Test 2 McGraw-Hill Microbiology Chapter 10 & 11
True or false: A limitation of sequencing small subunit ribosomal DNA (SSU rDNA) is that cultures must first be grown in the lab before DNA can be extracted for sequencing.
False
True or false: Organisms cannot be identified unless they can first be cultivated.
False
True or false: Scientists now understand the true diversity of microbial life and have determined the relationships between the millions of prokaryotes that exist.
False
True or false: The three-domain system has always been used as the standard classification system for organisms.
False
Which of the following is a beneficial characteristic of some cyanobacteria?
Filamentous cyanobacteria can prevent soil erosion in cold desert areas such as the Colorado Plateau.
Why are sequence comparisons of the DNA coding for ribosomal RNA (rRNA) so useful in placing organisms on a phylogenetic tree?
Horizontal transfer of rDNA is rare Regions of rDNA are highly conserved. rDNA is present in all organisms
What are advantages of using amino acid sequences deduced from whole and partial genome sequences as a basis for determining relatedness?
It accounts for novel organisms not detected by standard techniques used to amplify SSU rDNA. Each organism has an assortment of different ribosomal proteins, allowing more comparisons of gene products.
Antibiotics that interfere with peptidoglycan synthesis are ineffective in the treatment of _______ infections because these organisms lack a cell wall.
Mycoplasma
Which of the following is NOT a medically-significant member of the genus Mycoplasma?
Mycoplasma leprae
Medically-significant members of the genus Neisseria include which of the following?
N. gonorrhoaeae N. meningitidis
Nitrogen-fixing cyanobacteria can incorporate both ______ and _______ into organic material, thus generating a form of these nutrients that can then be used by other organisms.
N2, nitrogen, or N CO2 or carbon dioxide
Members of the genus _________ are causative agents of gonorrhea and meningitis.
Neisseria
A reason why environments that are routinely exposed to O2 can support anaerobic growth is that ______.
O2-consuming organisms depletes the oxygen levels
When comparing two organisms using DNA hybridization, the process relies on what property of DNA?
The extent of hybridization reflects the degree of sequence similarity between the two organisms.
Which of the following is a major advantage of detecting specific nucleotide sequences to identify prokaryotes?
The organisms do not need to be grown in culture.
Which of the following statements about members of the family Enterobacteriaceae is NOT true?
They only reside in the intestinal tract of humans.
Which of the following accurately describe biochemical tests used to identify microorganisms?
They rely on differences in metabolic capabilities of microorganisms. They generally provide a more certain identification than just relying on colony morphology.
True or false: Advances in DNA sequencing methods are making it practical to use whole genome sequencing (WGS) to trace outbreaks of foodborne pathogens.
True
True or false: Cyanobacteria are morphologically diverse, ranging in shape from unicellular organisms to filamentous multicellular associations.
True
True or false: Methane gas produced by methanogens can be collected and used for generating electricity.
True
True or false: Purple non-sulfur bacteria can grow as phototrophs, or as chemotrophs in the absence of light.
True
True or false: Methane gas produced by methanogens can be collected and used for generating electricity.
True
Bacterial viruses are known as ______.
bacteriophages
The method used to characterize different strains of bacteria that relies on differences in their susceptibility to _______ is called phage typing.
bacteriophages
A group of strains that have a characteristic biochemical pattern is called a ______, or biotype.
biovar
Cyanobacteria as a group are capable of ______.
both photosynthesis and nitrogen fixation
The urea ________ test (UBT) is a biochemical test done on a patient to determine whether he or she is infected with Helicobacter pylori, a common cause of stomach ulcers.
breath
Species of Rickettsia and Ehrlichia are transmitted ______.
by blood-sucking arthropods
How do aerobic chemoorganotrophs obtain their energy?
by oxidizing organic compounds by using O2 as a terminal electron acceptor
Members of the Gram-negative genera Aquifex and Hydrogenobacter are hydrogen-oxidizing bacteria. An example of their metabolism involves using ______.
hydrogen as a source of energy and oxygen as a terminal electron acceptor, forming water
When sulfur is used as a terminal electron acceptor in the metabolism of an organic compound, the products are carbon dioxide and ______.
hydrogen sulfide
All of the statements about GC content of prokaryotes are true EXCEPT ______.
if the GC content of two organisms is identical or nearly the same, the organisms are closely related
Nitrogen fixation occurs ______.
in anaerobic conditions only
Members of the genus Vibrio ______.
include pathogens such as V. cholerae and V. vulnificus
Wolbachia pipientis ______.
infects arthropods and parasitic worms and is transmitted maternally
Enterobacteriaceae get their name because they reside in the ______ tract of humans and animals.
intestinal
The taxonomic category called _______ is a collection of similar phyla or divisions.
kingdom
Order from largest to smallest: family genus order kingdom class species phylum
kingdom phylum class order family genus species
In 2019, 137 reported cases of diarrheal disease involved a specific strain of Salmonella enterica that was linked to consumption of pre-cut melons. This led to a recall of the products by the supplier. Why was it important to identify the specific strain in order to limit this outbreak?
knowing the strain made it possible to link these 137 cases in order to identify the source
Enteric bacteria that ferment ______ are called coliforms.
lactose
Which of the following results indicate that the bacterial strain being tested is susceptible to a specific bacteriophage?
A clear area on the hazy layer of bacterial cells being tested
What is the definition of biovar or biotype?
A group of strains that have a characteristic biochemical pattern.
_______ gain energy via the oxidation of reduced inorganic chemicals, using O2 as a terminal electron acceptor.
Aerobic chemolithotrophs
When two prokaryotic strains are compared by DNA hybridization, what is the minimum percent similarity they need to show to generally be considered members of the same species?
