BIOL 3500 Full Quizlet

Phosphorylation of ________ regulates which direction a flagellum rotates, thus controlling whether an organism runs or tumbles. CheYCheZCheBCheAW

CheY

______________ can bind to the flagellum in order to allow tumbles to occur.

CheY-P

Genes that are encoded for polymerases, gyrases, ribosomal proteins, and other proteins essential to replication, transcription, and translation are present on chromosomes and plasmids. chromosomes. plasmids. neither chromosomes nor plasmids.

chromosome

There are several different types of mutations possible in the base sequence of DNA. If a GGC (glycine) codon were changed to UGC (cysteine), it would be termed a __________. nonsense mutationmissense mutationsilent mutationwild type

missense

A strategy used by T4 bacteriophage to control transcription by host cell RNA polymerase is __________. modification of the internal cell environmentdenaturation of host RNA polymerasedegradation of host cell RNA polymerasemodification of host RNA polymerase to recognize only virus-encoded promotersmodification of the promoter regions of host cell genes

modification of host RNA polymerase to recognize only virus-encoded promoters

Bacteriophage have a ________ complex structure than animal viruses, because ________. less / their prokaryotic cells have a simple structure compared to eukaryotic cellsmore / the bacteriophage must penetrate the peptidoglycan cell wallmore / bacteriophages must be coated by lipopolysaccharide to attach to bacterial cellsless / the bacteriophage does not have to penetrate the nucleus

more / the bacteriophage must penetrate the peptidoglycan cell wall

Peritrichous

multiple flagella, all over the cell

The addition of two bases to the genome of a prokaryote would be most damaging if located __________. anywhere within the coding region of a proteinin the middle of the coding region of a proteinnear the beginning of the coding region of a proteinat the very end of the coding region of a protein

near the beginning of the coding region of a protein

In general, prokaryotic genome size is correlated to lifestyle. Which type of prokaryote typically has the largest genome? parasite autotroph soil bacterium archaeaendosymbiont

soil bacterium

Termination of RNA synthesis is ultimately determined by specific nucleotide sequences on the template strand.special protein factors.terminases.exhaustion of RNA polymerase activity.

specific nucleotide sequences on the template strand.

The curved-rod shape typical of Caulobacter is due to A. crescentin. B. crescentin and MreB. C. MreB. D. neither crescentin nor MreB.

B. crescentin and MreB.

Five-carbon sugars are used in the A. biosynthesis of DNA and RNA. B. catabolic pentose phosphate pathway for carbon and energy. C. biosynthesis of DNA and RNA as well as catabolic pentose phosphate pathway. D. activation of pentoses to form glycogen for energy storage.

*A. biosynthesis of DNA and RNA.

Which of the following contribute to the increased tolerance or resistance of biofilm bacteria to antimicrobials? Select all that apply. A. dormancy B. increased drug efflux C. inactivation of antimicrobials by binding D. facilitation of horozontal gene transfer

*A. dormancy B. increased drug efflux C. inactivation of antimicrobials by binding D. facilitation of horozontal gene transfer

Drugs targeting which of the following would have the least selective toxicity? A. 70S ribosome B. RNA polymerase C. DNA major groove D. peptidoglycan E. LPS

*C. DNA major groove

Antibiotics effective in preventing growth of disease-causing bacteria are A. bacteriocidal. B. bacteriostatic. C. bacteriostatic or bacteriocidal D. bacteriolytic or bacteriocidal. E. bacteriolytic.

*C. bacteriostatic or bacteriocidal

Which of the following are true regarding DNA-binding proteins? Select all that apply. A. Homodimeric regulatory proteins interact with inverted repeats on DNA. B. The minor groove of DNA is the main site of protein binding. C. The lac repressor contains the helix-turn-helix structure. D. Small molecules influence binding of regulatory proteins to DNA. E. Most DNA-binding proteins interact with DNA in a sequence-specific manner.

?

If autophosphorylation of CheA protein does NOT occur, then E. coli cells must be in a gradient of a chemoattractant. in a gradient of a repellant. tumbling. rotating flagella clockwise. rotating flagella clockwise and tumbling When grading the question, it would appear as: Attenuation is a type of regulation that directly controls both transcriptional and translational activity. post-translational activity allosteric enzyme activity. translational activity. transcriptional activity. When grading the question, it would appear as: A mutation occurs so that that DnaK binds more tightly to RpoH. Which of the following would be an outcome of this mutation? Fewer misfolded proteins would be refolded. The heat shock response would maintain unchanged. More misfolded proteins would be refolded. The cell would grow faster. More heat shock genes would be transcribed.

A E A

Using quorum sensing, how do bacteria know when there are sufficient numbers present to express a specific gene? View Available Hint(s) A low concentration of an autoinducer in the cell triggers the two-component system to turn on transcription of the specific gene.A high concentration of autoinducer inside the cell triggers the two-component system to turn on transcription of the specific gene.A high concentration of autoinducer outside the cell triggers the two-component system to turn on transcription of the specific gene.A low concentration of an autoinducer outside the cell triggers the two-component system to turn on transcription of the specific gene.

A high concentration of autoinducer inside the cell triggers the two-component system to turn on transcription of the specific gene.

All of the following are characteristic of suppressor mutations EXCEPT Mutation in another gene produces an enzyme that replaces the mutated one.A mutation elsewhere in same gene restores function.A mutation at same site as the original mutation restores function.Mutation in another gene restores the function of the original mutated gene.All of the items are characteristic of suppressor mutations.

A mutation at same site as the original mutation restores function.

Bacteria can regulate gene expression due to changes in the environment. How are these changes communicated to the cell? View Available Hint(s) A sensor kinase on the cell membrane recognizes the change and transfers the information to the repressor or inducer molecule, which then binds to DNA.A sensor kinase on the cell membrane recognizes the change and transfers the information to a response regulator in the cytoplasm.A response regulator on the cell membrane recognizes the change and transfers the information to a sensor kinase in the cytoplasm.A sensor kinase in the cytoplasm recognizes a change and transfers the information to a response regulator on the cell membrane.

A sensor kinase on the cell membrane recognizes the change and transfers the information to a response regulator in the cytoplasm.

What is the benefit, for a virus, to be a temperate or lysogenic virus? View Available Hint(s) A single infection event can allow the virus to live in the host cell indefinitely.A single infection event can produce millions of new viral particles instead of hundreds of viral particles.A single infection event can produce hundreds of new viral particles.A single infection even can allow other host cells to be infected by the same virus.

A single infection event can produce millions of new viral particles instead of hundreds of viral particles.

What is thought to be the maximum temperature for life to exist? A. 150°C B. 125°C C. 250°C D. 500°C

A. 150°C

What is the most recent date when all cells on Earth still lacked a membrane-enclosed nucleus? A. 2 billion years ago B. 3.5 billion years ago C. 1 billion years ago D. 1.5 billion years ago E. 3 billion years ago

A. 2 billion years ago

The energy required for nutrient transport is supplied by A. ATP, the proton motive force, or phosphoenol pyruvate. B. phosphoenol pyruvate. C. ATP. D. the proton motive force.

A. ATP, the proton motive force, or phosphoenol pyruvate.

Which of the following statements regarding transport is FALSE? A. All three mechanisms of active transport require multiple proteins. B. In group translocation, the transported substance is chemically modified during the transport process. C. ABC transport systems have high substrate affinity and thus help microorganisms survive in low nutrient environments. D. Energy sources for active transport include the proton motive force, ATP, or other energy-rich compound. E. Transport occurs through a conformational change in the transmembrane transport protein.

A. All three mechanisms of active transport require multiple proteins.

Which of the following is (are) used by microorganisms to become resistant to a particular drug? Select all that apply. A. An alternate metabolic pathway that bypasses the drug-sensitive step B. Enzymatic inactivation of the drug C. Modification of the drug target D. Exclusion of the drug from the cell

A. An alternate metabolic pathway that bypasses the drug-sensitive step B. Enzymatic inactivation of the drug C. Modification of the drug target D. Exclusion of the drug from the cell

________ are charged molecules that are partially responsible for the ________ charge of the gram-positive bacterial cell surface. A. Teichoic acids / negative B. Lipopolysaccharides / negative C. Phospholipids / negative D. Diaminopimelic acids / positive E. Peptide interbridges / neutral

A. Teichoic acids / negative

What will happen to a cyanobacterium that has its photosystem II (PSII) blocked? A. Anoxygenic photosynthesis only using photosystem I (PSI) could occur by using cyclic photophosphorylation and an alternative electron donor such as H2S. B. Photons will generate excessive reactive oxygen species and the cyanobacterium will die as a consequence. C. It will die from being unable to obtain energy for photosynthesis. D. Additional electron acceptors, such as NADP+, will be required to oxidize oxygen and overcome the lost PSII process.

A. Anoxygenic photosynthesis only using photosystem I (PSI) could occur by using cyclic photophosphorylation and an alternative electron donor such as H2S.

Archaea and Bacteria both use whiplike structures in similar ways for locomotion, but the structures have different origins. This is an example of convergent evolution. What are some similarities and differences between archaella and bacterial flagella? Select all that apply. A. Archaella flagella have smaller diameters than bacterial flagella. B. Archaella propel archaeans by contracting and lengthening, but flagella propel Bacteria by rotating. C. Archaella are made of proteins unrelated to the flagellin in bacterial flagella. D. Archaella are powered directly by ATP, but bacterial flagella are powered by a proton motive force. E. Archaella are always associated with greater speeds than those allowed by bacterial flagella.

A. Archaella flagella have smaller diameters than bacterial flagella. C. Archaella are made of proteins unrelated to the flagellin in bacterial flagella. D. Archaella are powered directly by ATP, but bacterial flagella are powered by a proton motive force.

Different arrangements and structures of flagella contribute to changes in speed and direction when necessary. Which of the following correctly relates motility to flagellation? A. Bacteria with peritrichously arranged flagella change direction by changing the flagellar rotation and "tumbling." B. Bacteria with lophotrichously arranged flagella change direction only by changing the flagellar rotation. C. Certain flagellated prokaryotes exhibit gliding motility, a slower and smoother form of movement along the long axis of a cell. D. Peritrichously arranged flagella may only rotate counterclockwise.

A. Bacteria with peritrichously arranged flagella change direction by changing the flagellar rotation and "tumbling."

The major source of carbon was _________ for early cells and the major fuel for energy was __________ for early cells. A. CO2 ; H2 B. CO2 ; N2 C. O2 ; CO2 D. N2 ; H2

A. CO2 ; H2

Which of the following are true of capsules? Select all that apply. A. Capsules retain water and help prevent desiccation of the bacteria. B. Capsules occur in both Bacteria and Archaea. C. Capsules are considered part of the cell wall. D. Capsules help hide bacterial cells from the host immune system. E. Capsules are involved in the attachment of microorganisms to solid surfaces.

A. Capsules retain water and help prevent desiccation of the bacteria. B. Capsules occur in both Bacteria and Archaea. D. Capsules help hide bacterial cells from the host immune system. E. Capsules are involved in the attachment of microorganisms to solid surfaces.

Of the choices, which would be more related to chemotaxis (rather than adaptation)? A. CheB-P is present in high concentrations B. an MCP is fully methylated C. CheB is not phosphorylated D. a cell is exhibiting mostly runs E. a cell is exhibiting mostly tumbles F. CheY is unable to bind to the flagellar motor G. an MCP is fully unmethylated

A. CheB-P is present in high concentrations D. a cell is exhibiting mostly runs F. CheY is unable to bind to the flagellar motor

Which of the following statements are true regarding the genetic information of a bacterial cell? A. DNA is supercoiled by the enzyme DNA gyrase. B. Genetic information is composed of the nucleotides cytosine, guanine, adenine, and uracil. C. Genetic information is primarily contained within a double-stranded DNA helix. D. DNA is primarily contained within a membrane-bound nucleus. E. DNA is primarily linear with multiple copies. F. DNA is transcribed into mRNA, which is translated into functional proteins. G. Genetic information is also found on extra-chromosomal material, called plasmids.

A. DNA is supercoiled by the enzyme DNA gyrase. C. Genetic information is primarily contained within a double-stranded DNA helix. F. DNA is transcribed into mRNA, which is translated into functional proteins. G. Genetic information is also found on extra-chromosomal material, called plasmids.

During production of a drug, all work area surfaces must be disinfected using sterilized disinfectants. Which of the following statements about disinfectants are true? A. Disinfection can occur by physical or chemical means. B. Disinfection can be used to treat work surfaces as well as workers (i.e., washing hands). C. Disinfectants are used to inhibit or destroy pathogens. D. Disinfectants destroy all microbes present on a surface. E. Endospores and viruses can resist disinfectant treatment.

A. Disinfection can occur by physical or chemical means. C. Disinfectants are used to inhibit or destroy pathogens. E. Endospores and viruses can resist disinfectant treatment.

Distinguish how fermentation and respiration differ. A. Fermentation forms organic acids and takes place in the absence of oxygen, while respiration forms water and carbon dioxide in the presence of oxygen. B. Fermentation forms organic acids and takes place in the presence of oxygen, while respiration forms water and carbon dioxide in the presence of oxygen. C. Fermentation forms water and carbon dioxide and takes place in the absence of oxygen, while respiration forms water and carbon dioxide in the presence of oxygen. D.Fermentation forms water and carbon dioxide and takes place in the presence of oxygen, while respiration forms water and carbon dioxide in the presence of oxygen.

A. Fermentation forms organic acids and takes place in the absence of oxygen, while respiration forms water and carbon dioxide in the presence of oxygen.

Which of the following are true regarding both flagella and pili? Select all that apply. A. Flagella and pili are made up of proteins B. Their functions include motility. C. Both are extracellular surface appendages. D. Flagella and pili occur in both Bacteria and Archaea. E. Both flagella and pili are hollow inside.

A. Flagella and pili are made up of proteins B. Their functions include motility. C. Both are extracellular surface appendages.

Which of the following regarding the arbitrium system is FALSE? A. High concentrations of arbitrium promote the lytic pathway. B. Arbitrium inhibits expression of aimX. C. Arbitrium is a quorum-sensing signal. D. Different phages encode homologues of this system with different signal peptides. E. AimX silences expression of the phage cI repressor.

A. High concentrations of arbitrium promote the lytic pathway.

Which statement best illustrates the importance of a high surface-to-volume ratio that is found in microorganisms? A. If a cell has a high surface-to-volume ratio, there will be enough surface area to get the needed nutrients in to support cellular metabolism and the accumulated waste out. B. If a cell has a high surface-to-volume ratio, the volume of the cell will be much larger than the surface area. There would be enough surface area to get the needed nutrients in and the accumulated waste out. C. If a cell has a high surface-to-volume ratio, the volume of the cell will be much larger than the surface area. There would NOT be enough surface area to get the needed nutrients in and the accumulated waste out. D. If a cell has a high surface-to-volume ratio, there will NOT be enough surface area to get the needed nutrients in to support cellular metabolism and the accumulated waste out.

A. If a cell has a high surface-to-volume ratio, there will be enough surface area to get the needed nutrients in to support cellular metabolism and the accumulated waste out.

Mutation rates are similar in Bacteria and Archaea, yet certain stressful conditions cause mutation rates to increase. Why is the mutation rate not constant and close to zero all of the time? A. Increased mutation rates can be advantageous in rapidly changing environments because some random mutations may be useful for survival. B. Microorganisms carefully control the mutation rate of their DNA to match the environmental conditions and maximize evolution. C. Constant mutation rates would halt evolution completely. D. The increased mutation rate under stressful conditions is an indication that the microorganisms can no longer replicate their DNA properly and are about to die.

A. Increased mutation rates can be advantageous in rapidly changing environments because some random mutations may be useful for survival.

What is the function of bactoprenol? A. It is a hydrophobic alcohol that transports peptidoglycan precursors across the cytoplasmic membrane. B. It supplies the energy necessary for transpeptidation to occur. C. It is responsible for forming the peptide cross-links between muramic acid residues in adjacent glycan chains. D. It triggers the recruitment of FtsZ and the initiation of the divisome.

A. It is a hydrophobic alcohol that transports peptidoglycan precursors across the cytoplasmic membrane.

Select all the reasons why a microbial species is difficult to define. A. Microbes don't use sexual reproduction. B. Microbes are very difficult to sequence. C. There is a very limited fossil record for microbes. D. Molecular techniques don't work on microbes. E. Microbes have limited morphological features.

A. Microbes don't use sexual reproduction. C. There is a very limited fossil record for microbes. E. Microbes have limited morphological features.

What is the most likely outcome for the treatment of a suspension containing equal numbers of bacterial and archaeal cells in a hypotonic solution with lysozyme? A. Only the Bacteria will be lysed. B. None of the cells will be lysed. C. Only the Archaea will be lysed. D. All cells will be lysed.

A. Only the Bacteria will be lysed.

.Consider the Pseudomonas aeruginosa cells discussed in the introductory passage. How might chemotaxis and adaptation be interacting in this system? A. Over time, the bacteria show adaptation and epithelial cells begin to die. Newly damaged cells emit signals and the bacteria exhibit chemotaxis towards them. B. Over time, the bacteria exhibit negative chemotaxis away from toxic chemicals produced by the damaged cells. They later show adaptation to these chemicals and are able to return. C. Over time, the bacteria show increasing attraction to the damaged and dying epithelial cells. Adaptation to new chemicals allows them to begin to respond to signals from other locations. D. Over time, the dying epithelial cells produce repellants that cause chemotaxis away from the area. This allows the bacteria to reach new areas where they can find fresh nutrients.

A. Over time, the bacteria show adaptation and epithelial cells begin to die. Newly damaged cells emit signals and the bacteria exhibit chemotaxis towards them.

A microbe growing in a lake, using carbon dioxide as its carbon source, hydrogen sulfide as its source of electrons and light as its source of energy is a A. Photoautotrophic lithotroph B. Chemoautotrophic lithotrophs C. Chemoheterotrophic organotroph D. Photoheterotrophic organotrophs E. Photoautotrophic organotroph

A. Photoautotrophic lithotroph

DNA is composed of two strands, only one of which is used as a template for RNA synthesis. By what mechanism is the correct strand chosen? A. Promoter orientation acts to locate the RNA polymerase. B. RNA polymerase can read only 5' to 3', so the direction is predetermined. C. Only one strand has the start codon. D. Both strands are tried, and the one that works is chemically modified, so it will be used again. E. Only one DNA strand contains genes.

A. Promoter orientation acts to locate the RNA polymerase.

RNA viruses require which of the following enzymes to replicate their genome? A. RNA replicase B. RNA polymerase C. DNA polymerase D. reverse transcriptase E. Cas proteins

A. RNA replicase

You expose a bacterial strain to DNA containing bacitracin resistance. Then you plate the resulting culture onto a rich medium containing bacitracin. This is an example of A. Selection B. Both selection and screening C. Neither selection nor screening D. Screening

A. Selection

How do polysomes illustrate the energy efficiency of a cell? A. The cell can synthesize multiple copies of a protein from a single piece of mRNA. B. The cell can synthesize multiple copies of mRNA from a single gene on DNA. C. The cell can synthesize a single copy of a protein from one ribosome. D. The cell can synthesize multiple copies of mRNA from a single ribosome.

A. The cell can synthesize multiple copies of a protein from a single piece of mRNA.

Predict the effect of greatly reduced levels of FtsZ proteins in growing E. coli cells. A. The cells will continue to elongate but will be unable to form a septum and divide, leading to very elongated cells. B. The FtsZ ring will form at the center of the cell but will be unable to depolymerize, leading to cells that form septa but are permanently attached and form long chains. C. The cells will divide uncontrollably, leading to very small, almost coccoid cells. D. The cells would stop growing and soon die.

