MB351 Exam 2 T/F

Most prokaryotic genomes are comprised of a pair of diploid, circular chromosomes.

FALSE (a singular, supercoiled)

Some prokaryotic DNA chromosomes are not supercoiled.

FALSE (all, are)

Sulfate reducing bacteria and methanogens are largely responsible for transferring carbon from aerobic sediments to anaerobic sediments in aquatic regions.

FALSE (anaerobic to aerobic)

Syntrophy is common in aerobic freshwater ecosystems.

FALSE (anaerobic)

Nitrifying eukaryotes can use nitrite (NO2-) as an electron donor for an aerobic, chemoautotrophic respiration.

FALSE (bacteria)

The carbon cycle requires macromolecular hydrolysis by heterotrophic organisms to return the element of carbon to biosynthetic processes.

False

There are two types of bacterial transcription initiation - Rho-dependent and Rho-independent.

False

Transformational competence is most prevalent at low cell density.

False (high cell)

Purple sulfur bacteria grown in stagnant, anoxic waters using organic sulfur for energy.

False (hydrogen sulfide)

Transcriptional termination is the most common form of gene regulation in prokaryotes.

False (initiation)

Antisense RNA anneals/binds to complementary DNA, disrupting polymerase assocation and terminating transcription.

False (mRNA, blocking translation and therefore protein production)

An operon is a single gene controlled by a variety of regulatory elements.

False (multiple gene controlled by single promoter)

A symbiotic relationship in which both partners benefit is known as commensal.

False (mutual)

Lichens are a symbiois between a fungus and the root cells of an angiosperm plant.

False (mycorrhizae)

Lichens are a symbiosis between a fungus and the root cells of an angiosperm plant.

False (mycorrhizae)

Plant root cells provide water, minerals and protection to the mycorrhizial symbionts.

False (mycorrhizial symbionts, plant root cells)

Microbes unable to detoxify oxygen radicals would exhibit positive aerotaxis.

False (negative)

Assimilatory nitrate reduction (nitrate to ammonia) is an exclusively prokaryotic process.

False (not exclusively)

Competence factor is only produced and excreted by cells at a sufficiently high cell density.

False (not only)

Pseudomonads are polar flagellated rods with facultative anaerobic metabolisms.

False (obligate aerobic/anaerobic)

The nitrifying bacteria are mostly facultative chemoheterotrophs capable of oxidizing ammonia or nitrite for energy.

False (obligate chemoautotrophs)

Spirochetes are monotrichously flagellated organisms associated with diseases such as syphilis and Lyme disease.

False (periplasmic endoflagella)

Inducible prokaryotic operons under negative control have transcription factors requiring effector binding to induce transcription.

False (positive)

Transposition is a frequent event in prokaryotic chromosomes.

False (rare event)

Prokaryotic genomes experience frequent transposition events.

False (rare)

Quorum sensing allows cells to begin production of certain compounds only upon reaching a certain size.

False (react to local cell density, rather than absolute cell number or cell size.)

A group of transcriptional units controlled by the same regulatory protein is called an operon.

False (regulon)

The genes controlling conjugal plasmid transfer are normally expressed.

False (repressed)

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.

False (rich)

Prokaryotic metabolic processes are necessary to return vital nutrients from the land back to the sea.

False (sea to land)

Lichens form symbiotic reproductive structures, known as medulla.

False (soredium)

Endospores are highly durable bacterial reproductive structures.

False (survival)

Directed cell movement in response to a stimulus is genetically regulated behavior.

False (tactic)

Using the genetic cross technique, the highest co-transduction efficiency corresponds to the greatest distance between genes.

False (the lowest)

Transposons have led to large amounts of "junk" DNA in most prokaryotic genomes.

False (there is little "junk" DNA)

Catabolite repression is regulated by a repressor protein CRP.

False (transcription factor)

Polycistronic mRNA contains transcriptional control sequences for ribosome binding and translational termination.

False (transcription)

Antisense RNA anneals/binds to complementary mRNA sequences blocking transcription.

False (translation and therefore protein production)

Conjugal pili are only synthesized by cells harboring a prophage.

False (transmissible plasmid)

Strong promoters work best with operons requiring dynamic control.

False (weak promoters)

Strong promoters work best with operons requiring dynamic control.

False (weak)

Transcription of a bacterial operon leads to a single mRNA and a single polyprotein, which is then cleaved into individually functional proteins.

False (which contains distinct translational control sequences for ribosome binding at each gene)

16s rRNA phylogenies describe three major lines of descent or kingdoms.

False- domains

Conjugation and transduction mapping score neutral phenotype mutations in recombinant cells after genetic crosses.

false

DNA gyrase overwinds the archaeal chromosome into a positive supercoil.

false

F' strains mobilize large segments of the host chromosome to recipient cells at high frequency.

false

MCP binding to an attractant induces phosphorylation of CheA, which leads to a signal for the bacteria to tumble.

false

Microbes accumulate high concentrations of nutrients near the cells with low concentrations only a few millimeters away.

false

Odd numbers of crossover between endo- and exogenotes result in recombinant chromosomes.

false

Prokaryotic cells couple genetic recombination with DNA replication due to increased access of chromosomal domains.

false

Psuedomonads are polar flagellated rods with facultative anaerobes metabolis.

false

Quorum sensing allows cells to being production of certain compounds only upon reaching a certain size.

false

Rho-dependent transcriptional termination requires formation of a stem-loop secondary structure in the developing mRNA coupled with a string of A-U base pairs for successful dissociation.

