MB 351 Quiz 2
Neutral mutations only occur in stretches of DNA encoding protein.
F
Nitrifying eukaryotes can use nitrite (NO2-) as an electron donor for an aerobic, chemoautotrophic respiration.
F
Prokaryotic genomes typically have 25-50 nucleotides between genes.
F
Sigma proteins assist RNA polymerase with promoter binding in all prokaryotes and dissociate after transcription initiation.
F
Prokaryotic species are typically defined as a group of strains more similar to each other than to other strains.
F
Mycorrhizial symbionts provide water, minerals and protection to plant root cells.
T
Recombination is a separate process from replication in a prokaryotic cell.
T
Syntrophy is also known as interspecies hydrogen transfer.
T
Conjugal pili are only synthesized by cells harboring a prophage
False (harboring a transmissible plasmid)
Transcriptional termination is the most common form of gene regulation in prokaryotes
False (initiation)
Microbes unable to detoxify oxygen radicals would exhibit positive aerotaxis
False (negative)
Many organisms cannot directly incorporate atmospheric nitrogen into their biological molecules.
T
Ectomycorrhizae produce haustauria, which penetrate through plant root cell walls - growing into the root cells.
F
Free-swimming chemotactic bacteria power their transmembrane flagella motors with ATP.
F
Horizontal gene transfer occurs less often among microbes within a biofilm than it does among free-floating microbes.
F
Hyperthermophilic bacteria have optimal growth temperatures between 45 and 60 degrees Celsius.
F
In the absence of lactose, the lac operon is transcriptionally active.
F
Lichens are a symbiois between a fungus and the root cells of an angiosperm plant.
F
Microbes accumulate high concentrations of nutrients near the cells with low concentrations only a few millimeters away.
F
Microbial communities are comprised of "guilds", determined by the morphological characteristics and the geographic location of an organism within the community.
F
Most prokaryotic genomes are comprised of a pair of diploid, circular chromosomes.
F
Oxygen consumption in the animal intestinal tract is entirely due to obligate anaerobes.
F
Plasmids encode essential prokaryotic cell functions.
F
Prokaryotes are classified into species by the same criteria used to classify animals by species.
F
Purple non-sulfur bacteria grow in stagnant, anoxic waters using hydrogen sulfide for energy.
F
Purple sulfur bacteria grown in stagnant, anoxic waters using organic sulfur for energy.
F
Quorum sensing allows cells to begin production of certain compounds only upon reaching a certain size.
F
Repressible prokaryotic gene regulation systems use effectors to start gene transcription
F
Rhizobium bacteriods provide fixed nitrogen for the water fern Azolla, leading to increased rice crop yields.
F
Rhizobium bacterioids produce leghemoglobin to maintain a low oxygen concentration in the legume symbiosome.
F
Carl Linneaus first proposed groups of organisms sharing similar features are related by descent from a common ancestor.
F (Charles Darwin)
Antisense RNA anneals/binds to complementary mRNA sequences blocking transcription.
F (blocking translation and therefore protein production)
Inducible prokaryotic operons under negative control have transcription factors requiring effector binding to induce transcription
False (positive)
Catabolite repression is regulated by a repressor protein CRP.
False (regulated by transcription factor)
Transformation is when DNA - released by a competent cell - is taken up by a donor cell.
False (released by donor cell, recipient cell)
The genes controlling conjugal plasmid transfer are normally expressed
False (repressed)
Prokaryotic metabolic processes are necessary to return vital nutrients from the land back to the sea.
False (sea to land)
Endospores are highly durable bacterial reproductive structures.
False (survival structures)
Strong promoters work best with operons requiring dynamic control
False (weak)
Deinococci are known for their extreme radiation and ultraviolet (UV) light resistance.
T
Endomycorrhizae produce haustauria, which penetrate through plant root cell walls - growing into the root cells.
T
Endospores show no measurable metabolic activity.
T
Expression of different sigma factors allows E. coli to regulate gene transcription in response to different environmental conditions.
