Deck 14: Biogeochemical Cycles

Question 1

The main primary producers in aquatic environments are _______,while in terrestrial environments the main primary producers are __________.

A)plants,plants
B)microbes,microbes
C)plants,microbes
D)microbes,plants
E)microbes and plants contribute equally in both environments

Answer 1

D

Question 2

Many metabolic reactions in anaerobic environments are driven by methanogens because of the rapid utilization of this material during methanogenesis.

A)carbon dioxide
B)sulfate
C)formate
D)hydrogen
E)nitrogen

Answer 2

D

Question 3

When considering biogeochemical cycles,the earth is divided into these four major reservoirs.

A)Ocean,terrestrial,sedimentary and earth's crust.
B)Atmosphere,earth's crust,biological and land.
C)Atmosphere,terrestrial,biological and aquatic.
D)Terrestrial,aquatic,biological and earth's crust.
E)Ocean,freshwater,sedimentary and terrestrial.

Answer 3

C

Question 4

What is the oxidation state of carbon in methane?

A)+1
B)+ 2
C)-1
D)-2
E)-4

Question 5

Select the correct choice for the abundances of elements found in cells,from lowest to highest:

A)carbon,sulfur,nitrogen,phosphorous
B)sulfur,phosphorus,nitrogen,oxygen
C)carbon,nitrogen,oxygen,sulfur
D)carbon,potassium,phosphorous,hydrogen
E)carbon,oxygen,nitrogen,sulfur

Question 6

Which of these is linked with production of cement for construction of highways?

A)A decrease in sand.
B)An increase in atmospheric carbon dioxide.
C)A decrease in limestone.
D)A decrease in fossil fuel consumption.
E)An increase of atmospheric nitrogen.

Question 7

Bacteria that rely on methanotrophy for carbon and energy metabolism utilize one of these two unique pathways for carbon assimilation.

A)Serine pathway and the ribulose monophosphate pathway.
B)Acetyl-CoA pathway and the serine pathway.
C)Reductive TCA pathway and the acetyl-CoA pathway.
D)Ribulose monophosphate pathway and the reductive TCA pathway.
E)Acetyl-CoA pathway and the ribulose monophosphate pathway.

Question 8

What is the oxidation state of carbon in lactic acid (C₃H₆O₃)?

A)0
B)-2
C)-4
D)+2
E)+4

Question 9

Methanotrophs,in contrast to non-methanotrophic methylotrophs,may contain this enzyme.

A)methane carboxylase
B)methane lyase
C)methane monooxygenase
D)methane dehydrogenase
E)methane kinase

Question 10

In methane-producing environments large polymers are broken down by a consortium of microbes.This consortium includes:

A)obligate aerobic bacteria and methanogens.
B)polymer hydrolyzing microbes,fermenters,and methanogens.
C)aerobic polymer hydrolyzing microbes and fermenters.
D)primary aerobic respiratory microbes and methanogens.
E)sulfate-reducing microbes and methanogens.

Question 11

Which of these is true regarding soil humus?

A)It is quickly broken down by microorganisms.
B)It is a minor component of organic carbon in the soil.
C)It is degraded very slowly over time.
D)It is primarily inorganic in composition.
E)It is a polymer of glucose.

Question 12

What is the oxidation state of carbon in carbon dioxide?

A)0
B)-2
C)-4
D)+2
E)+4

Question 13

Which compound listed below would NOT be utilized by an obligate methylotroph?

A)methanol
B)dimethylamine
C)acetate
D)formate
E)formaldehyde

Question 14

Which of these statements is TRUE regarding oxygen use and utilizers of methanogenesis?

A)It is aerobic,and carried out by Bacteria.
B)It is aerobic,and carried out by Archaea.
C)It is anaerobic,and carried out by Bacteria.
D)It is anaerobic,and carried out by Archaea.
E)It is anaerobic,and carried out by Eukarya.

Question 15

Methane utilization by methylotrophs is an environmentally important process.Why?

A)Methane is a dead-end energy source.
B)The process prevents methane,a greenhouse gas,from entering the atmosphere.
C)Methane is toxic to fish.
D)Methane inhibits photosynthesis.
E)The process prevents lakes from becoming anoxic.

Question 16

Which of these would occur in an "ideal" food web?

A)Organic carbon production > carbon dioxide production.
B)Organic carbon production < carbon dioxide production.
C)Organic carbon production = carbon dioxide consumption.
D)Carbon dioxide consumption < than organic carbon production.
E)Carbon dioxide consumption > organic carbon production.

Question 17

Why is carbon dioxide considered a greenhouse gas?

A)It is fixed by plants during photosynthesis.
B)It is produced during the oxidation of organic compounds.
C)It is found in high concentrations in greenhouses.
D)It absorbs heat attempting to escape the atmosphere.
E)It is utilized by suspended microbes in the atmosphere.

Question 18

Which carbon reservoir is most actively cycled?