false

STARI is a red, expanding "bulls eye" lesion around a lone star tick bite caused by Borrelia burgdorferi.

false

Sigma factor association with RNA polymerase is irreversible, and thus progression to an alternative sigma factor requires transcription and formation of new RNA polymerase complexes.

false

Strains of E. coli either contain the F plasmid or lack the F plasmid (Hfr).

false

The B anthracis vaccine strain was developed by growing a culture of B. anthracis cells at lower temperatures than normal.

false

The carbon cycle requires macromolecular hydrolysis by heterotrophic organisms to return the element of carbon to biosynthesis processes.

false

The carbon cycle requires macromolecular hydrolysis by heterotrophic organisms to return the element of carbon to biosynthetic processes.

false

The plantomycetes are a group of obligate, intracellular parasites.

false

The prokaryotic conversion of organic compounds to CO2 returns carbon to the sea from the land.

false

Transformation is when DNA - released by a competent cell - is taken up by a donor cell.

false

Odd numbers of crossovers between endo- and exogenotes result in recombinant chromosomes.

false (even)

Prokaryotic transcriptional units are typically transcribed in the opposite direction the chromosome is replicated.

false (same)

Host legume symbiosome cells produce leghemoglobin molecules to maintain a low oxygen concentrations for Rhizobium bacteriods.

true

In many symbioses the prokaryote partner provides fixed nitrogen.

true

Inducible prokaryotic genetic regulatory systems use effectors to start gene transcription.

true

Initiation of endospore development is regulated by quorum sensing.

true

Interrupted mating experiments allow scientists to create linkage map of relative gene distance by exploiting bacterial conjugation.

true

Irreversible DNA rearrangements occur in the mother cell during endosporulation.

true

Lichens form symbiotic reproductive structures known as soredium.

true

Low internal gluclose-6-phosphate concentration generates high cAMP levels.

true

Low internal glucose-6-P concentration generates high cAMP levels

true

Low internal glucose-6-P concentration generates high cAMP levels.

true

Many prokaryotic cells demonstrate negative chemotactic responses away from repellants.

true

Many prokaryotic cells demonstrate negative chemotactic responses away from repellents.

true

Many prokaryotic cells demonstrate positive chemotactic responses toward attractants.

true

Methanogens dominate in freshwater sediments.

true

Methylation of chemotaxis proteins increases their sensitivity to increasing attractant concentrations.

true

Microbes unable to detoxify oxygen radicals would exhibit negative aerotaxis.

true

Microbial communities are comprised of "guilds", determined by the metabolic roles an organism performs within the community.

true

Molecular chronometers are commonly-held DNA sequences accumulating neutral mutations at a constant rate.

true

Molecular chronometers provide evidence of evolutionary relatedness while avoiding the confusion of convergence.

true

Most lichens are comprised of a single fungus in symbiosis with a single phototrophic organism.

true

Most lichens are comprised of a single fungus in symbiosis with a single phototropic organism.

true

Most of the prokaryotic genome is coding sequence.

true

Most prokaryote genomes are comprised of a single, circular DNA chromosome.

true

Most prokaryotic transcriptional units have one or more regulatory sites controlling the rate of transcription.

true

Mycorrhizial symbionts provide water, minerals and protection to plant root cells.

true

Negative genetic control uses repressor proteins to turn off gene transcription.

true

Neutral mutations in protein coding genes can change the amino acid sequence without changing protein function.

true

Nitrosomonas are a genus of nitrifying bacteria.

true

Operons are comprised of multiple genes grouped together into a single transcriptional unit under the control of a single promoter.

true

Oxygen consumption in the animal intestinal tract is entirely due to facultative anaerobes.

true

Phylogeny reflect the history of a single gene across microbial genomes, but other parts of the genome may relate differently due to horizontal gene transfer.

true

Planctomyces are the only bacterial lineage known to lack peptidoglycan entirely.

true

Planctomycetes are the only bacterial lineage lacking peptidoglycan in their cell walls.

true

Plasmids are often present in multiple copies.

true

Plasmids are usually much smaller than chromosomes.

true

Plasmids may be circular or linear.

true

Plasmids may be present in some, but not all, members of a prokaryotic species.

true

Positive genetic control involves regulatory proteins referred to as transcription factors.

true

Prokaryotic cells exclusively convert nitrates to N2 gas.

true

Prokaryotic genes are typically organized into operons.

true

Prokaryotic genomes contain multiple transposons and insertion sequences.

true

Prokaryotic metabolic processes return nutrients from the sea to the land.

true

Prokaryotic transcription initiation is controlled by allosteric proteins.

true

Prokaryotic transcriptional units are typically transcribed in the same direction the chromosome is replicated.

true

Pseudomonads are polar flagellated rods with obligate aerobic/anaerobic respiratory metabolisms.

true

Pseudomonads can be opportunistic pathogens associated with burn patients and Cystic Fibrosis sufferers.

true

Purple non-sulfur bacteria are inhibited by high sulfide concentrations, they can appear orange, red, brown or purple and demonstrate phototaxis.

true

Purple sulfur bacteria grown in stagnant, anoxic waters using hydrogen sulfide for energy.

true

Quorum sensing allows cells to react to local cell density, rather than absolute cell number or cell size.

true

Quorum sensing induces expression of operons involved in biofilm, surfactant and antibiotic production.

true

RNA polymerases in eukaryotic microbes have multiple subunit RNA polymerases with no sigma-like subunit.