T
Gram positive bacteria use short peptides as autoinducer (AI) molecules.
T
Heterocysts lose photosystem II and specific DNA sequences compared to vegetative cells.
T
Hfr strains mobilized large segments of the host chromosome to recipient cells at high frequency
T
In many symbioses the prokaryote partner provides fixed nitrogen.
T
Initiation of endospore development is regulated by quorum sensing.
T
Lichens form symbiotic reproductive structures known as soredium.
T
Many prokaryotic cells demonstrate positive chemotactic responses toward attractants.
T
Metagenomic analysis can identify a microbe without the need to isolate the microbe in pure culture.
T
Microbes unable to detoxify oxygen radicals would exhibit negative aerotaxis.
T
Molecular chronometers provide evidence of evolutionary relatedness while avoiding the confusion of convergence.
T
Most lichens are comprised of a single fungus in symbiosis with a single phototrophic organism
T
Most prokaryotic transcriptional units have one or more regulatory sites controlling the rate of transcription.
T
Neisseria gonorrheae can be transmitted to a newborn during childbirth.
T
Organisms are currently classified into one of three domains based on analysis of their 16s rRNA sequences.
T
Oxygen consumption in the animal intestinal tract is entirely due to facultative anaerobes.
T
Planctomyces are the only bacterial lineage known to lack peptidoglycan entirely.
T
Prokaryotic cells exclusively convert nitrates to N2 gas.
T
Prokaryotic genomes contain multiple transposons and insertion sequences.
T
Prokaryotic transcription initiation is controlled by allosteric proteins
T
Prokaryotic transcriptional units are typically transcribed in the same direction the chromosome is replicated.
T
Purple non-sulfur bacteria are inhibited by high sulfide concentrations, they can appear orange, red, brown or purple and demonstrate phototaxis
T
Purple sulfur bacteria grown in stagnant, anoxic waters using hydrogen sulfide for energy.
T
Quorum sensing allows cells to react to local cell density, rather than absolute cell number or cell size.
T
Quorum sensing induces expression of operons involved in biofilm, surfactant and antibiotic production.
T
RNA polymerases in eukaryotic microbes have multiple subunit RNA polymerases with no sigma-like subunit.
T
Recombination following prokaryotic horizontal gene transfer is facilitated by the RecA protein.
T
Repressors and transcription factors sometimes bind at two distant sites forming a DNA loop.
T
Since Hfr formation is reversible, every Hfr or F+ culture is a mixture of both.
T
Some proteins can function as both repressors and transcription factors.
T
Specialized transduction can produce partial diploids. (merozygotes)
T
Specialized transduction is the result of a rare mistake of prophage excision.
T
Spirochetes are characterized by their distinct helix or spiral morphological shape.
T
Spirochetes are characterized by their periplasmic endoflagella.
T
Sulfate reducers dominate in marine sediments.
T
Symbiotic relationships are dynamic - often depending on the condition of the host.
T
The MCP chemotactic signaling pathway in E. coli controls flagellar rotation.
T
The PatS oligopeptide is produced by the heterocyst at a constant rate.
T
The Planctomcyes are mostly unicellular budding bacteria associated with aquatic/marine environments.
T
The RecA protein facilitates proper DNA recombination and repair.
T
The first E.coli linkage map was created using Hfr conjugation and phage transduction.
T
The high viscosity of most bacterial environments results in little to no coasting when bacteria engage in a tumble.
T
The most commonly used sequence for phylogeny construction is the 16s rRNA gene.
T
The nitrifying bacteria are mostly obligate chemoautotrophs capable of oxidizing ammonia or nitrite for energy.
T
The rarest recombination event occurs at the lowest frequency in a genetic cross.
T
Topoisomerase overwinds the archaeal chromosome into a positive supercoil
T
Transcription factors bind to DNA sequences adjacent weak promoters allowing RNA polymerase to recognize them.
T
Transduction is the transfer of DNA from one bacterial cell to another via a phage.
T
Transfer of DNA via conjugation requires a pilus.