70%
The O157:H7 strain of E. coli is particularly virulent. The O refers to the antigenic type of the _______, and the H refers to the antigenic type of the _______.
lipopolysaccharide; flagella
Nitrifying bacteria _______. Thus, levels of this gas can quickly decrease in aquatic environments.
oxidize nitrogen compounds using O2
As a group, chemolithotrophs ______ to obtain energy.
oxidize reduced inorganic chemicals such as hydrogen gas
Acidithiobacillus species can be used to prevent acid rain, a problem that occurs when sulfur-containing coals and oils are burned. The bacteria are allowed to ______, a form that can then be extracted.
oxidize the sulfur to sulfate
Aerobic chemolithotrophs obtain energy by oxidizing reduced inorganic chemicals, using ________ as a terminal electron acceptor.
oxygen, oxygen gas, or O2
The cell walls of members of the domain _________ typically contain a polymer called peptidoglycan.
Bacteria
A probe used to identify a microorganism ______.
is a single-stranded piece of nucleic acid has a detectable tag or label is complementary to the sequence of interest
On what general principle do commercial variations of traditional biochemical tests operate?
A series of tiny wells containing different media are inoculated; metabolic activities yield a pattern of color changes used for identification.
Which of the following is an example where a stain would be strongly suggestive of a particular pathogen?
Acid-fast stain of sputum from a respiratory infection suggestive of Mycobacterium tuberculosis.
True or false: Some methods of detecting specific nucleotide sequences make it possible to identify organisms that cannot yet be grown in culture.
True
True or false: When attempting to identify the organism causing a disease, it is not generally necessary to identify each and every organism present.
True
media are designed to reveal specific colony characteristics that can help in the initial identification of bacteria in clinical samples.
Differential
You work in a clinical lab. A sample you cultivated overnight on blood agar yielded β-hemolytic colonies, suggestive of Streptococcus pyogenes, a member of the lactic acid bacteria. Unlike most bacteria that grow in the presence of O2, lactic acid bacteria are catalase-negative. If a catalase test on a colony yielded a positive result, what would this tell you about the identity of your organism?
Your sample is not Streptococcus pyogenes.
family order class phylum
a collection of similar genera a collection of similar families a collection of similar orders a collection of similar classes
A dichotomous key is a ______.
a flowchart of tests that each yield a positive or negative result to aid in identifying bacteria
In a MALDI-TOF assay,
a microorganism's proteins are separated and sorted by mass to generate a profile that provides a fast way to identify a colony.
A major advantage of commercial variations of traditional biochemical tests such as API strip tests is that they ______.
are less labor-intensive than traditional biochemical tests
In higher organisms such as plants and animals, the basic taxonomic unit of species is considered to be organisms that ______.
are morphologically similar can interbreed to produce fertile offspring
All of the following information can generally be determined from microscopic examination of a microorganism EXCEPT ______.
definitively determining the genus and species of the microorganism
When considering its taxonomic classification, Escherichia coli belongs to the ______ Enterobacteriaceae.
family
In 1969, R. H. Whittaker proposed a system of _______ based largely on _______.
five kingdoms; morphological differences
The ______ stain distinguishes between the two major groups of bacteria, an essential first step in the identification process.
gram
What term describes the evolutionary history of organisms?
phylogeny
Consider the image of the catalase test. The bubbles coming from the sample on the left indicate what?
production of O2, a positive result indicating the presence of catalase
A group of closely related strains or individuals comprises a taxonomic category called
species
The basic taxonomic unit is the
species
The species designation gives a formal taxonomic status to a group of related isolates, or ______.
strains
is the science that studies organisms in order to arrange them into groups; it can be viewed as three separate interrelated areas: identification, classification, and nomenclature.
taxonomy
Bacteria are given names according to internationally recognized rules based on which of the following?
the International Code of Nomenclature of Prokaryotes
In the picture shown, which culture shows a positive test for catalase production?
the culture on the left
In MALDI-TOF mass spectrometry, a protein profile is generated as the detector records the ionized molecules that arrive through a flight tube. The "time of flight" is based on ______.
the mass of the ions, with smaller ions arriving faster
Regardless of whether they are genetically related or not, certain groups of bacteria (e.g. lactic acid bacteria) are often grouped together by scientists because ______.
they have similar physiological characteristics
In this figure of sugar fermentation, tube D is an uninoculated control. Match the other three tubes to the correct result.
tube A - negative test tube B- positive test with gas production tube C- positive test with no gas production
Facultative anaerobes preferentially use aerobic respiration if _______ is present.
O2
I say: "Gram-negative bacteria, that are typically kidney-bean-shaped cocci in pairs. You say:
"Neisseria"
Mycoplasma is medically significant because it includes a pathogen that causes ______.
"walking pneumonia" which cannot be treated with antimicrobials that target peptidoglycan synthesis
Early chemotrophs may have used all of the following pathways to harvest energy EXCEPT ______.
- aerobic respiration
Match the following genera of organisms with their description. 1 Lactococcus 2 Lactobacillus 3 Enterococcus
1 Lactococcus - Includes species used to make cheese 2 Lactobacillus - Common members of the microbiota in the mouth and the vagina during childbearing years 3 Enterococcus - Members typically inhabit the intestinal tract
Match the organism with the disease that it causes. 1. Chlamydia trachomatis 2. Chlamydophila pneumoniae 3. Chlamydophila psittaci
1. Chlamydia trachomatis - A common sexually transmitted disease 2. Chlamydophila pneumoniae - Atypical pneumonia 3. Chlamydophila psittaci - Psittacosis
You have a sample containing bacteria that cannot yet be grown in culture. You decide to use 16s rDNA sequences to identify the bacteria. What is the correct order of steps you should use? Start with the earliest at the top.