true

Recombination is a separate process from replication in a prokaryotic cell.

true

Repressible prokaryotic gene regulation systems use effectors to stop gene transcription.

true

Repressor proteins bind to DNA sequences adjacent to promoters and prevent RNA polymerase binding.

true

Repressors and transcription factors bind DNA sequences in the major groove.

true

Repressors and transcription factors sometimes bind at two distant sites forming a DNA loop.

true

Rhizobium bacteroids provide fixed nitrogen to their plant hosts in exchange for a stable environment.

true

Rho-independent transcriptional termination requires formation of a stem-loop secondary structure in the developing mRNA coupled with a string of A-U base pairs for successful dissociation.

true

Riftia tube worms are mutualistic symbionts with carbon-fixing sulfide oxidizers in geothermal vent ecosystems.

true

Sea floor methane hydrate is metabolized through a syntrophic relationship between methanotrophic archaea and sulfate-reducing bacteria.

true

Sea floor methane hydrate is metabolized through a syntropic relationship between methanotropic archaea and sulfate-reducing bacteria.

true

Since Hfr formation is reversible, every Hfr or F+ culture is a mixture of both

true

Since Hfr formation is reversible, every Hfr or F+ culture is a mixture of both.

true

Some prokaryotic genomes have linear as well as circular chromosomes.

true

Some prokaryotic genomes have multiple circular chromosomes.

true

Some proteins can function as both repressors and transcription factors.

true

Specialized transduction can be used to understand the cis/trans nature of a regulatory region or protein.

true

Specialized transduction can produce partial diploids. (merozygotes)

true

Specialized transduction is the result of a rare mistake of prophage excision.

true

Spirochetes are characterized by their distinct helix or spiral morphological shape.

true

Spirochetes are characterized by their periplasmic endoflagella.

true

Sulfate reducers dominate in marine sediments.

true

Supercoiling is essential to pack the chromosome into a small volume.

true

Symbiotic relationships are dynamic - often depending on the condition of the host.

true

Syntrophy is also known as interspecies electron transfer.

true

Syntrophy is also known as interspecies hydrogen transfer.

true

Syntrophy is common in anaerobic freshwater ecosystems.

true

The B. anthracis vaccine strain lacks a plasmid present in disease causing B. anthracis strain.

true

The B. anthracis vaccine strain lacks a plasmid present in disease-causing B. anthracis strain

true

The B. anthracis vaccine strain lacks a plasmid present in disease-causing B. anthracis strain.

true

The PatS oligopeptide is produced by the heterocyst at a constant rate.

true

The PatS oligopeptide is produced by the heterocysts at a constant rate.

true

The Planctomcyes are mostly unicellular budding bacteria associated with aquatic/marine environments.

true

The RecA protein facilitates proper DNA recombination and repair.

true

The Rho protein separates a newly transcribed mRNA from its DNA template and the RNA polymerase.

true

The Volkswagen syndrome represents how the use of phenotypes instead of genotypes to relate different organisms will not accurately determine relatedness.

true

The extensive secondary structure in 16S rRNA assists in sequence alignment.

true

The first Bacillus anthracis vaccine strain was developed by Louis Pasteur.

true

The first E. coli linkage map was created using HFr conjugation and phage transduction.

true

The first E.coli linkage map was created using Hfr conjugation and phage transduction.

true

The high viscosity of most bacterial environments results in little to no coasting when bacteria engage in a tumble.

true

The high viscosity of most bacterial environments results in little to no coasting when bacteria engage in a tumble.

true

The most commonly used sequence for phylogeny construction is the 16s rRNA gene.

true

The nitrifying bacteria are mostly obligate chemoautotrophs capable of oxidizing ammonia or nitrite for energy.

true

The nitrifying bacteria are mostly obligate chemoautotrophs capable of reducing ammonia or nitrite for energy.

true

The prokaryotic conversion of nitrates to N2 gas serves to return nitrogen runoff from the sea to the land.

true

The prokaryotic conversion of organic compounds to CO2 returns carbon from the sea to the land.

true

The purpose of biological classification systems are to group and relate all organisms.

true

The rarest recombination event occurs at the lowest frequency in a genetic cross.

true

The rarest recombination event occurs at the lowest frequency in a three point genetic cross.

true

The recombination frequencies of a pair-wise combination of genes can indicate the linear order of the genes.

true

The relatedness of molecular clock sequences can be determined by distance, parsimony and likelihood methods of sequence analysis.

true

The sulfate-reducing bacteria are ubiquitous in anaerobic environments and predominant in marine sediments.

true

There are estimated to be 4-6 x 1030 living prokaryotic cells on planet Earth.

true

There are estimated to be 4-6 x10^30 living prokaryotic cells on planet Earth.

true

There are two types of bacterial transcription termination - Rho-dependent and Rho-independent.

true

Thermotoga is a bacterial kingdom of hyperthermophilic fermentative chemoheterotrophs.

true

Thermotoga is a hyperthermophilic fermentative chemoheterotroph.

true

Topoisomerase overwinds the archaeal chromosome into a positive supercoil.

true

Transcription factors bind to DNA sequences adjacent weak promoters allowing RNA polymerase to recognize them.

true

Transcription initiation is the most common form of gene regulation in prokaryotes.

true

Transcription of a bacterial operon leads to a single mRNA which contains distinct translational control sequences for ribosome binding at each gene.

true

The aerobic sulfur bacteria are found exclusively in marine sediments.

