Exam 5 Microbiology

The sum of all microbes from a given host or environment is referred to as a ____________, and the sum of all the DNA recovered from those microbes is their _____________.

- microbiome -metagenome

Which of the following statements is true about the relationship between the concentration of organic compounds in a body of water and its biochemical oxygen demand (BOD)? Choose one: A. As the concentration of organic compounds increases, so does the BOD. B. As the concentration of organic compounds decreases, the BOD increases. C. The concentration of organic compounds does not affect the BOD. D. As the concentration of organic compounds increases, the BOD decreases.

A. As the concentration of organic compounds increases, so does the BOD.

Which trophic level consists solely of microbes? Choose one: A. Decomposers B. Producers C. Consumers D. Grazers

A. Decomposers

An organism that is a strict anaerobe (cannot grow in the presence of oxygen) is most likely to be found in which habitat? Choose one: A. Hypolimnion B. Euphotic zone of the ocean C. Organic horizon D. Epilimnion

A. Hypolimnion

Which of the following is an example of vertical transmission? Choose one: A. Insects pass the yellow fever virus to their offspring in their eggs. B. A child catches a cold because her mother sneezed and coughed on her. C. Insects pass the yellow fever virus to humans upon biting them. D. Children get ill from food prepared by their mother.

A. Insects pass the yellow fever virus to their offspring in their eggs.

Which of the following is one of Cornelis van Niel's postulates of microbial ecology? Choose one: A. Microbes are found in every environment on Earth. B. All organisms possess genomes that encode proteins to enable catabolism. C. Some carbon compounds cannot be used as a source of energy by any microbes. D. All organisms depend, directly or indirectly, on the presence of other organisms.

A. Microbes are found in every environment on Earth

Which of the following is a true statement? Choose one: A. Plants can have bacterial and fungal pathogens and bacterial and fungal mutualists. B. All plant pathogens are fungi. C. Plants do not interact with bacteria or fungi in their environment. D. All plant-fungal interactions are pathogenic.

A. Plants can have bacterial and fungal pathogens and bacterial and fungal mutualists.

Suppose various legume plant parts are rubbed with a protein gel. Which plant part is most likely to test positive for nitrogenase? Choose one: A. Roots B. Leaves C. Stems D. Flowers

A. Roots

Through a search of the genetic databases it is found that a protein expressed by a microbial pathogen resembles a host protein. What is this resemblance most likely to indicate? Choose one: A. The microbial protein mimics the host protein's function. B. The microbial protein is not a virulence factor. C. The microbial protein binds to the similar host protein. D. The microbial protein is in the same location as the host's protein.

A. The microbial protein mimics the host protein's function.

Which of the following statements about virulence factors is true? Choose one: A. They increase the ability of a pathogen to cause disease. B. They are defined as being any genes that are required for microbial survival. C. They always activate host defenses. D. They are found in nonpathogenic strains of a microbe as well as pathogenic strains.

A. They increase the ability of a pathogen to cause disease.

Which of the following is true of opportunistic pathogens? Choose one: A. They may arise from normal microbiota. B. They only infect unvaccinated people. C. They are always untreatable, being antibiotic resistant. D. They usually infect people with normal, functioning immune systems.

A. They may arise from normal microbiota.

Extracellular pathogens can attempt to avoid immune detection by Choose one: A. altering their cell-surface proteins. B. inhibiting phagosome-lysosome fusion. C. tolerating acidic conditions. D. growing within a phagolysosome.

A. altering their cell-surface proteins.

Identifying patient zero and having a reporting system in place allows epidemiologists to Choose one: A. contain any outbreaks. B. identify risk factors for outbreaks. C. identify effective treatment techniques. D. predict future outbreaks.

A. contain any outbreaks.

Which of the following represent prokaryotic primary producers? Choose one or more: A. cyanobacteria B. moss C. viruses D. fungi E. protists F. seaweed G. lithoautotrophs

A. cyanobacteria G. lithoautotrophs

Biochemical oxygen demand (BOD) is controlled by the concentration of Choose one: A. heterotrophic microorganisms. B. benthic microorganisms. C. autotrophic microorganisms. D. multicellular organisms.