T
Transformation is likely the true horizontal gene transfer mechanism for prokaryotes.
T
Vegetative cells provide adjacent heterocysts sugar molecules that can be used to generate energy.
T
The conversion of gaseous nitrogen into ammonia is called? a) Denitrification b) Nitrate respiration c) Nitrification d) Nitrogen fixation
d) Nitrogen fixation
Low internal glucose-6-P concentration generates high cAMP levels
True (Also true for high internal glucose-6-P conc generates low cAMP levels)
Which of the following diseases is NOT caused by an endospore-forming bacterium? a) Botulism b) Tetanus c) Anthrax d) Syphilis
d) Syphilis
Which of the following morphological changes does NOT occur during heterocyst formation? a) Reorganization of the nitrogenase operon b) Formation of new cell wall layers c) Loss of photosystem II d) All of these changes occur during heterocyst formation. e) None of these changes occur during heterocyst formation.
d) All of these changes occur during heterocyst formation.
Endospore development can result from a scarcity of this nutrient? a) Carbon b) Nitrogen c) Phosphorus d) Endospores can develop when any of these nutrients is scarce. e) Endospores do not develop when any of these nutrients is scarce.
d) Endospores can develop when any of these nutrients is scarce.
Many prokaryotic cells demonstrate negative chemotactic responses away from repellents
t
Negative genetic control uses repressor proteins to turn off gene transcription
t
Some prokaryotic genomes have multiple circular chromosomes
t
The extensive secondary structure in 16S rRNA assists in sequence alignment
t
The first Bacillus anthracis vaccine strain was developed by Louis Pasteur
t
Prokaryotic genes are always organized into operons.
False (often not always)
DNA replication during conjugation occurs via the rolling circle mechanism.
T
Which of the following characteristics of cyanobacteria species are true? (select all that apply) Select one or more: a. Cyanobacteria can be morphologically diverse. b. Cyanobacteria can perform nitrogen fixation to generate N2 gas. c. Cyanobacteria are an ancient group of obligate photoautotrophs. d. Cyanobacteria can be physiologically diverse. e. Cyanobacteria are the only prokaryotes performing anoxygenic photosynthesis. f. Cyanobacteria can convert nitrogen gas to ammonia.
C. Cyanobacteria are an ancient group of obligate photoautotrophs., A. Cyanobacteria can be morphologically diverse., F. Cyanobacteria can convert nitrogen gas to ammonia.
2) Plasmids encode genes with functions that are essential for replication of the chromosomal DNA.
F
A symbiotic relationship in which both partners benefit is known as commensal.
F
A vaccine is not available against Corynebacteria diphtheriae.
F
All flagellated chemotactic cells in a liquid medium move via run and tumble motion
F
Anaerobic niches in marine or freshwater sediments are typically devoid of significant organic material, and therefore facilitate colonization by carbon and nitrogen fixing organisms only.
F
Assimilatory nitrate reduction (nitrate to ammonia) is an exclusively prokaryotic process.
F
Biofilm formation in humans is unusual and indicates the presence of a disease.
F
CheY is a chemotactic receptor on the surface of cells that binds chemoattractant molecules.
F
Competence factor is only produced and excreted by cells at a sufficiently high cell density.
F
Deinococci are the only bacterial lineage to lack peptidoglycan entirely, having a protein cell wall.
F
Deinococci stain gram positive despite lacking peptidoglycan within their cell wall due to a thick protein S-layer.
F
Rho-independent transcriptional termination requires formation of a stem-loop secondary structure in the developing mRNA coupled with a GC-rich region of DNA for successful dissociation.
F
Riftia tube worms fix carbon for bacterial chemoautotroph symbionts who, in turn, provide ammonia, hydrogen sulfide and carbon dioxide from geothermal vents to the Riftia worms.
F
STARI is a red, expanding "bulls eye" lesion around a lone star tick bite caused by Borrelia burgdorferi
F
Spirochetes are monotrichously flagellated organisms associated with diseases such as syphilis and Lyme disease.