False

High internal glucose-6-P concentration generates low cAMP levels.

true

Horizontal Gene Transfer among distantly related organisms confuses phylogenies.

true

Horizontal gene transfer among distantly related organisms confuses phylogenies.

true

Anabaena can develop specialized cells called heterocysts when Select one: a. nitrogen concentrations become limiting. b. cells gain noncyclic photophosphorylation components. c. the nitrogenase operon is turned on. d. oxygen concentrations become too low. e. fixed-nitrogen or ammonia concentrations become limiting.

A

In the depiction of biofilm formation below, what is occurring during step 5? Select one: a. Pioneer microbes are dispersing from a mature biofilm to seed new biofilms. b. Microbes begin dying and are pushed out of the biofilm. c. Microbes begin producing enzymes to break down the extracellular polysaccharide matrix and escape the biofilm. d. Free swimming microbes are able to reversibly attach of from the surface.

A

The development of similar biological traits in organisms of different lineages is called Select one: a. convergence b. phylogeny c. hybridization d. divergence

A

What form of sulfur can be used as an electron acceptor in anaerobic respiration? Select one: a. sulfate b. sulfite c. No form of sulfur is used as an electron acceptor in anaerobic respiration. d. hydrogen sulfide

A

What greenhouse gas is also a common end-product of many microbial fermentations? Select one: a. carbon dioxide b. nitrogen gas c. hydrogen sulfide d. sulfate

A

What is the role of a promoter in prokaryotic transcription? a. The promoter is a DNA sequence where RNA polymerase binds and initiates transcription. b. The promoter is a protein that facilitates the interaction of RNA polymerase with different sigma factors. c. The promoter is a protein that binds the DNA and facilitates transcription by RNA polymerase. d. The promoter is a protein that binds RNA polymerase and facilitates transcription of the DNA.

A

Which drawing in the figure represents the pathogenic bacterial species responsible for syphilis, Lyme disease, and relapsing fever?

A

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 begin to establish symbiosis. b. to act as a chemorepellent to non-symbiotic strains of bacteria. c. to act as a chemoattractant to specific strains of rhizobium bacteria. d. to kill parasitic bacteria in the soil environment.

A and C

Which of the following are characteristics of dead zones?

A dead zone is a low oxygen or hypoxic area in an ocean or lake, The northern Gulf of Mexico has one of the largest dead zones in the world, The purple bacteria are found in anaerobic environments like marine dead zones.

Which of the following characteristics of cyanobacteria species are true? (select all that apply) Select one or more: a. Cyanobacteria are an ancient group of obligate photoautotrophs. b. Cyanobacteria can perform nitrogen fixation to generate N2 gas. c. Cyanobacteria can convert nitrogen gas to ammonia. d. Cyanobacteria can be physiologically diverse. e. Cyanobacteria are the only prokaryotes performing anoxygenic photosynthesis. f. Cyanobacteria can be morphologically diverse.

A. C. F. Cyanobacteria are an ancient group of obligate photoautotrophs., Cyanobacteria can be morphologically diverse., Cyanobacteria can convert nitrogen gas to ammonia.

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 are the only prokaryotes performing anoxygenic photosynthesis. c. Cyanobacteria can perform nitrogen fixation to generate N2 gas. d. Cyanobacteria are an ancient group of obligate photoautotrophs. e. Cyanobacteria can be physiologically diverse. f. Cyanobacteria can convert nitrogen gas to ammonia.

A. D. F.

Anthrax is a potential bioterrorism agent because Select one: a. there is no drug treatment available for this viral infection. b. it forms endospores capable of surviving harsh conditions. c. there is no vaccine available. d. it generates a localized disease symptoms of the skin, making it transmissible between people.

B

Bioluminescence in the bobtail squid results from: Select one: a. transcription of bioluminescence genes by both the bobtail squid and bacteria within the bobtail squid. b. transcription of bioluminescence genes by bacteria within the bobtail squid. c. transcription of bioluminescence genes by the bobtail squid. d. All of these events lead to bioluminescence in the bobtail squid.

B

In the presence of arabinose, Select one: a. AraC acts as a repressor to turn off transcription of the genes for arabinose synthesis. b. AraC binds the effector, arabinose, and acts as a transcription factor. c. AraC binds the effector, arabinose, and acts as a repressor. d. AraC acts as a transcription factor to turn on transcription of the genes for arabinose synthesis.

B

What greenhouse gas is also a common end-product of many microbial fermentations? Select one: a. sulfate b. carbon dioxide c. hydrogen sulfide d. nitrogen gas

B

You perform a DNA hybridization experiment to compare organism A and organism B. DNA from these two organisms annealed and is over 90% complementary. What statement could you make about the genetic relationship of organism A and organism B? Select one: a. DNA hybridization provides no information about the genetic relationship among organisms. b. Organism A and organism B are classified within the same species. c. Organism A and organism B are classified in different genera. d. Organism A and organism B are classified in the same genus but different species.

B

Of the following statements, what is TRUE of the transport between the heterocyst and adjacent vegetative Anabaena cells. (select all that apply) Select one or more: a. Ammonia is transported from the heterocyst to the adjacent vegetative cells. b. The amino acid glutamine is transported from the heterocyst to the adjacent vegetative cells. c. Vegetative cells provide sucrose to feed the core metabolic energy pathways of the heterocyst cell to generate ATP. d. Vegetative cells provide ATP directly to heterocyst cells.

