Biogeochemical Cycling And Global – Ch.28 | Exam Questions

Prescott's Microbiology, 11e (Willey)

Chapter 28 Biogeochemical Cycling and Global Climate Change

1) ________ have been defined as communities of organisms and their physical and chemical environments that function as self-regulating units.

2) Some microbes convert iron to magnetite, which is then used as an internal compass to help position the microbe correctly in its environment.

3) Inorganic phosphorus complexed with cations in the environment is most available to microbes at pH 4 and below because of solubility considerations.

4) The use of sulfate as a terminal electron acceptor by Desulfovibrio is an example of assimilatory sulfate reduction.

5) Nutrients are often transformed and cycled by oxidation-reduction reactions that can change the chemical and physical characteristics of the nutrients.

6) An example of biomagnification is the ability of Desulfovibrio to catalyze production of methyl mercury, which is lipid soluble, thereby increasing the concentration of mercury in the food chain.

7) Nitrogen fixation is an energy-yielding process.

8) Which organisms would most likely be present on the bottom or closest to the attachment surface of a complex microbial biofilm?

A) Anaerobic sulfate-reducing bacteria

B) Cyanobacteria

C) Facultative chemoorganotrophs

D) Eukaryotic protists

9) Microbes sometimes make metals such as mercury more volatile and lipid soluble by ________.

A) phosphorylation

B) aggregation

C) methylation

D) None of the choices are correct.

10) Which of the following microbes can oxidize ferrous iron while using chlorate or perchlorate as the electron acceptor?

A) Pseudomonas denitrificans

B) Thiobacillus ferrooxidans

C) Ferribacterium limneticum

D) Dechlorosoma suillum

11) 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 ________.

A) light

B) carbon dioxide

C) oxygen

D) None of the choices are correct.

12) Which of the following is not an example of symbiotic nitrogen fixation?

A) Rhizobium with leguminous plants

B) Azotobacter with certain photosynthetic protists

C) Anabaenea with a water fern

D) Frankia with woody shrubs

13) The release of excess nitrogen into the environment when certain complex organic substrates are used to make new microbial biomass is called ________.

A) mineralization

B) nitrification

C) denitrification

D) dissimilation

14) Degradation of organic matter is influenced by ________.

A) nutrient availability

B) abiotic conditions

C) the nature of the microbial community present

D) All of the choices are correct.

15) Which of the following does not contribute to the increasing levels of methane in the atmosphere?

A) Methane production in termites

B) Methane production in rice paddies

C) Methane production at sewage treatment plants

D) Methane production beneath an aerobic water column

16) The carbon cycle begins with ________.

A) the conversion of carbon dioxide to methane

B) carbon dioxide fixation

C) aerobic respiration

D) anaerobic respiration

17) The process of nitrogen fixation involves the transformation of ________.

A) ammonia to organic matter nitrogen

B) nitrogen gas to ammonia

C) nitrate to nitrogen gas

D) ammonia to nitrate

18) The removal of nutrients from nutrient cycling when those nutrients are converted to biomass is referred to as nutrient ________.

19) Microbes such as Geobacter metallireducens obtain energy from organic matter under anaerobic conditions by using MnO2 as a/an ________ ________.

20) Sulfate and sulfite reductions carried out by Desulfovibrio and related microorganisms are assimilatory processes.

21) When a usable organic electron donor is present, sulfate serves as a terminal electron acceptor during anaerobic respiration by ________.

A) Desulfovibrio

B) Desulfonema

C) Archaeoglobus

D) All of the choices are correct.

22) 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 ________.

A) nitrogen fixation

B) denitrification

C) anammox reaction

D) All of the choices are correct.

23) Bacterioplankton (floating bacteria) use ________ as a sulfur source for protein synthesis.

24) Methane is usually released directly to the atmosphere in environments without an overlying ________ water zone.

25) Biological nitrogen fixation is carried out ________.

A) by prokaryotes and some protists

B) only by prokaryotes in symbiotic relationships with plants

C) only in totally anaerobic environments

D) only by a limited number of prokaryotes

26) In the anammox reaction ________.

A) anaerobic oxidation of ammonia is coupled to the reduction of nitrite

B) nitrogen gas is evolved

C) all reactions must take place in the absence of O2

D) All of the choices are correct.

27) The oxidized form of inorganic iron that results from microbial oxidative processes is ________.

A) ferrous iron

B) ferric iron

C) sulfate iron

D) nitrate iron

28) Biomagnification involves compounds having higher relative concentrations in ________.

A) top consumers

B) lower trophic levels

C) higher trophic levels

D) top consumers or higher trophic levels

29) Peat bogs occur in flooded areas because the rate of decomposition of ________ is slower under anaerobic conditions.

A) starch

B) lignin

C) protein

D) lipids

30) A major fully reduced form of carbon, important in biogeochemical cycling is ________.

A) carbon dioxide

B) carbohydrate

C) methane

D) hydrogen sulfide

31) The process of denitrification involves the transformation of ________.

A) ammonia to organic matter nitrogen

B) nitrogen gas to ammonia

C) nitrate to nitrogen gas

D) ammonia to nitrate

32) Since the beginning of the twentieth century, the rate at which ________ and other so-called greenhouse gases have entered the atmosphere has been faster than at any other time in the known history of life on Earth.

33) The manufacture of fertilizer is an energy-intensive process that uses ________ gas to reduce N2 to NH4+ at high temperature and pressure.

34) Forests are generally regarded as CO2 ________.

A) sources

B) sinks

C) both a source and a sink

D) None of the choices are correct.

35) A single outbreak of a tropical infectious disease in a temperate climate is considered evidence of the effects of global climate change on infectious disease epidemiology.

36) ________ is measured over decades and includes many parameters and this change is directly correlated with fossil fuel combustion to CO2. Seeing more of the "hottest days on record" and noting the average global surface temperature is predicted to rise between 1.1 and 6.48°C by 2100 is connected to ________.

37) Since the beginning of the twentieth century, the rate at which CO2, CH4, and nitrogen oxides have been released into the atmosphere has outpaced the rate at which they can be recycled. Thus these ________ ________ are accumulating in Earth's atmosphere and are correlated with an increase in the global annual-mean surface air temperature. 

38) The accumulation of greenhouse gases leads to reflection of heat from the Earth's surface in the atmosphere and is often called "global warming."  However, with the changes in patterns of wind, precipitation, and ocean temperature also involved, the term ________ ________ ________ is more accurate. 

39) Microbes that use ammonium and nitrate as a source of electrons and CO2 as their sole source of carbon are said to be ________.

40) All of the following statements concerning nitrogen fixation are true EXCEPT which one?

A) Nitrogen fixing microbes convert N2 to ammonia.

B) The products of nitrogen fixation are incorporated into amino acids and nucleic acids.

C) The amount of carbon that is taken up by plants and microbes can be dictated by how much nitrogen is available to support growth. 

D) Nitrogen fixation does not affect the rate of carbon flux.

41) Despite the dramatic increase in microbial nitrification fueled by fertilizer use, nitrification is not a major contributor to the increase in greenhouse Nox gases because nitrate can be immobilized by plants and microbes.

42) Which of the following contribute to atmospheric CO2 levels? (Check all that apply.)

A) Respiration

B) Chemoautotrophy

C) Photosynthesis

D) Burning fossil fuel

E) Deforestation