Microbial Ecology Test Questions & Answers Chapter 28 nan

Nester’s Microbiology, 9e (Anderson)

Chapter 28 Microbial Ecology

1) An early contributor to the understanding of nitrogen fixation was

A) Hooke.

B) Pasteur.

C) Winogradsky.

D) Beijerinck.

E) Lister.

2) The term used to describe the interrelationship between the living and non-living environments in an area is called a(n)

A) group.

B) community.

C) ecosystem.

D) ecological niche.

E) habitat.

3) The role that an organism plays in its environment is called its

A) role.

B) niche.

C) position.

D) ecosystem.

E) habit.

4) The region of the earth inhabited by living organisms is called the

A) biosphere.

B) niche.

C) ecosystem.

D) community.

E) environment.

5) The environment immediately surrounding an individual cell is called its

A) macroenvironment.

B) microenvironment.

C) microniche.

D) colony.

E) macrohabitat.

6) Which group is composed of autotrophs?

A) Primary consumers

B) Secondary consumers

C) Decomposers

D) Rotters

E) Primary producers

7) Biofilms are likely to be found in environments

A) that are nutrient rich.

B) that are relatively warm.

C) with rapidly flowing water.

D) with low nutrients.

E) with abundant nutrients.

8) A microbial mat

A) is a form of biofilm.

B) is poorly organized.

C) contains only obligate anaerobes.

D) is constructed to prevent interactions between the various layers of microorganisms.

E) is a form of biofilm AND is poorly organized.

9) The practice of cells turning on the production of some enzymes and turning off others in response to a changing environment is called

A) compromise.

B) adaptation.

C) metabolism.

D) nutritional metabolism.

E) quorum sensing.

10) The problem of not being able to cultivate most microorganisms has led to the use of

A) FISH.

B) microscopy with fluorescent dyes.

C) 16s rRNA analysis.

D) FISH and 16s rRNA analysis.

E) All of these methods help identify microorganisms in the environment.

11) Nutrient poor waters are described as being

A) hypoxic.

B) oligotrophic.

C) autotrophic.

D) eutrophic.

E) anoxic.

12) Eutrophic waters

A) are nutrient rich AND contain 3.5% salt.

B) may become hypoxic AND lack phosphate, nitrate, and iron.

C) lack phosphate, nitrate, and iron AND contain 3.5% salt.

D) contain 3.5% salt AND are alkaline.

E) are nutrient rich AND may become hypoxic.

13) It is estimated that the mass of bacteria and fungi in the top six inches of an acre of soil is

A) 2 tons.

B) 100 lbs.

C) 10 tons.

D) 500 lbs.

E) 2 kilograms.

14) The bacteria cultured from a soil sample typically represents

A) all the bacteria present in that sample.

B) a very small number of bacteria present in that soil.

C) all the metabolically active bacteria.

D) all the metabolically inactive bacteria.

E) most of the types of bacteria in that soil.

15) Bacteria survive adverse conditions by forming

A) zygotes.

B) capsules.

C) endospores.

D) glycocalyx.

E) capsules AND endospores.

16) The organic matter in soil is referred to as

A) mineral soil.

B) humus.

C) inorganic substance.

D) bedrock.

E) mulch.

17) Geosmins are

A) a strain of Bacillus.

B) nitrogen-fixing bacteria.

C) metabolites that give soil its odor.

D) produced by Rhizobium.

E) metabolites that give soil its odor AND produced by Rhizobium.

F) metabolites that give soil its odor AND produced by Bacillus.

18) Streptomyces

A) may produce antibiotics.

B) may produce antivirals.

C) are typically found in the air.

D) are frequently transmitted by vectors.

E) will swarm together to form fruiting bodies.

19) Which of the following soil organisms play a major role in decomposing plant matter?

A) bacteria AND fungi

B) bacteria AND viruses

C) fungi AND protozoa

D) protozoa AND viruses

E) viruses AND fungi

20) The major effect of excess water in the soil is to

A) increase the level of oxygen.

B) lower the amount of oxygen.

C) reduce the pH.

D) increase the amount of nitrogen.

E) reduce the amount of carbon.

21) The zone of soil that surrounds the roots and contains a variety of organic exudates is called the

A) mycorrhizae.