B and C

Which of the following are advantages to biofilm formation? (select all that apply) Select one or more: a. Biofilms prevent quorum sensing. b. Biofilms protect microbial cells from predation by eukaryotic microbes. c. Biofilms decrease horizontal gene transfer. d. Attachment to a solid surface prevents cells from being washed out of a flowing habitat.

B. D.

Bacteria can acquire new DNA from the immediate environment in the process of: a. the SOS response. b. conjugation. c. transformation. d. recombination. e. transposition.

C

How does the amount of extracellular glucose impact the transcription of the lac operon? Select one: a. The level of extracellular glucose does not impact transcription of the lac operon. b. Low levels of extracellular glucose decrease activation of CRP which decreases transcription of the lac operon. c. High levels of extracellular glucose decrease activation of CRP which decreases transcription of the lac operon. d. High levels of extracellular glucose decrease activation CRP which increases transcription of the lac operon.

C

Ruminants provide __________ to their microbial symbionts, and then absorb the products of symbiont __________. Select one: a. nutrients, carbon-fixation b. a protected environment, nitrogen-fixation c. nutrients, fermentation d. a protected environment, carbon-fixation e. nutrients, nitrogen-fixation f. a protected environment, fermentation

C

The host-pathogen relationship is an example of what type of symbiosis? Select one: a. commensalism b. mutualism c. parasitism

C

The rhizobium-legume relationship is an example of what type of symbiosis? Select one: a. commensalism b. parasitism c. mutualism

C

What is the name of the structure labeled A? Select one: a. cell wall b. cortex c. septum d. spore coat e. Z-ring

C

Which of the following statements is TRUE of bacterial plasmids? Select one: a. They are always found in the nucleoid. b. They carry genes for essential metabolic functions. c. They are usually small circular DNA molecules. d. All of these statements are true. e. Plasmids are present in every bacterial species.

C

Which of the following structures is responsible for the run and tumble movements observed in motile bacteria. Select one: a. Autoinducer b. Pili c. Flagella d. Cilia

C

Termination of bacterial transcription select all that apply: a. is Rho-dependent - requires the Rho protein to recognize specific termination sequences in the mRNA. b. is Rho-independent - does not require the Rho protein and is completely random. c. 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.

C and D

is the leading vector-borne bacterial pathogen capable of causing blindness in the developing world.

Chlamydia trachomatis

Avirulent Corynebacterium diphtheriae cells can be converted to disease-causing cells after exposure to a __________ that introduces a(n) __________. Select one: a. transmissible plasmid; antibiotic resistance gene b. generalized transducing phage; toxin gene c. generalized transducing phage; antibiotic resistance gene d. specialized transducing phage; toxin gene e. specialized transducing phage; antibiotic resistance gene f. transmissible plasmid; toxin gene

D

In the following diagram of homologous DNA recombination, what is the name of the protein labeled A? a. AI-1 b. single-stranded Binding Protein or ssBP c. ligase d. RecA

D

Nitrosomonas species are capable of oxidizing ammonia (NH3) for __________. Select one: a. fermentation. b. carbon fixation. c. nitrogen fixation. d. energy production.

D

Sigma factors are involved in the regulation of bacterial a. transformation. b. mutation repair. c. DNA replication. d. transcription. e. translation.

D

The bacterial chromosome is Select one: a. found in a nucleus. b. usually circular. c. found in a nucleoid. d. usually circular and found in a nucleoid. e. usually circular and found in a nucleus.

D

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. Algael digestion of the microbial life can quickly deplete the dissolved oxygen in the water. c. Water containing too much dissolved oxygen causes most marine animal life to die or flee. d. A dead zone is a low oxygen or hypoxic area in an ocean or lake. e. The purple bacteria are found in anaerobic environments like marine dead zones. f. The northern Gulf of Mexico has one of the largest dead zones in the world

D. E. F.

What bacterial species are known for extraordinary DNA repair systems and a thicker-than-average peptidoglycan layer?

Deinococcus species

Endospores survive a variety of harsh conditions in part because of the presence of Select one: a. beta-lactamases b. lipopolysaccharide c. glycoproteins d. mycolic acids e. dipicolinic acid

E

Prokaryotes contribute to the global cycling of which of the following elements? Select one: a. carbon b. Prokaryotes do not contribute to the global cycling of any of these elements. c. sulfur d. nitrogen e. Prokaryotes contribute to the global cycling of all of these elements.

E

Which of the following is NOT a feature of prokaryotic classification? Select one: a. None of the these are features of prokaryotic classification. b. Prokaryotes are grouped based on differences in their 16s rRNA sequence. 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. All of the these are features of prokaryotic classification.

E

Which of the following is NOT involved in the regulation of the lac operon? a. cyclic AMP b. a repressor protein c. glucose d. an effector e. a siRNA

E

What is the name of the structure connecting these two E. coli cells in this image?

F-pilus

Specialized transduction is used to order adjacent genes by determining cotransduction frequency.

FALSE

Quorum sensing induces expression of operons involved in microbial metabolism, DNA replication and cell wall synthesis.

FALSE ( biofilm, surfactant and antibiotic production)

Hyperthermophilic bacteria have optimal growth temperatures between 45 and 60 degrees Celsius.

FALSE (70 and 85)

Carl Linneaus first proposed groups of organisms sharing similar features are related by descent from a common ancestor.

FALSE (Charles Darwin)

Specialized transduction occurs when the phage capsid is accidentally packaged with exclusively host DNA.