A. heterotrophic microorganisms.

Microbes that colonize the skin need to be resistant to __________ salt and __________ pH. Choose one: A. high; low B. low; high C. high; high D. low; low

A. high; low

Plants have a microbiome analogous to the gut microbiome. These microbes, called endophytes, benefit the plants by Choose one: A. providing protection from herbivores, removing toxins, and providing protection from adverse environmental conditions. B. causing disease in humans. C. fixing nitrogen. D. fixing carbon.

A. providing protection from herbivores, removing toxins, and providing protection from adverse environmental conditions.

Pseudomembranous enterocolitis is caused by an overgrowth of the bacteria Clostridioides difficile. This overgrowth can be caused by antibiotic therapy in which sensitive members of the microbiome are killed or inhibited by the antibiotic drug, but the resistant C. difficile is not. Because the C. difficile infection is resistant to many antibiotics, it is hard to treat. Cases of pseudomembranous enterocolitis have been cured with fecal transplants in which the gut microbiome of a donor healthy person is transferred into the patient. Fecal transplants work to cure this resistant infection because Choose one: A. the donor's healthy microbiome outcompetes the C. difficile and restores balance to the gut microbiome in the patient. B. a different strain of C. difficile from the healthy donor replaces the patient's strain.

A. the donor's healthy microbiome outcompetes the C. difficile and restores balance to the gut microbiome in the patient.

Which of the following approaches are useful for functional annotation after assembly of a partial genome? Choose one or more: A. Comparing with previously sequenced metagenomes. B. Determining G+C content of the genome. C. Searching for ORFs that have an upstream promoter and ribosome-binding site. D. Identifying restriction endonuclease-recognition sites. E. Searching for motifs characteristic of particular classes of proteins or enzymes.

A.Comparing with previously sequenced metagenomes. C.Searching for ORFs that have an upstream promoter and ribosome-binding site. E.Searching for motifs characteristic of particular classes of proteins or enzymes.

An individual' susceptibility to disease can be influenced by which of the following factors Select all correct answers emotional disturbances antibiotic therapy poor nutrition genetic background lifestyle choices

All answers are correct

Which of the following does NOT contribute to eutrophication? Choose one: A. Organic pollutants B. Antibiotic runoff C. Algal blooms D. Excessive nitrogen inputs

B. Antibiotic runoff

An organism classified as a barophile is most likely to be found in which habitat? Choose one: A. Euphotic zone B. Benthic zone C. Epilimnion D. Aerated horizon

B. Benthic zone

Microbes alone drive movement of which element between its abiotic and biotic forms? Choose one: A. Oxygen B. Nitrogen C. Phosphorus D. Carbon

B. Nitrogen

Which of the following are examples of virulence factors? Choose one or more: A. DNA polymerase of Mycobacterium tuberculosis that replicates the bacterial DNA B. botulinum toxin produced by Clostridium botulinum that blocks host nerve transmission C. Rubisco enzyme that fixes carbon dioxide in cyanobacteria D. Rab1b protein in Yersinia pestis that prevents the fusion of lysosomes and phagosomes in host macrophages E. hemagglutinin envelope protein on the surface of the influenza virus that binds to a receptor on the surface of host cells F. capsule of Neisseria meningitidis that prevents phagocytes from adhering to the bacteria

B. botulinum toxin produced by Clostridium botulinum that blocks host nerve transmission D. Rab1b protein in Yersinia pestis that prevents the fusion of lysosomes and phagosomes in host macrophages E. hemagglutinin envelope protein on the surface of the influenza virus that binds to a receptor on the surface of host cells F. capsule of Neisseria meningitidis that prevents phagocytes from adhering to the bacteria

Epidemiology is the study of Choose one: A. bioethics in medicine and medical research. B. frequency and distribution of diseases in populations. C. etiological agents of disease. D. pathogenicity.

