Deck 14: Biogeochemical Cycles

Question 1

What is the oxidation state of carbon in methane?

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

Answer 1

E

Question 2

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

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

Answer 2

C

Question 3

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

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

Answer 3

A

Question 4

What is the oxidation state of carbon in carbon dioxide?

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

Question 5

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 6

Which carbon reservoir is most actively cycled?

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

Question 7

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

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

Question 8

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 9

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

Question 10

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

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

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

How can Type I and Type II methanotrophs be distinguished from one another?

A) By carbon assimilation pathways and Gram stain.
B) By Gram stain and cellular shape.
C) By Gram stain and internal membrane structures.
D) By carbon assimilation pathways and internal membrane structures.
E) By cellular shape and internal membrane structures.

Question 13

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 14

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

Question 15

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 16

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 17

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

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

Question 18

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 19

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 20

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 21

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 22

Which of these summarizes the overall process of nitrogen fixation?

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

Question 23

Which of these summarizes the overall reaction for nitrification?

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

Question 24

The process of denitrification is an anaerobic process.

Question 25

Which of these best describes nitrification?

A) chemoorganotrophic
B) chemolithotrophic
C) phototrophic
D) heterotrophic
E) obligate anaerobic

Question 26

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 27

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 28

What is the oxidation state of nitrogen in ammonia?

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

Question 29

The carbon reservoir in the atmosphere is actively cycled.

Question 30

Methane is a very potent greenhouse gas.

Question 31

The oxidation state of carbon in carbonate (CO₃²⁻)is +4)

Question 32

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

Question 33

Methanogenesis is an anaerobic process.

Question 34

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 35

Carbon dioxide is a greenhouse gas.

Question 36

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

Question 37

Methane cannot be oxidized back to CO₂ under anaerobic conditions.

Question 38

The oxidation state of nitrogen in dinitrogen (N₂)is +1.

Question 39

Which is the major nitrogen reservoir on Earth?

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

Question 40

What is the oxidation state of nitrogen in nitrate?

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

Question 41

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

Question 42

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

Question 43

Describe the metabolic process of nitrification and specific roles of representative microorganisms responsible for the process.

Question 44

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

Question 45

The enzyme ___________ ____________ is used by methanotrophs to oxidize methane to methanol.

Question 46

Describe the processes involved in the decomposition of polymers in an anaerobic environment for the ultimate production of methane.

Question 47

The oxidation state of the carbon atom in methanol (CH₃OH)is ______.

Question 48

What two major human activities have contributed to an increase of carbon dioxide in the atmosphere? What are the consequences of high carbon dioxide in the atmosphere?

Question 49

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

Question 50

Methanogens are members of the Domain _______.

Question 51

The process of nitrification is carried out by chemoautotrophic bacteria.