FALSE (Generalized transduction)

Rhizobium bacterioids produce leghemoglobin to maintain a low oxygen concentration in the legume symbiosome.

FALSE (Host legume symbiosome cells, for Rhizobium bacteroids)

An example of syntrophy is methanogens generating hydrogen gas used by the fermentative chemoautotrophs to oxidizing butyrate to acetate.

FALSE (chemoheterotrophs)

Strains of E. coli either contain the F plasmid (F+) or lack the F plasmid (Hfr).

FALSE (contain both)

A majority of Earth's carbon is dissolved in ocean waters.

FALSE (crust)

Rhizobium bacteriods provide fixed nitrogen for the water fern Azolla, leading to increased rice crop yields.

FALSE (cyanobacterium Anabaena azollae)

Prokaryotic species are defined the same as animal and plant species.

FALSE (different from)

16S rRNA phylogenies describe three major lines of descent - or kingdoms.

FALSE (domains)

Deinococci stain gram positive despite lacking peptidoglycan within their cell wall due to a thick protein S-layer.

FALSE (due to a thick peptidoglycan layer despite not being gram positive bacteria)

Ectomycorrhizae produce haustauria, which penetrate through plant root cell walls - growing into the root cells.

FALSE (endomycorrhizae)

Odd numbers of crossovers between endo- and exogenotes result in recombinant chromosomes.

FALSE (even)

Plasmids are typically responsible for functions essential for cell growth.

FALSE (for no functions)

Three-point genetic crosses require triple-phenotype bacterial strains.

FALSE (genotype)

Transformational competence is most prevalent at low cell density.

FALSE (high cell)

Generalized transducing phage carry both host and virus DNA.

FALSE (host DNA)

The Volkswagen syndrome explains how secondary structure of a molecule assists with sequence alignment.

FALSE (how the use of phenotypes instead of genotypes to relate different organisms will not accurately determine relatedness)

Transcriptional termination is the most common form of gene regulation in prokaryotes.

FALSE (initiation)

The B. anthracis vaccine strain contains a plasmid missing from disease-causing B. anthracis strain.

FALSE (lacks)

Antisense RNA anneals/binds to complementary DNA, disrupting polymerase assocation and terminating transcription.

FALSE (mRNA, blocking translation and therefore protein production)

Microbes unable to detoxify oxygen radicals would exhibit positive aerotaxis.

FALSE (negative)

Neutral mutations often result in convergence.

FALSE (never)

Plasmids encode essential prokaryotic cell functions.

FALSE (no essential)

STARI is a red, expanding "bulls eye" lesion around a lone star tick bite caused by Borrelia burgdorferi.

FALSE (not Borrelia burgdorferi or lyme)

STARI is a red, expanding "bulls eye" lesion around a lone star tick bite caused by Borrelia burgdorferi.

FALSE (not caused by Borrelia burgdorferi or lyme)

Strong bacterial promoters share an identical DNA sequence, known as the "consensus" sequence.

FALSE (not identical)

E.coli cells moves in the direction of increasing attractant concentrations via a random walk.

FALSE (not random walk)

Prokaryotic genes are always organized into operons.

FALSE (often)

Proteins recognize the difference between DNA base pairs viewed from inside the DNA helix but not from outside of the DNA helix.

FALSE (outside)

Topoisomerase underwinds the bacterial chromosome into a positive supercoil.

FALSE (overwinds)

The spoA cascade is initiated by a series of sigma factors.

FALSE (phosphorylation by protein Kinases)

Deinococci are the only bacterial lineage to lack peptidoglycan entirely, having a protein cell wall.

FALSE (planctomyces)

Inducible prokaryotic operons under negative control have transcription factors requiring effector binding to induce transcription.

FALSE (positive)

A group of transcriptional units controlled by the same regulatory protein is called an operon.

FALSE (regulon)

The genes controlling conjugal plasmid transfer are normally expressed.

FALSE (repressed)

Prokaryotic transcriptional units are typically transcribed in the opposite direction the chromosome is replicated.

FALSE (same)

All prokaryotic genomes are comprised of a single, circular DNA chromosome.

FALSE (some)

Plasmids are present in all members of a prokaryotic species.

FALSE (some)

Inducible operons under negative control have effectors binding repressor to prevent transcription.

FALSE (start/induce)

Repressible prokaryotic gene regulation systems use effectors to start gene transcription.

FALSE (stop)

Purple non-sulfur bacteria grow in stagnant, anoxic waters using hydrogen sulfide for energy.

FALSE (sulfur)

Endospores are highly durable bacterial reproductive structures.

FALSE (survival)

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.

FALSE (switch order)

Directed cell movement in response to a stimulus is genetically regulated behavior.

FALSE (tactic)

The hyperthermophilic bacterial kingdoms include Thermodesulfobacterium, Aquifex and Deinococci.

FALSE (thermotoga)

Though prokaryotic organisms are the most abundant organisms on Earth, they do not represent a majority of the Earth's biomass due to the dramatic difference in size between prokaryotes and multicellular eukaryotes.

FALSE (they do)

Catabolite repression is regulated by a repressor protein CRP.

FALSE (transcription factor)

There are three types of bacterial transcription termination.

FALSE (two)

In a batch culture, secondary microbial metabolites are generated during the balanced/exponential growth phase.

FALSE → (secondary are generated during the Stationary phase growth)

Antisense RNA anneals/binds to complementary DNA, disrupting polymerase association and terminating transcription.

FALSE, (mRNA, blocking translation and therefore protein production)

Neutral changes in DNA sequence are not a good measure of relationship.