B. frequency and distribution of diseases in populations.

Lichens are an example of a mutualism between an alga and a(n) Choose one: A. bacterium. B. fungus. C. animal. D. plant.

B. fungus.

Soil food webs differ from marine food webs in that Choose one: A. oxygen is present throughout. B. primary production is done mostly by plants. C. the role of bacteria is greater than in all trophic levels. D. decomposition is much less important.

B. primary production is done mostly by plants.

Which of the following questions would require a metagenomics approach to answer? Choose one or more: A. Which species are most often co-isolated from infections involving Staphylococcus aureus? B. Does sleep deprivation cause a shift in the ratio of various bacterial phyla in a human's intestine? C. What percentage of organisms within a soil ecosystem possess lignin degradation genes? D. How many Gram-negative species can be cultured from a carton of spoiled milk? E. Under what condition(s) does Escherichia coli upregulate genes for the pentose phosphate pathway? F. What strain of influenza virus was responsible for the most recent outbreak in the United States? G. How do microbial communities of freshwater lakes differ from hypersaline ones?

B.Does sleep deprivation cause a shift in the ratio of various bacterial phyla in a human's intestine? C.What percentage of organisms within a soil ecosystem possess lignin degradation genes? G.How do microbial communities of freshwater lakes differ from hypersaline ones?

A localized, focal point of infection found within a patient's catheter is most likely employing which virulence mechanism? Choose one: A. Endotoxin B. Pili C. Biofilm D. Ubiquitylation enzymes

C. Biofilm

Which of the following is the most oxidized form of carbon? Choose one: A. Methanol (CH3OH) B. Formic acid (HCOOH) C. Carbon dioxide (CO2) D. Methane (CH4)

C. Carbon dioxide (CO2)

Virulence is measured by __________, or the dose needed to __________ of hosts.

C. ID50; cause symptoms in 50%

Which of the following statements defines a niche? Choose one: A. All the material tied up in organismal bodies B. Metabolic process of acquiring elements and fixing them into biomass C. Set of conditions that enable an organism to grow and reproduce D. Position in food web based on consumption of biomass

C. Set of conditions that enable an organism to grow and reproduce

Which of the following is not an example of dysbiosis? Choose one: A. gut microbes in the urinary tract B. methanogens in the gut that cause other microbes to produce an increased amount of acetate C. bacteriocin-secreting E. coli in the gut D. increased amount of Clostridioides difficile in the gut caused by antibiotic therapy

C. bacteriocin-secreting E. coli in the gut

Syntrophy means Choose one: A. two organisms eating at the same trophic level. B. coupled metabolic pathways in one organism to achieve negative ΔG. C. multiple organisms needed to complete a metabolic pathway with negative ΔG. D. using two metabolic pathways simultaneously.

C. multiple organisms needed to complete a metabolic pathway with negative ΔG.

Microbes carry out many unique forms of metabolism that are essential for uptake and recycling of nutrients in ecosystems. In fact, of the processes listed here, the only one also performed by animals is: Choose one: A. anaerobic respiration. B. nitrogen fixation. C. protein degradation. D. anoxygenic photosynthesis. E. lignin degradation.

C. protein degradation.

Which of the following is the best definition of an operational taxonomic unit (OTU)? Choose one: A. two or more genes that are cotranscribed from a single promoter B. a completely reconstructed microbial genome C. the metagenomics equivalent of a microbial species D. all of the protein-coding sequences in a genome E. a set of genes controlled as a unit by the same regulatory protein

C. the metagenomics equivalent of a microbial species

The E. coli O104:H4 outbreak of 2011 was caused by a strain that had Shiga toxin and antibiotic resistance traits not present in its closest relative. This most likely indicates Choose one: A. this is a completely new strain of Shigella that appears more like E. coli. B. the strain evolved through genome duplication and divergence. C. there was a horizontal gene transfer event. D. there was a multiple mutation event increasing the virulence of this strain.