A. The cells will continue to elongate but will be unable to form a septum and divide, leading to very elongated cells.

Which statement below demonstrates why the majority of organisms are heterotrophs? A. The majority of organisms obtain their carbon from organic sources. B. The majority of organisms conserve energy from inorganic sources and their carbon from organic sources. C. The majority of organisms obtain their carbon from inorganic sources. D. The majority of organisms conserve energy from inorganic sources.

A. The majority of organisms obtain their carbon from organic sources.

Explain why promoters for the same sigma subunit do not have identical sequences in all organisms. A. The sequences within the promoter region at -10 and -35 are the most important for recognition by the sigma subunit. B. Only the last 10 bases in the promoter region are needed for sigma subunit recognition. C. Different organisms will have different DNA sequences. D. Only the first 35 bases in the promoter region are needed for sigma subunit recognition.

A. The sequences within the promoter region at -10 and -35 are the most important for recognition by the sigma subunit.

Which of the following is LEAST commonly associated with endospore-forming bacteria? A. They are coccus-shaped organisms. B. They are primarily soil dwellers. C. They are saprophytic. D. They can survive adverse environmental conditions.

A. They are coccus-shaped organisms.

If chromosomal DNA from a host is the only type of DNA carried by a transducing particle, what can be concluded regarding transduction in this case? A. Transduction is generalized. B. Transduction is specialized. C. Transduction could be generalized or specialized depending on the phage involved. D. Transduction is neither generalized nor specialized.

A. Transduction is generalized.

The codon for phenylalanine is UUU. Which of the following codons also most likely encodes for phenylalanine? A. UUC B. CUU C. AAA D. AUG E. AUU

A. UUC

Which statement illustrates the chemical basis for the predominant type of fatty acids in the plasma membrane of a psychrophile? A. Unsaturated fats have kinked side chains that prevent tight packing as temperatures drop. B. Unsaturated fats have straight side chains that prevent tight packing as temperatures drop. C. Saturated fats have kinked side chains that prevent tight packing as temperatures drop. D. Saturated fats have straight side chains that prevent tight packing as temperatures drop.

A. Unsaturated fats have kinked side chains that prevent tight packing as temperatures drop.

Global regulatory systems include all of the following EXCEPT A. amino acid synthesis. B. stringent response. C. stationary phase. D. heat shock response. E. catabolite repression.

A. amino acid synthesis.

The amino group of amino acids is typically derived from what source in the environment? A. an inorganic nitrogen source B. an organic nitrogen source C. nitrogen gas D. nitrogen bases

A. an inorganic nitrogen source

Arrange the following types of microorganisms in the order in which they evolved on Earth. A. anaerobes, anoxygenic phototrophs, oxygenic phototrophs, aerobes, multicellular organisms B. anaerobes, multicellular organisms, aerobes C. anaerobes, anoxygenic phototrophs, aerobes, oxygenic phototrophs, multicellular organisms D. oxygenic phototrophs, aerobes, anoxygenic phototrophs, anaerobes, multicellular organisms

A. anaerobes, anoxygenic phototrophs, oxygenic phototrophs, aerobes, multicellular organisms

Arrange the types of microorganism in the order they evolved on Earth. A. anaerobes, anoxygenic phototrophs, oxygenic phototrophs, aerobes, multicellular organisms B. aerobes, oxygenic phototrophs, anoxygenic phototrophs, anaerobes, multicellular organisms C. anaerobes, multicellular organisms, aerobes D. anaerobes, anoxygenic phototrophs, aerobes, oxygenic phototrophs, multicellular organisms

A. anaerobes, anoxygenic phototrophs, oxygenic phototrophs, aerobes, multicellular organisms

The earliest stromatolites were probably formed by A. anoxygenic phototrophs. B. oxygenic lithotrophs. C. anoxygenic lithotrophs. D. oxygenic phototrophs.

A. anoxygenic phototrophs.

Microbial mats differ from biofilms in that they __________. A. are currently found only in extreme habitats B. are found only attached to surfaces C. contain more than one species of microorganism in the community D. have different environmental conditions at various depths within the community

A. are currently found only in extreme habitats

A chemical that denatures proteins is most likely to be classified as a(n) ________ agent. A. bacteriocidal B. bacteriostatic C. detergent D. antiseptic

A. bacteriocidal

A plasmid differs from the bacterial chromosome in that it is __________. A. significantly smaller B. double-stranded C. always found as a single copy of DNA in a cell D. circular

A. significantly smaller

All of the following are true of biofilms EXCEPT that __________. A. biofilms are composed of only one species at a time B. biofilm formation and dispersal are regulated processes C. biofilms protect organisms from antibiotics D. biofilms form on virtually all submerged surfaces in nature

A. biofilms are composed of only one species at a time

Microbial growth on the two-carbon acetate substrate invokes A. both the citric acid and glyoxylate pathways. B. the glyoxylate and glycolysis pathways. C. the glyoxylate pathway. D. the citric acid cycle for aerobic catabolism.

A. both the citric acid and glyoxylate pathways.

Normal PrPC is converted into infectious pathogenic PrPSc _________. A. by PrPSc that binds to the normal protein and causes it to become misfolded B. by a virus that binds to the normal protein and causes it to become misfolded C. by interaction of PrPC from one species with that of a second species D. by an enzyme that cleaves off parts of the normal protein E. as a result of a mutation in the normal gene.

A. by PrPSc that binds to the normal protein and causes it to become misfolded

Regulation of chemotaxis requires that organisms such as P. aeruginosa respond to chemicals in the environment. What types of signals do these organisms sense and use as a basis for response? A. changes in concentration of a chemical over time B. the absolute concentration of a chemical C. both temporal and spatial changes in chemical concentration D. spatial gradients of a chemical

A. changes in concentration of a chemical over time

Based on their energy source, primitive cells, such as those that might have evolved at deep sea vents, were most likely A. chemolithotrophs B. phototrophs, chemoorganotrophs or chemolithotrophs C. chemoorganotrophs or chemolithotrophs D. phototrophs E. chemoorganotrophs

A. chemolithotrophs

You are studying 12 new isolates from the human skin. Their 16S rRNA gene sequence identity is 97%.The isolates would most likely be A. classified as individual strains of the same species. B. classified as individual species of the same genus. C. classified as the same species if they can mate via conjugation. D. split into different families.

A. classified as individual strains of the same species. (prof. Taller says B. is a better answer because supposed to be <3% to be same species)

Which of the following molecules involved in electron transport has the most positive reduction potential? A. cytochromes B. quinones C. NADH dehydrogenase D. flavoproteins

A. cytochromes

To speed up the growth rate in a chemostat, the ___ should be increased. To increase the cell yield as well, _____ should be increased. A. dilution rate / limiting nutrient B. limiting nutrient / limiting nutrient C. dilution rate / dilution rate D. limiting nutrient / dilution rate

A. dilution rate / limiting nutrient

What molecules reduce the water content of a bacterial endospore? A. dipicolinic acid and calcium B. small acid-soluble proteins and dipicolinic acid C. small acid-soluble and core proteins D. peptidoglycan and calcium E. diaminopimelic acid and calcium

A. dipicolinic acid and calcium

The Par system is necessary for A. distribution of genetic material in replicating Caulobacter. B. elongation of bacillus prior to cell division. C. formation of a replication fork in Escherichia coli. D. septum formation.

A. distribution of genetic material in replicating Caulobacter.

The Par system is necessary for A. distribution of genetic material in replicating Caulobacter. B. formation of a replication fork in Escherichia coli. C. septum formation. D. elongation of bacillus prior to cell division.

A. distribution of genetic material in replicating Caulobacter.

Bacteriophage genomes are typically composed of A. double-stranded DNA. B. single-stranded DNA. C. single-stranded RNA. D. all of these genomes are equally common in phage E. double-stranded RNA.

A. double-stranded DNA.

When describing the bacteriophage genome, which terms could be used? Select all that apply. A. ds DNA B. ss DNA C. ds RNA D. ss RNA

A. ds DNA B. ss DNA C. ds RNA D. ss RNA

Mechanisms for controlling enzyme activity include which of the following? Select all that apply. A. feedback inhibition. B. covalent modification of the enzyme. C. addition of short sections of new amino acid sequence. D. phosphorylation. E. degradation of the enzyme.

A. feedback inhibition. B. covalent modification of the enzyme. D. phosphorylation. E. degradation of the enzyme.

Predict which type of organism would be more difficult to treat with antibiotics and why. A. gram-negative organisms -- extra layer of LPS B. gram-negative organisms -- thinner peptidoglycan layer C. gram-positive organisms -- no LPS layer D. gram-positive organisms -- thicker peptidoglycan layer

A. gram-negative organisms -- extra layer of LPS

Proteins MinC, MinD, and MinE interact to A. help guide FtsZ to the cell midpoint. B. initiate peptidoglycan synthesis. C. assist chromosome segregation. D. determine cell shape.

A. help guide FtsZ to the cell midpoint.

Compared to Eukaryotes, Bacteria and Archaea have ________ surface-to-volume ratios, causing ________ nutrient exchange and growth rates. A. higher / higher B. lower / lower C. higher / lower D. lower / higher

A. higher / higher

In a culture grown in a chemostat (continuous culture), the best way to increase the yield of bacteria (numbers of cells per mL) would be to __________. A. increase the concentration of nutrients in the medium B. increase the growth rate C. increase the dilution rate (rate of addition of medium) D. increase the temperature

A. increase the concentration of nutrients in the medium

Chemical mutagens, UV radiation, and ionizing radiation all increase mutation rates, but they have different mechanisms. Which type of mutagen would be best suited for creating large deletions and rearrangements within a genome? A. ionizing radiation B. chemical mutagens C. UV radiation D. Chemical, UV, and ionizing radiation would create large deletions and rearrangements if used in a very high dose.

A. ionizing radiation

Starting from the inside of the outer membrane to the outside, what is the composition of lipopolysaccharide? A. lipid A, core polysaccharide, O-specific polysaccharide B. O-specific polysaccharide, lipid A, core polysaccharide C. O-specific polysaccharide, core polysaccharide, lipid A D. lipid A, O-specific polysaccharide, core polysaccharide

A. lipid A, core polysaccharide, O-specific polysaccharide

Accurately counting cells in a biofilm would be challenging when using A. microscopic direct county, turbidity measurement, and viability counts with spread plating. B. microscopic direct counting. C. viability counts with spread plating. D. turbidity measurement.

A. microscopic direct county, turbidity measurement, and viability counts with spread plating.

The phylogenetic trees of the nifH and SSU rRNA genes are incongruent because A. of horizontal gene transfer. B. nitrogenase is an anaerobic enzyme. C. very few microbes have the nifH gene. D. nitrogenase evolves rapidly.

A. of horizontal gene transfer.

The ability to form endospores in bacteria within Bacillales and Clostridiales suggests the genotype/phenotype evolved A. only once in an ancestor to these two orders, due to the high number of genes required. B. either at least once and horizontal gene transfer among relatives occurred or once in a common ancestor. C. at least two separate times in these divergent orders. D. at least once, and horizontal gene transfer among relatives explains its presence in other orders.

A. only once in an ancestor to these two orders, due to the high number of genes required.

Fermentation occurs when there is no usable external electron acceptor (like O2) available for respiration. The fermentation products are made following glycolysis as a result of reactions that __________. A. oxidize NADH so that NAD+ can be reused again in glycolysis B. get rid of toxic waste products generated during glycolysis C. generate more ATP energy from the substrate D. synthesize more NAD+ from substrate molecules

A. oxidize NADH so that NAD+ can be reused again in glycolysis

A halotolerant facultative aerobic bacterium would grow BEST in a ________ environment. A. oxygenated non-saline B. oxygen depleted saline C. oxygen depleted non-saline D. oxygenated saline

A. oxygenated non-saline

Two separate photosystems involved in electron flow is a hallmark of A. oxygenic phototrophs. B. purple bacteria. C. green sulfur bacteria. D. anoxygenic phototrophs.

A. oxygenic phototrophs.

All microorganisms require A. phosphorus, selenium, and sulfur. B. carbon, iron, and sodium. C. phosphorus, aluminum, and sodium. D. calcium, potassium, and magnesium.

A. phosphorus, selenium, and sulfur.

Which of the following bacterial structures serves the same function as adipose tissue (fat) in animals? A. polyhydroxyalkanoate granules B. sulfur globules C. polyphosphate granules D. magnetosomes

A. polyhydroxyalkanoate granules

The cellular basis for bacterial resistance to antimicrobials can include (select all that apply) A. prevention of drug entry into the cell. B. removal of drug from cell by efflux C. bacterial chromosomal mutations. D. modification of target structure E. synthesis of enzymes that alter drug structure.

A. prevention of drug entry into the cell. B. removal of drug from cell by efflux C. bacterial chromosomal mutations. D. modification of target structure E. synthesis of enzymes that alter drug structure.

In contrast to chlorophylls, carotenoids function A. primarily as photoprotection (but they also transfer some absorbed energy into reaction centers). B. as accessory pigments that enable absorption of energy from higher wavelengths. C. to convert reactive oxygen species into usable energy. D. to quench toxic oxygen species.

A. primarily as photoprotection (but they also transfer some absorbed energy into reaction centers).

Molecular chaperones function to _______. Select all that apply. A. recognize unfolded or partially denatured proteins B. guide normal, functional proteins to their cellular location C. prevent incorrect folding of proteins D. provide ATP to proteins that require it E. fold newly formed proteins to their proper shape

A. recognize unfolded or partially denatured proteins C. prevent incorrect folding of proteins E. fold newly formed proteins to their proper shape

When DNA is transferred into a prokaryotic cell it may (Select all that apply) A. remain in the cytoplasm, unable to replicate. B. recombine with the host chromosome. C. replicate independent of the host chromosome. D. be degraded by enzymes.

A. remain in the cytoplasm, unable to replicate. B. recombine with the host chromosome. C. replicate independent of the host chromosome. D. be degraded by enzymes.

Which two antimicrobials affect bacterial nucleic acid synthesis? A. rifampin and quinolones B. trimethoprim and sulfonamides C. tetracycline and bacitracin D. tetracycline and amphotericin B E. penicillin and vancomycin

A. rifampin and quinolones

Type V secretion systems A. start with Sec-dependent transport across the plasma membrane, but the transported protein then forms a channel in the outer membrane through which it autotransports. B. are used by pathogens to secrete virulence factors from the cytoplasm, across both the plasma membrane and outer membrane, and into host cells. C. move proteins from the cytoplasm across both the plasma membrane and the outer membrane. D. can transport DNA during conjugation, in addition to proteins.

A. start with Sec-dependent transport across the plasma membrane, but the transported protein then forms a channel in the outer membrane through which it autotransports.

The destruction or removal of all viable organisms is called A. sterilization. B. sanitization. C. disinfection. D. Pasteurization. E. antisepsis.

A. sterilization.

Eukaryotes have ________ in their cytoplasmic membranes, which serve to strengthen and stabilize the membrane and make it less flexible. Many bacteria have similar molecules, known as ________, in their cytoplasmic membranes that have a similar role. A. sterols / hopanoids B. phospholipids / lipopolysaccharides C. ether bonds / ester bonds D. lipids / phospholipids

A. sterols / hopanoids

The reduction potential (E0′) of a substance reflects its tendency to donate or accept electrons. The larger the difference (ΔE0′) between the reduction potentials of the electron donor and the electron acceptor, __________. A. the greater the change in free energy (ΔG0′), and the greater the energy released B. the greater the change in free energy (ΔG0′), and the less energy is released C. the more enzymes will be required to catalyze the reaction(s) D. the closer the substances are on the electron tower

A. the greater the change in free energy (ΔG0′), and the greater the energy released

Mycoplasma species are bacteria that do not possess a cell wall. What accounts for the extra strength and rigidity of a mycoplasmal cell membrane? A. the presence of sterols in their membranes B. the presence of LPS in their membranes C. the presence of hopanoids in their membranes D. the presence of ether-linked lipids in their membranes. E. the near absence of proteins in their membranes

A. the presence of sterols in their membranes

Currently, the best defined method for transferring DNA into certain archaeal cells is __________. A. transformation B. conjugation C. transduction D. transposition

A. transformation

β-lactam antibiotics inhibit peptidoglycan A. transpeptidation. B. glycan tetrapeptide precursor formation. C. transglycosylation. D. transglycosylation and transpeptidation. E. autolysins.

A. transpeptidation.

Applying your knowledge of metabolism, glycolysis starts with one molecule of glucose (6C) and produces a net total of __________. A. two pyruvates; 2 NADH; 2 ATP B. one pyruvate; 2 NADH; 4 ATP C. two pyruvates; 4 NADH; 2 ATP D. one pyruvates; 2 NADH; 2 ATP

A. two pyruvates; 2 NADH; 2 ATP

Identifying carboxysomes in a bacterium suggests it A. will use the Calvin cycle convert the concentrated CO2 into biomass. B. has a deficient Calvin cycle and accumulated CO2. C. contains the reverse citric acid cycle. D. is in a carboxylic acid rich environment and is storing excess quantities for potentially harsh conditions.

A. will use the Calvin cycle convert the concentrated CO2 into biomass.

Explain how small RNA (sRNA) molecules can regulate translation of a piece of mRNA. View Available Hint(s) sRNAs can increase degradation rate of mRNA. sRNAs can base pair to mRNA and block translation. sRNAs can decrease degradation rate of mRNA. All of the listed responses are correct. sRNAs can change the secondary structure of mRNA.

ALL ABOVE

Which of the following is most similar to lysogeny? A. F' state B. F- state C. Hfr state D. F+ state

C. Hfr state

Many pharmaceutical drugs specifically inhibit transcription in Bacteria but not Archaea or Eukarya. Why would drugs that inhibit transcription only affect Bacteria and not Archaea even though they are both prokaryotes? Archaea lack operons.Archaea and Eukarya have very similar RNA polymerases that are different than bacterial RNA polymerases.Archaea and Eukarya have very similar ribosomes that are different than bacterial ribosomes.Bacteria lack a nucleus.

Archaea and Eukarya have very similar RNA polymerases that are different than bacterial RNA polymerases.

Which of the following regarding Archaeal gene expression is FALSE? Multiple transcription factors are required for transcription initiation. Archaeal promoter structure is the same as for Bacterial promoters. Archaea contain operons. Some archaeal transcription termination is intrinsic. Archaeal RNA polymerase resembles a eukaryotic RNA polymerase.

Archaeal promoter structure is the same as for Bacterial promoters.

A major function of prokaryotic gas vesicles is to A. store oxygen for aerobic growth when oxygen becomes depleted in the environment. B. confer buoyancy on cells by decreasing their density. C. serve as a reservoir for oxygen and carbon dioxide. D. keep the cell's organelles separated during flagellar motion.

B. confer buoyancy on cells by decreasing their density.

From a plate count experiment in which you spread 0.1 ml onto each of two different agar plates from a 1:100,000 dilution of a culture, you count 150 colonies on one plate and 122 colonies on a duplicate plate. How many bacteria/ml were there in the original sample? A. 1.36 × 10^5 bacteria/ml B. 1.36 × 10^8 bacteria/ml C. 1.36 × 10^6 bacteria/ml D. 136 bacteria/ml

B. 1.36 × 10^8 bacteria/ml

DNA replication always proceeds in only one direction because the ________ of the incoming nucleotide is attached to the free ________ of the growing DNA strand. A. 3'-phosphate / 5'-hydroxyl B. 5'-phosphate / 3'-hydroxyl C. 3'-base / 5'-deoxyribose D. 5'-deoxyribose / 3'-base

B. 5'-phosphate / 3'-hydroxyl

Using quorum sensing, how do bacteria know when there are sufficient numbers present to express a specific gene? A. A high concentration of autoinducer outside the cell triggers the two-component system to turn on transcription of the specific gene. B. A high concentration of autoinducer inside the cell triggers the two-component system to turn on transcription of the specific gene. C. A low concentration of an autoinducer outside the cell triggers the two-component system to turn on transcription of the specific gene. D. A low concentration of an autoinducer in the cell triggers the two-component system to turn on transcription of the specific gene.