1. Extract DNA from bacteria 2. Amplify the bacterial DNA 3. Sequence the 16S rDNA 4. Compare the 16S rDNA sequence with sequence of known organism
A membrane-bound nucleus is only found in organisms that belong to the domain
Eukarya
Place in order the events that occur when performing phage typing. Start with the earliest event at the top.
1. The test organism 2. Drops of different 3. If the organism 4. The pattern of clearing
Of the different ribosomal RNA molecules found in prokaryotes, which is the most useful in taxonomy?
16S
In taxonomy, the most useful rRNA molecule is the _______ rRNA in prokaryotes and the _______ rRNA in eukaryotes.
16S 18S
What method are researchers today most likely to use in order to group organisms into a classification scheme?
16S rDNA sequence data
This figure shows the ribosomal components in prokaryotes. Which component is most often used in taxonomy?
16S rRNA
Most methods that use nucleic acid probes to detect DNA sequences rely on a step that increases the amount of DNA in the sample. How can this be accomplished?
A preliminary in vitro DNA amplification step can be performed. The specimen can be inoculated onto an agar medium so that each cell multiplies, forming a colony.
Which of the following scenarios would be least likely to require a nucleic acid amplification test?
A researcher trying to identify a flask of E. coli among a dozen mislabeled flasks of other microbes of medical importance growing in lab.
What is the best definition of a signature sequence?
A sequence in rRNA that characterizes either a certain species or a group of related organisms.
Describe some growth conditions or characteristics that enable Pseudomonas aeruginosa to be a problem in hospital environments.
Ability to grow in nutrient-poor environments Resistant to disinfectants Resistant to antibiotics
Why can DNA sequences be viewed as evolutionary chronometers?
Accumulations of random mutations provide a relative measure of time elapsed since organisms diverged from a common ancestor.
______ species are Gram-negative, strictly anaerobic, make up about a third of the bacteria in fecal matter in humans, and are associated with abscesses and bloodstream infections.
Bacteroides
Which of the following genera consists of anaerobic Gram-positive rods that are commonly found as intestinal microbiota, particularly in breastfed infants?
Bifidobacterium
Presence of the enzyme ________ is a key characteristic of Staphylococcus species that is used to distinguish them from Gram-positive cocci that do not respire aerobically, such as Streptococcus species.
Catalase
An organism that harvests energy by oxidizing inorganic chemicals, but not organic chemicals, is a
Chemolithotrophs
When comparing phenotypic and genotypic methods of classification of organisms, which of the following best describe phenotypic methods?
Classification schemes that group organisms by phenotype have been largely replaced by DNA sequencing data. Phenotypic methods still provide an important foundation for prokaryotic identification. Some taxonomists believe classification should be based on more than just genotypic traits.
This graph, which charts the behavior of a double-stranded DNA molecule exposed to a range of high temperatures, illustrates the temperature at which the molecule denatures, or ________ __________ curve.
DNA melting
You are attempting to identify a bacterium that you are unable to culture in lab. Which set of techniques would best help you attempt to identify this bacterium?
DNA amplification followed by rDNA sequencing
A single-stranded piece of DNA labeled with a detectable tag (e.g., fluorescent dye or radioisotope) is called a ______.
DNA probe
Which of the following pairs are matched correctly?
Enterococcus: found in the intestinal tract Lactobacillus: found in milk and other dairy products
DNA-DNA hybridization has demonstrated that members of what two genera would actually be grouped in the same species?
Escherichia and Shigella
A technique that uses probes that can bind 16S rRNA and does not require an amplification step because numerous copies of rRNA are present in multiplying cells is called which of the following?
Fluorescence in situ hybridization (FISH)
he base ratio of an organism is usually expressed as the percent of guanine plus cytosine, which is called the
GC
Assuming all molecules are equal in size, a DNA with a higher ______ will melt at a higher temperature.
GC content
A group of bacteria called green bacteria are ______.
Gram-negative
Species of the genus Haemophilus have what characteristics?
Gram-negative coccobacilli "blood loving," as their name reflects often common inhabitants of the respiratory tract
Members of the family Enterobacteriaceae are _______.
Gram-negative rods
Which of the following describe characteristics of members of the genus Vibrio?
Gram-negative straight or curved rods Typically found in marine environments
Like the green and purple bacteria, members of the genus Heliobacterium are also examples of anoxygenic phototrophs. They are ______ bacteria related to members of the genus Clostridium
Gram-positive rod-shaped endospore-forming
Bifidobacterium species are ______.
Gram-positive, irregular rod-shaped anaerobes part of the intestinal microbiota
Which of the following is the goal of phylogenetic classification?
Group organisms according to their evolutionary relatedness.
You sequence the genome of an organism and measure the relative amount of each nucleotide. After measuring the percent of cytosine at 20%, what can you safely conclude about the percentages of the remaining nucleotides?
Guanine is 20%; adenine and thymine are each 30%.
During photosynthesis, anoxygenic phototrophs use _______ as a source of electrons to make reducing power.
H2S
Aside from green and purple bacteria, Gram-positive endospore forming rods of the genus ______ are also anoxygenic phototrophs.
Heliobacterium
Match the Roman numeral with the correct serotype designation.
I- H antigen II- K antigen III- O antigen
What is an advantage of phage typing for identifying different strains of bacteria?