C. there was a horizontal gene transfer event.

Which of the following would be considered a bacterial virulence factor (e.g., contributes to the bacteria's pathogenicity)? Select all correct answers Capsules Ribosomes Endospores Axial filaments/Flagella Cell wall components Cell membranes

Capsules Endospores Axial filaments/ Flagella Cell wall compoenets

Which of the following locations is LEAST likely to harbor commensal microbes? Choose one: A. Skin B. Vagina C. Mouth D. Blood

D. Blood

Which of the following is NOT a factor in dysbiosis? Choose one: A. Dietary changes B. Antibiotic therapy C. Emotional stress D. Fecal transplant

D. Fecal transplant

A pathogenic bacterium has a low lethal dose 50% (LD50). Which of the following statements about the bacteria is true? Choose one: A. The bacteria have a high infectious dose 50% (ID50). B. A small dose of an antibiotic drug is sufficient to kill the bacteria. C. The bacteria have a low virulence. D. Only a few of the bacteria are required to kill 50% of infected hosts.

D. Only a few of the bacteria are required to kill 50% of infected hosts.

An organism fixes nitrogen for the production of amino acids. This is an example of Choose one: A. predation. B. habitat. C. dissimilation. D. assimilation.

D. assimilation.

Which of the following is NOT a generally accepted and valid definition of disease epidemiology? Choose one: A. determine the source of a disease outbreak and factors that influence transmission B. examine the distribution and determinants of disease frequency in human populations C. evaluate the effectiveness of therapeutic measures and identify new syndromes D. diagnose why a patient's immune system will not establish immunomemory to a pathogen

D. diagnose why a patient's immune system will not establish immunomemory to a pathogen

Moderate fever can actually be beneficial because it Choose one: A. increases iron availability to pathogens. B. increases inflammation. C. causes enzymatic denaturation. D. moves the temperature outside the pathogens' optimal range.

D. moves the temperature outside the pathogens' optimal range.

Which of the following best describes the index case? Choose one: A. the patient with the most severe signs and symptoms of a disease B. the patient who has recovered and has passed convalescent phase C. patient zero, who is the first infected person to die from the disease D. patient zero, who is the first case of the disease in a defined area

D. patient zero, who is the first case of the disease in a defined area

The current research shows the link between obesity and the microbiome is likely based on the Choose one: A. absence of protists in the microbiome. B. genetics of the host in terms of propensity for inflammatory disorders. C. food types ingested by the host. D. specific species composition of the microbiota.

D. specific species composition of the microbiota.

Many marine microbes cannot be readily cultured because Choose one: A. the salt requirements of the media are too high to enable long-term culturing. B. they are primarily anaerobic. C. many have specific nutritional requirements that cannot be met in laboratory-produced media. D. they are dependent upon other members of their natural communities.

D. they are dependent upon other members of their natural communities.

The gut microbiome benefits the host in many ways. One benefit of the gut microbiome is that it helps to prevent infection by pathogenic microbes. To directly compete with and inhibit the growth of pathogenic microbes, members of the gut microbiome do which of the following? Choose one or more: A. synthesize vitamins B. degrade mucin C. compete for mates D. compete for nutrients E. degrade complex carbohydrates F. secrete substances that inhibit the growth of pathogens G. occupy attachment receptors

D.compete for nutrients F.secrete substances that inhibit the growth of pathogens G.occupy attachment receptors

Which of the following represents an important limitation of small-subunit (SSU) rRNA analysis from a metagenome? Choose one: A. The method requires sophisticated culturing techniques. B. Methods do not yet exist for obtaining data on the archaeal fraction of communities. C. Small-subunit rRNA analysis cannot identify microbes below the level of phylum. D. The method cannot be used on mixed-species communities. E. The "universal" primers for amplification of target genes may actually miss many uncharacterized taxa.