A)the atmosphere
B)ocean waters
C)underground limestone
D)forest mulch
E)ocean sediments

Question 19

Select the correct choice for the abundances of elements found in cells,from highest to lowest:

A)carbon,sulfur,nitrogen,phosphorous
B)sulfur,phosphorus,nitrogen,sodium
C)carbon,nitrogen,oxygen,sulfur
D)carbon,potassium,phosphorous
E)carbon,oxygen,nitrogen,sulfur

Question 20

Elemental movement between reservoirs is termed:

A)flux
B)source
C)sink
D)oxidation
E)reduction

Question 21

Which of these endergonic reactions would be most easily permitted to take place via the activity of hydrogenotrophic methanogens?

A)butyrate oxidation
B)propionate oxidation
C)ethanol oxidation
D)all will be oxididized with equal efficiency
E)the reactions cannot proceed under any conditions because of the positive ΔGo' values

Question 22

Biological uses for phosphorus include:

A)incorporation into lipids
B)incorporation into cofactors
C)incorporation into nucleic acids
D)protein activity regulation
E)all are correct

Question 23

Which industrial process is used for the production of ammonia for land application?

A)Mattox
B)Havel - Brill
C)Dalgarno
D)Haber-Bosch
E)Anderson-Plamann

Question 24

Which of these bacteria has the most adverse influence on global warming?

A)Denitrifier species
B)Annamox species
C)Brocadia
D)Candidatus
E)Jettenia

Question 25

Which of these best describes nitrification?

A)chemoorganotrophic
B)chemolithoautotrophic
C)photolithoautotrophic
D)photoorgano heterotrophic
E)photlithoautotrophic

Question 26

What is the oxidation state of nitrogen in ammonia?

A)-3
B)-1
C)0
D)+1
E)+3

Question 27

Ammonia monooxygenase characteristics include:

A)conversion of nitrite to nitrate
B)conversion of nitrate to nitrite
C)conversion of ammonia to nitrate
D)conversion of ammonia to nitrite
E)conversion of ammonia to hydroxylamine

Question 28

The anaerobic oxidation of methane by some archaeons may occur syntrophically with these organisms.

A)nitrogen fixing bacteria
B)nitrifying bacteria
C)denitrifying bacteria
D)iron-oxidizing bacteria
E)sulfate-reducing bacteria

Question 29

Why is the process of denitrification detrimental to the soil?

A)It leads to acidification of the soil.
B)It leads to loss of utilizable nitrogen from the soil.
C)It leads to loss of oxygen in the soil.
D)It leads to loss of organic matter from the soil.
E)It leads to the production of toxic nitrogen intermediates.

Question 30

The difference between a methanotroph and a methylotroph can be explained as:

A)a methanotroph can oxidize any substrate which lacks C-C bonds,while a methylotroph oxidizes only methane
B)a methylotroph can oxidize any substrate which lacks C-C bonds,while a methanotroph oxidizes only methane
C)methylotrophs can always oxidize methane while methanotrophs cannot
D)methylotrophs can never oxidize compounds with C-C bonds while methanotrophs oxidize them
E)all statements are correct

Question 31

Which of these summarizes the overall process of nitrogen fixation?

A)ammonia → N₂
B)N₂ → biomass
C)NO₃⁻ → biomass
D)NO₃⁻ →N₂
E)ammonia → NO₃⁻

Question 32

Which of these summarizes the overall process of denitrification?

A)N₂ → NH₃
B)biomass → ammonia
C)NO₃⁻ → ammonia → biomass
D)NO₃⁻ →N₂
E)ammonia → NO₃⁻

Question 33

Methane monooxygenase activity:

A)both donates to and accepts electrons from an electron transport chain
B)cannot occur in the cytosol
C)generates reduced methanol
D)removes protons from the proton-motive force of the cell
E)none is a correct statement

Question 34

How can denitrification of soil be reduced?

A)By adding lime to the soil.
B)By adding ammonia to the soil.
C)By keeping the soil well aerated.
D)By adding potash to the soil.
E)By flooding the soil with water.

Question 35

Which of these microbial activities would be first in a chain of metabolite production culminating in methane production?

A)yeast ethanol production
B)bacterial fatty acid oxidation
C)bacterial acetate production
D)archaeal conversion of hydrogen to methane
E)bacterial conversion of acetate to methane

Question 36

Which is the major nitrogen reservoir on Earth?

A)plants
B)microbes
C)the atmosphere
D)ocean biomass
E)organic matter in soil

Question 37

Which of these summarizes the overall reaction for nitrification?

A)NO₃⁻ → NO₂⁻
B)NO₂⁻ → NO₃⁻
C)NO₃⁻ → ammonia → biomass
D)NO₃⁻ →N₂
E)ammonia → NO₃⁻

Question 38

Bacteria which assist in making phosphorous available to plants include;

A)Desulfovibrio
B)Candidatus
C)Clostridium
D)Bacillus
E)None is a correct choice

Question 39

What is the oxidation state of nitrogen in nitrate?