B) rootsphere.

C) rhizosphere.

D) geosmin.

E) biosphere.

22) The organisms that obtain energy by oxidation of hydrogen sulfide and use carbon dioxide as a carbon source are called

A) heterotrophs.

B) chemolithoautotrophs.

C) chemoheterotrophs.

D) autotrophs.

E) chemoliths.

23) Which of the following may be used by prokaryotes, under anaerobic conditions, as terminal electron acceptors?

A) nitrate

B) nitrite

C) sulfate

D) carbon dioxide

E) All of the choices are correct.

24) The carbon cycle revolves around

A) nitrogen.

B) carbon dioxide.

C) water.

D) phosphorus.

E) carbon monoxide

25) The organisms that convert carbon dioxide into organic matter are the

A) secondary consumers.

B) primary consumers.

C) producers.

D) decomposers.

E) secondary decomposers.

26) Turning inorganic carbon into organic carbon is called

A) mineralization.

B) eutrophication.

C) respiration.

D) carbon fixation.

E) carbonation.

27) During aerobic decomposition of organic matter the primary gas produced is

A) oxygen.

B) hydrogen sulfide.

C) nitrogen.

D) carbon dioxide.

E) ethylene dioxide.

28) During anaerobic decomposition of organic matter with carbon dioxide as the terminal electron acceptor, the primary gas(es) produced is/are

A) oxygen.

B) hydrogen sulfide.

C) methane.

D) hydrogen.

E) methane AND hydrogen.

29) Next to carbon and oxygen, the element organisms most require is

A) sulfur.

B) phosphorus.

C) iron.

D) potassium.

E) nitrogen.

30) Atmospheric nitrogen is

A) used directly by plants.

B) used directly by animals.

C) turned into ammonia by microorganisms.

D) directly used to make carbohydrates.

E) converted into urea by bacteria.

31) Nitrogen is

A) an important constituent of carbohydrates AND primarily fixed by fungi.

B) turned into ammonia by microorganisms AND ultimately used in making amino acids and nucleotides.

C) primarily fixed by fungi AND ultimately used in making amino acids and nucleotides.

D) ultimately used in making amino acids and nucleotides AND an important constituent of carbohydrates.

E) turned into ammonia by microorganisms AND ultimately used in making bacterial capsules.

32) The nitrogen in our atmosphere is only usable to us after it is converted to

A) ammonia.

B) amino acids.

C) fertilizer.

D) nitrous oxide.

E) oxygen.

33) Azotobacter

A) are the chief suppliers of fixed nitrogen in grasslands.

B) form symbiotic associations with algae.

C) have a very low respiratory rate.

D) are methanogens.

E) are the chief suppliers of fixed nitrogen in grasslands AND form symbiotic associations with algae.

34) Nitrifiers

A) are obligate anaerobes.

B) are chemolithotrophs.

C) convert nitrate to nitrite.

D) are reducers.

E) are thermophiles.

35) Sulfur occurs in all living matter primarily as a component of

A) fatty acids.

B) nucleotides.

C) amino acids.

D) carbohydrates.

E) DNA and RNA.

36) The sulfur cycle is similar to the cycle of

A) carbon.

B) oxygen.

C) phosphorus.

D) water.

E) nitrogen.

37) Phosphorus is a component of all of the following EXCEPT

A) RNA and DNA.

B) phospholipids.

C) nucleotides.

D) carbohydrates.

E) ATP.

38) In many aquatic habitats, the growth of algae and cyanobacteria is limited by the amount of

A) nitrogen.

B) phosphorus.

C) calcium.

D) sulfur.

E) nitrites.

39) The conical sea floor vents that spout sulfide-rich, super-heated water at temperatures up to 300ºC are called

A) hydrothermal vents.

B) yellow smokers.

C) warm vents.

D) hot vents.

E) hyperthermophiles.

40) The organisms isolated from hydrothermal vents are typically

A) phototrophs.

B) chemolithoautotrophs.

C) rhizobia.

D) bacteroid.

E) phototrophs, rhizobia, AND bacteroid.

41) Which of the following refers to a symbiotic association between plant roots and fungi?

A) Lichens

B) Geosmins

C) Extremophiles

D) Ant gardens

E) Mycorrhizae

42) Mycorrhizae are a symbiotic association of

A) bacteria and algae.