F
Strains of E. coli either contain the F plasmid (F+) or lack the F plasmid (Hfr).
F
Syntrophy is common in aerobic freshwater ecosystems.
F
The Planctomyces are a group of obligate, intracellular parasites.
F
The genes needed for conjugation are always being expressed by a prokaryotic cell.
F
The lac Z, Y, and A genes are each transcribed as individual mRNA molecules and can be independently regulated.
F
The low genetic diversity of Neisseria gonorrheae populations has made it easy to eliminate gonorrhea infections with antibiotics.
F
The nitrifying bacteria are mostly facultative chemoheterotrophs capable of oxidizing ammonia or nitrite for energy.
F
The nitrifying bacteria are mostly obligate chemoautotrophs capable of reducing ammonia or nitrite for energy.
F
The nitrogen cycle can be completed in the absence of prokaryotic organisms.
F
The spoA cascade is initiated by a series of sigma factors.
F
The sulfate-reducing bacteria are found wherever organic matter is decomposing aerobically.
F
The term spore and endospore refer to the same structure.
F
Three-point genetic crosses require triple-phenotype bacterial strains.
F
Transcription of a bacterial operon leads to a single mRNA and a single polyprotein, which is then cleaved into individually functional proteins.
F
Transcriptional termination is the most common form of gene regulation in prokaryotes.
F
Transduction is a common mechanism of horizontal gene transfer.
F
When repellent concentration is decreasing tumbling frequency increases.
F
An example of syntrophy is methanogens generating hydrogen gas used by the fermentative chemoautotrophs to oxidizing butyrate to acetate
FALSE (chemoheterotrophs)
More distant relationships are measured using DNA/RNA hybridization
False (DNA/DNA)
Prokaryotic chromosomes are exclusively diploid.
False (Haploid)
The first E. coli linkage map was created using massively parallel DNA sequencing.
False (Hfr conjugation and phage transduction)
A group of transcriptional units controlled by the same regulatory protein is called an operon
False (Regulon)
Odd numbers of crossovers between endo- and exogenotes result in recombinant chromosomes
False (even)
Transformational competence is most prevalent at low cell density
False (high cell)
Plant root cells provide water, minerals and protection to the mycorrhizial symbionts.
False (mycorrhizial symbionts provide)
DNA gyrase underwinds the bacterial chromosome into a negative supercoil.
T
3) Insertion sequences and transposons can change location within a genome.
T
A Sigma protein equivalent has not been identified in archaea or eukarya.
T
A group of transcriptional units controlled by the same regulatory protein(s) is called a regulon.
T
A modulon is group of operons controlled by the same global control system.
T
An insertion sequence (IS) is capable of both replicative and nonreplicative transposition.
T
Anaerobic ecosystems are maintained by microbial oxygen consumption
T
Bacterial promoters with consensus base sequences from multiple bacterial promoters are considered ideal.
T
Catabolite repression is the inhibitory effect of a preferred carbon and energy source on the induction of enzymes for the transport and metabolism of other carbon and energy sources
T
Conjugation can transfer DNA from prokaryotic cells across great genetic distances.
T
Continued prokaryotic gene expression requires continuous mRNA transcription.
T
Which statement best describes the intestinal tract of humans? a) Facultative anaerobes metabolize oxygen that enters the intestines. b) Strict anaerobes metabolize oxygen that enters the intestines. c) The intestinal tract of humans is aerobic because high concentrations of oxygen enters this site. d) The intestinal tract of humans is anaerobic because no oxygen enters this site.
a) Facultative anaerobes metabolize oxygen that enters the intestines.
How does the amount of extracellular glucose impact the transcription of the lac operon? a) High levels of extracellular glucose decrease activation of CRP which decreases transcription of the lac operon. b) High levels of extracellular glucose decrease activation CRP which increases transcription of the lac operon. c) Low levels of extracellular glucose decrease activation of CRP which decreases transcription of the lac operon. d) The level of extracellular glucose does not impact transcription of the lac operon.
a) High levels of extracellular glucose decrease activation of CRP which decreases transcription of the lac operon.
