Exam Prep Microorganisms In Terrestrial Ecosystems Ch31

Prescott's Microbiology, 11e (Willey)

Chapter 31 Microorganisms in Terrestrial Ecosystems

1) Microorganisms in soil are located in thin water films on particle surfaces where oxygen is present at high levels.

2) Oxygen diffuses equally well through waterlogged soil and dry soil.

3) A mineral soil contains less than 20% organic carbon while an organic soil contains at least that amount.

4) The common building block of _______ is the phenylpropene unit, which consists of a hydroxylated six-carbon aromatic benzene ring and a three-carbon linear side chain.

5) Lignin degradation by basidiomycetes is an aerobic process that is catalyzed by phenoloxidases.

6) In bog soils, the decomposition rate of lignin-cellulose complexes is accelerated by the waterlogged, predominately anoxic conditions.

7) A carbon to nitrogen (C/N) ratio of 20 or less in soil results in the loss of soluble nitrogen from the system.

8) Ionized ammonia applied to soil is effectively retained because clays in the soil have a charge that is ________.

A) positive

B) negative

C) uncharged

D) None of the choices are correct. 

9) An average gram of forest soil contains about ________.

A) 2 × 109 bacteria and archaea

B) 4 × 107 bacteria and archaea

C) 4 × 107 protists

D) 2 × 109 fungi

10) Fungi can be present at up to several hundred meters of hyphae per gram of soil.

11) Molecular techniques have shown that Cyanobacteria are not present in soil.

12) One of the more important genera of gram-positive aerobic actinomycetes found in soils is ________.

A) Streptomyces

B) Bdellovibrio

C) Acinetobacter

D) Pseudomonas

13) The vast majority of microorganisms found in soils have been successfully cultured in the laboratory.

14) Geosmin, which contributes to the characteristic earthy odor of soils, is produced primarily by the genus ________.

A) Streptomyces

B) Paramecium

C) Caenorhabditis

D) Armillaria

15) Soil protists often utilize bacteria as a nutrient source.

16) Filamentous fungi found in soils are able to form bridges across aggregates and facilitate nutrient transfer processes.

17) A unique feature of terrestrial filamentous fungi that allows them to bridge open areas between soil particles is/are ________.

A) oxygen-impermeable structures including sclerotia and hyphal cords

B) formation of flagellated spores that aid in spore dispersal

C) mitochondria with highly invaginated cristae that permit more rapid diffusion of oxygen for oxidative phosphorylation

D) All of the choices are correct.

18) Most organic matter found in soils results from primary producers such as ________.

A) cyanobacteria

B) vascular plants

C) photosynthetic protists

D) None of the choices are correct.

19) Microbes that live on the surface of plants are called ________.

20) Which of the following is inconsistent with the current understanding of how plants and microbes interact with each other? 

A) Plants are able to send chemical signals to microbes but they are not able to receive signals from the microbes. 

B) Plants produce chemical signaling molecules that microbes can detect and react to. 

C) Microbes produce chemical signaling molecules that plants can react to. 

D) All of these statements are inconsistent with our understanding of how plants and microbes interact with each other. 

21) A common resident of the rhizosphere that can enhance plant growth is ________.

A) Azotobacter

B) Erwinia

C) Sphingomonas

D) Pseudomonas

22) A major organism involved in associative nitrogen fixation in the rhizosphere of many plants is ________.

A) Azospirillum

B) Rhizobium

C) Frankia

D) Pseudomonas

23) The region of soil in the immediate vicinity of the roots of plants is called the ________.

A) plant crust

B) rhizosphere

C) phyllosphere

D) microbivory

24) The bacterial genera that produces pigments which protect plant leaves from UV irradiation is ________.

A) Nocardia

B) Cellulomonas

C) Sphingomonas

D) Arthrobacter

25) The stems and leaves of plants, called the ________, provide a habitat for a wide variety of microorganisms.

A) plant crust

B) rhizosphere

C) phyllosphere

D) microbivory

26) The plant leaf surface is called the rhizosphere.

27) An important bacterial mediated process that occurs on the surface of plant roots is called ________ nitrogen fixation.

28) The surface of a plant root is called the ________.

29) Mycorrhizae are formed by the association of plants with ________.

A) algae

B) actinomycetes

C) cyanobacteria

D) fungi

30) Mycorrhizal fungi can either be intracellular or extracellular.

31) In a mycorrhizal relationship, the fungal component can assist in providing phosphorus and water to the plant. The plant in turn provides the fungus with ________.

A) metal cofactors

B) organic carbon

C) nitrogen

D) carbon dioxide

32) Which of the following statements is correct?

A) All plants maintain a mycorrhizal relationship.

B) Most plants maintain a mycorrhizal relationship.

C) Some plants maintain a mycorrhizal relationship.

D) Only a few plants maintain a mycorrhizal relationship.