B) plant roots and fungi.

C) bacteria and virus.

D) fungi and virus.

E) plants roots and bacteria.

43) Truffles

A) are endomycorrhizas.

B) are a mushroom.

C) are a lichen.

D) form a sheath around a root of an appropriate tree.

E) are endomycorrhizas AND form a sheath around a root of an appropriate tree.

44) The rumen is

A) found in horses and rabbits.

B) an anaerobic fermentation vessel found in herbivores.

C) found in carnivores.

D) an offshoot of the colon.

E) an anaerobic fermentation vessel found in most carnivores.

45) Which of the following involve symbiotic relationships?

A) rhizobia AND ruminants

B) mycorrhizae AND ruminants

C) ruminants AND myxobacteria

D) myxobacteria, ruminants, AND rhizobia

E) rhizobia, mycorrhizae, AND ruminants

46) Bacteria are the most numerous soil inhabitants, but the biomass of fungi is greater.

47) A mycorrhiza is a symbiotic association between roots and fungi.

48) Streptomyces produces geosmins which give soil a characteristic musty odor.

49) Protozoa, algae, and fungus are typically found near the surface of soil.

50) Fungi are able to handle acidic environments much better than bacteria.

51) Oligotrophic waters are usually hypoxic.

52) The organisms found near warm vents on the bottom of the ocean are typically chemoautotrophic.

53) Many orchids require fungi for seeds to germinate.

54) No eukaryotic organisms have been shown to fix nitrogen without the aid of prokaryotes.

55) Sulfur occurs in all living matter primarily as a component of carbohydrates.

56) Explain how nutrient-rich runoff can cause waters to become hypoxic.

A) Algae and cyanobacteria flourish on the nutrients in the runoff. Heterotrophic microbes then flourish on the organic molecules produced by these organisms, using oxygen in the process and leading to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area.

B) Algae and cyanobacteria flourish on the nutrients in the runoff, using oxygen in the process. This consumption of oxygen leads to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area.

C) The nutrients in the runoff often include chemicals that spontaneously oxidize in the presence of oxygen. They tend to deplete the amount of oxygen present in an area simply by being present themselves. This consumption of oxygen leads to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area.

D) The nutrients in the runoff often include toxic chemicals that kill anaerobes such as cyanobacteria. Aerobes flourish, depleting the amount of oxygen present. This consumption of oxygen leads to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area.

E) It doesn't. This claim is a scare tactic used by environmental extremists to prevent farmers and individuals from fertilizing their crops and lawns. There is no induction of a hypoxic state in bodies of water where runoff occurs.

57) How can the biomass of fungi in soil be greater than that of bacteria, considering that bacteria are more numerous?

A) Fungi are always multicellular organisms, while bacteria are unicellular. As such, biomass of fungi would always be larger than that of bacteria, since they possess more cells in each individual organism.

B) This is a matter of size. Fungi, whether unicellular or multicellular, are eukaryotic and are generally larger than bacteria (which are prokaryotic). This means that, even with a lower overall number, they will have more total biomass.

C) It depends on where they grow. Fungi generally grow in the most moist areas near the top of soil, giving them an advantage over bacteria. They may not be as numerous, but this advantage in location and nutrients is what makes them larger than the bacteria (and therefore having more biomass). 

D) Fungi are capable of incorporating the dead materials around them into themselves as nutrient sources. This capacity allows them to greatly increase their biomass per each organism, well beyond what a simple bacterial cell could hold. This capability is what allows them to achieve higher biomass than bacteria.

E) Bacteria may be more numerous, but in soil they exist mostly in a dehydrated state. Because they lack moisture, they weigh less than fungi, which may occur in lower numbers but are heavier because they are well hydrated in all soil environments.

58) Gardeners sometimes plant clover between productive growing seasons. Why would this practice be beneficial?

A) Several types of nitrogen-fixing bacteria form a symbiotic relationship with the roots of clover. This would increase the amount of nitrogen in the soil available for subsequent seasons of other plants' growth.

B) Clover is consumed by a number of animals. This would encourage the animals to feed/graze on the areas, leaving behind nitrogen-rich manure (feces) that would act as a natural fertilizer for subsequent seasons of other plants' growth.