B. A high concentration of autoinducer inside the cell triggers the two-component system to turn on transcription of the specific gene.

Which of the following conditions favors a lysogenic life cycle in bacteriophages? A. The presence of abundant hosts. B. A lack of host bacteria. C. Having ssRNA. D. Having ssDNA.

B. A lack of host bacteria.

Bacteria can regulate gene expression due to changes in the environment. How are these changes communicated to the cell? A. A sensor kinase on the cell membrane recognizes the change and transfers the information to the repressor or inducer molecule, which then binds to DNA. B. A sensor kinase on the cell membrane recognizes the change and transfers the information to a response regulator in the cytoplasm. C. A sensor kinase in the cytoplasm recognizes a change and transfers the information to a response regulator on the cell membrane. D. A response regulator on the cell membrane recognizes the change and transfers the information to a sensor kinase in the cytoplasm.

B. A sensor kinase on the cell membrane recognizes the change and transfers the information to a response regulator in the cytoplasm.

Many pharmaceutical drugs specifically inhibit transcription in Bacteria but not Archaea or Eukarya. Why would drugs that inhibit transcription only affect Bacteria and not Archaea even though they are both prokaryotes? A. Archaea lack operons. B. Archaea and Eukarya have very similar RNA polymerases that are different than bacterial RNA polymerases. C. Bacteria lack a nucleus. D. Archaea and Eukarya have very similar ribosomes that are different than bacterial ribosomes.

B. Archaea and Eukarya have very similar RNA polymerases that are different than bacterial RNA polymerases.

While examining a rock surface, you have discovered an interesting new organism. Which of the following criteria will allow you to classify the organism as belonging to Bacteria but not Archaea or Eukarya? A. The organism lacks a nucleus. B. Cell walls are made primarily of peptidoglycan. C. The lipids in its plasma membrane consist of glycerol bonded to isoprenoid side chains. D. It can survive at a temperature over 100°C.

B. Cell walls are made primarily of peptidoglycan.

Bacteria and Archaea are the only domains which A. can catalyze incorporation of inorganic nitrogen species into biomolecules. B. contain diazotrophs. C. can catalyze transformation of inorganic nitrogen species for biosynthesis. D. can assimilate nitrogen.

B. Contain diazotrophs

In which bacteria would you find MreB proteins and why? A. Mycoplasma pneumoniae, because it is pleomorphic B. E. coli, because it is rod-shaped. C. Staphylococcus aureus, because it is coccus-shaped D. Neisseria gonorrhea, because it is coccus-shaped

B. E. coli, because it is rod-shaped.

All of the following regarding endospores are true EXCEPT A. All endospore-forming bacteria are gram-positive Firmicutes. B. Endospores serve as reproductive structures and enable survival in harsh environments. C. Endospore formation begins when growth ceases due to the lack of an essential nutrient. D. Botulism, tetanus and several foodborne bacterial infections are caused by endospore-forming bacteria.

B. Endospores serve as reproductive structures and enable survival in harsh environments.

Due to the number of phosphate groups, ATP has approximately three times more energy stored than AMP, and ADP has approximately two-thirds the energy stored of ATP. A. True B. False

B. False

Which statement shows which adaptations are necessary for hyperthermophilic proteins to stay functional at temperatures above 80°C? A. Hyperthermophiles synthesize proteins with completely unique amino acid sequences to stabilize the proteins. B. Hyperthermophiles have increased ionic bonds to stabilize the proteins. C. Hyperthermophiles have highly hydrophilic interiors to stabilize the proteins. D. Hyperthermophiles have decreased ionic bonds to stabilize the proteins.

B. Hyperthermophiles have increased ionic bonds to stabilize the proteins.

Which is/are a function(s) of the cytoplasmic membrane in prokaryotes? A. It is an anchor for many proteins involved in bioenergetic reactions and transport. B. It serves as a permeability barrier, a docking station for proteins involved in bioenergetics reactions and transport, and a site for energy conservation. C. It functions as a permeability barrier. D. It is a major site of energy conservation.

B. It serves as a permeability barrier, a docking station for proteins involved in bioenergetics reactions and transport, and a site for energy conservation.

What does the minimum inhibitory concentration (MIC) of a chemical tell you? A. It tells you the lowest concentration of an organism that is needed for chemical control. B. It tells you the lowest concentration of the chemical that is needed to inhibit the growth of a specific microorganism. C. It tells you the lowest concentration of the chemical that is needed to kill a specific microorganism. D. It tells you the lowest concentration of the chemical that is needed to inhibit the growth of any microorganism.

B. It tells you the lowest concentration of the chemical that is needed to inhibit the growth of a specific microorganism.

Differences between mitochondrial and E. coli electron transport chains include the following: A. The electron transport chain does not involve membranes in E. coli. B. The E. coli ETC is branched, with growth phase affecting which branch is used. C. Higher values of ATP produced per NADH are observed in E. coli. D. The fundamental principles on which the electron transport chains operate are different. E. Mitochondrial and E. coli ETC are very similar. Submit

B. The E. coli ETC is branched, with growth phase affecting which branch is used.

If photosynthetic organisms were present when the earth was primarily anoxic, why was the development of cyanobacteria critical for the oxidation of the atmosphere? A. The early forms of photosynthesis were carried out in the water and there was no way for the oxygen to move into the atmosphere. B. The early forms of photosynthesis did not produce oxygen as a waste product. C. Cyanobacteria carry out anoxic photosynthesis. D. The early forms of photosynthesis did produce oxygen, but it was not enough to make a difference in the atmosphere.

B. The early forms of photosynthesis did not produce oxygen as a waste product.

What would be the most likely effect of a mutation in the operator of a lac operon? A. The repressor would not be produced. B. The genes would be constitutively expressed. C. Regulation would occur normally. D. Beta-galactosidase would not be produced.

B. The genes would be constitutively expressed.

In negative control of transcription by the lac operon, how does the presence of an inducer affect transcription? A. The inducer binds to the operator. B. The inducer prevents the repressor from binding to the operator. C. The inducer causes the repressor to bind to the operator. D. The inducer does not bind to the operator.

B. The inducer prevents the repressor from binding to the operator.

Which statement illustrates how prokaryotes determine where to begin translation so the correct protein is synthesized? A. The mRNA recognizes the correct start codon with the aid of a downstream ribosomal binding site. B. The rRNA recognizes the correct start codon with the aid of an upstream Shine-Dalgarno sequence. C. The rRNA recognizes the correct start codon with the aid of a downstream ribosomal binding site. D. The mRNA recognizes the correct start codon with the aid of an upstream ribosomal binding site.

B. The rRNA recognizes the correct start codon with the aid of an upstream Shine-Dalgarno sequence.

If two microbes were going to be considered for the same species, what criteria would apply? (Check all that apply) A. The two microbes must be found colonizing the same environment. B. The two microbes must have phenotypic similarity. C. The two microbes must be grown in pure culture. D. There must be less than 3% divergence in rRNA gene sequences between the two microbes. E. The two microbes must have at least 70% whole genome similarity, as determined by DNA-DNA hybridization.

B. The two microbes must have phenotypic similarity. D. There must be less than 3% divergence in rRNA gene sequences between the two microbes. E. The two microbes must have at least 70% whole genome similarity, as determined by DNA-DNA hybridization.

Which of the following statements is TRUE of disinfectants? A. They are used on living tissue. B. They are used on inanimate surfaces. C. They are used for sterilization. D. They are always effective in destroying endospores.

B. They are used on inanimate surfaces.

Regulation by induction and repression are called negative control because __________. A. Transcription proceeds in the presence of the repressor protein. B. Transcription proceeds in the absence of the repressor protein. C. Translation proceeds in the absence of the repressor protein. D. Translation proceeds in the presence of the repressor protein.

B. Transcription proceeds in the absence of the repressor protein.

All of the following statements regarding protein secretion are true EXCEPT A. Type III, IV and VI secretion systems require ATP. B. Type I, II and V secretion systems are Sec- or Tat-dependent. C. Types I through VI secretion systems specifically recognize substrates based on amino acid sequence. D. Type III, IV and VI secretion systems secrete molecules into another cell. E. Type IV secretion systems can transport DNA in addition to proteins

B. Type I, II and V secretion systems are Sec- or Tat-dependent.

In Archaea, some regulatory proteins that control transcription can act as repressors, activators, or both. How is this possible? A. The regulatory protein is only synthesized when it is needed to be an activator, not when repression is required. B. When acting as a repressor, the regulatory protein binds to a different DNA sequence than when it is acting as an activator. C. When acting as an activator, the regulatory protein has an inducer bound to its allosteric site; when acting as a repressor it has a corepressor bound to it. D. When acting as an activator, the regulatory protein always has an inducer bound to its allosteric site; as a repressor it does not.

B. When acting as a repressor, the regulatory protein binds to a different DNA sequence than when it is acting as an activator.

Which of the following examples describes a type of catabolite repression? A. A mutation in the promoter of the lac operon prevents the expression of the genes needed for the bacterium to utilize lactose. B. When glucose is present, the lac operon is inhibited. C. Allolactose binds to a repressor, preventing it from binding to the operator of the lac operon. D. The presence of abundant tryptophan inhibits the trp operon.

B. When glucose is present, the lac operon is inhibited.

One group of chemical mutagens includes the base analogs. How do these lead to mutations? A. They lead to the formation of pyrimidine dimers. B. When replication occurs, complementary base pairing may fail because the base analog may not be treated in the same way as the base that it replaced. C. Base analogs push apart and distort the double helix. This distortion can lead to insertions and deletions (including frameshift mutations). D. They lead to alkylation, which can lead to substitutions.

B. When replication occurs, complementary base pairing may fail because the base analog may not be treated in the same way as the base that it replaced.

The replisome is a large complex of proteins that contains many enzymes involved in DNA replication. Hypothesize why these enzymes do NOT function independently of each other. A. With the replisome, plasmids can be replicated along with the chromosome. B. With the replisome, it can replicate both strands of DNA at the same time. C. With the replisome, the strands of DNA can be copied individually. D. With the replisome, mRNA can be transcribed faster.

B. With the replisome, it can replicate both strands of DNA at the same time.

Which organism would likely harbor the MOST two-component regulatory systems? A. a parasitic bacterium living inside another organism B. a bacterium occupying a heterogeneous niche with high nutrient mixing C. an organism capable of quorum sensing D. an archaeon living in an extreme environment

B. a bacterium occupying a heterogeneous niche with high nutrient mixing

A microbial ecologist wants to study a bacterium that is adapted to growth in lake water containing very low nutrient concentrations. Assuming that a suitable growth medium is available for this organism, which type of culture would be best to use for growing this organism in the lab? A. a batch culture using a low-nutrient medium B. a chemostat using a low-nutrient medium C. This organism cannot be grown in the lab. D. on Petri plates containing a low-nutrient medium

B. a chemostat using a low-nutrient medium

Proofreading of newly-synthesized DNA is important because __________. A. any protein made from mutated DNA will not function properly B. a high fidelity in the copying of DNA is necessary for good heredity C. DNA pol III has a high error rate during replication D. the cell will invariably die if any mutations occur during replication

B. a high fidelity in the copying of DNA is necessary for good heredity

Which statement is the correct definition of polycistronic mRNA? A. multiple pieces of mRNA from a single operon B. a single piece of mRNA that contains the transcript for multiple genes. C. a single piece of mRNA from a single gene D. multiple mRNA molecules from the same gene in different organisms

B. a single piece of mRNA that contains the transcript for multiple genes.

The main functions of the bacterial cell wall include all EXCEPT the following __________. A. conferring a specific shape to the cell B. actively transporting solutes against the concentration gradient C. resisting cell lysis due to osmotic forces D. limiting cell size

B. actively transporting solutes against the concentration gradient

Of the choices, which would be more related to adaptations (rather than chemotaxis)? A. CheB-P is present in high concentrations B. an MCP is fully methylated C. CheB is not phosphorylated D. a cell is exhibiting mostly runs E. a cell is exhibiting mostly tumbles F. CheY is unable to bind to the flagellar motor G. an MCP is fully unmethylated

B. an MCP is fully methylated C. CheB is not phosphorylated E. a cell is exhibiting mostly tumbles G. an MCP is fully unmethylated

Archaea with a plasma membrane composed of a tetraether monolayer would most likely be found ______. A. at a pH of 2 B. at a temperature of 90oC C. in the soil D. in the mammalian gut E. in an anaerobic environment

B. at a temperature of 90oC

Type IV pili are involved in A. twitching motility and attachment of cells to surfaces. B. attachment to surfaces, twitching motility, and pathogenesis. C. twitching motility. D. pathogenesis. E. attachment of cells to surfaces.

B. attachment to surfaces, twitching motility, and pathogenesis.

Transcriptional control in Archaea most closely resembles that in ________ and utilizes ________. A. eukaryotes; regulatory proteins B. bacteria; regulatory proteins C. eukaryotes; transcription factors D. bacteria; transcription factors

B. bacteria; regulatory proteins

Bacterial cells must regulate chromosome replication such that the chromosome is completely replicated prior to cell division but also so that the cell does not make too many copies of the chromosome. DnaA facilitates replication when bound to DNA in the origin of replication in E. coli. Which of the following is NOT a form of regulation that inhibits initiation of another round of replication once the replication forks have been formed? A. binding of the SeqA protein to GATC sequences in the oriC region, blocking DnaA binding B. binding of ATP to DnaA, forming DnaA-ATP C. binding of SeqA proteins to the GATC sequence in the dnaA promoter, causing repression D. hemimethylation of adenine residues in the GATC sequences on the chromosome

B. binding of ATP to DnaA, forming DnaA-ATP

A nucleotide-altering chemical A. can cause double-stranded breaks in the DNA. B. can alter nitrogenous bases of DNA, resulting in incorrect base pairing. C. can slip in between stacked bases, causing bulges in the DNA structure. D. can generate free radicals, resulting in double-stranded breaks in the DNA. E. can be incorporated into the DNA, to cause a mispairing of bases.

B. can alter nitrogenous bases of DNA, resulting in incorrect base pairing.

Which of the following are likely autotrophic? A. chemolithotrophs and chemoorganotrophs B. chemolithotrophs and phototrophs C. phototrophs D. chemolithotrophs E. chemoorganotrophs and phototrophs

B. chemolithotrophs and phototrophs

The early energy reactions used hydrogen, which is a powerful ________ and could have been used to form ________. A. oxidant / the proton motive force B. electron donor / the proton motive force C. electron acceptor / oxygen D. oxidant / oxygen

B. electron donor / the proton motive force

Based on recent research, eukaryotic cells are believed to have arisen A. by mutations that led to changes in plasma membranes, leading to internal membrane-bound organelles. B. from a fusion of archaeal cells and bacterial cells. C. from the fusion of multiple archaeal cells into a larger, more complex cell. D. independently from prokaryotic cells by mutations that led to changes in plasma membranes, leading to internal membrane-bound organelles. E. independently from prokaryotic cells.

B. from a fusion of archaeal cells and bacterial cells.

Which metabolic cycle or pathway is LEAST likely to be needed during the biosynthesis of DNA? A. pentose phosphate pathway B. gluconeogenesis C. glycolysis D. citric acid cycle

B. gluconeogenesis

Quorum sensing is important in the regulation of all the following EXCEPT A. antibiotic production. B. heat shock proteins. C. virulence. D. bioluminescence. E. biofilm production.

B. heat shock proteins.

If autophosphorylation of CheA protein does NOT occur, then E. coli cells must be A. rotating flagella clockwise and tumbling. B. in a gradient of a chemoattractant. C. in a gradient of a repellant. D. rotating flagella clockwise. E. tumbling.

B. in a gradient of a chemoattractant.

When water activity is low, an organism must A. decrease its external solute concentration. B. increase its internal solute concentration. C. increase its external solute concentration. D. decrease its internal solute concentration.

B. increase its internal solute concentration.

Initiation of biofilm formation in many organisms is at least in part regulated by c-di-GMP, which alters gene expression and enzyme activity leading to all of the following EXCEPT __________. A. initiation of extracellular polysaccharide production B. initiation of flagella formation C. formation of cell surface attachment proteins D. production of intercellular signaling molecules

B. initiation of flagella formation

Your laboratory supervisor has given you a plastic petri dish filled with soil to sterilize using radiation. What type of radiation will you use? A. solar radiation B. ionizing radiation C. UV radiation D. microwave radiation

B. ionizing radiation

Integration of linear transforming DNA into the chromosome A. is not required for the expression for the transformed genes. B. is catalyzed by the RecA gene. C. almost never occurs because restriction endonuclease will degrade the DNA before it is integrated. D. only occurs in laboratory-based systems in artificial competent cells.

B. is catalyzed by the RecA gene.

Which of the following events signals the end of the initiation phase of bacterial transcription? A. formation of the first phosphodiester bond between the first two nucleotides of the mRNA B. loss of the sigma factor from the RNA polymerase C. binding of RNA polymerase to the promoter D. unwinding of the DNA

B. loss of the sigma factor from the RNA polymerase

How is the activity of a riboswitch controlled? A. repressor binding can change its structure B. metabolite binding can change its structure C. small RNA complementary binding disrupts its function D. sigma factor binding alters its structure E. by other riboswitches

B. metabolite binding can change its structure

The addition of thioglycolate into a growth medium would LEAST support the growth of a(n) A. obligate anaerobe. B. microaerophilic aerobe. C. facultative aerobe. D. aerotolerant anaerobe.

B. microaerophilic aerobe.

A strategy used by T4 bacteriophage to control transcription by host cell RNA polymerase is __________. A. degradation of host cell polymerase B. modification of RNA polymerase to recognize only virus-encoded promoters C. modification of the internal cell environment D. modification of the promoter regions of host cell genes E. denaturation of host RNA polymerase

B. modification of RNA polymerase to recognize only virus-encoded promoters

Cyclic dimeric guanosine monophosphate (c-di-GMP) serves as a messenger molecule in bacterial cells to coordinate a shift from ________ to ________ growth. A. sessile / planktonic B. planktonic / sessile C. stationary / exponential D. monomorphic / polymorphic

B. planktonic / sessile

Chemotaxis by Pseudomonas aeruginosa requires regulation of macromolecules in response to signals. Protein regulation is very important and can be grouped into two categories: those that are based on protein activity and those that are based on the amount of protein present. Based on the information in the chapter, select the type of regulation described that does NOT affect the amount of protein present. A. catabolite repression B. post-translational modification C. regulation of transcription D. regulating amount of mRNA made E. small RNA (sRNA) regulation F. controlling whether mRNA is translated G. attenuation

B. post-translational modification

Diazotrophs maximize nitrogenase activity by A. producing specialized structures to protect nitrogenase from oxygen. B. producing specialized structures or fixing N2 at times when oxygen is absent to protect nitrogenase from oxygen. C. fixing N2 at times when oxygen is absent or in low concentrations. D. closely coupling N2 fixation with high rates of photosynthesis.

B. producing specialized structures or fixing N2 at times when oxygen is absent to protect nitrogenase from oxygen.

Which of the following activities is a result of cyclic di-guanosine monophosphate synthesis? Select all that apply. A. synthesis of flagella B. reduction in activity of flagellar motor C. transition from planktonic to sessile growth during biofilm formation D. biosynthesis of extracellular matrix during biofilm formation E. transition from sessile to planktonic growth during biofilm dispersal

B. reduction in activity of flagellar motor C. transition from planktonic to sessile growth during biofilm formation D. biosynthesis of extracellular matrix during biofilm formation

Metagenomics involves the analysis of a microbial community by __________. A. sequencing all of the community RNA in an environment B. sampling and sequencing all of the genes in an environment C. generating a phylogenetic tree based on all of the versions of a gene in an environment D. generating a complete sequence of the genomes of all of the organisms in an environment

B. sampling and sequencing all of the genes in an environment

The number of colonies obtained in a plate count does NOT depend on the A. incubation time. B. size of the colonies. C. type of culture medium. D. inoculum volume.