It is a useful tool for laboratories that lack equipment to do genomic testing.
Which of the following are accurate descriptions of PulseNet?
It is used to more readily recognize and trace multistate foodborne disease outbreaks It is a database cataloging whole genome sequences of certain foodborne bacterial pathogens.
Anoxygenic phototrophs typically live in which of the following environments?
Lakes Upper layers of mud Bogs
You isolate Gram-positive cocci that are obligately aerobic. They are salt-tolerant and form colonies that have a yellow pigment. This organism is most likely a member of the genus ______.
Micrococcus
Several species of _______ are notable pathogens. These include the bacteria that cause tuberculosis and leprosy.
Mycobacterium
You isolate pleomorphic rods that are difficult to stain with the Gram-staining procedure. This organism is most likely a member of the genus ______.
Mycobacterium
When undergoing photosynthesis, anoxygenic phototrophs use hydrogen sulfide or organic compounds as a source of electrons to make reducing power. Thus, they do not generate ______.
O2
A diverse group of Gram-negative bacteria that obtain energy by oxidizing inorganic nitrogen compounds such as ammonium or nitrate are known as
Nitrifiers
The enzyme complex that catalyzes nitrogen fixation is called
Nitrogenase
Methods used to increase the number of copies of specific DNA sequences can collectively be referred to as which of the following?
Nucleic acid amplification tests (NAATs)
Which of the following can purple non-sulfur bacteria use as an electron source?
Organic compounds Hydrogen sulfide Hydrogen gas
What are some difficulties in using phenotypic characterizations for the phylogenetic classification of prokaryotes?
Organisms that appear dissimilar may be closely related. Phenotypic differences can be due to only a few gene products. Phenotypically similar organisms may be only distantly related.
Members of which bacterial genus are used to make Swiss cheese?
Propionibacterium
An anoxic atmosphere lacks
Oxygen
Which of the following does Wolbachia pipientis directly infect?
Parasitic worms Arthropods
Which of the following is not a characteristic of the lactic acid bacteria?
Possess the enzyme catalase
Which of the following are diseases caused by member of the Chlamydia and Chlamydophila species?
Psittacosis, a form of pneumonia A sexually transmitted infection that mimics gonorrhea Eye infections Atypical pneumonia
In order to better track foodborne disease outbreaks, the CDC established a database called _________, which catalogs whole genome sequences of certain foodborne pathogens.
PulseNet
Describe some growth conditions or characteristics that enable Pseudomonas aeruginosa to be a problem in hospital environments
Resistant to antibiotics Ability to grow in nutrient-poor environments Resistant to disinfectants
Why are ribosomal components (ribosomal RNA and ribosomal proteins) considered reliable indicators of evolutionary relatedness?
Ribosomes are present in all organisms. Ribosomes perform crucial and functionally constant tasks. Ribosomal genes are not commonly horizontally transferred.
Which of the following is a limitation of using ribosomal DNA sequence analysis for determining the phylogeny of organisms?
Sequence analysis of 16s rDNA is often unreliable for distinguishing closely related species.
Which of the following is considered the most reliable indicator of evolutionary relatedness in prokaryotes?
Sequences of ribosomal components
The designation O157:H7 of E. coli is an example of which of the following?
Serological typing
Why are nitrifiers of concern regarding their environmental impact?
They consume dissolved O2 from waterways contaminated with nitrogen-containing wastes. They convert ammonium fertilizer to nitrate, which is more easily leached from soils.
Lactic acid bacteria include all of the following genera EXCEPT _______.
Staphylococcus
Members of the genus ______ thrive in the dry and salty environment of the skin.
Staphylococcus
Which of the following bacteria is typically a harmless resident of the skin?
Staphylococcus epidermidis
This member of the lactic acid group is a Gram-positive coccus that grows in the oral cavity and can cause pharyngitis.
Streptococcus pyogenes
Nomenclature
System of assigning names to organisms
Unlike many nucleic acid detection techniques, why does fluorescence in situ hybridization (FISH) not require an amplification step?
The probe binds to 16S rRNA, many copies of which are naturally present in multiplying cells.
Why are sequences of ribosomal RNA so useful in microbial classification and identification?
The sequences are relatively stable, since the ribosome would not function with too many mutations. Once a sequence is determined, it can be compared with sequences of known organisms by searching extensive databases. They allow identification without culturing the organism.
More than 300 cases of salmonellosis occur within a large city. Each time, Salmonella enterica is isolated from the feces of the patient. Based on that information, the news media report that there must be a common source to all these cases. What additional information would be needed to support or disprove this view?
The specific strain of the Salmonella would need to be identified.
Which of the following statements about Pseudomonas species are true?
They are able to metabolize unusual sugars and amino acids. They can degrade environmental compounds that many other organisms cannot.
Which of the following statements describe Bordetella species?
They are aerobic Gram-negative coccobacilli. The most significant medical species causes whooping cough.
Which of the following accurately describe DNA probes?
They are short, single-stranded pieces of DNA of a particular sequence of interest. They rely on complementary base pairing in order to bind their target DNA.
Which of the following are characteristics of the genus Propionibacterium?
They can ferment lactic acid. They are Gram-positive.
What are the characteristics of purple nonsulfur bacteria?
They grow as phototrophs. They lack gas vesicles.
Genera of the family Enterobacteriaceae include all the following EXCEPT one. Which?
Vibrio
Which of the following statements about microbial diversity is true?
We are only now beginning to understand the diversity of prokaryotes.