E. The "universal" primers for amplification of target genes may actually miss many uncharacterized taxa.

Avoiding the host's defenses is the critical step in a pathogen being able to cause disease. True False

False

The most acute signs and symptoms of a disease appear during the prodromal phase of an infectious disease. True False

False

Rank the following nitrogen compounds from the least oxidized to the most oxidized.

NH3 N2 NO2- NO3-

Part 1:Mycobacterium tuberculosis infects the lungs and can spread to other organs from the lungs. When an infected individual coughs, the bacteria can enter the air and infect nearby individuals. The mode of transmission for the M. tuberculosis pathogen is the ______________ route. The portal of entry for M. tuberculosis is _______________. Part 2:Typhoid Mary was a professional cook at the turn of the twentieth century who was an asymptomatic carrier of the bacteria Salmonella Typhi. She infected many people who ate at the eating establishments where she worked through contaminated food. The mode of transmission for the S. Typhi pathogen is the ____________ route. The portal of entry for S. Typhi is _______________. Part 3:Lyme disease is caused by the bacteria Borrelia burgdorferi, which is transmitted through the bite of a tick. The mode of transmission for the B. burgdorferi pathogen is the ________________ route. The portal of entry for B. burgdorferi is ________________.

Part 1: - direct airborn - respiratory Part 2: - indirect vehicle - oral Part 3: - indirect vector - paternal

Part 1:When discussing a disease, epidemiologists distinguish between the prevalence and incidence of active cases. ______________ describes the total number of active cases of a disease in a given location, regardless of when the case first developed. On the other hand, __________________ refers to the number of new cases of a disease in that location over a specified time. Part 2:___________________ rates can provide insight into whether efforts to limit a disease are working.

Part 1: - prevalance - incidence Part 2: - incidence

The epidemiologic triad (triangle) of disease refers to: Source, mode of transmission, susceptible host Time, place, person John Snow, Robert Koch, Florence Nightingale Pathogen, susceptible host, environment

Pathogen, susceptible host, environment

Eutrophic lakes typically support ten times the microbial concentrations of an oligotrophic lake. Which of the following statements is NOT true of eutrophic lakes? Nitrogen and phosphorous levels are usually high. Population of aquatic animals like fish increases due to an abundance of oxygen. Algal blooms are common. Biochemical oxygen demand is high due to an abundance of organic material.

Population of aquatic animals like fish increases due to an abundance of oxygen.

Microorganisms that reside on or within a host without causing infection/disease are referred to as the normal microbiota (microbiome). True False

True

Ebola epidemics occasionally occur. Where does the virus that causes Ebola "hide" in between epidemics? It is thought that bats naturally harbor the virus, and thus bats would be considered a fomite a vector a dead end host a reservoir a carrier

a reservoir

An endotoxin is a toxic protein secreted by a bacterial cell. a superantigen that causes an excessive activation of the immune system. a toxic substance that forms during endospore formation. a toxic lipid that is a component of the outer LPS membrane of Gram negative bacteria

a toxic lipid that is a component of the outer LPS membrane of Gram negative bacteria

Fungi play a much larger and more significant role in the decomposition of terrestrial biomass than they do in marine ecosystems. This is because fungi decompose leghemoglobin rapidly. degrade human waste faster than bacteria. do not thrive in a marine environment. outcompete bacteria in terrestrial habitats. can degrade the abundant lignin in terrestrial habitats.

can degrade the abundant lignin in terrestrial habitats.

