Ch27 Test Questions & Answers Microbial Interactions

Prescott's Microbiology, 11e (Willey)

Chapter 27 Microbial Interactions

1) Which of the following processes is not one that is common to all symbionts?

A) Predation

B) Colonization

C) Reproduction

D) Persistence

2) Several cases of an emerging infectious disease are reported in workers at a research station that borders a tropical rainforest region. The pathogen is identified as a species of bacteria carried by nematodes that infect mosquitos, and disease transmission occurs in a human host following a mosquito bite. Which organisms should be targeted in the treatment of infected patients?

A) Mosquito, nematode, and bacteria

B) Mosquito and nematode

C) Nematode and bacteria

D) Mosquito and bacteria

3) Why were the advent of metagenomics, and the application of molecular techniques such as single-cell and next-generation sequencing, important for defining a microbial relationship?

A) Newer methods revealed that symbiotic relationships exist between a host and one to thousands or more microorganisms, challenging the former definition of a symbiotic relationship as one that occurs between a single microbe and its host.    

B) Newer methods revealed that symbiotic relationships exist between a host and only one microbe, challenging the former definition of a symbiotic relationship as one that occurs between thousands to trillions of microbes and its host.  

C) Microbiologists originally defined symbiotic relationships as those existing only between bacteria and animal hosts; the advent of newer methods broadened the definition of a host to include organisms other than animals.

D) Microbiologists originally defined symbiotic relationships as those that were parasitic, where the microbe harmed the host; the advent of newer methods broadened the definition of symbiosis to include mutualistism and commensalism.

4) The rickettsial parasite Wolbachia pipientis can ________.

A) sometimes alter the sex of an infected wasp

B) confer toxicity to the sting of an infected wasp

C) enhance the lifespan of an infected wasp

D) None of the choices are correct.

5) Any microorganism that spends a portion of its life associated with another organism of a different species is engaged in ________.

A) symbiosis

B) synergy

C) parasitism

D) commensalism

6) A close physical relationship between two different species that may or may not be beneficial is called ________.

7) A relationship in which one organism is found on the surface of another is referred to as a(n) ________.

8) ________ arises when different microbes within a population or community try to acquire the same resource.

A) Amensalism

B) Competition

C) Disruption

D) Syntropism

9) Microorganisms in the human colon are more often being described as mutualistic with human hosts rather than commensalistic. Why has this change in the definition of a symbiotic relationship occurred?

A) As we learn more about the ecology of the human microbiome, we recognize our dependence on these organisms for immunity, vitamin production, and other essential processes.

B) As we learn more about the ecology of the human microbiome, we have learned that these organisms are dependent on the nutrients that we provide for their survival.

C) As we learn more about the makeup of the human digestive tract, we realize that some microorganisms are potentially pathogenic, while others are not.

D) All of the choices are correct.

10) Dinoflagellates that exist endosymbiotically within a variety of marine invertebrates are called ________.

A) endoflagellates

B) parasites

C) endotrophic

D) zooxanthellae

11) Insects frequently contain bacteria in their cytoplasm, and these bacteria form a mutualistic association with their host.

12) How are termite-related protists and aphid-related proteobacteria similar?

A) Both are mutualists with their respective hosts.

B) Both are parasites to their respective hosts.

C) Both are types of endosymbiotic bacteria.

D) Both are protozoans that live within insect hosts.

13) ________ is a beneficial relationship similar to mutualism, in which the relationship is not obligatory.

14) In mutualism ________.

A) the mutualist is dependent on the host

B) a reciprocal benefit accrues to both partners

C) the partners will not survive separately in many cases

D) All of the choices are correct.

15) When two different microbes are engaged in a cooperative relationship, they do as well when living separately as they do when living together.

16) A researcher proposes that the relationship between a particular bacterial species that produces a fat-soluble vitamin is mutualistic with its insect host. Which of the following procedures would best test the researcher's hypothesis?

A) Determine which antibiotic kills the bacteria without harming the host, then administer this antibiotic to the insect and compare its growth with and without the vitamin.

B) Determine which insecticide kills the insect without harming the bacterial host, then compare vitamin production by the bacteria from insects treated with the insecticide to those from untreated insects.

C) Design a method to isolate the bacteria from the insect, then mutate the bacteria in the region of DNA that controls vitamin production and compare growth of the mutant and wild-type bacteria on minimal media.

D) Extract the DNA from the bacteria and from the insect, then use reverse-transcriptase PCR and primers specific to the gene that controls vitamin synthesis to compare transcription of RNA in both organisms.