E. coli cells would display what type of movement in the presence of increasing concentrations of chemoattractant? a) Increasing runs, decreasing tumbles b) Decreasing runs, increasing tumbles c) Equal periods of runs and tumbles d) None of the above
a) Increasing runs, decreasing tumbles
The binding of an effector molecule to a repressor protein activates the repressor protein to bind DNA. What form of transcriptional control will result? a) Negative control of a repressible operon. b) Positive control of a repressible operon. c) Negative control of an inducible operon. d) Positive control of an inducible operon.
a) Negative control of a repressible operon.
Which process can only occur if phage DNA is integrated into a host cell's chromosome? a) Specialized transduction b) Generalized transduction c) Transformation d) Conjugation e) None of these processes require the integration of phage DNA into a host cell's chromosome.
a) Specialized transduction
In the presence of arabinose, Select one: a. AraC binds the effector, arabinose, and acts as a transcription factor. b. AraC binds the effector, arabinose, and acts as a repressor. c. AraC acts as a transcription factor to turn on transcription of the genes for arabinose synthesis. d. AraC acts as a repressor to turn off transcription of the genes for arabinose synthesis.
a. AraC binds the effector, arabinose, and acts as a transcription factor.
Which of the following contributes to the packaging of bacterial chromosomes? Select one: a. DNA gyrase b. histones c. nucleosomes d. DNA helicase e. Okazaki fragments
a. DNA gyrase
Which of the following statements correctly describe syntrophy? Select one or more: a. Syntrophy commonly results in hydrogen gas production by one microbe and hydrogen gas consumption by another microbe. b. Microbial syntrophy only involves a single microbial species. c. Microbial syntrophy occurs exclusively in aerobic environments. d. Microbial syntrophy is common in anaerobic freshwater sediments.
a. Syntrophy commonly results in hydrogen gas production by one microbe and hydrogen gas consumption by another microbe. d. Microbial syntrophy is common in anaerobic freshwater sediments.
In the endospore formation cascade, SpoOA (select all that apply) Select one or more: a. acts as a transcription factor. b. is the sensor that becomes phosphorylated. c. is phosphorylated by KinB. d. turns on synthesis of sigma factor H.
a. acts as a transcription factor. d. turns on synthesis of sigma factor H.
Termination of bacterial transcription (select all that apply) Select one or more: a. is Rho-dependent - requires the Rho protein to displace RNA polymerase. b. is Rho-dependent - requires the Rho protein to recognize specific termination sequences in the mRNA. c. is Rho-independent - does not require the Rho protein and is completely random. d. is Rho-independent - does not require the Rho protein and relies on specific sequences in the mRNA.
a. is Rho-dependent - requires the Rho protein to displace RNA polymerase. d. is Rho-independent - does not require the Rho protein and relies on specific sequences in the mRNA.
Anthrax is a potential bioterrorism agent because Select one: a. it forms endospores capable of surviving harsh conditions. b. it generates a localized disease symptoms of the skin, making it transmissible between people. c. there is no vaccine available. d. there is no drug treatment available for this viral infection.
a. it forms endospores capable of surviving harsh conditions.
The conversion of gaseous nitrogen into ammonia is called? Select one: a. nitrogen fixation b. nitrification c. denitrification d. nitrogen respiration
a. nitrogen fixation
The host-pathogen relationship is an example of what type of symbiosis? Select one: a. parasitism b. commensalism c. mutualism
a. parasitism
The legume's roots excrete a mixture of chemical compounds into the soil that function (select all that apply) Select one or more: a. to act as a chemoattractant to specific strains of rhizobium bacteria. b. to kill parasitic bacteria in the soil environment. c. to act as a chemorepellent to non-symbiotic strains of bacteria. d. to begin to establish symbiosis.
a. to act as a chemoattractant to specific strains of rhizobium bacteria. d. to begin to establish symbiosis.