B. size of the colonies.

An organism of the genus Staphylococcus is ________, while an organism of the genus Spirochaeta is ________. A. spherical / rod shaped B. spherical / spiral C. rod shaped / spiral D. spiral / spherical

B. spherical / spiral

The process of synthesizing proteins involves translating one "language," nucleic acid sequences, into another "language," amino acid sequences. The cellular component that does the actual translating from codons to amino acids is the __________. A. RNA polymerase B. tRNA C. mRNA D. rRNA

B. tRNA

Which of the following choices can indicate horizontal gene transfer? A. the presence of gene duplications B. the presence of genes that encode proteins typically found only in distantly related species C. the location of genes in different operons than found in closely related bacteria D. the presence of regulatory gene segments

B. the presence of genes that encode proteins typically found only in distantly related species

Transport proteins (transporters) require energy expenditure for each molecule of substrate transported. The reason for this energy requirement is __________. A. the conformational shape of the solute must be changed during transport B. the solute must be transported against a concentration gradient C. the solute must be chemically altered D. the solute must be forced through the hydrophobic membrane

B. the solute must be transported against a concentration gradient

Referring to attenuation in the regulation of the tryptophan operon, when there are high levels of tryptophan available to the organism, ____. A. tryptophan inactivates the repressor protein B. transcriptional termination is likely when ribosomes pause at the end of the leader peptide C. transcriptional termination is likely when ribosomes stall at a tryptophan codon D. amino acids will bind to the tryptophan riboswitch and turn it off E. the tryptophan operon is being transcribed at relatively high levels

B. transcriptional termination is likely when ribosomes pause at the end of the leader peptide

Which of the following is the correct abbreviation for a mutation in a gene that synthesizes one of the enzymes involved in tryptophan production? A. TrpC (italicized) B. trpC1 (italicized) C. trp D. Trp-

B. trpC1 (italicized)

You are examining an enzyme associated with cysteine biosynthesis. You would expect expression of this enzyme to be A. under posiitve control by induction. B. under negative control by repression. C. under positive control. D. under negative control by induction. E. induced by cysteine.

B. under negative control by repression.

One alternative to autoclaving for sterilization of liquids is filtration. Imagine that you are using a filter to sterilize a drug solution. You use a filter with a 0.22 micron pore size. Which of the following microbes will effectively be removed by this filter? A. small viruses B. yeast C. bacteria such as E. coli D. fungi

B. yeast C. bacteria such as E. coli D. fungi

All of the following indicate a way in which viruses differ from living organisms except A. Viruses have DNA or RNA, not both B.Viruses are obligate parasites and no living organisms are obligate parasites. C. Viruses are acellular and all living things are made up of cells D. Viruses depend on their host to synthesize the essential components of new viruses (e.g., genetic material and proteins), while living organisms are capable of synthesizing these components even if they require a host for food, shelter, or other necessities.

B.Viruses are obligate parasites and no living organisms are obligate parasites.

Which of the following is FALSE regarding the pentose phosphate pathway? A. It is an amphibolic pathway. B. It produces NADPH for biosynthesis. C. It synthesizes sugars from non-carbohydrate precursors. D. It is a major pathway for pentose production. E. It produces important precursor metabolites such as ribose-5-phosphate.

C. It synthesizes sugars from non-carbohydrate precursors.

Which of the following is false regarding both DNA and RNA synthesis? The template strand is complementary to the newly synthesized strand.DNA is the template for both DNA and RNA synthesis.The overall direction of chain growth is from the 5' to 3' end.The template strand is antiparallel to the newly synthesized strand.Both processes require an RNA primer to begin.

Both processes require an RNA primer to begin.

Which of the following regarding DNA and RNA synthesis is FALSE? The template strand is antiparallel to the newly synthesized strand.DNA is the template for both DNA and RNA synthesis.Both processes require an RNA primer to begin.The template strand is complementary to the newly synthesized strand. The overall direction of chain growth is from the 5' to 3' end.

Both processes require an RNA primer to begin.

Protein Synthesis & Processing Participation Quiz Answers The three stages of translation, initiation, elongation, and termination, _____. all require at least one protein factor and all require ATP all require base pairing between two RNAs all require at least one protein factor and all require GTP all require at least one protein factor all require ATP To add a single amino acid to a growing polypeptide chain, a grand total of ________ molecules of ATP or GTP are utilized. three two six four All of the following are true regarding prokaryotic protein secretion EXCEPT Sec and Tat pathways both are fueled by ATP hydrolysis. Proteins are inserted into the cell membrane by co-translational Sec secretion. The basic information for locating a protein in the right place is contained within its sequence. Some gram-negative secretion systems do not require Sec or Tat. Proteins with complex cofactors, such as iron-sulfur proteins, are Tat secreted.

C A A

Proteomic analysis of a microbial community indicated an abundance of phycobiliproteins. Which phototrophic group is likely active and abundant in this community? A. prochlorophytes B. eukaryotic phototrophs C cyanobacteria D. green bacteria

C cyanobacteria

Which of the following features are common to transformation, transduction, and conjugation? (1) unidirectional transfer of genes (2) incomplete gene transfer (3) homologous recombination (4) meiosis occurring in the recipient A. 1, 2 B. 1, 2, 4 C. 1, 2, 3 D. 3, 4

C. 1, 2, 3

All of the following are characteristic of suppressor mutations EXCEPT A. A mutation elsewhere in same gene restores function. B. Mutation in another gene produces an enzyme that replaces the mutated one. C. A mutation at same site as the original mutation restores function. D. Mutation in another gene restores the function of the original mutated gene. E. All of the items are characteristic of suppressor mutations.

C. A mutation at same site as the original mutation restores function.

______________ is the coupling protein that associates with MCP.

CheW

What is the benefit, for a virus, to be a temperate or lysogenic virus? A. A single infection event can produce hundreds of new viral particles. B. A single infection event can allow the virus to live in the host cell indefinitely. C. A single infection event can produce millions of new viral particles instead of hundreds of viral particles. D. A single infection even can allow other host cells to be infected by the same virus.

C. A single infection event can produce millions of new viral particles instead of hundreds of viral particles.

Although the archaellum is distinct from the bacterial flagellum, researchers believe that it is an example of divergent evolution and related to the type IV pilus of bacteria. What are some similarities and differences between archaella and the bacterial type IV pilus? Select all that apply. A. Archaella are powered directly by ATP, but bacterial type IV pili are powered by a proton motive force. B. Archaella and type IV pili are both important in attachment to host tissues. C. Archaella and type IV pili have genetic similarities revealed by genomic studies. D. Archaella and type IV pili both act by rotating. E. Archaella are important for swimming motility, while type IV pili are important in twitching motility.

C. Archaella and type IV pili have genetic similarities revealed by genomic studies. E. Archaella are important for swimming motility, while type IV pili are important in twitching motility.

All of the following are required for homologous recombination EXCEPT A. Long regions of sequence homology B. RecA C. Att site D. Endonuclease E. All of these are required for homologous recombination.

C. Att site

An example of a free-living nitrogen-fixing bacterium that is NOT a cyanobacterium is __________. A. Nostoc B Nitrobacter C. Azotobacter D. Rhizobium E. Treponema

C. Azotobacter

Which of the following is false regarding both DNA and RNA synthesis? A. The template strand is complementary to the newly synthesized strand. B. The overall direction of chain growth is from the 5' to 3' end. C. Both processes require an RNA primer to begin. D. DNA is the template for both DNA and RNA synthesis. E. The template strand is antiparallel to the newly synthesized strand.

C. Both processes require an RNA primer to begin.

Phosphorylation of ________ regulates which direction a flagellum rotates, thus controlling whether an organism runs or tumbles. A. CheAW B. CheB C. CheY D. CheZ

C. CheY

What is the difference between a coenzyme and a prosthetic group? A. Coenzymes are essential for an enzymes function and prosthetic groups only enhance its reaction rate. B. Coenzymes require additional ions to bind to enzymes but prosthetic groups are able to directly interact with enzymes. C. Coenzymes are weakly bound whereas prosthetic groups are strongly bound to their respective enzymes. D. Coenzymes are organic cofactors and prosthetic groups are inorganic cofactors.

C. Coenzymes are weakly bound whereas prosthetic groups are strongly bound to their respective enzymes.

During DNA replication, which of the following enzymes removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments? A. ligase B. primase C. DNA polymerase I D. helicase E. DNA polymerase III

C. DNA polymerase I

What cellular component is NOT a molecular chaperone? A. GroEL B. GroES C. DnaA D. DnaK E. DnaJ

C. DnaA

T4 genes are transcribed by host RNA polymerase, yet the transcription of T4 genes is carefully controlled so that groups of T4 genes are transcribed at specific times after infection. How is this accomplished? A. Each group of T4 genes has a different promoter that indicates that order in which they should be transcribed in based on the affinity of the promoter for the host RNA polymerase. B. Early T4 genes encode proteolytic enzymes that destroy the host RNA polymerase. Subsequently a viral polymerase is created that transcribes the middle and late genes in the correct order. C. Early and middle T4 genes encode proteins that modify the activity of sigma factors and host RNA polymerase to regulate the expression of T4 genes. D. Rolling circle replication of the viral genome ensures that the genes are available for transcription in the correct order.

C. Early and middle T4 genes encode proteins that modify the activity of sigma factors and host RNA polymerase to regulate the expression of T4 genes.

Consider the following experiment. First, large populations of two mutant strains of Escherichia coli are mixed, each requiring a different, single amino acid. After plating them onto a minimal medium, 45 colonies grew. Which of the following may explain this result? A. The colonies may be due to back mutation (reversion). B. The colonies may be due to recombination. C. Either A or B is possible. D. Neither A nor B is possible.

C. Either A or B is possible.

Which statement about endotoxins is true? A. Endotoxins are components of the cell wall of gram-positive bacteria. B. The source of endotoxins is endospores. C. Endotoxins are released only when Gram negative bacteria die and their cell walls break down. D. Endotoxins are released by lysozyme. E. Endotoxins are proteins secreted by prokaryotes.

C. Endotoxins are released only when Gram negative bacteria die and their cell walls break down.

How is generalized transduction different from specialized transduction? A. Generalized transduction is initiated by a lysogenic bacteriophage; specialized transduction is initiated by a lytic phage. B. Specialized transduction uses animal viruses instead of bacteriophage. C. Generalized transduction is initiated during lytic cycle of a virulent bacteriophage; specialized transduction is initiated during the lysogenic cycle of a temperate bacteriophage. D. Only one specific host gene is transferred in both specialized transduction and generalized transduction.

C. Generalized transduction is initiated during lytic cycle of a virulent bacteriophage; specialized transduction is initiated during the lysogenic cycle of a temperate bacteriophage.

Which of the following describes the essential parts of all viruses? A. Genetic material (RNA or DNA), a protein capsid, and an envelope B. Genetic material (RNA and DNA) and a protein capsid C. Genetic material (RNA or DNA) and a protein capsid D. Genetic material (RNA or DNA), a protein capsid, an envelope, and enzymes

C. Genetic material (RNA or DNA) and a protein capsid

Which of the following statements regarding LUCA is FALSE? A. LUCA is the ancestor of archaea and bacteria. B. LUCA fixed carbon and nitrogen. C. LUCA was the first form of life. D. None of the statements are false. E. LUCA was likely a hyperthermophile living at hydrothermal vents.

C. LUCA was the first form of life.

All of the following are functions of Cas proteins EXCEPT A. Process pre-CRISPR RNA B. Integrate new spacers into the CRISPR gene C. None of the functions are incorrect D. Use RNA transcribed from segments of foreign DNA to recognize and destroy foreign DNA E. Stop viral attacks before they can take over the cell

C. None of the functions are incorrect

Since glucose, a hexose, is the major source of energy for most prokaryotes, why would they need to have pentose sugars available? A. Pentose sugars are needed for protein synthesis. B. Pentose sugars are needed for membrane synthesis. C. Pentose sugars are needed for nucleic acid synthesis. D. Pentose sugars are needed for transport processes.

C. Pentose sugars are needed for nucleic acid synthesis.

The number of organisms in a broth culture was determined using the standard plate count method (SPC) and spectrophotometry (SPEC). Which of the results below would you expect to see from each method? A. SPC = 100 cfu/ml; SPEC = 10 cfu/ml B. SPC = 12 × 10^6 cfu/ml; SPEC = 12 × 10^6 cfu/ml C. SPC = 12 × 10^6 cfu/ml; SPEC = 11 × 10^7 cfu/ml D. SPC = 12 × 10^7 cfu/ml; SPEC = 11 × 10^3 cfu/ml

C. SPC = 12 × 106 cfu/ml; SPEC = 11 × 107 cfu/ml

Which statement best explains why positively controlled genes have weak promoters and need an activator protein to help the RNA polymerase bind? A. So translation only stops when the substrate for the gene product is present. B. So translation only occurs when the substrate for the gene product is present. C. So transcription occurs only when the substrate for the gene product is present. D. So transcription stops when the substrate for the gene product is present.

C. So transcription occurs only when the substrate for the gene product is present.

Consider solution A (pH 6) and solution B (pH 9). Which of the following statements is CORRECT? A. Solution B is 3,000 times more alkaline (basic) than solution A B. Solution A is 3 times more acidic than solution B C. Solution B is 1,000 times more alkaline (basic) than solution D. Solution A is 300 times more acidic than solution B

C. Solution B is 1,000 times more alkaline (basic) than solution

Gliding motility in bacteria involves which of the following? A. Specialized cell-surface proteins B. Slimy polysaccharides C. Specialized cell-surface proteins and slimy polysaccharides D. Specialized cell-surface proteins, flagella, and slimy polysaccharides E. Flagella

C. Specialized cell-surface proteins and slimy polysaccharides

Which statement is TRUE regarding protein synthesis? A. Messenger RNA catalyzes peptide bond formation in the growing polypeptide chain. B. Transfer RNAs catalyze peptide bond formation in the growing polypeptide chain. C. The 23S rRNA catalyzes peptide bond formation in the growing polypeptide chain. D. Ribosomal proteins catalyze peptide bond formation in the growing polypeptide chain.

C. The 23S rRNA catalyzes peptide bond formation in the growing polypeptide chain.

The preferred method of sterilization during drug production is heat. Heat sterilization can occur in two forms: moist or dry. Autoclaving is the most commonly used application of moist heat for sterilization. Which of the following statements about autoclaving is true? A. When autoclaving solid items, they should be wrapped in foil to help maintain sterility. B. Autoclaving is preferred over dry heat because it can effectively be used to sterilize a wide variety of items, including liquids, powders, metal instruments, and glassware. C. The effectiveness of an autoclave is dependent on an increase in pressure and corresponding increase in temperature. D. Autoclaving requires extensive exposure times in order to achieve sterilization.

C. The effectiveness of an autoclave is dependent on an increase in pressure and corresponding increase in temperature.

A single base substitution happens to cause a nonsense mutation early in the gene for a protein. What will be the result? A. The protein will be truncated a great deal, but is likely to function normally. B. The protein will be truncated a small amount, but is unlikely to function normally. C. The protein will be truncated so much that it is unlikely to function normally. D. The protein will be truncated a small amount, but is likely to function normally.

C. The protein will be truncated so much that it is unlikely to function normally.

Explain why the presence of a capsule or slime layer would benefit a bacterial cell. A. These outer layers can help the immune system recognize foreign organisms. B. These outer layers can prevent added virulence during a bacterial infection. C. These outer layers can aid in attachment to solid surfaces. D. These outer layers prevent water from entering the cell, causing rapid dehydration.

C. These outer layers can aid in attachment to solid surfaces.

One type of archaeon, Haloquadratum walsbyi, is shaped like a postage stamp with dimensions of 2 µm x 3 µm x 0.25 µm. What likely advantage would this shape provide? A. This shape is more conducive to the formation of biofilm communities. B. This shape is difficult for phagocytic cells to attach to and engulf. C. This shape increases the surface to volume ratio enabling more efficient nutrient uptake. D. This shape enables this bacteria to float on surfaces and obtain better light exposure.

C. This shape increases the surface to volume ratio enabling more efficient nutrient uptake.

Which of the following regarding Archaeal gene expression is false? A. Archaeal RNA polymerase resembles a eukaryotic RNA polymerase. B. Archaeal molecular properties resemble those of eukaryotes more than Bacteria. C. Transcription initiation involves alternate sigma factors. D. Some Archaeal genes are organized into operons.

C. Transcription initiation involves alternate sigma factors.

Which of the following is true about viral infection? A. Viruses have what is needed to infect a host cell; they do not need anything specific from the host cell in order to cause infection and therefore can infect a wide range of cells. B. Viruses can infect any cell in a particular species; it does not matter which tissue they infect as long as the species (or group of similar species) is correct. C. Viruses are very specific in which cells they infect. For a virus to be taken up by a cell, it must find a cell with appropriate receptors on the surface. It cannot be taken up by cells without the appropriate receptors. D. Viruses can infect any cells within a large group, but they are not more specific than that. For example, there are plant viruses that can affect many types of plants, bacteriophages that affect many types of bacteria, and animal viruses that affect a range of viruses.

C. Viruses are very specific in which cells they infect. For a virus to be taken up by a cell, it must find a cell with appropriate receptors on the surface. It cannot be taken up by cells without the appropriate receptors.

One way that regulation is often studied is by examining the effects of mutations. For example, mutations within the parts of the lac operon have been well studied. Which of these mutants would be considered a constitutive mutant? A. a mutation in the gene for beta-galactosidase permease B. a mutation that disables the promoter for the operon C. a mutation that disables the repressor D. a mutation in the gene for beta-galactosidase

C. a mutation that disables the repressor

A point mutation refers to mutations involving A. the gain of a base pair (microinsertion). B. a base-pair substitution. C. a substitution, deletion, or addition of one base-pair. D. the deletion of a base pair (microdeletion).

C. a substitution, deletion, or addition of one base-pair.

The function of NAD+/NADH in the cell is best described as __________. A. a way to transport electrons to the mitochondria for energy generation in bacteria B. a way to increase the types of redox reactions that occur in the cell by acting as an intermediary between similar compounds C. a way to increase the types of redox reactions that occur in the cell by acting as an intermediary between dissimilar compounds D. a way to transport protons to the plasma membrane for energy generation in bacteria

C. a way to increase the types of redox reactions that occur in the cell by acting as an intermediary between dissimilar compounds

The three stages of translation, initiation, elongation, and termination, __________. A. all require at least one protein cofactor and base pairing between two RNAs B. all require base pairing between two RNAs C. all require at least one protein cofactor and all require GTP D. all require ATP E. all require at least one protein cofactor and all require ATP

C. all require at least one protein cofactor and all require GTP

Diglycerol tetraether lipids A. form typical bilayer membranes. B. are found in some bacteria and some Archaea. C. are a characteristic feature of thermophilic Archaea. D. tend to make the membrane less rigid. E. All of the choices are correct.

C. are a characteristic feature of thermophilic Archaea.

Type IV pili are involved in A. twitching motility and attachment of cells to surfaces. B. attachment of cells to surfaces. C. attachment to surfaces, twitching motility, and pathogenesis. D. pathogenesis. E. twitching motility.

C. attachment to surfaces, twitching motility, and pathogenesis.

The enzyme lysozyme kills bacterial cells by cleaving the beta 1,4-glycosidic bonds in the peptidoglycan. This leads to which of the following? A. lysis of the cell due to the same mechanism used by penicillin B. out of control cell growth C. breaches of the cell wall and cell lysis due to osmotic swelling D. the inability of the cell to grow and divide

C. breaches of the cell wall and cell lysis due to osmotic swelling

Microorganisms play key roles in the cycling of important nutrients in plant nutrition, particularly those of A. carbon and nitrogen B. nitrogen. C. carbon, nitrogen, sulfur, and phosphorus. D. sulfur. E. carbon.