Cyanobacteria living in aquatic environments can ______.
accumulate in larger numbers, which is referred to as a bloom move vertically through a water column using gas vesicles
Filamentous sulfur oxidizers ______.
accumulate sulfur as intracellular granules
A special staining procedure called the ______ is used in the identification of Mycobacterium species.
acid-fast stain
The photosystems of cyanobacteria are similar to those of ______.
algae plants
In addition to being photosynthetic, many cyanobacteria have the ability to convert nitrogen gas (N2) into ______, a process known as nitrogen fixation.
ammonia
Nitrifiers are composed of two metabolically distinct groups: the _________ oxidizers, which convert ammonia to nitrite, and the _______ oxidizers, which convert nitrite to nitrate.
ammonia or ammonium nitrite
Two metabolically distinct groups of nitrifiers, the ______, typically grow in close association and together can oxidize ammonium to nitrate.
ammonia oxidizers and nitrite oxidizers
Chemoorganotrophs that perform ______ often use sulfur or sulfate as a terminal electron acceptor.
anaerobic respiration
An atmosphere that lacks O2 is called
anoxic or anaerobic
Which of the following were likely the earliest photosynthesizing organisms?
anoxygenic phototrophs
Antibiotic susceptibility patterns, like the one shown, are called
antibiograms
Most of the anaerobic chemolithotrophs that have been discovered are members of what domain?
archaea
Methanogens are a group of _______ that produce methane by oxidizing _______.
archaea; H2
Nitrifiers can be described as bacteria that ______.
are Gram-negative obtain energy by oxidizing inorganic nitrogen compounds such as ammonium or nitrite
Haemophilus species ______.
are Gram-negative coccobacilli that require hematin and/or NAD for growth
Sulfur-reducing bacteria have a positive impact on the environment because they ______.
are an essential component of the sulfur cycle
Based on their defining characteristics, members of the family Enterobacteriaceae ______.
are facultative anaerobes ferment glucose possess peritrichous flagella if motile
Purple non-sulfur bacteria would not be found in ______.
arid environments
As a group, anaerobic chemoorganotrophs ______.
can obtain energy via fermentation produce ATP via substrate level phosphorylation
Sulfur-oxidizing bacteria ______.
can use hydrogen sulfide or thiosulfate as an energy source can sometimes grow in filaments
Coxiella burnetti is an oblicate intracellular bacterium that ______.
causes Q fever can form small cell variants (SCVs) that survive well in the environment
Coxiella burnetti ______.
causes Q fever can form spore-like small cell variants (SCVs) that survive well in the environment
A key characteristic of the genus Mycoplasma is that they lack a ________ ________, instead usually relying on sterols in their membrane to provide strength and rigidity.
cell wall
The cells of species in the genus Neisseria are ______.
cocci Gram-negative typically found in pairs
The earliest oxygenic phototrophs probably belonged to a group of bacteria called the
cyanobacteria
Which of the following groups of bacteria is best described as a diverse group of photosynthetic Gram-negative bacteria that inhabit a wide range of environments?
cyanobacteria
Heterocysts are structures found in ______ and are involved in _______.
cyanobacteria; nitrogen fixation
Unlike in other anoxygenic phototrophs, in purple bacteria, the components of the photosynthetic apparatus are all located in the cell's ________ membranes.
cytoplasmic
Campylobacter jejuni infections are commonly associated with ______.
diarrhea
Phage typing relies on which of the following?
differences in susceptibility of various strains of a given bacterial species to bacteriophages
In order to distinguish different strains of bacteria, an antibiogram relies on ______.
differences in susceptibility to various antibiotics
Gram-positive pleomorphic rods that are club-shaped and arranged to form V shapes or palisades (side-to-side stacks) are referred to as ______ or ______.
diphtheroids coryneforms
Phage typing is used to ______.
distinguish different bacterial strains
Because the skin is ______, growth of many organisms is prevented.
dry and salty
Wolbachia pipientis can be found inside parasitic worms that cause ______.
elephantiasis river blindness
The _________ produced by the genus Clostridium have the ability to survive harsh environmental conditions that can commonly kill the vegetative bacterial cells.
endospores
The presence of coliforms such as Escherichia coli in food and water indicates the possibility of ________contamination.
fecal
An anaerobic chemoorganotroph that uses glucose for energy and pyruvate as its terminal electron acceptor is performing ______.
fermentation
Facultative anaerobes can use aerobic respiration if O2 is present and _______if O2 is not available
fermentation
Beggiatoa and Thiothrix species are examples of ______.
filamentous sulfur oxidizers
Methanogens are organisms that ______.
generate methane obtain energy by oxidizing hydrogen gas use CO2 as a terminal electron acceptor
All of the following are characteristic of green sulfur bacteria EXCEPT one. Which?
have color pigments that are located in structures called trichomes
As a group, Pseudomonas species ______.
have extremely diverse biochemical capabilities
Cyanobacteria have photosystems that ______.
have pigments other than chlorophyll that contribute to their blue-green or reddish color
An important trait of species of the thermophilic Thermus is their ______.
heat-stable enzymes
On blood agar, Streptococcus pyogenes produces β-_________ , a characteristic used to differentiate this organism from the normal oral microbiota.
hemolysis
In the filamentous bacterium Anabaena, specialized cells called _______ are used for nitrogen fixation in order to protect nitrogenase from O2.
heterocyst
In this micrograph of a cyanobacterial species, the structure that is labeled A is called a(n) _______.
heterocyst
Deinococcus species have the ability to withstand ______.
high doses of radiation
Choose the pair of phrases that best completes the following scenario: Consider two organisms that diverged from a common ancestor at some point in history. If there are many differences in the sequences of their DNA, this indicates they diverged ______: if there are few differences, this indicates they diverged ______.