FALSE, Neutral mutations never result in convergence. Thus, neutral changes in DNA sequence can be a good measure of relationship.

Pseudomonads utilize type IV pili to undergo twitching motility.

FALSE, move by flagella

MCP binding to an attractant induces phosphorylation of CheA, which leads to a signal for the bacteria to tumble.

FALSE, phosphorylation is not induced

An operon is a single gene controlled by a variety of regulatory elements.

FALSE, regulon

Rhizobium bacterioids produce leghemoglobin to maintain a low oxygen concentration in the legume symbiosome.

FALSE, rhizobium host cell

Sigma factor association with RNA polymerase is irreversible, and thus progression to an alternative sigma factor requires transcription and formation of new RNA polymerase complexes.

FALSE, the mother cell undergoes irreversible changes during endospore

Transformational competence is more prevalent at low cell density.

FALSE-high

Changes in heterocyst nitrogenase genes are reversible under high oxygen conditions.

False

Inducible prokaryotic operons under negative control have transcription factors requiring effector binding to induce transcription.

False

Most prokaryotic transcriptional units are under the control of strong promoters to allow rapid, dynamic genetic response to changes in environment.

False

Prokaryotic metabolic processes are necessary to return vital nutrients from the land back to the sea.

False

Prokaryotic genomes typically have 25-50 nucleotides between genes.

False (3-9)

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.

False (A-U base pair)

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.

False (AU base pairs)

Carl Linneaus first proposed groups of organisms sharing similar features are related by descent from a common ancestor.

False (Charles Darwin)

The Planctomyces are a group of obligate, intracellular parasites.

False (Chlamydia)

Repressor proteins bind to newly synthesized mRNA sequences and induce polymerase dissociation.

False (DNA)

More distant relationships are measured using DNA/RNA hybridization.

False (DNA/DNA)

Cyanobacteria are known for their extreme radiation and ultraviolet (UV) light resistance.

False (Deinococci)

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)

F' strains mobilize large segments of the host chromosome to recipient cells at high frequency.

False (Hfr)

Deinococci are the only bacterial lineage to lack peptidoglycan entirely, having a protein cell wall.

False (Planctomyces)

Free-swimming chemotactic bacteria power their transmembrane flagella motors with ATP.

False (a chemiosmotic gradient)

Plasmids are present in all archaeal and bacterial species.

False (are not present)

Sigma proteins assist RNA polymerase with promoter binding in all prokaryotes and dissociate after transcription initiation.

False (bacteria)

Neutral mutations only occur in stretches of DNA encoding protein.

False (can occur)

Free-swimming chemotactic bacteria power their transmembrane flagella motors with ATP.

False (chemiosmotic gradient)

Geothermal vent ecosystems are based on bacterial chemoheterotrophic symbionts.

False (chemoautotrophs)

All flagellated chemotactic cells in a liquid medium move via run and tumble motion.

False (chemotactic prokaryotic)

Prokaryotic species are typically defined as a group of strains more similar to each other than to other strains.

False (clade - a group of strains determined to have descended a common ancestor due to a predominance of homologous features)

Specialized transduction can transfer DNA across great evolutionary distances.

False (conjugation)

Chromosome domains are tightly packed sequences of DNA located between relaxed cytoplasmic loops.

False (created by nicking DNA between areas of high protein binding)

A majority of Earth's carbon is dissolved in ocean waters.

False (crust)

When repellent concentration is decreasing tumbling frequency increases.

False (decreases)

Transformation is when DNA - released by a competent cell - is taken up by a donor cell.

False (donor cell, recipient cell)

Plasmids replicate by the rolling circle mechanism before conjugation.

False (during) DNA transfer to a recipient cell and plasmid replication using a rolling circle mechanism occur simultaneously.

Oxygen consumption in the animal intestinal tract is entirely due to obligate anaerobes.

False (facultative anaerobes)

Any host genes can be transduced. -

Generalized transduction

How does PatS contribute to the spacing of heterocysts?

Heterocyst development is initiated in cells with the lowest PatS level.

How does the amount of extracellular glucose impact the transcription of the lac operon?

High levels of extracellular glucose decrease activation of CRP which decreases transcription of the lac operon.

This transmembrane protein binds chemoattractant and initiates a signaling pathway that alters flagella rotation.

MCP

A terminally differentiated cell type -

Mother cells

You perform a DNA hybridization experiment to compare organism A and organism B. DNA from these two organisms annealed and is over 90% complementary. What statement could you make about the genetic relationship of organism A and organism B?

Organism A and organism B are classified within the same species.

A single cell produces either transducing particles or phage particles. -

Specialized transduction

Transducing particles are formed as a result of a mistake in the excision of a prophage. -

Specialized transduction

Transducing particles contain host and phage DNA -

Specialized transduction

In 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?

The bacterial population in the light organ had reached saturation and is beginning to die.

Which of the following statements best describes the above graphic of bacterial chemotaxis.

The bacterium is moving from low to high concentration of chemoattractant.

Which of the following best describes the regulation of the lac operon?

The lac repressor is bound to the lac operator in the absence of lactose

Which of the following is true of genetic diversity?

Transformation, conjugation, and transduction all create genetic diversity. Genetic diversity is created in prokaryote populations by mutation and horizontal gene transfer. Genetic diversity can lead to advantageous adaptions to changing environmental conditions.