C) Clover is a unique plant that is capable of atmospheric nitrogen-fixation (pulling nitrogen directly out of the air and turning it into ammonia or amino acids). This directly provides nitrogen compounds for the soil for subsequent seasons of other plants' growth.

D) The beneficial effect is more for water retention and elimination of soil erosion in between growing seasons than for any nutrient value. It has nothing to do with nitrogen compounds in the soil.

E) Several types of oxygen-fixing bacteria form a symbiotic relationship with the roots of clover. This would increase the amount of oxygen in the soil available for subsequent seasons of other plants' growth.

59) Which statement describes the relationship between ammonia oxidizers and nitrite oxidizers?

A) Ammonium oxidizers use ammonium as an energy source, oxidizing it to nitrite. The nitrite produced then serves as the energy source for nitrite oxidizers.

B) Ammonium oxidizers use ammonium as an energy source, oxidizing it to nitrate. The nitrate produced then serves as the energy source for nitrite oxidizers.

C) Ammonium oxidizers use urea as an energy source, oxidizing it to nitrite. The nitrite produced then serves as the carbon source for nitrite oxidizers.

D) Ammonium oxidizers use ammonium as an energy source, reducing it to nitrate. The nitrate produced then serves as the energy source for nitrite oxidizers.

E) None of these explains the relationship—ammonia and nitrite are produced by different nutrient cycles which also involve sulfur reduction.

60) How do bacteriocins benefit bacteria in their natural habitat?

A) They protect the bacteria from the effects of antibiotics in the environment.

B) They provide a source of nutrients during adverse environmental conditions.

C) They allow bacteria to compete against other bacteria that may attempt to use the same or similar resources.

D) They are protective structures that allow bacteria to survive adverse environmental conditions.

E) They induce resistance in the bacteria, helping them survive when medications are introduced into their habitat.

61) Which of the following statements regarding microbial identification is false?

A) FISH can be used to distinguish subsets of prokaryotes that contain a specific nucleotide sequence.

B) Studying the genome of one organism can give insights into the characteristics of another organism.

C) 16S rRNA sequences can be used to determine taxonomic similarity among prokaryotes.

D) Metagenomics involves comparison of gene sequences in DNA from environmental samples to known gene sequences in databases.

E) Culture techniques are an accurate way of determining which members in a microbial community are most common.

62) What gene sequences are used to identify the prokaryote organisms present in an environmental sample?

A) 18S rRNA genes

B) 16S rRNA genes

C) 70S rRNA genes

D) 80S rRNA genes

E) All of these

63) What is the likely fate of a fish living in a eutrophic stream?

A) Fish will first thrive as they have more oxygen from the increase in photosynthetic organisms; eutrophic streams are low in nutrients however, so they will quickly die.

B) Eutrophic streams have high levels of carbon dioxide. Fish will be able to use this for aerobic respiration, so will thrive in this environment.

C) Eutrophic streams are always anoxic. This means that only anaerobic fish will be able to survive in a eutrophic environment.

D) Fish will first thrive as they have more food from the increase in photosynthetic organisms; as they deplete the dissolved oxygen, however, they will die. 

E) Eutrophic streams have low levels of nutrients in them. Only fish that feed off other fish will be able to survive in these streams.

64) Please select the correct sequence of steps involved in the creation of a dead zone in a water body.

1. Heterotrophic microbes metabolize the organic compounds synthesized by primary producers.

2. Water becomes hypoxic and toxic algal blooms may occur; animals in the area either flee or die.

3. Water accumulates nutrients as it runs through agricultural, industrial, and urbanized regions.

4. Dissolved O2 is consumed by metabolic activity of heterotrophs.

5. Excess nitrate and phosphate in nutrient-rich water causes algae and cyanobacteria to flourish.

A) 3; 5; 1; 4; 2

B) 3; 1; 4; 2; 5

C) 1; 3; 4; 2; 5

D) 5; 3; 4; 2; 1

E) 2; 1; 4; 3; 5

65) Which of the following is not a matching pair?

A) Soil—minimal biodiversity

B) Bacillus—endospores

C) Streptomyces—geosmin production

D) Fungi—lignin degradation

E) Rhizosphere—soil that adheres to plant root