Microbio Ch 28

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Which organisms would most likely be present on the bottom or closest to the attachment surface of a complex microbial biofilm? -Eukaryotic protists -Facultative chemoorganotrophs -Cyanobacteria -Anaerobic sulfate-reducing bacteria

Anaerobic sulfate-reducing bacteria

NH4--> N2

Anammox

SO4 --> Organic S

Assimilatory Sulfate Reduction

NO3 --> Organic N

Assimilatory nitrate reduction

Which of the following is not an example of symbiotic nitrogen fixation? -Anabaenea with a water fern -Azotobacter with certain photosynthetic protists -Rhizobium with leguminous plants -Frankia with woody shrubs

Azotobacter with certain photosynthetic protists

Organic N --> NH4

Decay and mineralization

Organic S --> H2S

Decay and mineralization

Which of the following microbes can oxidize ferrous iron while using chlorate or perchlorate as the electron acceptor? -Thiobacillus ferrooxidans -Dechlorosoma suillum -Ferribacterium limneticum -Pseudomonas denitrificans

Dechlorosoma suillum

N2 --> NH3 --> Organic N

N2 fixation

Chemolithoautotrophs use ______ and NO₂- as a source of ___________ and CO₂ as their carbon source, producing organic carbon and ___________ as their metabolic biproducts.

NH₄+ electrons nitrate

Nitrification occurs in

aerobic conditions

Anammox occurs in

anaerobic conditions

Denitrification occurs in

anaerobic conditions

Methanogenesis occurs in

anaerobic conditions

Nitrogen fixation occurs in

anaerobic conditions

Sulfate reduction occurs in

anaerobic conditions

When reviewing the carbon cycle, inorganic carbon (CO2) and organic carbon can be reduced _________. -anaerobically to methane (CH4) -aerobically to methane (CH4) -anaerobically to carbon monoxide (CO) -aerobically to carbon monoxide (CO)

anaerobically to methane (CH4)

Nitrate can be reduced by organisms carrying out ________________ nitrate reduction or returned to the atmosphere as _______ following ________________ by anaerobes. Nitrogen-fixing microbes produce ammonia for incorporation into proteins and nucleic acids, the production of which often dictates the amount of carbon flux in the environment by supporting microbial growth.

assimilatory N₂ denitrification

Biogeochemical cycles are dynamic, interconnected processes that over geological time allow the ___________ to be self-sustaining.

biosphere

Carbon fixation occurs in

both aerobic and anaerobic conditions

Fermentation occurs in

both aerobic and anaerobic conditions

Methane oxidation occurs in

both aerobic and anaerobic conditions

Respiration occurs in

both aerobic and anaerobic conditions

Sulfur oxidation occurs in

both aerobic and anaerobic conditions

The carbon cycle begins with _________. -the conversion of carbon dioxide to methane -carbon dioxide fixation -anaerobic respiration -aerobic respiration

carbon dioxide fixation

Microbes can fix carbon in anoxic environments using anoxygenic photosynthesis as well as by _________. -chemolithoautotrophy in the presence of light -chemolithoautotrophy in the absence of light -chemoorganoautotrophy in the absence of light -chemoorganoautotrophy in the presence of light

chemolithoautotrophy in the absence of light

The oxidized form of inorganic iron that results from microbial oxidative processes is ________. -sulfate iron -nitrate iron -ferric iron -ferrous iron

ferric iron

The reduced __________ form of iron (_______) can be a source of electrons through _____________ iron oxidation.

ferrous Fe²⁺ lithotrophic

Carbon fixation found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

found in eukaryotes, bacteria, and archaea

Fermentation found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

found in eukaryotes, bacteria, and archaea

Respiration found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

found in eukaryotes, bacteria, and archaea

These organisms must oxidize vast amounts of ____________ compounds to generate enough energy to fix CO₂

inorganic

In addition to the carbon, nitrogen, and sulfur cycles, the _______ and manganese cycles are also based on redox reactions.

iron

Anammox found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

only in bacteria and archaea

Denitrification found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

only in bacteria and archaea

Methane Oxidation found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

only in bacteria and archaea

Methanogenesis found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

only in bacteria and archaea

Nitrification found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

only in bacteria and archaea

Nitrogen fixation found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

only in bacteria and archaea

Sulfate Reduction found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

only in bacteria and archaea

Sulfur Oxidation found in -only in bacteria and archaea -found in eukaryotes, bacteria, and archaea

only in bacteria and archaea

Because of the high requirement for reducing power in nitrogen fixation, the nitrogenase enzyme that carries out the reaction is very sensitive to the presence of _________. -light -carbon dioxide -oxygen -None of the choices are correct.

oxygen

Other biogeochemical cycles do not involve redox transformations such as the ____________ cycle.

phosphorus

Biomagnification involves compounds having higher relative concentrations in _________. -top consumers -lower trophic levels -higher trophic levels -top consumers or higher trophic levels

top consumers or higher trophic levels

Organic matter --> CO2 type and name

Oxidative and redox neutral Respiration and fermentation

Methanogenesis include

-acetate, formate, or H2 + CO2, supply carbon and electrons -strict anaerobes -product is CH4 -anaerobic respiration -methanogens

Methano- and methylotrophy include

-aerobic bacteria -anaerobic archaea -single carbon molecules such as methane and formate supply carbon and electrons -product is CO2