Specialized transduction can produce partial diploids. (merozygotes)

True

The Planctomcytes are mostly unicellular budding bacteria associated with aquatic/ marine environments.

True

The carbon cycle requires carbon fixation by autotrophs to return the element of carbon to biosynthetic processes.

True

A Vibrio fischeri species, Vibrio strain A, produces an autoinducer molecule incapable of binding LuxR. What conclusion can you draw about Vibrio strain A?

Vibrio strain A present in the light organ of a bobtail squid will be unable to produce light.

In the Azolla/Anabaena symbiotic relationship, cyanobacterial nitrogen fixation supports the growth of

both the Azolla fern and the Anabaena cyanobacteria

Formed by bacteria most commonly belonging to the genera Bacillus and Clostridium -

endospores

Highly resistant to heat, desiccation, and irradiation -

endospores

A parasitic symbiotic relationship is detrimental to both partners.

false

An example of syntrophy is methanogens generating hydrogen gas used by the fermentative chemoautotrophs to oxidizing butyrate to acetate.

false

Changes in heterocyst nitrogenase genes are reversible under high oxygen conditions.

false

Chemotaxis in E.coli is based on net running and tumbling in the direction of decreasing attractant concentration.

false

The horizontal gene transfer process known as transduction

involves a virus.

A phage concatemer

is packaged into the virus capsid using a headful mechanism., refers to multiple, contiguous copies of the phage genome.

Anthrax is a potential bioterrorism agent because

it forms endospores capable of surviving harsh conditions.

What is the predominate group of microbes in freshwater sediments?

methanogens

Hfr strains mobilized large segments of the host chromosome to recipient cells at high frequency.

true

Bacterial DNA genes are arranged in a(an) _____________, which allows for coordinated control of transcription of those genes.

operon

The host-pathogen relationship is an example of what type of symbiosis?

parasitism

Heterocysts lose photosystem II and undergo significant morphological differentiation.

true

Disseminated reproductive structures of plants, fungi and some bacteria -

spores

What form of sulfur can be used as an electron acceptor in anaerobic respiration?

sulfate

A Sigma protein equivalent has not been identified in archaea or eukarya.

true

A group of transcriptional units controlled by the same regulatory protein(s) is called a regulon.

true

A modulon is group of operons controlled by the same global control system.

true

A more methylated MCP has less affinity for chemoattractants (only binds higher concentrations).

true

A nucleotide base sequence shares positional homology with another sequence when both sets of bases are descended from the same base in a common ancestor.

true

A transposon is a DNA sequence capable of changing its location in a host genome.

true

An accurate molecular chronometer is universal, changes at a constant rate and is large enough for the changes in it to be statistically significant.

true

An insertion sequence (IS) is capable of both replicative and nonreplicative transposition.

true

Anaerobic ecosystems are maintained by microbial oxygen consumption.

true

Antisense RNA anneals/binds to complementary mRNA sequences, blocking translation and therefore protein production.

true

Antisense RNA regulation functions at the level of translation.

true

Bacterial promoters with consensus base sequences from multiple bacterial promoters are considered ideal.

true

Carbon dioxide is a major end product of many prokaryotic fermentations.

true

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.

true

Charles Darwin first proposed groups of organisms sharing similar features are related by descent from a common ancestor.

true

Chromosome domains are created by nicking DNA between areas of high protein binding.

true

Competence factor is a small, continuously-excreted protein.

true

Conjugation can transfer DNA from prokaryotic cells across great genetic distances.

true

Continue prokaryotic gene expression requires continuous mRNA transcription.

true

Continued prokaryotic gene expression requires continuous mRNA transcription.

true

Convergent evolution describes the acquisition of similar traits by unrelated lineages.

true

DNA gyrase underwinds the bacterial chromosome into a negative supercoil.

true

DNA replication during conjugation occurs via the rolling circle mechanism.

true

Deinococci are known for their extreme radiation and UV light resistance.

true

Deinococci are known for their extreme radiation and ultraviolet (UV) light resistance.

true

Deinococci stain as if they are gram positive due to a thick peptidoglycan layer despite not being gram-positive bacteria.

true

Directed cell movement in response to light intensity is termed phototaxis.

true

Endomycorrhizae produce haustauria, which penetrate through plant root cell walls - growing into the root cells.

true

Endospores are cryptobiotic - manifesting no measurable living activity.

true

Endospores are cryptobiotic-manifesting no measurable living activity.

true

Free-swimming chemotactic bacteria power their transmembrane flagella using a chemiosmotic gradient.

true

Genetic regulation at the modulon level is mediated by differential expression of sigma proteins/factors.

true

Geothermal vent ecosystems are based on bacterial chemoautotrophic symbionts.

true

Gram positive bacteria use short peptides as autoinducer (AI) molecules.

true

Gram-negative transformation is species specific and uptakes DNA in double-stranded form.

true

Gram-negative transformation is species specific and uptakes DNA in double-stranded form.

true

Gram-positive transformation is nonspecific for the DNA sequences taken up.

true

Heterocysts lose photosystem II and specific DNA sequences compared to vegetative cells.

true

Transcription of a bacterial operon leads to a single mRNA which contains distinct translational control sequences for ribosome binding at each gene.

true

Transformation is likely the true horizontal gene transfer mechanism for prokaryotes.

true

Transformational competence is regulated by a quorum-sensing mechanism.

true

Weak promoters are recognized less effectively by RNA polymerases and as a result are good for operons requiring dynamic control.

true

The bacterial chromosome is

usually circular and found in a nucleoid.