If E. coli is grown in liquid media containing equal amounts of glucose and lactose, which sugar will the bacteria use as a carbon source? a) E. coli will use the lactose until it is depleted and then begin to use the glucose. b) E. coli will use the glucose until it is depleted and then begin to use the lactose. c) E. coli will use the glucose and lactose simultaneously until they are both depleted. d) E. coli does not use glucose or lactose as a carbon source.
b) E. coli will use the glucose until it is depleted and then begin to use the lactose.
Under which condition is transformation most likely to occur? a) Low cell density b) High cell density c) Low autoinducer concentration d) Transformation can occur under all of these conditions.
b) High cell density
Heterocysts develop under which of the following conditions? a) Low oxygen conditions b) Low nitrogen conditions c) High oxygen conditions d) High nitrogen conditions e) Heterocysts develop under all of these conditions.
b) Low nitrogen conditions
What is the most common mechanism of regulating gene expression? a) Regulation of replication b) Regulation of transcription c) Regulation of translation d) None of the above
b) Regulation of transcription
Two microbes that produce energy via a set of chemical reactions that neither can perform alone is an example of: a) Hybridization b) Syntrophy c) Conjugation d) Transposition
b) Syntrophy
Which of the following does NOT represent an example of convergence? a) The fur of a cat and feathers of a bird. b) The different beaks of two similar species of birds. c) The forearm of a human and wing of a bird.
b) The different beaks of two similar species of birds.
Which of the following occurs during conjugation? a) The original donor plasmid is transferred to the recipient cell. b) The donor plasmid is replicated and a copy is transferred to the recipient cell. c) Two cells exchange pieces of their chromosome. d) The donor plasmid is transferred to recipient cells containing the same plasmid.
b) The donor plasmid is replicated and a copy is transferred to the recipient cell.
Which of the following best describes the regulation of the lac operon? a) The lac repressor is bound to the lac operator in the presence of lactose. b) The lac repressor is bound to the lac operator in the absence of lactose. c) The lacI repressor is an effector molecule that regulates transcription of the lac operon. d) Lactose binds the promoter and helps initiate transcription of the lac operon.
b) The lac repressor is bound to the lac operator in the absence of lactose.
What is the role of a promoter in prokaryotic transcription? a) The promoter is a protein that binds the DNA and facilitates transcription by RNA polymerase. b) The promoter is a DNA sequence where RNA polymerase binds and initiates transcription. c) The promoter is a protein that binds RNA polymerase and facilitates transcription of the DNA. d) The promoter is a protein that facilitates the interaction of RNA polymerase with different sigma factors.
b) The promoter is a DNA sequence where RNA polymerase binds and initiates transcription.
In prokaryotes, why is translational silencing a less common mechanism of gene regulation than transcriptional control? a) Translational silencing is nonspecific; it does not inhibit translation of specific mRNA molecules. b) Translational silencing is less energy efficient than transcriptional control. c) Actually, translational silencing is more common than regulation of transcriptional control. d) Actually, prokaryotes show no preference in the mechanisms used for gene regulation.
b) Translational silencing is less energy efficient than transcriptional control.
This term describes a bacterium that has the capacity to take up DNA via transformation. a) autoinducer b) competent c) phage d) conjugate
b) competent
Which of the following could be used as a research tool to directly inhibit translation of a specific mRNA molecule? a) repressor protein b) siRNA c) transcription factor d) sigma factor e) All of these could be used to directly inhibit translation.
b) siRNA
Which of the following is NOT a feature of prokaryotic classification? Select one: a. None of the these are features of prokaryotic classification. b. All of the these are features of prokaryotic classification. c. Since prokaryotes do not reproduce sexually, they are not grouped by species using the same criteria as eukaryotes. d. Horizontal gene transfer among prokaryotes makes genetic classification more difficult. e. Prokaryotes are grouped based on differences in their 16s rRNA sequence.
b. All of the these are features of prokaryotic classification.