longer ago; more recently
Choose the environments that would most likely support the growth of methanogens.
marine sediment sewage human digestive tract swamp
Filamentous anoxygenic phototrophic bacteria ______.
may possess chlorosomes exhibit gliding motility
Based purely on DNA-DNA hybridization criteria used for bacteria, humans and chimpanzees would be ______.
members of the same species
Species of Campylobacter and Helicobacter are ______.
microaerophilic curved, Gram-negative rods
If the GC content of two organisms is 67%, the organisms ______.
might be related
The normal habitat of Bacteroides species in humans includes the ______.
mouth genital tract intestines
The green bacteria are Gram-_________ organisms that are typically green or brownish in color.
negative
Many cyanobacteria can convert nitrogen gas (N2) to ammonia, which is a process called ______.
nitrogen fixation
An organism that cannot reproduce outside of a host cell is termed an _______ _______ parasite.
obligate intracellular
Hydrogen-oxidizing bacteria such as Aquifex and Hydrogenobacter are ______.
obligate chemolithotrophs Gram-negative thermophilic
Chlamydia and Chlamydophila are transmitted directly from person-to-person and live within host cells as ______ parasites.
obligate intracellular
Pseudomonas aeruginosa can be described as a(n) _________ pathogen because it usually causes disease in patients who have underlying medical conditions.
opportunistic
In a healthy individual, anaerobes can regularly be found on and in the ______.
oral cavity skin intestinal tract
Chemoorganotrophs oxidize _________ compounds such as glucose to obtain energy.
organic
Pseudomonas species are Gram-negative rods that, unlike members of the family Enterobacteriaceae, are ______.
oxidase-positive nonfermenters
Aerobic chemoorganotrophs gain energy via the _______, using O2 as a terminal electron acceptor.
oxidation of organic compounds
Viruses that infect bacteria and replicate in them are specifically called
phages
Microscopic morphology, culture characteristics, and fatty acid analysis are all examples of ______ characteristics used to identify prokaryotes.
phenotypic
Cyanobacteria are a group of _______ bacteria.
photosynthetic Gram-negative
A diagram that uses a branching pattern to depict the evolutionary heritage of organisms is called a(n) ___________ ____________.
phylogenetic tree
A branching diagram showing the evolutionary relationships among various organisms is referred to as a(n) ______.
phylogenetic tree
The evolutionary relatedness of organisms is called
phylogeny
Members of the genus Corynebacterium are Gram-positive rods that exhibit a variety of shapes. This difference in shape is referred to as being ______.
pleomorphic
Species of Pseudomonas ______.
possess polar flagella use oxygen as a terminal electron acceptor
Which of the following can distinguish members of the genus Staphylococcus from Streptococcus, Enterococcus, and Lactococcus species?
presence of the enzyme catalase
Nitrogen fixation, or the process of converting nitrogen gas (N2) into ammonia, is an exclusive ability of ______.
prokaryotes
Propionibacterium species produce _______ acid as their major fermentation end product.
propionic
The characteristic flavor and holes of Swiss cheese are caused by the fermentation products _______ and _______, respectively.
propionic acid; CO2
Serological typing distinguishes different bacterial strains based on characteristics of which of the following?
proteins and carbohydrates such as those that make up flagella, capsules, and lipopolysaccharide molecules
Beneficial characteristics of nitrogen-fixing cyanobacteria include ______.
providing an important source of usable nitrogen and carbon in nutrient poor environments limiting atmospheric CO2 buildup
The genes that encode ribosomal RNA (rRNA) are referred to as
rDNAs
Unicellular sulfur oxidizers can be used to ______.
recover metals prevent acid rain
The purple bacteria are Gram-negative organisms that can appear ______ due to their light-harvesting pigments.
red orange purple
By definition, obligate intracellular parasites cannot ______.
replicate outside of a host cell
Obligate aerobes obtain energy using _______ exclusively; none of them can ferment.
respiration
Members of the filamentous bacterial species Anabaena protect the nitrogenase enzyme from O2 by ______.
restricting the process of nitrogen fixation to heterocysts where O2 is not generated
For characterizing strain differences among prokaryotes, whole genome sequencing (WGS) has now largely replaced _______.
restriction fragment length polymorphisms (RFLPs).
Chlamydia and Chlamydophila species can exist in the host as non-infectious ________ bodies which can replicate and later differentiate into smaller, dense-appearing infectious ________ bodies.
reticulate elementary
The rDNA genes specify the information needed to synthesize _________ RNA molecules. (No abbreviations please)
ribosomal
To differentiate species in the family Enterobacteriaceae, a microbiologist could use which of the following methods?
serological tests biochemical tests
Escherichia coli O157:H7 is an enterohemorrhagic strain responsible for many cases of foodborne illness. The O157:H7 refers to the antigenic type of its lipopolysaccharide (the O antigen) and flagella (the H antigen). E. coli O157:H7 is therefore a ______ of E. coli.
serotype or serovar
A group of strains that have cell surface antigens different from other strains is called a
serovar
A sequence in rRNA that characterizes either a certain species or a group of related organisms is called a(n) _____ sequence.
signature
Staphylococcus epidermidis is part of the normal microbiota of the
skin
Bordetella species are ______.
small aerobic Gram-negative coccobacilli nutritionally fastidious
he 16S rRNA molecule is part of the _______ subunit of the prokaryotic ribosome, and is equivalent to the ______ rRNA of eukaryotes.