17) The relationship between Trichonympha protozoa and its termite host, and Xenorhabdus bacteria and its nematode host, are both obligatory relationships.

18) Buchnera aphidicola provides ________ to its aphid host that are essential to the survival of the insect.

A) carbohydrates

B) vitamins

C) amino acids

D) cellulases

19) Methanogens are always engaged in relationships with other microbes because methane production requires ________.

A) removal of oxygen from the environment by another microbe

B) energy provided by another microbe

C) interspecies hydrogen transfer

D) None of the choices are correct.

20) Coral bleaching where the photosynthetic endosymbiont is lost or becomes nonfunctional can be caused by temperature increases as small as 2oC.

21) The reason coral reefs are among the most productive and successful ecosystems is due to ________.

A) the coral-dinoflagellate mutualistic relationship

B) the lichen mutualistic relationship

C) commensalisms

D) All of the choices are correct.

22) In the rumen, the carbohydrate fermentation end products include ________.

A) acetate

B) carbon dioxide

C) methane

D) All of the choices are correct.

23) Riftia tube worms make a unique kind of hemoglobin to ________.

A) transport oxygen

B) transport hydrogen sulfide

C) to assist in the transport of carbon dioxide

D) All of the choices are correct.

24) The ectosymbionts of ruminant animals are useful to their hosts in which of the following ways?

A) They digest the cellulose of plant cell walls.

B) They produce most of the vitamins needed by the ruminant.

C) They convert glucose to organic acids.

D) All of the choices are correct.

25) The specialized structure in a tube worm in which endosymbiotic, chemolithotrophic bacteria live is called a(n) ________.

26) ________ enzymes catalyze the hydrolysis of beta (1–4) linkages between successive D-glucose residues of cellulose.

27) In the rumen, food is quickly attacked by cellulase ________.

A) enzymes produced by the ruminant

B) enzymes produced by microbes

C) enzymes produced by both the ruminant and the microbe

D) archeons

28) A unidirectional process where a specific compound released by one organism has a negative effect on another organism is called ________.

A) predation

B) commensalism

C) negative cooperation

D) amensalism

29) In commensalism ________.

A) the host and commensal can be separated and remain viable

B) the commensal is metabolically dependent on the host

C) the host provides some factor that the commensal cannot get otherwise

D) the host and commensal cannot be separated and remain viable and the commensal is metabolically dependent on the host

30) The term ________ is used to describe a mutually beneficial association in which the growth of an organism is dependent on one or more growth factors, nutrients, or substrates provided by another organism in the same vicinity.

31) Which of the following is not a category of symbiosis?

A) Mutualism

B) Communalism

C) Commensalism

D) Parasitism

32) Pseudonocardia is an organism that is hosted by ________.

A) wood-eating insects

B) marine invertebrates

C) ants that cultivate fungal gardens

D) people with severe acne

33) Biofilm formation by Pseudomonas bacteria on the surface of a natural loofa sponge kept in the shower is an example of which type of relationship? 

A) Commensalism

B) Mutualism

C) Parasitism

D) Predation

34) A ________ is any disease-producing microorganism.

35) The loss of genetic information no longer needed for an intracellular existence by an obligate parasite is called genomic ________.

36) In the host-parasite relationship, it is advantageous for the parasite to disable and kill its host as quickly as possible.

37) ________ is a predator that bores a hole through the outer membrane of its Gram-negative bacterial prey and then reproduces in the periplasm.

A) Vampirococcus

B) Bdellovibrio

C) Mycococcus

D) Syntrophobacter

38) Which of the following is not part of the lichen association?

A) Ascomycetes

B) Green algae

C) Brown algae

D) Cyanobacteria

39) An example of microbial ________ is the ability of Vampirococcus to attach to the outer membrane of its prey and then secrete degradative enzymes that result in the release of the prey's cytoplasmic contents.

40) In a lichen, the fungal partner ________.

A) protects the alga from excess light intensities

B) provides water and minerals to the alga

C) provides a substratum within which the alga grows

D) All of the choices are correct.

41) In lichens, the fungi send projections of their hyphae across the algal cell wall in order to obtain nutrients from the photosynthetic partner. These projections are called ________.

A) mycelia

B) hyphal extensions

C) haustoria

D) lichenthropes

42) When Nitrobacter utilizes nitrite produced from ammonia by Nitrosomonas to obtain energy by converting the nitrite to nitrate, the relationship between the two organisms is ________.

A) commensal

B) amensal

C) mutual

D) parasitic