What bacterial species are known for extraordinary DNA repair systems and a thicker-than-average peptidoglycan layer? Select one: a. Mycobacteria species b. Deinococcus species c. Planctomyces species d. Rickettsia species e. Bacillus species
b. Deinococcus species
What is the name of the structure connecting these two E. coli cells in this image? (PICTURE FROM FRONT OF PP #17) Select one: a. flagellum b. F pilus c. transfer plasmid d. pro-phage e. type 4 pilus
b. F pilus
Which of the following structures is responsible for the run and tumble movements observed in motile bacteria. Select one: a. Pili b. Flagella c. Autoinducer d. Cilia
b. Flagella
Microbial cells display directed movement, or taxis, to which of the following stimuli? Select one: a. Microbial cells do not display directed movement toward any of these stimuli. b. Microbial cells display directed movement toward all of these stimuli. c. Oxygen concentration d. Chemical concentration e. Light intensity
b. Microbial cells display directed movement toward all of these stimuli.
What disease causes a rash, a red, expanding "bulls eye" lesion around a tick bite, followed by fatigue, fever, headache, muscle and joint pains? Select one: a. Rocky mountain spotted fever b. Southern Tick Associated Rash Illness c. Lyme disease d. Borrelia burgdorferi e. Rickettsia rickettsia f. Rickettsia prowazeki
b. Southern Tick Associated Rash Illness
Which of the following best describes the regulation of the lac operon? Select one: a. The lac repressor is bound to the lac operator in the presence of lactose. b. The lac repressor is bound to the lac operator in the absence of lactose. c. The lacI repressor is an effector molecule that regulates transcription of the lac operon. d. Lactose binds the promoter and helps initiate transcription of the lac operon.
b. The lac repressor is bound to the lac operator in the absence of lactose.
Which of the following are characteristics of dead zones? (select all that apply) Select one or more: a. Dead zones are exclusively the result of human activity. b. The purple bacteria are found in anaerobic environments like marine dead zones. c. The northern Gulf of Mexico has one of the largest dead zones in the world. d. A dead zone is a low oxygen or hypoxic area in an ocean or lake. e. Algael digestion of the microbial life can quickly deplete the dissolved oxygen in the water. f. Water containing too much dissolved oxygen causes most marine animal life to die or flee.
b. The purple bacteria are found in anaerobic environments like marine dead zones. c. The northern Gulf of Mexico has one of the largest dead zones in the world. d. A dead zone is a low oxygen or hypoxic area in an ocean or lake.
A small molecule that binds a regulatory protein and alters gene transcription is called a? a) Promoter b) RNA polymerase c) Effector d) Operon
c) Effector
One technique to identify a microbe using a fluorescent probe that binds to DNA sequences specific to that microbe is called: a) Syntrophy b) Metagenomics c) FISH d) Transformation
c) FISH
How are prokaryotic chromosomes most commonly organized? a) Multiple, linear DNA molecules b) Multiple, plasmid DNA molecules c) Single, circular DNA molecules d) Single, linear DNA molecules
c) Single, circular DNA molecules
What region of the United States has the highest rate of gonorrhea infection? a) Midwest b) Northeast c) South d) Northwest
c) South
Through what mechanism do some avirulent strains of C. diphtheriae acquire a diphtheria toxin gene? a) Conjugation b) Transformation c) Transduction d) All of the above
c) Transduction
Which of the following is not a prokaryotic benefit of symbiosis? Select one: a. osmotic balance b. access to minerals and nutrients c. bioluminescence d. consistent temperature e. protection from predators
c. bioluminescence
This term describes a bacterium that has the capacity to take up DNA via transformation. Select one: a. recipient b. autoinducer c. competent d. transformable e. conjugate
c. competent
What is the predominate group of microbes in freshwater sediments? Select one: a. aerobic and sulfate-reducing microbes b. aerobic microbes c. methanogens d. methanogens and sulfate-reducing microbes e. sulfate-reducing microbes
c. methanogens
What form of sulfur can be used as an electron acceptor in anaerobic respiration? Select one: a. sulfite b. hydrogen sulfide c. sulfate d. No form of sulfur is used as an electron acceptor in anaerobic respiration.
c. sulfate
Which of the following is a benefit of biofilm formation? a) Microbes are protected from predation by other organisms. b) Microbes are protected from environmental changes. c) Microbes are held within a specific habitat. d) These are all potential benefits of biofilm formation.
d) These are all potential benefits of biofilm formation.