C. carbon, nitrogen, sulfur, and phosphorus.

The only organisms that perform photosynthesis are ones that produce some form of A. carotenoids. B. phycocyanin. C. chlorophyll or bacteriochlorophyll. D. phycoerythrin.

C. chlorophyll or bacteriochlorophyll.

Most of the carbon in amino acid biosynthesis comes from A. glycolysis products. B. glycolysis intermediates and products. C. citric acid cycle intermediates and glycolysis products. D. citric acid cycle intermediates.

C. citric acid cycle intermediates and glycolysis products.

A mutation in the gene encoding the lactose repressor (lacI) that prevents lactose from binding to the LacI protein would result in A. constant expression of the lac operon in the absence of lactose. B. constant expression of the lac operon in the presence of lactose. C. constant repression of the lac operon in the presence of lactose. D. constant repression of the lac operon in the absence of lactose.

C. constant repression of the lac operon in the presence of lactose.

Which of the following proteins is mismatched with its eukaryotic homologue? A. MreB - actin B. FtsZ - tubulin C. crescentin - tubulin D. FtsA - actin

C. crescentin - tubulin

Which choice illustrates best what occurs in the stationary phase of bacterial growth? A. balanced growth, where the number of dead cells equals the number of new cells B. unbalanced growth, where the number of dead cells increases while the number of new cells decreases C. cryptic growth, where the number of new cells equals the number of dying cells D. cryptic growth, where the number of dead cells decreases while the number of new cells increases

C. cryptic growth, where the number of new cells equals the number of dying cells

All of the following are TRUE statements concerning binary fission of microbial cells EXCEPT A. elongation of the cell occurs and the chromosomes are pushed apart. B. the chromosome of the cell is replicated. C. daughter cells produced can be of different sizes. D. a septum is formed across the midline of the cell.

C. daughter cells produced can be of different sizes.

Improperly functioning acyl carrier proteins (ACPs) would likely result in A. a physiological shift to anaerobic metabolism where an energized membrane is less important for energy production. B. enhanced growth of a bacterium due to faster growth substrate uptake by a weakened membrane. C. death for a bacterium due to poor lipid bilayer integrity. D. no harm to bacteria, because only archaeons and eukaryotes use ACPs for fatty acid biosynthesis.

C. death for a bacterium due to poor lipid bilayer integrity.

Optical density and viable cell concentration are LEAST proportional to each other during the A. exponential growth phase. B. lag phase. C. death phase. D. stationary phase.

C. death phase.

Relative to enzymes in mesophilic microorganisms, which of the following is NOT characteristic of enzymes in psychrophiles? A. less hydrogen bonds B. decreased beta sheets C. decreased alpha helices D. less ionic bonds

C. decreased alpha helices

What genome composition makes viruses most susceptible to destruction by prokaryotic restriction endonucleases? A. dsRNA B. all DNA genomes are equally susceptible C. dsDNA D. ssDNA E. all of these genomes are equally susceptible

C. dsDNA

Endospores represent a challenge to the fields of industrial and medical microbiology because A. they are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive. B. endospores are significantly smaller than vegetative cells. C. endospores are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive, and endospore-forming organisms are often dangerous pathogens. D. endospores are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive, endospore-forming organisms are often dangerous pathogens, and endospores are significantly smaller than vegetative cells. E. endospore-forming organisms are often dangerous pathogens.

C. endospores are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive, and endospore-forming organisms are often dangerous pathogens.

Hydrolysis of energy rich compounds provides energy for endergonic reactions. All of the following are energy-rich compounds except A. succinyl-CoA B. ADP C. glucose-6-phosphate D. phosphoenolpyruvate E. acetyl-coA

C. glucose-6-phosphate

In which group of microorganisms would the Calvin cycle LEAST likely be found? A. anoxygenic Bacteria B. chemolithotrophic Bacteria C. green Bacteria D. Archaea E. cyanobacteria

C. green Bacteria

Organic micronutrients are commonly called __________. A. trace metals B. trace elements C. growth factors D. growth elements

C. growth factors

Which type of organism will grow in low water activity but grows best at high water activity? A. extreme halophile B. osmophile C. halotolerant D. halophile E. alkaliphile

C. halotolerant

When you see a publication describing an enzyme from Candidatus Pseudomonas utahensis you can infer that this organism (select all that apply) A. is described in Bergey's Manual of Systematic Bacteriology. B. has been deposited in a culture collection. C. has not been grown in pure culture. D. has been grown in pure culture. E. has not been formally recognized as a species.

C. has not been grown in pure culture. E. has not been formally recognized as a species.

Most prokaryotic cells reside A. in lakes, rivers, and oceans. B. on Earth's surface. C. in the oceanic and terrestrial subsurfaces. D. in and on nonprokaryotic organisms (including humans and other animals).

C. in the oceanic and terrestrial subsurfaces.

The synthesis of β-galactosidase is regulated by __________. A. repression B. induction C. induction and catabolite repression D. catabolite repression

C. induction and catabolite repression

In a batch culture, bacterial cultures typically exhibit four different phases of growth. In which phase are the cells rapidly synthesizing proteins, but cell numbers are not changing? A. exponential phase B. death phase C. lag phase D. stationary phase

C. lag phase

Which of the following habitats is home to the largest percentage of prokaryotic biomass on Earth? A. oceans B. surface soils C. marine subsurface D. freshwater E. terrestrial subsurface

C. marine subsurface

Like all forms of life on Earth, all microbial cells perform three major types of activities: __________. A. growth, genetic exchange, and evolution B. metabolism, growth, and genetic exchange C. metabolism, growth, and evolution D. growth, differentiation, and metabolism

C. metabolism, growth, and evolution

The largest mass of living material on Earth comes from A. animals. B. plants and animals together. C. microorganisms. D. plants.

C. microorganisms.

You have discovered a new coccoid-shaped microorganism with no nucleus, a rigid cell wall, and a diameter of 2 µm. Chemical tests reveal that its cell wall does NOT contain peptidoglycan. The new microorganism is A. most likely a eukaryote. B. either a bacterium or an archaeon. C. most likely an archaeon. D. most likely a bacterium.

C. most likely an archaeon.

The addition of two bases to the genome of a prokaryote would be most damaging if located __________. A. at the very end of the coding region of a protein B. anywhere within the coding region of a protein C. near the beginning of the coding region of a protein D. in the middle of the coding region of a protein

C. near the beginning of the coding region of a protein

Bacteria can survive the presence of antibiotics through a variety of mechanisms. Which of the following would NOT be a genetically inherited form of antibiotic resistance? A. efflux pumping B. enzymatic inactivation of the antibiotic C. persistence D. modification of the antibiotic target

C. persistence

A student has a pure culture of bacteria growing in a flask and wants to know how many living cells are in the culture at a given time. Which method should she employ to get an estimate? A. Any of these methods would work equally well in this case, assuming that standard curves are produced. B. turbidity measurements C. plate counts D. microscopic counts

C. plate counts

Viral proteins are categorized as early, middle, and late. Early proteins typically are necessary for A. packaging of DNA into the nucleocapsid. B. copying the viral genome. C. production of viral mRNA and copying the viral genome. D. production of viral mRNA.

C. production of viral mRNA and copying the viral genome.

A microbe growing in a refrigerator is likely A. hyperthermophilic. B. mesophilic. C. psychrotolerant or psychrophilic. D. psychrophilic.

C. psychrotolerant or psychrophilic.

The Ames test is based on __________. A. frequency of lethal mutations B. recombination frequency of the wild-type strain C. reversion rates of an auxotroph D. mutation rates of wild-type strains

C. reversion rates of an auxotroph

Peptide bond formation is catalyzed by __________ and occurs between the __________ sites of the ribosome. A. ribosomal proteins; P and E sites B. ribosomal proteins; A and P sites C. ribosomal RNA (rRNA); A and P sites D. ribosomal RNA (rRNA); P and E sites

C. ribosomal RNA (rRNA); A and P sites

Termination of RNA synthesis is ultimately determined by A. exhaustion of RNA polymerase activity. B. terminases. C. specific nucleotide sequences on the template strand. D. special protein factors.

C. specific nucleotide sequences on the template strand.

The prokaryotic transport system that involves a substrate-binding protein, a membrane-integrated transporter, and an ATP-hydrolyzing protein is A. simple transport. B. group translocation. C. the ABC transport system. D. symport.

C. the ABC transport system.

The presence of the F plasmid in a cell alters all the following properties of a cell EXCEPT __________. A. the ability to create Hfr strains B. the ability to mobilize DNA for transfer C. the ability to replicate DNA D. the ability to generate a pilus E. alteration of cell surface receptors so the cell cannot act as a recipient in conjugation.

C. the ability to replicate DNA

Bioremediation is _____. A. the use of prokaryotes in producing transgenic organisms B. the use of prokaryotes in producing pharmaceutical products C. the use of organisms to remove pollutants from the environment D. the modification of prokaryotes for industrial purposes E. the use of biological processes to remedy diseases

C. the use of organisms to remove pollutants from the environment

The promoters of positively controlled operons require activator proteins because A. they are needed to bind to the allosteric site of RNA polymerase. B. they are required to inactivate the repressor proteins. C. they have nucleotide sequences which are not close matches to the consensus sequence and thus bind RNA polymerase weakly. D. RNA polymerase easily recognizes the consensus sequence.

C. they have nucleotide sequences which are not close matches to the consensus sequence and thus bind RNA polymerase weakly.

In E. coli, the consensus sequence for the Pribnow box (the -10 sequence) is TATAAT. Therefore, __________. A. TATACT will be a very weak -10 promoter sequence B. the sigma factor will only recognize this -10 sequence C. this will be the strongest -10 promoter sequence D. this sequence will always be transcribed into RNA

C. this will be the strongest -10 promoter sequence

Which of the following is NOT a function of the pentose phosphate pathway? A. to produce a precursor for aromatic amino acids B. to produce precursors for nucleic acid synthesis C. to produce additional ATP D. to provide a source of NADPH

C. to produce additional ATP

Most riboswitches control A. tRNA synthesis. B. transcription. C. translation. D. ribosome synthesis.

C. translation.

___________ undergoes autophosphorylation at a higher rate when the attractant concentration decreases.

CheA

____________ is the sensor kinase that associates with MCP.

CheA

____________ contributes a phosphate to ___________, which determines the direction of movement of the flagellum.

CheA-P/ CheY

All of the following are true of natural competence EXCEPT Competence is induced during certain growth phases.Competence requires special DNA uptake, DNA binding, and integration proteins.Competence rarely occurs with high efficiency in nature.Competence is required for transformation.Competence occurs with high efficiency in E coli.

Competence occurs with high efficiency in E coli.

Explain how small RNA (sRNA) molecules can regulate translation of a piece of mRNA. A. sRNAs can decrease degradation rate of mRNA. B. sRNAs can base pair to mRNA and block translation. C. sRNAs can increase degradation rate of mRNA. D. All of the listed responses are correct. E. sRNAs can change the secondary structure of mRNA.

D. All of the listed responses are correct.

Explain how small RNA (sRNA) molecules can regulate translation of a piece of mRNA. A. sRNAs can increase degradation rate of mRNA. B. sRNAs can change the secondary structure of mRNA. C. sRNAs can base pair to mRNA and block translation. D. All of the listed responses are correct. E. sRNAs can decrease degradation rate of mRNA.

D. All of the listed responses are correct.

Fts proteins are essential for bacterial cell division because they __________. A. are involved in peptidoglycan synthesis B. are involved in the forming of the divisome C. are involved in the pulling apart the two copies of the chromosome D. All of the listed responses are correct.

D. All of the listed responses are correct.

Scientists believe life may have begun as an RNA world because __________. A. RNA can have catalytic activity B. RNA can bind small molecules C. RNA is essential to processes found in all cells D. All of the listed responses are correct.

D. All of the listed responses are correct.

Which of these statements is/are TRUE? A. Nonphototrophic organisms are able to grow at higher temperatures than phototrophic organisms. B. The most thermophilic prokaryotes are species of Archaea. C. In general, prokaryotic organisms can grow at higher temperatures than eukaryotic organisms. D. All of the statements are true.

D. All of the statements are true.

All of the following are true regarding energy-rich compounds EXCEPT A. The energy released in redox reactions is conserved in compounds that contain energy-rich phosphate or sulfur bonds. B. Phosphoenolpyruvate is energy-rich. C. Hydrolysis of coenzyme A derivatives yields sufficient free energy to synthesize ATP. D. All phosphate bonds are energy-rich. E. For longer term energy storage, microorganisms produce insoluble polymers that can be used to make ATP.

D. All phosphate bonds are energy-rich.

Which type of active transport protein uses one protein to pump two different molecules? A. Symport B. Uniport, Antiport, and Symport C. Uniport D. Antiport and Symport E. Antiport

D. Antiport and Symport

You are working with a newly described microorganism that has a rotatary appendage that is solid, 10 nm in diameter, and driven by the hydrolysis of ATP. Based on the nature of this appendage, which type of organism is this? A. Bacteria B. Algae C. Bacteria or Archaea D. Archaea E. Protozoa

D. Archaea

Alternative autotrophic routes to the Calvin cycle such as the reverse citric acid cycle and the hydroxypropionate pathway are unified in their requirement for A. NAD(P)H. B. organic compound(s) formed. C. coenzyme A. D. CO2.

D. CO2.

All of the following are true of natural competence EXCEPT A. Competence is induced during certain growth phases. B. Competence requires special DNA uptake, DNA binding, and integration proteins. C. Competence is required for transformation. D. Competence occurs with high efficiency in E coli. E. Competence rarely occurs with high efficiency in nature.

D. Competence occurs with high efficiency in E coli.

Which statement illustrates why DNA polymerase cannot initiate a new DNA strand? A. DNA polymerase requires a free 5′-phosphate group to add nucleotides. B. DNA polymerase requires a free 5′-hydroxyl group to add nucleotides. C. DNA polymerase requires a free 3′-phosphate group to add nucleotides. D. DNA polymerase requires a free 3′-hydroxyl group to add nucleotides.

D. DNA polymerase requires a free 3′-hydroxyl group to add nucleotides.

In DNA replication there are leading and lagging strands, because A. one strand of DNA is copied faster than the other. B. the strands of DNA are parallel and are copied in the same direction simultaneously. C. DNA replication is conservative and a completely new DNA molecule must be made. D. DNA replication is semiconservative and each strand is copied simultaneously in opposite directions.

D. DNA replication is semiconservative and each strand is copied simultaneously in opposite directions.

Initiation of prokaryotic DNA replication at the origin of replication is controlled by _____. A. Primase B. Gyrase C. Helicase D. DnaA E. DNA polymerase

D. DnaA

Define what an effector is in genetic regulation. A. Effectors are another name for the repressor protein that binds to DNA in negative control. B. Effectors are small molecules that only induce transcription of a specific gene. C. Effectors are small molecules that only repress transcription of a specific gene. D. Effectors are small molecules that induce or repress transcription of a specific gene.

D. Effectors are small molecules that induce or repress transcription of a specific gene.

Membrane transport proteins are required for which mode(s) of antibiotic resistance? A. Efflux pumps and modification of porins B. Modification of a porins C. Efflux pumps D. Efflux pumps, beta-lactamases, and modification of porins E. Beta-lactamases

D. Efflux pumps, beta-lactamases, and modification of porins

The lipids in the cytoplasmic membrane of Bacteria and ________ contain ester linkages, while the cytoplasmic membrane of ________ contain ether linkages. A. Eukarya / prokaryotes B. Archaea / Eukarya C. Archaea / fungi D. Eukarya / Archaea

D. Eukarya / Archaea

What is the difference between an F+ and an Hfr bacterium? A. F+ bacteria have an F plasmid that includes some nuclear genes, while Hfr (high frequency recombinant) bacteria have an F plasmid with only the essential genes for conjugation. B. F+ bacteria have an integrated F plasmid, while Hfr bacteria have a nonintegrated F plasmid. C. F+ bacteria have a plasmid with only the essential genes for conjugation, while Hfr (high frequency recombinant) bacteria have an F plasmid that includes some nuclear genes. D. F+ bacteria have a nonintegrated F plasmid, while Hfr bacteria have an F plasmid that is integrated into their main chromosome.

D. F+ bacteria have a nonintegrated F plasmid, while Hfr bacteria have an F plasmid that is integrated into their main chromosome.

A mutation occurs so that that DnaK binds more tightly to RpoH. Which of the following would be an outcome of this mutation? A. The cell would grow faster B. The heat shock response would maintain unchanged. C. More heat shock genes would be transcribed. D. Fewer misfolded proteins would be refolded. E. More misfolded proteins would be refolded.

D. Fewer misfolded proteins would be refolded.

Penicillin inhibits which of the following molecules during cell division? A. MinE B. FtsK C. FtsA D. FtsI E. FtsZ

D. FtsI

Porins are present in ______________bacteria because, in these organisms, molecules entering the cell must pass through an extra layer of ___________. A. Gram-positive; membrane B. Gram-positive; peptidoglycan C. Gram-negative; peptidoglycan D. Gram-negative; membrane E. both Gram-negative and Gram-positive; membrane

D. Gram-negative; membrane

Which of the following statements is FALSE? A. There are no known pathogenic Archaea. B. Eighty percent of life's history on Earth is exclusively microbial. C. Microbial biomass on Earth likely exceeds that of higher organisms. D. Humans contain 10 times more bacterial cells than human cells. E. Estimates of the total number of prokaryotic cells on Earth are about 2.5 x10^30.

D. Humans contain 10 times more bacterial cells than human cells.

A bacterium does not continuously swim at one speed in one direction. Different arrangements and structures of flagella contribute to changes in speed and direction when necessary. How does motility relate to flagellation? Select all the correct answers. A. Bacteria with lophotrichously arranged flagella change direction only by changing the flagellar rotation. B. Certain flagellated prokaryotes exhibit gliding motility, a slower and smoother form of movement along the long axis of a cell. C. Peritrichously arranged flagella may only rotate counterclockwise. D. In general, organisms with polar flagella move more quickly than peritrichously flagellated organisms. E. Bacteria with amphitrichously arranged flagella change direction by periodically stopping to reorient themselves or by changing the flagellar rotation. F. Bacteria with peritrichously arranged flagella change direction by changing the flagellar rotation and "tumbling."

D. In general, organisms with polar flagella move more quickly than peritrichously flagellated organisms. E. Bacteria with amphitrichously arranged flagella change direction by periodically stopping to reorient themselves or by changing the flagellar rotation. F. Bacteria with peritrichously arranged flagella change direction by changing the flagellar rotation and "tumbling."

Which of the following statements is FALSE? A. Pathogenesis in Corynebacterium diphtheriae is due to phage conversion. B. Lysogeny confers resistance to infection by viruses of the same type. C. If an Hfr cell is mated with an F- cell, the F- cell will remain F-. D. In specialized transduction, virtually any genetic marker can be transferred from donor to recipient.

D. In specialized transduction, virtually any genetic marker can be transferred from donor to recipient.

Which of the following statements about fermentation is true? A. It allows the electron transport chain to continue in the absence of oxygen. B. It provides additional protons to allow the electron transport chain to continue. C. It is an alternative way for a cell to produce reducing power. D. It is an alternative way to return electron carriers to their oxidized state.

D. It is an alternative way to return electron carriers to their oxidized state.

The major shape-determining factor in Bacteria is the protein A. FtsZ. B. MinD. C. crescentin. D. MreB.

D. MreB.

Are viruses that infect Archaea different from bacterial viruses? A. Yes; they have only DNA genomes. B. Yes; the structure of archaeal viruses is always completely different from other bacterial viruses. C. Yes; they do not have protein coats because of the extreme conditions where they live. D. No; they consist of nucleic acid and protein like other bacterial viruses.