What types of bacteria will carry out nitrification (oxidation of nitrates & nitrites)? chemoheterotrophs fastidious heterotrophs chemolithotrophs chemoorganotrophs phototrophs

chemolithotrophs

Michael has Acquired Immunodeficiency Syndrome (AIDS) caused by the Human Immunodeficiency Virus (HIV). The damage that the virus has done to Michael's immune system has made him susceptible to a yeast infection of his respiratory tract, called Candidiasis. Individuals with a healthy immune system do not develop this yeast infection. Michael is a(n) ____________________ and the yeast that causes Candidiasis is a(n) __________________.

compromised host opportunistic pathogen

The hygiene hypothesis states that the modern indoor lifestyle and ubiquitous antimicrobial substances have led to a(n) ______________ in the diversity of the microbes that make up the human microbiome, which in turn has led to a(n) __________ in inflammatory diseases in humans.

decrease increase

A disease is ____________if it is always present in a population at a low frequency.

endemic

Bacteria found growing in between crystals of solid bedrock as deep as 3 km below Earth's surface are called decomposers. endoliths. saprophytes. endophytes. symbionts

endoliths.

Vascular abuscular mycorrhizae (VAM) are an example of which of the following? nitrogen fixer lignin decomposer endomycorrhizae free-living fungus ectomycorrhizae

endomycorrhizae

A disease is _____________ when larger-than-normal numbers of individuals in a population become infected over a short time.

epidemic

An island nation normally has low background level of cholera. After an earthquake, sanitation is disrupted and cholera cases spike to high levels on the island but not in other areas of the world. The spike in cholera cases is an example of a(n) opportunistic disease epidemic disease endemic disease pandemic disease

epidemic disease

Lily (who has lice) brings a comb to school for picture day. After Lily combs her hair, Leticia asks to borrow the comb. Leticia later is diagnosed with lice. In this example, the comb is a(n) portal incubator vector fomite carrier

formite

Vaccinating domesticated and wild (if possible) animals - reduces the emergence of drug-resistant bacteria. - has no effect on human health. -eliminates the migration of microbes into new geographical regions. -lowers the number of reservoirs and reduces transmission of zoonotic diseases to humans.

lowers the number of reservoirs and reduces transmission of zoonotic diseases to humans.

Wastewater treatment generates which of the following gases during anaerobic sludge digestion in quantities sufficient for recovery as a fuel source? hydrogen sulfide oxygen carbon dioxide nitrous oxide methane

methane

Generally speaking, which of the following is the most commonly used portal of entry for pathogens? skin (cutaneous membrane) placenta parenteral mucus membranes (e.g., gastrointestinal, respiratory, genitourinary)

mucus membranes (e.g., gastrointestinal, respiratory, genitourinary)

Which region of marine habitat refers to the microscopic interface between water and air? benthic zone pelagic zone neuston euphotic zone aphotic zone

neuston

Lichens consist of an intimate mutualistic symbiosis between a fungus, an alga, and/or cyanobacteria. What is one primary role of the cyanobacteria in this association? degradation of lignin recycling of waste products decomposition of toxic compounds nitrogen fixation protection of the symbionts

nitrogen fixation

A patient in the hospital with a urinary catheter develops a bladder infection during their hospital stay. This is an example of a(n) ________ infection. sporadic nosocomial emerging community acquired endemic

nosocomial

A/an _________________ is a disease outbreak that occurs over a wide geographic area, usually the world. These may be long-lived, such as the bubonic plague in the fourteenth century and the AIDS in the late twentieth and early twenty-first centuries, or they may be short-lived, as with the 1918 flu.

pandemic

Microorganisms using the ____ route of entry invades tissues via injections, bites, cuts, and/or surgical procedures. mucus membranes (e.g., gastrointestinal, respiratory, genitourinary) skin (cutaneous membrane) placenta parenteral

parenteral

All of the following are likely to be found among the benthic microbes EXCEPT barophiles. psychrophiles. thermophiles. methanogens. phototrophs.

phototrophs.

Microbes participate in which step of wastewater treatment by decomposing organic material? secondary tertiary every step primary preliminary

secondary

Which of the following is NOT an example of direct contact transmission? shaking hands sharing food or drinks kissing sexual intercourse

sharing food or drinks

Life on Earth relies on the production, consumption, and recycling of nutrients. The position that an organism occupies within a food web is referred to as its ____________.

trophic level

One of the basic goals of vaccination is to increase herd immunity. True False

true