A)-3
B)-1
C)+1
D)+3
E)+5

Question 40

Which one of the following is NOT a reservoir for oxygen?

A)the atmosphere
B)carbon dioxide
C)nitrate
D)ammonia
E)water

Question 41

The end-products of anaerobic methanotrophic metabolism include: (Select all that apply)

A)carbonate
B)carbon dioxide
C)acetate
D)formate
E)sulfate

Question 42

Siderophores are necessary for movement of iron into cells because:

A)free iron will otherwise pass electrons to oxygen and be unavailable
B)nitrate will compete for free iron under oxic conditions
C)nitrate will reduce Fe³+ under oxic conditions
D)neutral pH conditions such as those in cells will reduce Fe³+to Fe²+
E)none of the choices is correct

Question 43

Which microbes are directly responsible for methane production? (Select all that apply)

A)primary fermenters
B)secondary fermenters
C)homoacetogens
D)acetotrophic methanogens
E)hydrogenotrophic methanogens

Question 44

Aquatic sulfur is primarily:

A)Present as H₂S
B)Present as sulfate
C)Present as elemental sulfur
D)Present as dimethylsulfoniopropionate
E)Present as the amino acid cysteine

Question 45

Methanogenesis helps drive a number of other microbial processes in anaerobic environments through the removal of hydrogen gas.

Question 46

Which of these elements are atmospherically abundant? (Select all that apply)

A)oxygen
B)nitrogen
C)sulfur
D)phosphorous
E)sodium

Question 47

The process of denitrification is an anaerobic process.

Question 48

Which of the following are correct statements regarding methane monoxygenase? (Select all that apply)

A)the enzyme functions under anaerobic conditions
B)microbes possessing this enzyme often reside at the interface between aerobic and anaerobic zones
C)methane is converted to methanol in a single step
D)methane is converted to formaladehyde in a single step
E)electrons released by methane oxidation enter an electron transport chain which generates ATP and water as end products

Question 49

Methane cannot be oxidized back to CO₂ under anaerobic conditions.

Question 50

Marine.algae have the potential to reduce global warming through generation of:

A)Hydrogen sulfide
B)Sulfur dioxide
C)dimethylsulfoniopropionate
D)dimethylsulfide
E)methane

Question 51

Which of the following are correct statements regarding methane monoxygenase? (Select all that apply)

A)the enzyme functions under aerobic conditions
B)microbes possessing this enzyme often reside at the interface between aerobic and anaerobic zones
C)methane is converted to carbon dioxide in a single step
D)its activity requires membrane localization
E)electrons released by methane oxidation enter an electron transport chain which generates ATP and water as end products

Question 52

Bacteria capable of iron reduction include all of the following except:

A)Euryarchaeota
B)Crenarchaeota
C)Proteobacteria
D)Archaea
E)Firmicultes

Question 53

Which of these terms refers to a substance which does NOT reduce global warming?

A)Osmolyte
B)dimethylsulfoniopropionate
C)dimethylsulfide
D)methane
E)all reduce global warming

Question 54

Atmospheric sulfur is primarily:

A)Present as H₂S
B)Present as sulfate
C)Present as elemental sulfur
D)Present as dimethylsulfoniopropionate
E)Present as the amino acid cysteine

Question 55

Why may it take months to years for some zones of the Winogradsky colum to develop their characteristic colors? (Select all that apply)

A)oxygen intially present throughout the column may inhibit initial growth of anaerobes
B)some microbes grow more slowly than others
C)biofilm communities may have to form to allow microbial consortiums to exchange nutrients
D)the plastics of column containers need to be altered by sunlight to permit microbial metabolism
E)all are correct choices

Question 56

Which microbes metabolize hydrogen during methanogenesis? (Select all that apply)

A)primary fermenters
B)secondary fermenters
C)homoacetogens
D)acetotrophic methanogens
E)hydrogenotrophic methanogens

Question 57

Metabolism of a cyanobacterium can influence which biogeochemical cycles? (Select all that apply)

A)carbon
B)nitrogen
C)water
D)phosphorous
E)none of these is a correct choice

Question 58

Members of the Plantae are the primary producers in aquatic environments.

Question 59

The end-products of anaerobic methanotrophic metabolism include: (Select all that apply)

A)carbonate
B)carbon dioxide
C)acetate
D)formate
E)sulfate

Question 60

Carbon dioxide is a greenhouse gas.

Question 61

The chemoautotrophic process that results in the oxidation of ammonia to nitrite is called ____________.

Question 62

An interacting community of interdependent organisms is called a/an _________.

Question 63

Methanogens are members of the Domain _______.

Question 64

The anaerobic process that results in the reduction of nitrate to dinitrogen gas is called ______________.

Question 65

The burning of fossil fuels has contributed to an increase in the atmospheric gas _______ ________.