D. No; they consist of nucleic acid and protein like other bacterial viruses.

Which of the following statements regarding archaeal viruses is false? A. The majority of archaeal viruses do not lyse the host cell. B. Archaeal viruses are morphologically more diverse than Bacterial ones. C. Many archaeal viruses are enveloped. D. None of the statements are false. E. A and C are false.

D. None of the statements are false.

RNA viruses require which of the following enzymes to replicate their genome? A. Cas proteins B. DNA polymerase C. RNA polymerase D. RNA replicase E. reverse transcriptase

D. RNA replicase

What is one piece of evidence that supports the RNA world hypothesis? A. Early cells relied more heavily on RNA than on DNA. B. There are traces of RNA that have been dated and found to be older than any traces of DNA. C. RNA is more stable than DNA and therefore more likely to have been able to exist in such a harsh environment. D. RNAs can have catalytic activity. E. RNAs can replicate themselves.

D. RNAs can have catalytic activity.

Which of the following correctly describes a difference between the Embden-Meyerhof-Parnas pathway and the Entner-Doudoroff pathway? A. The Entner-Doudoroff pathway produces twice as much pyruvate from one glucose molecule as the Embden-Meyerhoff-Parnas pathway. B. The Embden-Meyerhoff-Parnas pathway produces half as much net ATP from one glucose molecule as the Entner-Doudoroff pathway. C. The Embden-Meyerhoff-Parnas pathway produces twice as much NADPH from one glucose molecule as the Entner-Doudoroff pathway. D. The Embden-Meyerhoff-Parnas pathway produces twice as much net ATP from one glucose molecule as the Entner-Doudoroff pathway.

D. The Embden-Meyerhoff-Parnas pathway produces twice as much net ATP from one glucose molecule as the Entner-Doudoroff pathway.

Which statement describes the difference between the normal neuron protein PrPC and the pathogenic version PrPSc? A. The PrPC protein contains more beta sheets while the PrPSc protein contains more alpha helices. B. PrPC is just a protein and the PrPSc is a protein with nucleic acid inside. C. The three-dimensional conformation is identical, but the amino acid sequence is different. D. The amino acid sequence is identical, but the three-dimensional conformation is different.

D. The amino acid sequence is identical, but the three-dimensional conformation is different.

Two-component regulatory systems rely on a balance of phosphorylation and dephosphorylation of sensor kinases and response regulators. If the response regulator became permanently phosphorylated due to lack of phosphatase activity, all of the following would occur EXCEPT A. The operon controlled by the response regulator would be always transcribed or never transcribed, depending upon the regulatory role of the response regulator. B. The cell would not be able to "reset" its response cycle. C. The cell would become insensitive to the environmental stimulus. D. The cell would become more sensitive to the environmental stimulus.

D. The cell would become more sensitive to the environmental stimulus.

The site of septum formation in E. coli is determined by the MinCDE proteins. Which of the following statements regarding the positioning of the septum are correct? A. MinCDE proteins are fixed at the site of septum formation. B. The concentration of MinCDE proteins is highest in the midpoint of the cell. C. MinCDE proteins form the scaffold for septum construction. D. The concentration of MinCDE proteins is lowest in the midpoint of the cell.

D. The concentration of MinCDE proteins is lowest in the midpoint of the cell.

The general steps of the viral lifecycle are similar in most viruses. One major exception, however, is entry into the host cell. How does this step differ between an animal cell and E coli? A. The virion fuses to the bacterial cell membrane of E coli, while the genome is injected into an animal cell. B. The virion randomly attaches to E coli, but viral binding to a specific receptor is required for entry into animal cells. C. The entire virion enters E coli, but only the nucleic acid is taken up by animal cells. D. The entire virion is taken into an animal cell, but only the viral genome enters E coli.

D. The entire virion is taken into an animal cell, but only the viral genome enters E coli.

All of the following are characteristic of Sec secretion systems except A. Translocation can occur during or after translation. B. Translocation requires energy. C. They are highly conserved and are universal in prokaryotes. D. They translocate folded proteins across the cell membrane. E. Translocation requires a signal sequence on the polypeptide.

D. They translocate folded proteins across the cell membrane.

Which of the following examples is an example of lysogenic conversion? A. T4 phages infect E. coli bacteria and are resistant to destruction by restriction enzymes. B. An RNA virus infects a cell and causes the production of new viruses. C. A lambda phage infects E. coli and enters the lytic cycle. D. Vibrio cholerae bacteria produce cholera toxin when infected with a phage.

D. Vibrio cholerae bacteria produce cholera toxin when infected with a phage.

A closed system, used for bacterial growth, where nothing is added and nothing is removed is called __________. A. a chemostat B. a continuous culture C. a lag culture D. a batch culture

D. a batch culture

Restriction is A. the viral process whereby the virus prevents other viruses from entering the cell. B. a general host mechanism to prevent virus particles from further infective action. C. the viral process whereby a host's DNA ceases normal functioning. D. a general host mechanism to prevent the invasion of foreign nucleic acid.

D. a general host mechanism to prevent the invasion of foreign nucleic acid.

A strain of E. coli produces a colicin, which is toxic to various pathogenic strains of E. coli. On what type of genetic element would you expect to find its gene? A. any of these is equally likely B. the chromosome C. a virus genome D. a plasmid E. a transposable element

D. a plasmid

A prophage replicates A. independently of its host while the lytic genes are not expressed. B. independently of its host while the lytic genes are expressed. C. along with its host while the lytic genes are expressed. D. along with its host while the lytic genes are not expressed.

D. along with its host while the lytic genes are not expressed.

Transcription of heat shock response genes is controlled by A. sRNAs. B. repressor proteins. C. a two-component regulatory system. D. alternate sigma factors. E. activator proteins.

D. alternate sigma factors.

What is Cas9 and what does it do? A. a DNA sequence that binds the Cas9 protein B. an RNA molecule that binds to target DNA via complementary base pairing C. a protein that functions in DNA repair and recombination D. an enzyme that cuts both strands of DNA at sites specified by a guide RNA

D. an enzyme that cuts both strands of DNA at sites specified by a guide RNA

Explain how organisms are placed into the three major cell lineages or domains. A. physical characteristics B. metabolic characteristics C. analysis of DNA D. analysis of ribosomal RNA

D. analysis of ribosomal RNA

The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is A. sanitization. B. disinfection. C. sterilization. D. antisepsis.

D. antisepsis.

The major distinguishing difference between antiseptics and disinfectants is __________. A. disinfectants can be used on living tissue B. disinfectants work well on biofilms C. antiseptics are not affected by the presence of organic matter D. antiseptics can be used on living tissue

D. antiseptics can be used on living tissue

In an electron tower, the electron donors with the most negative reduction potentials A. are at the bottom. B. are at the bottom and include water. C. are found in the middle and include succinate. D. are at the top and include glucose and NADH. E. are at the top and include carbon dioxide.

D. are at the top and include glucose and NADH.

Polycistronic transcription units are common in A. Eukarya. B. all three domains C. Archaea. D. both Archaea and Bacteria. E. Bacteria.

D. both Archaea and Bacteria.

Genes that encode polymerases, gyrases, ribosomal proteins, and other proteins essential to replication, transcription, and translation are present on A. chromosomes and plasmids. B. neither chromosomes nor plasmids. C. plasmids. D. chromosomes.

D. chromosomes.

What was produced by photosynthesis before the cyanobacterial lineage developed on Earth? A. oxygen B. hydrogen sulfide C. ferrous iron D. elemental sulfur

D. elemental sulfur

Nitrogenase is a critical enzyme in the nitrogen cycle because it catalyzes the A. oxidation of nitrogen gas into nitrate. B. dissimilative reduction of nitrate to nitrogen gas. C. assimilation of ammonia. D. fixation of nitrogen gas into ammonia.

D. fixation of nitrogen gas into ammonia.

Initial attachment of bacteria to a surface often involves ______. A. flagella and is irreversible B. exopolymers and is irreversible C. either flagella or exopolymers and is irreversible D. flagella and is reversible E. exopolymers and is reversible

D. flagella and is reversible

Scientists have identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains? A. microscopically observed staining characteristics of the cell wall B. ecological characteristics such as the ability to survive in extreme environments C. metabolic characteristics such as the production of methane gas D. genetic characteristics such as ribosomal RNA sequences E. metabolic characteristics such as chemoautotrophy and photosynthesis

D. genetic characteristics such as ribosomal RNA sequences

The major reductive amination pathway for incorporation of nitrogen into amino acids initially involves the production of __________ from alpha-ketoglutarate. A. tryptophan B. cysteine C. arginine D. glutamate E. glutamine

D. glutamate

Which two metabolic processes are MOST dissimilar? A. citric acid cycle and glycolysis B. pentose phosphate pathway and glycolysis C. proton motive force and substrate-level phosphorylation D. glycolysis and gluconeogenesis

D. glycolysis and gluconeogenesis

At some of the lowest light concentrations, ________ can still grow well due to their ________, which effectively harvest photons for energy. A. purple bacteria / antenna pigments B. purple bacteria / chlorosomes C. green bacteria / antenna pigments D. green bacteria / chlorosomes

D. green bacteria / chlorosomes

Green sulfur bacteria are often found at the greatest depths of all phototrophic cells in lakes, oceans, and microbial mats. This is because green sulfur bacteria A. are strict anaerobes. B. are very sensitive to UV irradiation, despite their reliance on light for energy. C. have phycobilisomes that are very efficient at harvesting light, allowing them to perform photosynthesis where light intensities are very low. D. have chlorosomes that are very efficient at harvesting light, allowing them to perform photosynthesis where light intensities are very low.

D. have chlorosomes that are very efficient at harvesting light, allowing them to perform photosynthesis where light intensities are very low.

Which of the following regarding microcompartments is false? Microcompartments A. include carboxysomes B. consist of a virion-like protein shell encapsulating enzymes. C. are to bacteria what membrane-bound organelles are to eukaryotic cells. D. include gas vesicles

D. include gas vesicles

All of the following structures contribute to the ability of pathogenic bacteria to cause disease EXCEPT A. exotoxins B. lipopolysaccharide. C. fimbriae. D. inclusions. E. capsules.

D. inclusions.

When water activity is low, an organism must A. increase its external solute concentration B. decrease its internal solute concentration C. decrease its external solute concentration D. increase its internal solute concentration

D. increase its internal solute concentration

A new protein has been described that transports a growth factor across the plasma membrane. This protein is most likely a/an: A. cytoplasmic protein. B. peripheral membrane protein, facing the cytoplasmic side. C. peripheral membrane protein, facing outward. D. integral membrane protein.

D. integral membrane protein.

The methyl-accepting chemotaxis proteins of bacteria A. are directly connected to the flagellar motor to guide the bacterium. B. are sensor kinases C. can only sense conditions that are favorable for bacterial growth. D. integrate multiple signals through a two component phospho-relay system. E. tell the bacterium which way to go.

D. integrate multiple signals through a two component phospho-relay system.

Fluorescent microscopy can be used to track the origin of replication (ori) on the chromosome during bacterial cell replication by performing all EXCEPT which of the following steps? A. performing time-lapse fluorescent photomicroscopy of labeled cells during cell replication B. introducing a sequence of DNA near the ori that will bind a fluorescent protein C. introducing a reporter gene into the chromosome that codes for a fluorescent protein that will bind to a specific DNA sequence near the ori D. introducing a reporter gene into the chromosome next to the ori

D. introducing a reporter gene into the chromosome next to the ori

Pasteurization is used to A. kill any pathogens present. B. sterilize beverages and retard spoilage. C. sterilize beverages. D. kill any pathogens present and retard spoilage. E. retard spoilage.

D. kill any pathogens present and retard spoilage.

Gram-negative bacteria have __________ peptidoglycan than gram-positive cells, and their cell walls are __________ complex structurally. A. more ... less B. more ... more C. less ... less D. less ... more E. None of the listed responses is correct.

D. less ... more

The metabolic diversity of photosynthetic bacteria stems from different A. chlorophylls they can have and organic compounds they can produce. B. bacteriochlorophylls and pigments they contain. C. unrelated taxa capable of photosynthesis. D. light-harvesting complexes, electron donors, and organic compounds they produce.

D. light-harvesting complexes, electron donors, and organic compounds they produce.

Which term is most relevant in describing the efficacy of an antimicrobial for use in a clinical setting? A. lethal dosage B. sterilization coefficient C. effective dose D. minimum inhibitory concentration (MIC)

D. minimum inhibitory concentration (MIC)

There are several different types of mutations possible in the base sequence of DNA. If a GGC (glycine) codon were changed to UGC (cysteine), it would be termed a __________. A. nonsense mutation B. silent mutation C. wild type D. missense mutation

D. missense mutation

Bacteriophage have a ________ complex structure than animal viruses, because ________. A. more / bacteriophages must be coated by lipopolysaccharide to attach to bacterial cells B. less / their prokaryotic cells have a simple structure compared to eukaryotic cells C. less / the bacteriophage does not have to penetrate the nucleus D. more / the bacteriophage must penetrate the peptidoglycan cell wall

D. more / the bacteriophage must penetrate the peptidoglycan cell wall

The morphology of a cell influences its A. motility. B. surface-to-volume ratio. C. metabolism. D. motility and surface-to-volume ratio.

D. motility and surface-to-volume ratio.

Lysozymes and penicillin both disrupt the bacterial cell wall peptidoglycan, leading to cell lysis. However, their mechanisms of action are different, resulting in the fact that __________. A. lysozyme cleaves the peptide cross-links in peptidoglycan. B. penicillin cleaves the glycosidic bonds in the peptidoglycan backbone C. penicillin kills both bacterial and eukaryotic cells D. penicillin kills only growing bacterial cells

D. penicillin kills only growing bacterial cells

What is the energy source for the import of an inorganic ion, such as Mg2+, through a simple symporter? A. concentration gradient of the transported molecule B. ATP C. phosphoenolpyruvate D. proton motive force E. any of the choices

D. proton motive force

Regulatory proteins A. bind to specific DNA sites. B. regulate transcription. C. are influenced by small molecules. D. regulate transcription, bind specific DNA sites, and can be influenced by small molecules.

D. regulate transcription, bind specific DNA sites, and can be influenced by small molecules.

A new antibiotic is able to bind the rho factor associated with transcription. As a result, this antibiotic would affect A. initiation of transcription. B. termination of all transcription. C. binding of RNA polymerase. D. termination of some transcription. E. elongation of transcription.

D. termination of some transcription.

During an oxidation reaction, A. the donor molecule loses an electron and becomes reduced. B. the acceptor molecule loses an electron and becomes oxidized. C. the donor molecule gains an electron and becomes oxidized. D. the acceptor molecule gains an electron and becomes reduced.

D. the acceptor molecule gains an electron and becomes reduced.

In the bacterial world, a gene located on which of the following would be the LEAST likely to be transferred? A. an F plasmid B. the phage Mu C. a resistance plasmid D. the chromosome

D. the chromosome

What was LUCA? A. the last eukaryote before eukaryotes diversified B. the type of prokaryote that evolved into a eukaryote C. the first cellular organism to evolve D. the last organism prior to the divergence of bacteria and archaea

D. the last organism prior to the divergence of bacteria and archaea

You are studying a protein in Salmonella typhimurium that you believe is a toxin. Whenever you attempt to purify the protein from lysed cell cultures, you get two forms of the protein. One form is smaller than the other and is missing 15 amino acids from the N-terminus compared to the larger form. This leads you to hypothesize that A. you need to re-do the experiment because there should only be one form. B. there are two termination sites in the mRNA. C. the protein requires chaperonins to fold properly. D. the protein is secreted and folds outside of the cell.

D. the protein is secreted and folds outside of the cell.

The first step of translation begins when __________. A. tRNA binds to the P site on the ribosome to initiate translation B. the initiator aminoacyl-tRNA binds to the start codon on the mRNA at the A site of the ribosome C. the 30S ribosomal subunit combines with the 50S ribosomal subunit, enclosing the mRNA D. the ribosome binding site (RBS) on the mRNA binds to the 16S rRNA E. the ribosome binding site (RBS) on the mRNA binds to the 23S rRNA

D. the ribosome binding site (RBS) on the mRNA binds to the 16S rRNA

An endotoxin is A. a toxin known for its primary attack on the epidermis of mammals. B. a toxin produced within archaeal cells. C. a toxin produced in the periplasm of most bacteria. D. the toxic portion of the LPS.

D. the toxic portion of the LPS.

Attenuation is a type of regulation that directly controls A. both transcriptional and translational activity. B. allosteric enzyme activity. C. translational activity. D. transcriptional activity. E. post-translational activity

D. transcriptional activity.

The uptake of free DNA from the environment is ________, while transfer of DNA with cell-to-cell contact would most likely result in ________. A. conjugation / transformation B. transduction / conjugation C. transformation / transduction D. transformation / conjugation

D. transformation / conjugation

β-lactam antibiotics inhibit peptidoglycan A. glycan tetrapeptide precursor formation. B. transglycosylation and transpeptidation. C. autolysins. D. transpeptidation. E. transglycosylation.

D. transpeptidation.

What type of regulation is used by Pseudomonas aeruginosa for the type of chemotaxis described in the introductory passage? A. by regulating the transcription of mRNA used to produce enzymes B. using a one-component system to inhibit enzymes that restrict flagellar movement C. by regulating the production of proteins used in flagella synthesis using a two-component system D. using a two-component system to regulate the activity of existing proteins

D. using a two-component system to regulate the activity of existing proteins

The SOS system repairs DNA that has gaps, breaks, and other lesions by A. stabilizing single-stranded DNA until the next round of normal replication. B. using available mRNA and a special RNA-dependent DNA polymerase to fill in the gaps and replace damaged DNA. C. cutting DNA from other parts of the genome and pasting it into the gaps or damaged areas. D. using specialized DNA polymerases that will synthesize a new DNA strand even if there is not a normal complementary DNA strand to act as a template.

D. using specialized DNA polymerases that will synthesize a new DNA strand even if there is not a normal complementary DNA strand to act as a template.

Nitrogen fixation is A. limited to Proteobacteria. B. common in Bacteria, but absent in Archaea. C. rare among microorganisms. D. widespread among microorganisms.

D. widespread among microorganisms.

Which feature of anaerobic and aerobic respiration is different between the two catabolic strategies? A. electron donor and terminal electron acceptor B. use of electron transport C. electron donor D. use of proton motive force E. terminal electron acceptor

E. terminal electron acceptor

During DNA replication, a series of steps are required to ensure that the genetic information in a cell is correctly and accurately duplicated. Place the following phrases in the correct order. Binding proteins stabilize the unwound double helix. DNA pol I replaces the RNA primer. Topoisomerase IV separates linked chromosomes. DNA pol III adds complementary nucleotides. DNA helicase unwinds the DNA double helix. DNA ligase seals any nicks in the DNA. DNA gyrase removes the DNA supercoils. Primase generates a RNA primer that binds to the origin.

DNA helicase unwinds the DNA double helix. Binding proteins stabilize the unwound double helix. DNA gyrase removes the DNA supercoils. Primase generates a RNA primer that binds to the origin. DNA pol III adds complementary nucleotides. DNA pol I replaces the RNA primer. DNA ligase seals any nicks in the DNA. Topoisomerase IV separates linked chromosomes.