33) The ________ mycorrhizae are the most common type of mycorrhizae.

A) arbuscular

B) ericaceous

C) orchidaceous

D) monotropoid

34) A substance that promotes binding of Rhizobium to plant root hairs is called a ________ factor.

35) Most ectomycorrhizae produce signaling molecules that limit the growth of root hairs.

36) Legume plants provide certain amino acids to the ________ so that they do not need to assimilate ________. In return, the bacteroids shuttle amino acids bearing the fixed nitrogen back to the plant.

A) bacteroids; nitrogen

B) bacteroids; phosphorus 

C) bacteroids; ammonia

D) root hairs; nitrogen

37) In the process of forming a root nodule, species of Rhizobium differentiate to form a type of cell called a ________.

A) lymph node

B) bacteroid

C) nucleoid

D) vesicle

38) The formation of an infection thread is an important initial part of microbial interactions with plants in the process of ________.

A) nitrification

B) nitrogen fixation

C) denitrification

D) sulfate reduction

39) When rhizobia approach a plant root, the plant initially responds by ________.

A) an oxidative burst

B) an increase in exudate

C) releasing flavonoid inducer molecules

D) producing leghemoglobin

40) Bacteroids are terminally differentiated—they can neither divide nor revert back to the nondifferentiated state.

41) Rhizobium and Bradyrhizobium are significant contributors to which process when engaged in a symbiotic relationship with leguminous plants?

A) Nitrification

B) Nitrogen fixation

C) Denitrification

D) Sulfate reduction

42) Which of the following are associated with the process of stem nodulation? 

A) Bacteria enter through ruptures in the stem epidermal cells.

B) A common bacterial species associated with stem nodulation is Bradyrhizobium. 

C) Nod factors are not part of stem nodulation. 

D) All of these choices are associated with stem nodulation.

43) The protein that maintains microaerobic conditions within a root nodule is called leghemoglobin.

44) Actinorhizae nodules can grow to be as large as sports balls.

45) Actinorhizae can benefit the plant by providing it with the products of ________.

A) nitrification

B) denitrification

C) nitrogen fixation

D) sulfate reduction

46) Ti plasmids in the species Agrobacterium tumefaciens ________.

A) is required for nitrogen fixation

B) causes the formation of tumors

C) carries the genes needed for root nodule development

D) carries the genes needed for formation of bacteroids

47) Agrobacterium has the ability to infect plants and produce tumor-like growths.

48) Biotrophic fungi would be most likely to consume which type of plant material? 

A) Dead plant matter

B) Living plant matter

C) Both living and dead plant matter

D) None of these are correct because biotrophic fungi provide nitrogen to the plant cells. 

49) A fungus that destroys host plant cells by releasing toxins and enzymes would be categorized as which of these? 

A) Biotrophic fungi

B) Enzytrophic fungi

C) Necrotrophic fungi

D) Parasitic fungi

50) Which organism was responsible for the Irish Potato Famine? 

A) Sclerotinia sclerotiorum

B) Botrytis cinerea

C) Tobacco mosaic virus

D) Phytophthora infestans

51) Which fungi are responsible for infecting hundreds of plant species and cause the loss of millions of pounds of produce each year?

A) White and gray mold fungus

B) Tobacco mosaic virus

C) Cryphonectria parasitica, which also causes chestnut blight

D) Agrobacterium tumefaciens

52) Recent studies indicate that active prokaryotic assemblages are present in high-temperature oil reservoirs, including genera such as ________.

A) Thermotoga

B) Thermoanaerobacter

C) Agrobacterium

D) only Thermotoga and Thermoanaerobacter

53) Porous geological structures below the plant root zone where water flows are known as glaciated subterranean lakes.

54) In the shallow subsurface, surface waters often move through ________, which are porous geological structures below the plant root zone.

55) Microbial processes take place in ________.

A) shallow subsurface where water flowing from the surface moves below the plant root zone

B) regions where organic matter, originating from the Earth’s surface in times past, has been transformed by chemical and biological processes to yield coal

C) zones where methane is being synthesized as a result of microbial activity

D) All of the choices are correct. 

56) A large reserve of methane is found in a pocket below the ocean floor and isotope analysis revealed that the 13C/12C ratio is lower than that predicted by the natural occurrence of these isotopes. This finding suggests that the methane was produced by ________.

A) a geochemical process

B) the metabolic activity of microorganisms

C) a radioactive decay process

D) oxidation of sulfite

57) Except for a shallow surface layer, the earth's crust is known to be free of microorganisms.

58) An organism found in the deep hot biosphere that used hydrogen as an electron donor and sulfate as a terminal electron acceptor would be categorized as which of the following?  

A) A sulfate-reducing chemoautotroph

B) A sulfate-oxidizing photoautotroph

C) A nitrogen-reducing chemoautotroph

D) A nitrogen-reducing photoautotroph