small; 18S
Members of the genera Treponema and Borrelia are characterized by their corkscrew shape and endoflagella, thus making them ______.
spirochetes
Green sulfur bacteria are ______.
strict anaerobes
Purple sulfur bacteria typically use hydrogen ________ (H2S) to generate reducing power.
sulfide
Treponema pallidum causes the sexually transmitted disease in humans called ______.
syphilis
All of the following are reasons why sequencing the genes of small subunit (SSU) rRNA is extremely useful in classifying organisms EXCEPT ______.
the genes are often horizontally transferred
Wolbachia pipientis is significant medically in diseases such as river blindness and elephantiasis because ______.
the immune response to the bacteria contributes to chronic inflammation in these diseases it resides within the filarial worms that cause these diseases
When trying to determine whether the patient has Helicobacter pylori, the cheaper and faster option would be ______.
the urea breath test
Members of Chloroflexus grow in hot springs, which makes them ______.
thermophilic
All of the following are true of the genus Clostridium EXCEPT ______.
they are Gram-negative rods
All of the following are characteristics shared by both Helicobacter and Campylobacter EXCEPT ______.
they cause diarrheal disease in humans
Rickettsia rickettsii causes Rocky Mountain spotted fever, which is transmitted through the bite of a ______.
tick
Some cyanobacteria have negative effects, such as producing ______.
toxins that can harm animals geosmin, which can influence the taste of drinking water
Which of the following are characteristic of Micrococcus species?
typically pigmented obligate aerobes salt tolerant
Humans infected with Helicobacter pylori may develop peptic
ulcer
The purple sulfur bacteria ______.
use hydrogen sulfide to generate reducing power may possess gas vesicles store sulfur in intracellular granules may be motile by flagella
Bacteria that oxidize sulfur are Gram-negative rods or spirals that ______.
use sulfur compounds as an energy source and oxygen as a terminal electron acceptor
How do obligate aerobes obtain energy?
using respiration only
Oxygenic phototrophs use ______ as a source of electrons for reducing power, generating O2.
water
Mycobacterium species stain poorly because their cell walls contain ______.
waxy lipids called mycolic acids
Pulse Net, Genome Trakr, and Global Microbial Identifier are examples of surveillance networks and programs that use ___________ ___________ sequence (WGS) data to help track infectious disease outbreaks both nationally and around the world.
whole genome
Deduced amino acid sequences from ______ are now used as a basis for determining relatedness.
whole and partial genome sequences
The Food and Drug Administration (FDA) recently began organizing Genome Trakr, a network of laboratories that collect ______ for use in tracking outbreaks caused by various foodborne pathogens.
whole genome sequencing (WGS) data
A strain is ______.
one of a group of related isolates within a species
Which of the following is a property of Archaea?
70S ribosomes
Which of the following are properties of Bacteria?
70S ribosomes peptidoglycan cell wall
A series of alternative choices that lead to the identification of an organism is referred to as a(n)
Dichotomous
testing uses antibodies to detect characteristic proteins or polysaccharides that make up microorganisms.
Serological
Determining the phylogeny, or evolutionary relatedness, of members of which of the following groups would likely be the least difficult?
Animals
The cytoplasmic membrane lipids of members of the domain _______ are composed of hydrocarbons (not fatty acids) linked to glycerol by ether linkage.
Archaea
The revolutionary system of classification proposed by Woese and his colleagues separated prokaryotes into two domains: _______ and ________.
Bacteria Archaea
What is the most important reference for taxonomic descriptions of bacteria?
Bergey's Manual of Systematic Bacteriology
Most bacteria that grow in the presence of O2 are which of the following?
Catalase-positive
Molecular techniques such as ______ have allowed scientists to determine the phylogeny of microorganisms.
DNA sequencing
What is a significant limitation of detecting specific nucleotide sequences in order to identify prokaryotes?
Each probe or amplification detects only a single possibility, so multiple probes/amplifications may be needed to uniquely identify.
True or false: Gram stain results are necessary and sufficient to diagnose the cause of an infection.
False
For the scientific name Staphylococcus aureus, Staphylococcus has which of the following designations?
Genus
Which of the following taxonomic designations is defined as a group of related species?
Genus
True or false: Scientists sort living organisms into different groups to show the relationships among the species.
True
Which of the following strategies is least important when attempting to identify the causative agent of a patient's disease symptoms?
Identifying each and every organism present in the patient or patient's sample.
Nucleic acid amplification tests (NAATs) are most useful for which of the following?
Increasing the number of copies of specific DNA sequences
Prior to the three-domain system, the most widely accepted scheme was the five-kingdom system, proposed by R. H. Whittaker in 1969. What were the major limitations of this system that the three-domain system solved?
It did not reflect the fundamental differences in chemical compositions of cell walls and cytoplasmic membranes between Archaea and Bacteria. It did not reflect ribosomal RNA data that indicates plants and animals are more closely related to each other than Archaea are to Bacteria.
Which of the following are accurate descriptions of the newest edition of Bergey's Manual of Systematic Bacteriology?
It includes information on methods for maintenance and preservation of organisms. It classifies all known prokaryotes based on their phylogeny. It includes information on ecology, methods of enrichment, culture, and isolation of organisms.
Starting with the most general and ending with the most specific, which is the correct order for taxonomic units?
Kingdom, phylum, class, order, family, genus, species
______ is a revolutionary new technology being used in clinical labs that can rapidly identify an organism based on its protein profile.
MALDI-TOF mass spectrometry
Why are pH indicators used in so many biochemical tests that aim to identify bacteria?
Many of the metabolic pathways being tested have acidic or basic end products, yielding a change in pH of the medium.