During DNA replication, which enzyme removes the RNA primer nucleotides and fills in complementary DNA nucleotides in the lagging strand? DNA polymerase IDNA polymerase IIIligasehelicaseprimase

DNA polymerase I

What cellular component is NOT a molecular chaperone? DnaJ GroEL DnaA DnaK GroES

DnaA

What cellular component is NOT a molecular chaperone? DnaJGroELDnaADnaKGroES

DnaA

During infection, viruses such as the Zika virus produce proteins that can be described as early proteins or late proteins. Sort the choices below based on whether they are produced early or late in a viral infection. A. proteins that interfere with host gene expression B.capsid components C. RNA replicase D. DNA polymerase E. virion structural components F. RNA polymerase G. proteins produced in small amounts H. proteins produced in large amounts

EARLY: A. proteins that interfere with host gene expression C. RNA replicase D. DNA polymerase F. RNA polymerase G. proteins produced in small amounts LATE: B. capsid components E. virion structural components H. proteins produced in large amounts

What is the correct scenario in which the trp operon becomes transcribed? Tryptophan must be present in high amounts causing repressor to fall off DNA. Tryptophan binds to an activator causing the transcription of the trp operon to increase. Tryptophan binds to the DNA and acts as a promoter for the trp operon. Tryptophan must be absent to allow activator to promote transcription of the trp operon. Tryptophan must be absent to prevent repressor from blocking transcription of the trp operon. What occurs when an inducer is added to an environment containing an organism with a metabolic pathway controlled by a repressor? The inducer binds to the promoter and activates the pathway. The inducer combines with the repressor and inactivates the pathway. The inducer combines with the repressor and activates the pathway. The inducer combines with the substrate and activates the pathway. You are studying regulation of a prokaryotic operon. Expression of the operon is increased when product levels are low. Based on this information, you conclude that the likely mode of regulation is the operon is ON in the absence of its regulatory protein. the presence of a promoter will always cause a repressor to bind the operator. the operon is OFF in the absence of its regulatory protein. the operon is ON in the presence of its regulatory protein.

E C A

The class of macromolecules in microorganisms that contributes LEAST to biomass is A. RNA B. carbohydrates. C. lipids. D. proteins. E. DNA.

E. DNA.

Which of the following molecules is shared by both Gram-positive and Gram-negative organisms? A. lipoteichoic acid B. lipopolysaccharide C. endotoxin D. lipid A E. N-acetylmuramic acid

E. N-acetylmuramic acid

All of the following are true regarding prokaryotic protein secretion EXCEPT A. Proteins with complex cofactors, such as iron-sulfur proteins, are Tat secreted. B. Some gram-negative secretion systems do not require Sec or Tat. C. Proteins are inserted into the cell membrane by co-translational Sec secretion. D. The basic information for locating a protein in the right place is contained within its sequence. E. Sec and Tat pathways both are fueled by ATP hydrolysis.

E. Sec and Tat pathways both are fueled by ATP hydrolysis.

The Calvin cycle A. is responsible for the fixation of CO2 into cell material. B. utilizes both NAD(P)H and ATP. C. uses CO2, NAD(P)H, and ATP to make biomass with ribulose bisphosphate carboxylase and phosphoribulokinase. D. requires both ribulose bisphosphate carboxylase and phosphoribulokinase. E. all of the above are correct.

E. all of the above are correct.

E. coli can use two pathways for ammonia assimilation, the reductive amination pathway or the GS-GOGAT pathway. Which of the following factors influences which pathway the organism will use? A. availability of nitrate B. availability of oxygen C. availability of NADH D. growth temperature E. ammonia concentration

E. ammonia concentration

Which regulatory mechanism does NOT depend on a conformational change in protein/enzyme structure to change activity? A. negative control B. catabolite repression C. feedback inhibition D. positive control E. attenuation

E. attenuation

Which of the following are NOT found within the photosynthetic gene cluster of Rhodobacter (a purple phototrophic bacterium)? A. genes encoding reaction center and light-harvesting photocomplexes B. genes encoding proteins involved in bacteriochlorophyll biosynthesis C. genes encoding proteins involved in carotenoid biosynthesis D. genes encoding photosynthetic vesicles or lamellae E. genes encoding proteins involved in phycobiliprotein biosynthesis

E. genes encoding proteins involved in phycobiliprotein biosynthesis

You discover a new transport system used by a newly discovered bacterial species. The sugars that are transported using this system are phosphorylated as they enter the bacterial cell. You would describe this transport system as _____. A. simple transport B. an antiport C. a symport D. an ABC transporter E. group translocation

E. group translocation

Chemical mutagens, UV radiation, and ionizing radiation all increase mutation rates, but they have different mechanisms. Which type of mutagen would be best suited for creating frameshift mutations within a genome? A. All of the choices are likely to create frameshift mutations. B. alkylating agents C. UV radiation D. base analogs E. intercalating agents

E. intercalating agents

In archaeal membranes, what serves the same function as the fatty acids of bacterial membranes? A. hopanoid molecules B. glycerophosphates C. phosphate groups D. glycerol E. isoprene derivatives

E. isoprene derivatives

Both lysozyme and penicillin disrupt the bacterial cell wall peptidoglycan, leading to cell lysis. However, their mechanisms of action are different, based on the fact that __________. A. penicillin cleaves the peptide cross-links in peptidoglycan. B. penicillin kills both bacterial and eukaryotic cells C. penicillin cleaves the glycosidic bonds in the peptidoglycan D. lysozyme cleaves the peptide cross-links in peptidoglycan. E. penicillin kills only growing cells

E. penicillin kills only growing cells

The topoisomerase ________ introduces positive supercoils in hyperthermophile DNA, which stabilizes DNA and prevents the DNA helix from denaturing at high temperatures. A. reverse ligase B. ligase C. helicase D. DNA gyrase E. reverse DNA gyrase

E. reverse DNA gyrase

Define what an effector is in genetic regulation. View Available Hint(s) Effectors are another name for the repressor protein that binds to DNA in negative control. Effectors are small molecules that induce or repress transcription of a specific gene. Effectors are small molecules that only repress transcription of a specific gene. Effectors are small molecules that only induce transcription of a specific gene.

Effectors are small molecules that induce or repress transcription of a specific gene.

Consider the following experiment. First, large populations of two mutant strains of Escherichia coli are mixed, each requiring a different, single amino acid. After plating them onto a minimal medium lacking the two amino acids, 45 colonies grew. Which of the following may explain this result? The colonies may be due to recombination.The colonies may be due to back mutation (reversion).Either A or B is possible.Neither A nor B is possible.

Either A or B is possible. The colonies may be due to recombination.The colonies may be due to back mutation (reversion)

Which of the following describes the essential parts of all viruses? Genetic material (RNA or DNA), a protein capsid, an envelope, and enzymesGenetic material (RNA or DNA) and a protein capsidGenetic material (RNA and DNA) and a protein capsidGenetic material (RNA or DNA), a protein capsid, and an envelope

Genetic material (RNA or DNA) and a protein capsid

All of the following are true of gliding motility EXCEPT Gliding motility requires surface contact.Gliding motility is well adapted for drier habitats.Gliding motility is characteristic of both Bacteria and ArchaeaGliding motility occurs via multiple mechanisms.Flagella are not involved in gliding motility.

Gliding motility is characteristic of both Bacteria and Archaea

Which of the following statements is FALSE? In specialized transduction, virtually any genetic marker can be transferred from donor to recipient.Lysogeny confers resistance to infection by viruses of the same type.If an Hfr cell is mated with an F- cell, the F- cell will remain F-.Pathogenesis in Corynebacterium diphtheriae is due to phage conversion.

In specialized transduction, virtually any genetic marker can be transferred from donor to recipient.

Mutation rates are similar in Bacteria and Archaea, yet certain stressful conditions cause mutation rates to increase. Why is the mutation rate not constant and close to zero all of the time? Constant mutation rates would halt evolution completely.Increased mutation rates can be advantageous in rapidly changing environments because some random mutations may be useful for survival.Microorganisms carefully control the mutation rate of their DNA to match the environmental conditions and maximize evolution.The increased mutation rate under stressful conditions is an indication that the microorganisms can no longer replicate their DNA properly and are about to die.

Increased mutation rates can be advantageous in rapidly changing environments because some random mutations may be useful for survival.

_________________ associates with a sensor kinase and a coupling protein to trigger autophosphorylation.

Methyl-accepting chemotaxis protein

Which of the following are true regarding DNA-binding proteins? Select all that apply. Most DNA-binding proteins interact with DNA in a sequence-specific manner.Homodimeric regulatory proteins interact with inverted repeats on DNA.Small molecules influence binding of regulatory proteins to DNA.The lac repressor contains the helix-turn-helix structure.The minor groove of DNA is the main site of protein binding.

Most DNA-binding proteins interact with DNA in a sequence-specific manner.Homodimeric regulatory proteins interact with inverted repeats on DNA.Small molecules influence binding of regulatory proteins to DNA.The lac repressor contains the helix-turn-helix structure.

Which of the following regarding molecular chaperones is FALSE? DnaKJ slows spontaneous folding of newly synthesized proteins to help insure that they fold properly.Chaperones undergo conformational changes during the folding process.Most unfolded proteins in E. coli are folded by GroEL/ES.Chaperone-assisted protein folding requires ATP.Chaperones are a type of heat shock protein

Most unfolded proteins in E. coli are folded by GroEL/ES.

All of the following are true regarding prokaryotic protein secretion EXCEPT The basic information for locating a protein in the right place is contained within its sequence.BamA inserts β-barrel proteins into OMs of gram-negative bacteria.Only unfolded proteins are secreted.Sec and Tat pathways have been identified in all domains of life.Protein secretion requires energy from ATP or the proton motive force.

Only unfolded proteins are secreted.

DNA is composed of two strands, only one of which is used as a template for RNA synthesis. By what mechanism is the correct strand chosen? Only one strand has the start codon.Promoter orientation acts to locate the RNA polymerase.Only one DNA strand contains genes.Both strands are tried, and the one that works is chemically modified, so it will be used again.RNA polymerase can read only 5' to 3', so the direction is predetermined.

Promoter orientation acts to locate the RNA polymerase.

All of the following support the RNA world hypothesis EXCEPT RNA nucleotides are components of essential cofactors and molecules in all cells.RNA has catalytic activity and can catalyze RNA synthesis.RNA can replicate itself.RNA has complex tertiary structure.RNA can bind small molecules.

RNA can replicate itself.

Which statement is TRUE? The nucleic acid polymerases used by viruses are eukaryotic.Viruses do not contain their own nucleic acid polymerases.RNA viruses contain their own nucleic acid polymerases.All viruses contain their own nucleic acid polymerases.

RNA viruses contain their own nucleic acid polymerases.

All of the following are true regarding the heat shock response EXCEPT Triggers include heat stress or high levels of UV or ethanol.Under non-stress conditions, RpoH is degraded by DnaK.Heat shock proteins include chaperones and proteases.RpoH is a chaperone.Heat shock inhibits RpoH degradation.

RpoH is a chaperone.

All of the following are true regarding prokaryotic protein secretion EXCEPT Sec and Tat pathways both are fueled by ATP hydrolysis. Some gram-negative secretion systems do not require Sec or Tat. Proteins with complex cofactors, such as iron-sulfur proteins, are Tat secreted. The basic information for locating a protein in the right place is contained within its sequence. Proteins are inserted into the cell membrane by co-translational Sec secretion.

Sec and Tat pathways both are fueled by ATP hydrolysis.

Which statement best explains why positively controlled genes have weak promoters and need an activator protein to help the RNA polymerase bind? View Available Hint(s) So translation only occurs when the substrate for the gene product is present. So translation only stops when the substrate for the gene product is present. So transcription occurs only when the substrate for the gene product is present. So transcription stops when the substrate for the gene product is present.

So transcription occurs only when the substrate for the gene product is present.

Two-component regulatory systems rely on a balance of phosphorylation and dephosphorylation of sensor kinases and response regulators. If the response regulator became permanently phosphorylated due to lack of phosphatase activity, all of the following would occur EXCEPT The cell would become insensitive to the environmental stimulus. The operon controlled by the response regulator would be always transcribed or never transcribed, depending upon the regulatory role of the response regulator. The cell would not be able to "reset" its response cycle. The cell would become more sensitive to the environmental stimulus.

The cell would become more sensitive to the environmental stimulus.

The general steps of the viral lifecycle are similar in most viruses. One major exception, however, is entry into the host cell. How does this step differ between an animal cell and E coli? The virion randomly attaches to E coli, but viral binding to a specific receptor is required for entry into animal cells.The entire virion is taken into an animal cell, but only the viral genome enters E coli.The virion fuses to the bacterial cell membrane of E coli, while the genome is injected into an animal cell.The entire virion enters E coli, but only the nucleic acid is taken up by animal cells.

The entire virion is taken into an animal cell, but only the viral genome enters E col

In negative control of transcription by the lac operon, how does the presence of an inducer affect transcription? The inducer does not bind to the operator.The inducer causes the repressor to bind to the operator.The inducer prevents the repressor from binding to the operator.The inducer binds to the operator.

The inducer prevents the repressor from binding to the operator.

Which of the following conclusions can be made if two identical insertion sequences are identified in separate locations on a chromosome? The insertion sequence was transferred via replicative transposition.The insertion sequence was a "cut-and-paste" transposon.The insertion sequence was transferred via conservative transposition.A mutation occurred during transposition of the insertion sequence.The insertion sequence was transferred via simple transposition.

The insertion sequence was transferred via replicative transposition.

Which of the following regarding prokaryotic DNA packing is FALSE? The normal state of DNA supercoiling is slightly positively supercoiled.Supercoiling further compacts DNA.DNA binding proteins fold DNA into loops organized around a central core.Cations bind to DNA to neutralize the negative charge.Nucleoid-associated proteins compact prokaryotic DNA.

The normal state of DNA supercoiling is slightly positively supercoiled.

Some organisms seem to change names, for example Vibrio fischerii is now Aliivibrio fischerii. How can it be known which is the proper name? The official source would be the most recent edition of a microbiology textbook.The official source is Bergey's Manual of Systematic Bacteriology.The official source would be The Prokaryotes.The official source is the International Journal of Systematic and Evolutionary Microbiology.

The official source is the International Journal of Systematic and Evolutionary Microbiology.

A single base substitution happens to cause a nonsense mutation early in the gene for a protein. What will be the result? The protein will be truncated a small amount, but is likely to function normally.The protein will be truncated a great deal, but is likely to function normally.The protein will be truncated a small amount, but is unlikely to function normally.The protein will be truncated so much that it is unlikely to function normally.

The protein will be truncated so much that it is unlikely to function normally.

Explain why promoters for the same sigma subunit do not have identical sequences in all organisms. View Available Hint(s) Only the last 10 bases in the promoter region are needed for sigma subunit recognition.Only the first 35 bases in the promoter region are needed for sigma subunit recognition.The sequences within the promoter region at -10 and -35 are the most important for recognition by the sigma subunit.Different organisms will have different DNA sequences.

The sequences within the promoter region at -10 and -35 are the most important for recognition by the sigma subunit.

All of the following are characteristic of Sec secretion systems except They are highly conserved and are universal in prokaryotes .They translocate folded proteins across the cell membrane. Translocation requires a signal sequence on the polypeptide. Translocation can occur during or after translation. Translocation requires energy.

They translocate folded proteins across the cell membrane.

All of the following are characteristic of Sec secretion systems except They are highly conserved and are universal in prokaryotes.They translocate folded proteins across the cell membrane.Translocation requires a signal sequence on the polypeptide.Translocation can occur during or after translation.Translocation requires energy.

They translocate folded proteins across the cell membrane.

Which of the following regarding Archaeal gene expression is false? Some Archaeal genes are organized into operons.Transcription initiation involves alternate sigma factors.Archaeal RNA polymerase resembles a eukaryotic RNA polymerase.Archaeal molecular properties resemble those of eukaryotes more than Bacteria.

Transcription initiation involves alternate sigma factors

Regulation by induction and repression are called negative control because __________. View Available Hint(s) Transcription proceeds in the absence of the repressor protein. Translation proceeds in the presence of the repressor protein. Transcription proceeds in the presence of the repressor protein. Translation proceeds in the absence of the repressor protein.

Transcription proceeds in the absence of the repressor protein.

All of the following statements regarding protein secretion are true EXCEPT Type III, IV and VI secretion systems require ATP.Type III, IV and VI secretion systems secrete molecules into another cell.Type I, II and V secretion systems are Sec- or Tat-dependent.Types I through VI secretion systems specifically recognize substrates based on amino acid sequence.Type IV secretion systems can transport DNA in addition to proteins.

Type I, II and V secretion systems are Sec- or Tat-dependent.

The codon for phenylalanine is UUU. Which of the following codons also most likely encodes for phenylalanine? CUU AUG UUC AAA AUU

UUC

The codon for phenylalanine is UUU. Which of the following codons also most likely encodes for phenylalanine? CUUAUGUUCAAAAUU

UUC

Which of the following examples is an example of lysogenic conversion? View Available Hint(s) A lambda phage infects E. coli and enters the lytic cycle.An RNA virus infects a cell and causes the production of new viruses.Vibrio cholerae bacteria produce cholera toxin when infected with a phage.T4 phages infect E. coli bacteria and are resistant to destruction by restriction enzymes.

Vibrio cholerae bacteria produce cholera toxin when infected with a phage.

All of the following indicate a way in which viruses differ from living organisms except View Available Hint(s) Viruses have DNA or RNA, not both Viruses depend on their host to synthesize the essential components of new viruses (e.g., genetic material and proteins), while living organisms are capable of synthesizing these components even if they require a host for food, shelter, or other necessities. Viruses are acellular and all living things are made up of cells Viruses are obligate parasites and no living organisms are obligate parasites.

Viruses are obligate parasites and no living organisms are obligate parasites.

Which of the following is true about viral infection? View Available Hint(s) Viruses can infect any cells within a large group, but they are not more specific than that. For example, there are plant viruses that can affect many types of plants, bacteriophages that affect many types of bacteria, and animal viruses that affect a range of viruses.Viruses are very specific in which cells they infect. For a virus to be taken up by a cell, it must find a cell with appropriate receptors on the surface. It cannot be taken up by cells without the appropriate receptors.Viruses have what is needed to infect a host cell; they do not need anything specific from the host cell in order to cause infection and therefore can infect a wide range of cells.Viruses can infect any cell in a particular species; it does not matter which tissue they infect as long as the species (or group of similar species) is correct.

Viruses are very specific in which cells they infect. For a virus to be taken up by a cell, it must find a cell with appropriate receptors on the surface. It cannot be taken up by cells without the appropriate receptors.

Under which conditions would the gluconeogenesis pathway be necessary? A. When cells are growing on a mixture of sugars B. When cells are limited for nitrogen in the form of ammonia C. When cells are growing on protein as their sole carbon source D. When cells are growing on glucose as their sole carbon source

When cells are growing on protein as their sole carbon source

Which of the following examples describes a type of catabolite repression? View Available Hint(s) A mutation in the promoter of the lac operon prevents the expression of the genes needed for the bacterium to utilize lactose.The presence of abundant tryptophan inhibits the trp operon.Allolactose binds to a repressor, preventing it from binding to the operator of the lac operon.When glucose is present, the lac operon is inhibited.

When glucose is present, the lac operon is inhibited.

One group of chemical mutagens includes the base analogs. How do these lead to mutations? Base analogs push apart and distort the double helix. This distortion can lead to insertions and deletions (including frameshift mutations).They lead to alkylation, which can lead to substitutions.When replication occurs, complementary base pairing may fail because the base analog may not be treated in the same way as the base that it replaced.They lead to the formation of pyrimidine dimers.

When replication occurs, complementary base pairing may fail because the base analog may not be treated in the same way as the base that it replaced.

Which organism would likely harbor the MOST two-component regulatory systems? a bacterium occupying a heterogeneous niche with high nutrient mixinga parasitic bacterium living inside another organisman archaeon living in an extreme environmentan organism capable of quorum sensing

a bacterium occupying a heterogeneous niche with high nutrient mixing

Restriction is a general host mechanism to prevent the invasion of foreign nucleic acid.the viral process whereby a host's DNA ceases normal functioning.the viral process whereby the virus prevents other viruses from entering the cell.a general host mechanism to prevent virus particles from further infective action.

a general host mechanism to prevent the invasion of foreign nucleic acid.