Aerobic oxidation of organic carbon include

-aerobic respiration -chemoorganoheterotrophs -product is CO2

Anaerobic oxidation of organic carbon include

-chemoorganoheterotrophs -product is CO2 -anaerobic respiration -fermentation

Evaluate the environments below and select those that are capable of sustaining methanogenesis. -human oral cavity -marshes -sewage treatment plants -rice paddies -refrigerator -freshwater stream -coal mines -landfills -laboratory incubator -ruminant gut

-marshes -sewage treatment plants -rice paddies -coal mines -landfills -ruminant gut

Biological nitrogen fixation is carried out _________. -only by a limited number of prokaryotes -by prokaryotes and some protists -only by prokaryotes in symbiotic relationships with plants -only in totally anaerobic environments

-only by a limited number of prokaryotes

CO2 fixation include

-oxygenic photosynthesis -photolithoautotrophs -anoxygenic photosynthesis -chemolithoautotrophs -product is a organix carbon

Degradation of organic matter is influenced by _________. -nutrient availability -abiotic conditions -the nature of the microbial community present -All of the choices are correct.

All of the choices are correct.

In the anammox reaction _________. -anaerobic oxidation of ammonia is coupled to the reduction of nitrite -nitrogen gas is evolved -all reactions must take place in the absence of O2 -All of the choices are correct.

All of the choices are correct.

You are performing an experiment in which you have three different incubation chambers: Chamber 1: Aerobic chemoorganotrophic bacteria that use aerobic respiration. Chamber 2: Anaerobic chemoorganotrophic bacteria that use anaerobic respiration. Chamber 3: Anaerobic chemoorganotrophic bacteria that use fermentation. Each chamber has the same concentration or organic carbon. You have added nitrate and phosphate (at a ratio of about 16:1) to each as well as organic molecules to provide a source of other elements. Which chamber do you predict will most likely become nitrate limited (i.e., run out of nitrate) first and which will most likely run out of phosphorus first? -Chamber 1 will run out of nitrate first and chamber 2 will run out phosphate first. -Chamber 2 will run out of nitrate first and chamber 3 will run out phosphate first. -Chamber 1 will run out of nitrate first and chamber 3 will run out phosphate first. -Chamber 2 will run out of nitrate first and chamber 1 will run out phosphate first.

Chamber 2 will run out of nitrate first and chamber 1 will run out phosphate first.

Which of the following does not contribute to the increasing levels of methane in the atmosphere? -Methane production beneath an aerobic water column -Methane production at sewage treatment plants -Methane production in rice paddies -Methane production in termites

Methane production beneath an aerobic water column

NH4 --> NO2 --> NO3

Nitrification (Nitrobacter, Nitrococcus)

All of the following statements concerning nitrogen fixation are true EXCEPT which one? -The products of nitrogen fixation are incorporated into amino acids and nucleic acids. -Nitrogen fixing microbes convert N2 to ammonia. -The amount of carbon that is taken up by plants and microbes can be dictated by how much nitrogen is available to support growth. -Nitrogen fixation does not affect the rate of carbon flux.

Nitrogen fixation does not affect the rate of carbon flux.

Carbon Monoxide occurs in

Occurs in aerobic conditions

From CH4 --> CO2 type and name

Oxidative Methano- and methylotrophy

CO2 --> organic matter type and name

Reductive Co2 fixation photo and chemoautotrophy

NO3 --> N2

denitrification

When nitrate is reduced to dinitrogen gas (N2), nitrogen is removed from the ecosystem and returned to the atmosphere through a series of reactions collectively known as _________. -nitrogen fixation -denitrification -anammox reaction -All of the choices are correct.

denitrification

NO3 --> N2O

dissimilatory nitrate reduction

NO3 --> NO2

dissimilatory nitrate reduction

S2O3 --> H2S

dissimilatory sulfate reduction

SO4 --> S --> H2S

dissimilatory sulfate reduction

In the iron cycle, the oxidized _________ form of iron (_______) can be used as the terminal electron acceptor for anaerobic respiration through ____________ iron reduction.

ferric Fe³⁺ dissimilatory

Peat bogs occur in flooded areas because the rate of decomposition of _________ is slower under anaerobic conditions. -lipids -lignin -protein -starch

lignin

Similarly, in the manganese cycle, some microbes use oxidized ____________ ions in _________ as a terminal electron acceptor for anaerobic respiration and reduced _____________ ions (_______) as a source of electrons.

manganic MnO₂ manganous Mn²⁺

The nitrogen and carbon cycles are linked by microorganisms having different _____________ strategies to create balance in an ecosystem.

metabolic

A major fully reduced form of carbon, important in biogeochemical cycling is _________. methane carbohydrate carbon dioxide hydrogen sulfide

methane

Microbes sometimes make metals such as mercury more volatile and lipid soluble by _________. phosphorylation aggregation methylation None of the choices are correct.

methylation

The release of excess nitrogen into the environment when certain complex organic substrates are used to make new microbial biomass is called __________. nitrification dissimilation denitrification mineralization

mineralization

Phosphorus from organic matter can be _____________ to PO₄ and then _____________ to an organic form.

mineralized immobilized

The process of denitrification involves the transformation of _________. -ammonia to organic matter nitrogen -ammonia to nitrate -nitrate to nitrogen gas -nitrogen gas to ammonia

nitrate to nitrogen gas

The process of nitrogen fixation involves the transformation of _________. -nitrate to nitrogen gas -nitrogen gas to ammonia -ammonia to organic matter nitrogen -ammonia to nitrate

nitrogen gas to ammonia

CO2 --> CH4 type and name

reductive methanogenesis

H2S --> S

sulfide oxidation: hydrogen sulfide serves as electron donor

S --> S2O3

sulfur oxidation: elemental sulfur serves as electron donor


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