrogen-fixing bacteria have adaptations to protect nitrogenase from oxygen, but the process itself fundamentally requires an environment where oxygen is limited or absent.
Step 5: Conclude that nitrogen fixation takes place under anaerobic conditions, so the correct answer corresponds to option b.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Nitrogen Fixation
Nitrogen fixation is the biological process where atmospheric nitrogen (N₂) is converted into ammonia (NH₃), a form usable by plants. This process is primarily carried out by certain bacteria and archaea, often in symbiosis with plants, enabling nitrogen to enter the ecosystem's nutrient cycle.
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Aerobic vs. Anaerobic Conditions
Aerobic conditions require oxygen, while anaerobic conditions occur without oxygen. Microbial processes can be strictly aerobic, anaerobic, or facultative, meaning oxygen presence can influence or inhibit certain biochemical pathways, including nitrogen fixation.
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Oxygen Sensitivity of Nitrogenase Enzyme
The nitrogenase enzyme complex responsible for nitrogen fixation is highly sensitive to oxygen, which can inactivate it. Therefore, nitrogen fixation typically occurs under anaerobic or microaerophilic conditions, or within specialized structures that protect nitrogenase from oxygen exposure.
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Related Practice
Textbook Question
Give one possible explanation of why Penicillium would make penicillin, given that the fungus does not get bacterial infections.
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Textbook Question
In the sulfur cycle, microbes degrade organic sulfur compounds, such as (a) _________________, to release H₂S, which can be oxidized by Acidithiobacillus to (b) _________________. This ion can be assimilated into amino acids by (c) _________________ or reduced by Desulfovibrio to (d) _________________. H2S is used by photoautotrophic bacteria as an electron donor to synthesize (e) _________________. The sulfur-containing by-product of this metabolism is (f) _________________.
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Textbook Question
For the following question, answer whether
a. The process takes place under aerobic conditions.
b. The process takes place under anaerobic conditions.
c. The amount of oxygen doesn’t make any difference.
Methane production
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Textbook Question
For the following question, answer whether
a. The process takes place under aerobic conditions.
b. The process takes place under anaerobic conditions.
c. The amount of oxygen doesn’t make any difference.
Denitrification
685
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Textbook Question
Identify where the following processes occur: ammonification, decomposition, denitrification, nitrification, nitrogen fixation. Name at least one organism responsible for each process.
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