Choose the methods used to identify prokaryotes that are based on phenotypic characteristics.
Metabolic capabilities Culture characteristics Microscopic morphology
You are working in a clinical lab and are given a stool sample to analyze for suspected roundworms. What phenotypic characterization approach would give you the fastest presumptive answer?
Microscopic morphology
Members of the genus ________ , such as the causative agents of tuberculosis and Hansen's disease, are examples of acid-fast organisms.
Mycobacterium
In some cases, a presumptive diagnosis can be made just from a visual identification based on knowledge of the patient's symptoms. For example, intracellular Gram-negative diplococci found in a urethral sample from a male are indicative of ______.
Neisseria gonorrhoeae
Which is a nucleic acid amplification test (NAAT)?
Polymerase chain reaction
Classification
Process of arranging organisms into similar or related groups, primarily to make it easier to identify and study them
Identification
Process of characterizing an isolate to determine the group (taxon) to which it belongs
Which of the following help to explain why it is more difficult to determine the phylogeny of prokaryotes than that of plants and animals?
Prokaryotes have few differences in size and shape. The definition of species does not apply to prokaryotes in the same way as it does to plants and animals.
Which of the following are benefits of using a Gram stain to characterize an unknown prokaryote?
Provides information on the shape and arrangement of bacterial cells Can be conducted quite quickly in the laboratory Shows whether organisms appear to be growing as a pure culture or with other bacteria and/or host cells Distinguishes between Gram-positive and Gram-negative bacteria to narrow the list of possible identities
Choose the correct descriptions of serological tests.
Rely on differences of surface structure molecules such as components of the cell wall, capsule, flagella, or pili. Require detection by antibodies.
Colony morphology can give hints as to the identity of the organism. Match the following examples of specific morphological features with the correct organism. Serratia marcescens Pseudomonas aeruginosa Streptococcus pyogenes
Serratia marcescens -often red when incubated at 22oC Pseudomonas aeruginosa- has a distinct fruity odor; often produces a soluble greenish pigment Streptococcus pyogenes- forms β-hemolytic colonies on blood agar
You are attempting to identify an unknown bacterium by detecting nucleotide sequences. The bacterium could be one of seven different species or related groups. How many different probes do you need in order to identify this culture?
Seven
What is the basic unit of taxonomic classification?
Species
If a Gram stain of human sputum showed many white blood cells and Gram-positive diplococci, the most likely bacterium is which of the following?
Streptococcus pneumoniae
Consider the four sugar fermentation tubes. The left tube is a negative control, and on the right is an uninoculated tube. What does the tube second from the left indicate?
The organism fermented the provided sugar to yield acid and gas.
The image shows results of the urease test. What does the positive result (pink tube on the left) tell us about the organism?
The organism produces urease, which degrades urea to CO2 and ammonia, increasing the pH of the medium to produce a color change in the indicator.
Consider the urease tests, shown. The tube on the right is an uninoculated control. What does the tube on the left tell us?
The tube on the left is a positive result for urease production.
The catalase test detects a microorganism's ______.
ability to break down hydrogen peroxide to form O2 and water
Before molecular techniques were available, bacteria were often classified based on ______.
ability to degrade different compounds cell wall type
When a patient is suspected of having tuberculosis, what staining procedure is often done on the patient's sputum sample to help identify Mycobacterium tuberculosis?
acid-fast stain
According to the rules of nomenclature, the name of a bacterium or archaeon ______.
can honor a scientist can reflect the habitat of the organism needs to include a Latin suffix
The _______ test detects the ability of the organism to produce an enzyme that breaks down hydrogen peroxide to form O2 and water.
catalase
Choose the properties that are representative of members of the domain Eukarya.
cell membranes that contain fatty acids linked to glycerol by an ester linkage membrane-bound nucleus introns
In a clinical lab, microscopic examination of a specimen is often enough to diagnose ______ because of their size and characteristic shape.
certain infections by eukaryotic parasites
A _______ indicator is commonly used in biochemical tests to show the production of acid or base by changing from one color to another.
chemical
Which of the following taxonomic designations is inclusive of all the others listed?
domain
Match the following taxonomic ranks of the bacterium Escherichia coli with the correct category. domain phylum family genus species
domain - bacteria phylum - proteobacteria family - enterobacteriaceae genus - Escherichia species - coli
When diagnosing Helicobacter pylori infections, the urea breath test is preferred because ______ than other options.
it is cheaper and faster it is less invasive
A patient suspected of having Helicobacter pylori would drink a solution containing ______ in order to test for the presence of the enzyme ______.
labeled urea; urease
Examples of genetically unrelated bacteria that are informally grouped based on certain distinctive characteristics include ______.
lactic acid bacteria sulfate reducers endospore-formers
The system for classifying organisms changes constantly because ______.
new information is always being discovered
The three-domain system of classification is based upon comparisons of ______ made by Carl Woese and colleagues in the late 1970s.
nucleotide sequences of ribosomal RNA
Taxonomic categories include ________, which is defined as a grouping of similar families, and _______, which is a grouping of similar classes
order phylum
MALDI-TOF mass spectrometry is an important new technology in bacterial identification because it can identify an organism from a colony ______.
rapidly, often in less than 15 minutes based on the profile of its proteins
All of the following are examples of biochemical tests EXCEPT one. Which?
serology
Scientists group bacteria into different groups in order to ______. tell them apart from eukaryotic organisms determine where they were isolated show how different species are related
show how different species are related
Microscopic examination is important in the presumptive identification of an organism because it can provide information on the organism's ______.
size and shape staining characteristics