What is the only bacterial lineage to lack peptidoglycan entirely, having a protein cell wall? Select one: a. Mycobacteria species b. Bacillus species c. Deinococcus species d. Planctomyces species e. Mycoplasma species
d. Planctomyces species
n lecture 20, you were prompted to watch a video of Dr. Bonnie Bassler discussing an example of quorum sensing using the Hawaiian bobtail squid and its symbiont, Vibrio fischeri . Each morning the squid pumps out 95% of the bacteria present in the light organ. Why? Select one: a. The bacteria begin to turn on virulence genes that could harm the squid. b. The squid senses that the concentration of autoinducer has become too low. c. The squid senses that the concentration of autoinducer has become too high. d. The bacterial population in the light organ had reached saturation and is beginning to die.
d. The bacterial population in the light organ had reached saturation and is beginning to die.
Which of the following best describes the regulation of the lac operon? Select one: a. Lactose binds the promoter and helps initiate transcription of the lac operon. b. The lacI repressor is an effector molecule that regulates transcription of the lac operon. c. The lac repressor is bound to the lac operator in the presence of lactose. d. The lac repressor is bound to the lac operator in the absence of lactose.
d. The lac repressor is bound to the lac operator in the absence of lactose.
What is the function of the Xis protein in heterocyst development? Select one: a. Xis fixes nitrogen gas into ammonia. b. Xis determines heterocyst spacing. c. Xis acts as a transcription factor to turn on expression of nifD and fdxN. d. Xis performs two irreversible DNA rearrangements.
d. Xis performs two irreversible DNA rearrangements.
Nitrosomonas species are capable of oxidizing ammonia (NH3) for __________. Select one: a. carbon fixation. b. fermentation. c. nitrogen fixation. d. energy production.
d. energy production.
Avirulent Corynebacterium diphtheriae cells can be converted to disease-causing cells after exposure to a __________ that introduces a(n) __________. Select one: a. transmissible plasmid; toxin gene b. specialized transducing phage; antibiotic resistance gene c. generalized transducing phage; toxin gene d. specialized transducing phage; toxin gene e. transmissible plasmid; antibiotic resistance gene f. generalized transducing phage; antibiotic resistance gene
d. specialized transducing phage; toxin gene
The bacterial chromosome is Select one: a. found in a nucleoid. b. usually circular and found in a nucleus. c. found in a nucleus. d. usually circular and found in a nucleoid. e. usually circular.
d. usually circular and found in a nucleoid.
Microbial cells can display directed movement, or taxis, to which of the following stimuli? a) Light b) Oxygen c) Chemicals d) Magnetic fields e) All of the above f) None of the above
e) All of the above
Which of the following contributes to the genetic diversity in prokaryotes? a) Sexual reproduction b) Mutations c) Horizontal gene transfer d) Sexual reproduction and mutations e) Horizontal gene transfer and mutations f) All of the above
e) Horizontal gene transfer and mutations
A DNA sequence used as a molecular clock should have which of the following features? a) The DNA sequence should be found in some organisms. b) The DNA sequence should not have accumulated any mutations. c) The DNA sequence should encode a protein that performs different functions in different organisms. d) All of the above. e) None of the above.
e) None of the above.
Quinolones are a group of antibacterial compounds that interfere with Select one: a. transcription. b. cell wall synthesis. c. macromolecular synthesis. d. translation. e. DNA replication.
e. DNA replication.
Anabaena can develop specialized cells called heterocysts when Select one: a. cells gain noncyclic photophosphorylation components. b. the nitrogenase operon is turned on. c. oxygen concentrations become too low. d. fixed-nitrogen or ammonia concentrations become limiting. e. nitrogen concentrations become limiting.
e. nitrogen concentrations become limiting.