One way that regulation is often studied is by examining the effects of mutations. For example, mutations within the parts of the lac operon have been well studied. Which of these mutants would be considered a constitutive mutant? View Available Hint(s) a mutation in the gene for beta-galactosidasea mutation in the gene for beta-galactosidase permeasea mutation that disables the promoter for the operona mutation that disables the repressor

a mutation that disables the repressor

Which intermediate compound(s) in the citric acid cycle is/are often used for biosynthetic pathways as well as carbon catabolism? a. α-ketoglutarate, oxaloacetate, and succinyl-CoA B. oxaloacetate C. succinyl-CoA D. α-ketoglutarate E.citrate and α-ketoglutarate

a. α-ketoglutarate, oxaloacetate, and succinyl-CoA

Which statement is the correct definition of polycistronic mRNA? View Available Hint(s) a single piece of mRNA that contains the transcript for multiple genes.a single piece of mRNA from a single genemultiple mRNA molecules from the same gene in different organismsmultiple pieces of mRNA from a single operon An operon is a sequence in DNA that codes for multiple genes. These genes are all regulated by the same promoter. Operons are not found in eukaryotic cells.

a single piece of mRNA that contains the transcript for multiple genes.

A point mutation refers to mutations involving a base-pair substitution.a substitution, deletion, or addition of one base-pair.the deletion of a base pair (microdeletion).the gain of a base pair (microinsertion).

a substitution, deletion, or addition of one base-pair.

In the biosynthesis of glucose polymers, each glucose molecule is added to a growing chain of glycogen or starch via a carrier molecule such as ________. A. uridine diphosphate glucose B. coenzyme A C. glucose-6-phosphate D. adenosine diphosphate glucose

adenosine diphosphate glucose

The three stages of translation, initiation, elongation, and termination, __________. all require at least one protein cofactor and all require ATPall require ATPall require base pairing between two RNAsall require at least one protein cofactor and base pairing between two RNAsall require at least one protein cofactor and all require GTP

all require at least one protein cofactor and all require GTP

The three stages of translation, initiation, elongation, and termination, __________. all require at least one protein cofactor and all require ATP all require ATP all require base pairing between two RNAs all require at least one protein cofactor and base pairing between two RNAs all require at least one protein cofactor and all require GTP

all require at least one protein cofactor and all require GTP Submit

An operon is a useful genetic element, because it encourages the binding of ribosomes in the correct location.allows coordinated expression of multiple related genes in prokaryotes.encourages the binding of RNA polymerase.translates DNA sequence into amino acid sequence.

allows coordinated expression of multiple related genes in prokaryotes.

A prophage replicates along with its host while the lytic genes are expressed.along with its host while the lytic genes are not expressed.independently of its host while the lytic genes are not expressed.independently of its host while the lytic genes are expressed.

along with its host while the lytic genes are not expressed.

Transcription of heat shock response genes is controlled by sRNAs.repressor proteins.activator proteins.alternate sigma factors.a two-component regulatory system.

alternate sigma factors.

Global regulatory systems include all of the following EXCEPT stationary phase.heat shock response.catabolite repression.amino acid synthesis.stringent response.

amino acid synthesis.

What is Cas9 and what does it do? an RNA molecule that binds to target DNA via complementary base pairinga protein that functions in DNA repair and recombinationan enzyme that cuts both strands of DNA at sites specified by a guide RNA a DNA sequence that binds the Cas9 protein

an enzyme that cuts both strands of DNA at sites specified by a guide RNA

The closest known prokaryotic relatives of eukaryotes: are LUCA are Asgard archaea have never been grown in culture are proteobacteria are euryarchaeaota

are asgard archaea

If autophosphorylation of CheA protein increases, then E. coli cells will swim in a run.are in a gradient of a repellant.will rotate flagella counterclockwise.are in an increasing gradient of chemoattractant.will rotate flagella counterclockwise and tumble.

are in a gradient of a repellant.

Which regulatory mechanism does NOT depend on a conformational change in protein/enzyme structure to change activity? feedback inhibitionpositive controlnegative controlattenuationcatabolite repression

attenuation

Transcriptional control in Archaea most closely resembles that in ________ and utilizes ________. eukaryotes; regulatory proteinseukaryotes; transcription factorsbacteria; regulatory proteinsbacteria; transcription factors

bacteria; regulatory proteins

Polycistronic transcription units are common in Bacteria.all three domainsArchaea.both Archaea and Bacteria.Eukarya.

both Archaea and Bacteria.

Normal PrPC is converted into infectious pathogenic PrPSc _________. by an enzyme that cleaves off parts of the normal proteinas a result of a mutation in the normal gene.by interaction of PrPC from one species with that of a second speciesby PrPSc that binds to the normal protein and causes it to become misfoldedby a virus that binds to the normal protein and causes it to become misfolded

by PrPSc that binds to the normal protein and causes it to become misfolded

How do integral proteins become embedded in the plasma membrane? by splicing of proteins on either side of the membraneby post-translational import of the protein into the membraneby cotranslational insertion into the membrane via the Sec complexvia signal sequences that target polypeptides made in the cytosol for the membraneby protein chaperones that insert polypeptides into the membrane

by cotranslational insertion into the membrane via the Sec complex

A nucleotide-altering chemical can alter nitrogenous bases of DNA, resulting in incorrect base pairing.can generate free radicals, resulting in double-stranded breaks in the DNA.can cause double-stranded breaks in the DNA.can be incorporated into the DNA, to cause a mispairing of bases.can slip in between stacked bases, causing bulges in the DNA structure.

can alter nitrogenous bases of DNA, resulting in incorrect base pairing.

When a transposon is cut from one location in genome and pasted into a new location, it is called __________. transpositionreplicative transpositioncut and paste transpositionconservative transposition

conservative transposition

A mutation in the gene encoding the lactose repressor (lacI) that prevents lactose from binding to the LacI protein would result in constant expression of the lac operon in the presence of lactose.constant repression of the lac operon in the absence of lactose.constant repression of the lac operon in the presence of lactose.constant expression of the lac operon in the absence of lactose.

constant repression of the lac operon in the presence of lactose.

Mechanisms for controlling enzyme activity include which of the following? Select all that apply. covalent modification of the enzyme.feedback inhibition.phosphorylationdegradation of the enzyme.addition of short sections of new amino acid sequence.

covalent modification of the enzyme.feedback inhibition.phosphorylationdegradation of the enzyme.

When damaged or single-stranded DNA activates the RecA protein, the RecA protein stimulates the cleavage of LexA. This results in increased transduction and recombination.derepression of the SOS system.repression of polymerase V and activation of endonuclease.activation of homologous recombination.

derepression of the SOS system.

Bacteriophage genomes are typically composed of all of these genomes are equally common in phagedouble-stranded DNA.double-stranded RNA.single-stranded RNA.single-stranded DNA.

double stranded dna

All of the following are true regarding prokaryotic protein secretion EXCEPT Sec and Tat pathways both are fueled by ATP hydrolysis.Some gram-negative secretion systems do not require Sec or Tat.Proteins with complex cofactors, such as iron-sulfur proteins, are Tat secreted.The basic information for locating a protein in the right place is contained within its sequence.Proteins are inserted into the cell membrane by co-translational Sec secretion.

ec and Tat pathways both are fueled by ATP hydrolysis

How is the activity of a riboswitch controlled? sigma factor binding alters its structuremetabolite binding can change its structuresmall RNA complementary binding disrupts its functionby other riboswitchesrepressor binding can change its structure

etabolite binding can change its structure

Lophotrichous

flagella located in a tuft on one end

Amphitrichous

flagella located in tufts on both ends

Some archaea have unique phospholipids in their cytoplasmic membrane that form a bilayer due to the presence of sterols.form a monolayer due to the presence of diglycerol tetraethers.form a bilayer due to the presence of phosphatidylethanolamine.form a stable ring structure due to the presence of crenarchaeol.

form a monolayer due to the presence of diglycerol tetraethers.

Quorum sensing is important in the regulation of all the following EXCEPT virulence. antibiotic production.biofilm production.heat shock proteins.bioluminescence.

heat shock proteins.

The synthesis of ββ-galactosidase is regulated by __________. View Available Hint(s) repressioncatabolite repressioninduction and catabolite repressioninduction

induction and catabolite repression

The methyl-accepting chemotaxis proteins of bacteria are directly connected to the flagellar motor to guide the bacterium.can only sense conditions that are favorable for bacterial growth.are sensor kinasestell the bacterium which way to go.integrate multiple signals through a two component phospho-relay system.

integrate multiple signals through a two component phospho-relay system.

Chemical mutagens, UV radiation, and ionizing radiation all increase mutation rates, but they have different mechanisms. Which type of mutagen would be best suited for creating large deletions and rearrangements within a genome? UV radiationionizing radiationchemical mutagensChemical, UV, and ionizing radiation would create large deletions and rearrangements if used in a very high dose.

ionizing radiation

Which of the following statements regarding DNA gyrase is FALSE? DNA gyrase is inhibited by antibiotics such as tetracyclines. None of the statements are false. removes positive supercoils during DNA unwinding. inserts negative supercoils into DNA by making double strand breaks. A strain of E. coli produces a colicin which is toxic to various pathogenic strains of E. coli. On what type of genetic element would you expect to find the colicin gene? the chromosome a virus an insertion element a plasmid any of these is equally likely

is inhibited by antibiotics such as tetracyclines. a plasmid

Supercoiling is important for DNA structure, because it condenses the DNA so that it can fit inside the cell. it holds together the antiparallel strands of DNA in the double helix .it prevents RNA from pairing with DNA in the double helix .it provides energy for transcription.

it condenses the DNA so that it can fit inside the cell.

You want to know whether the virulence genes present in Bordetella pertussis are evolutionarily related to genes in the less pathogenic species B. bronchiseptica or if the virulence genes were acquired via horizontal gene transfer. What characteristic(s) would you compare to answer this question? ribosomal RNA sequences of the two species percentage of GC content and codon usage in virulence genes number of genes that are different between the species genome size of the two species

percentage of GC content and codon usage in virulence genes

Which of these methods can be used to determine the number of viable microorganisms in a sample? Plate countingMicroscopic counting of DAPI stained cellsLight scattering in a spectrophotometerMeasuring total cell massAll of the choices are correct

plate counting

Viral proteins are categorized as early, middle, and late. Early proteins typically are necessary for production of viral mRNA and copying the viral genome.copying the viral genome.packaging of DNA into the nucleocapsid.production of viral mRNA.

production of viral mRNA and copying the viral genome.

Which of the following functions is NOT conferred by a plasmid? protein synthesisantibiotic resistancevirulence symbiotic nitrogen fixationherbicide degradation

protein synthesis

Analysis of a throat swab confirmed that the causative organism of Shelly's strep throat was Streptococcus pyogenes, a gram-positive organism. Imagine that you are the technician looking at the Gram stain from Shelly's culture. What would you expect to see as you look through the microscope? purple, spherical-shaped organisms arranged in chainlike formationspurple, spherical-shaped organisms arranged in grapelike clusterspink, spherical-shaped organisms arranged in grapelike clusterspink, spherical-shaped organisms arranged in chainlike formationspurple, rod-shaped organisms arranged in pairs

purple, spherical-shaped organisms arranged in chainlike formations

Molecular chaperones function to _______. Select all that apply. provide ATP to proteins that require it recognize unfolded or partially denatured proteins prevent incorrect folding of proteins fold newly formed proteins to their proper shape guide normal, functional proteins to their cellular location

recognize unfolded or partially denatured proteins prevent incorrect folding of proteins fold newly formed proteins to their proper shape

Molecular chaperones function to _______. Select all that apply. provide ATP to proteins that require itrecognize unfolded or partially denatured proteinsprevent incorrect folding of proteinsfold newly formed proteins to their proper shapeguide normal, functional proteins to their cellular location

recognize unfolded or partially denatured proteinsprevent incorrect folding of proteinsfold newly formed proteins to their proper shape

Regulatory proteins regulate transcription.are influenced by small molecules.bind to specific DNA sites.regulate transcription, bind specific DNA sites, and can be influenced by small molecules.

regulate transcription, bind specific DNA sites, and can be influenced by small molecules.

Considering the catabolite repression mechanism, which observation would make you suspect it is occurring? A. elevated levels of transcripts for maltose and sucrose catabolism B. relatively low intracellular cyclic AMP levels C. relatively low intracellular cyclic-di-GMP levels D.RNA polymerase bound to biosynthetic promoter sequences E. CRP bound to operator sites

relatively low intracellular cyclic AMP levels

Considering the catabolite repression mechanism, which observation would make you suspect it is occurring? elevated levels of transcripts for maltose and sucrose catabolismrelatively low intracellular cyclic AMP levelsRNA polymerase bound to biosynthetic promoter sequencesCRP bound to operator sitesrelatively low intracellular cyclic-di-GMP levels

relatively low intracellular cyclic AMP levels

The topoisomerase ________ introduces positive supercoils in hyperthermophile DNA, which stabilizes DNA and prevents the DNA helix from denaturing at high temperatures. ligasereverse ligasehelicasereverse DNA gyraseDNA gyrase

reverse DNA gyrase

The Ames test is based on __________. reversion rates of an auxotrophfrequency of lethal mutationsmutation rates of wild-type strainsrecombination frequency of the wild-type strain

reversion rates of an auxotroph

Peptide bond formation is catalyzed by __________ and occurs between the __________ sites of the ribosome. ribosomal proteins; P and E sites ribosomal RNA (rRNA); A and P sites ribosomal proteins; A and P sites ribosomal RNA (rRNA); P and E sites

ribosomal RNA (rRNA); A and P sites

Peptide bond formation is catalyzed by __________ and occurs between the __________ sites of the ribosome. ribosomal proteins; P and E sitesribosomal RNA (rRNA); A and P sitesribosomal proteins; A and P sitesribosomal RNA (rRNA); P and E sites

ribosomal RNA (rRNA); A and P sites

You expose a bacterial strain to DNA containing bacitracin resistance. Then you plate the resulting culture onto a rich medium containing bacitracin. This is an example of ScreeningSelectionBoth selection and screeningNeither selection nor screening

selection

A plasmid differs from the bacterial chromosome in that it is __________. always found as a single copy of DNA in a celldouble-strandedcircularsignificantly smaller

significantly smaller

When describing the bacteriophage genome, which terms could be used? Select all that apply. View Available Hint(s) ss RNAds DNA ds RNA ss DNA

ss RNAds DNA ds RNA ss DNA

Type V secretion systems start with Sec-dependent transport across the plasma membrane, but the transported protein then forms a channel in the outer membrane through which it autotransports.move proteins from the cytoplasm across both the plasma membrane and the outer membrane.can transport DNA during conjugation, in addition to proteins.are used by pathogens to secrete virulence factors from the cytoplasm, across both the plasma membrane and outer membrane, and into host cells.

start with Sec-dependent transport across the plasma membrane, but the transported protein then forms a channel in the outer membrane through which it autotransports.

Which of the following statements is FALSE concerning peptidyl transferase? It requires no outside source of additional energy, such as GTP.It catalyzes peptide bond formation.It is a ribozyme having catalytic activity.It moves the ribosome, so translation continues.It is a function of 23S rRNA.

t moves the ribosome, so translation continues.

A new antibiotic is able to bind the rho factor associated with transcription. As a result, this antibiotic would affect termination of all transcription.binding of RNA polymerase.termination of some transcription.elongation of transcription.initiation of transcription.

termination of some transcription.

Fluorescent in situ hybridization (FISH) can be used to determine __________. Select all that apply. A. how many Salmonella typhimurium cells are present in a sample of unpasteurized apple juice B. genes of interest in the genomes of individual microbial cells C. the phylogenetic diversity of an environmental sample

the phylogenetic diversity of an environmental sample genes of interest in the genomes of individual microbial cellshow many Salmonella typhimurium cells are present in a sample of unpasteurized apple juice

You are studying a protein in Salmonella typhimurium that you believe is a toxin. Whenever you attempt to purify the protein from lysed cell cultures, you get two forms of the protein. One form is smaller than the other and is missing 15 amino acids from the N-terminus compared to the larger form. This leads you to hypothesize that the protein requires chaperonins to fold properly .there are two termination sites in the mRNA. the protein is secreted and folds outside of the cell. you need to re-do the experiment because there should only be one form.

the protein is secreted and folds outside of the cell.

You are studying a protein in Salmonella typhimurium that you believe is a toxin. Whenever you attempt to purify the protein from lysed cell cultures, you get two forms of the protein. One form is smaller than the other and is missing 15 amino acids from the N-terminus compared to the larger form. This leads you to hypothesize that the protein requires chaperonins to fold properly.there are two termination sites in the mRNA.the protein is secreted and folds outside of the cell.you need to re-do the experiment because there should only be one form.

the protein is secreted and folds outside of the cell.

The first step of translation begins when __________. A) the ribosome binding site (RBS) on the mRNA binds to the 23S rRNA B) the 30S ribosomal subunit combines with the 50S ribosomal subunit, enclosing the mRNA C) the initiator aminoacyl-tRNA binds to the start codon on the mRNA at the A site of the ribosome D) the ribosome binding site (RBS) on the mRNA binds to the 16S rRNA E) tRNA binds to the P site on the ribosome to initiate translation

the ribosome binding site (RBS) on the mRNA binds to the 16S rRNA

The first step of translation begins when __________. View Available Hint(s) the ribosome binding site (RBS) on the mRNA binds to the 23S rRNA the 30S ribosomal subunit combines with the 50S ribosomal subunit, enclosing the mRNA the initiator aminoacyl-tRNA binds to the start codon on the mRNA at the A site of the ribosome the ribosome binding site (RBS) on the mRNA binds to the 16S rRNA tRNA binds to the P site on the ribosome to initiate translation

the ribosome binding site (RBS) on the mRNA binds to the 16S rRNA

In E. coli, the consensus sequence for the Pribnow box (the -10 sequence) is TATAAT. Therefore, __________. the sigma factor will only recognize this -10 sequenceTATACT will be a very weak -10 promoter sequencethis sequence will always be transcribed into RNAthis will be the strongest -10 promoter sequence

this will be the strongest -10 promoter sequence

What is the purpose of synthesizing a negative strand RNA in positive stranded ssRNA viruses? enable rolling circle amplification of the genome, which requires both strands of RNAto serve as the complementary template sequence in genome amplification of the positive strandproofreading of the genome to minimize mutations generated by the polymerase being passed onto virion progenyenable transcription of genes occurring on both the negative and positive strands of the genome, such as overlapping genes

to serve as the complementary template sequence in genome amplification of the positive strand

Attenuation is a type of regulation that directly controls post-translational activitytranslational activity.transcriptional activity.allosteric enzyme activity.both transcriptional and translational activity.

transcriptional activity

Referring to attenuation in the regulation of the tryptophan operon, when there are high levels of tryptophan available to the organism, ____. tryptophan inactivates the repressor proteinthe tryptophan operon is being transcribed at relatively high levelstranscriptional termination is likely when ribosomes pause at the end of the leader peptidetranscriptional termination is likely when ribosomes stall at a tryptophan codonamino acids will bind to the tryptophan riboswitch and turn it off

transcriptional termination is likely when ribosomes pause at the end of the leader peptide

Most riboswitches control tRNA synthesis.translation.ribosome synthesis.transcription.

translation

Which of the following is the correct abbreviation for a mutation in a gene that synthesizes one of the enzymes involved in tryptophan production? trpTrp-trpC1TrpC

trpC1

You are examining an enzyme associated with cysteine biosynthesis. You would expect expression of this enzyme to be under posiitve control by induction.under positive control.under negative control by induction.under negative control by repression.induced by cysteine.

under negative control by repression.

The SOS system repairs DNA that has gaps, breaks, and other lesions by using available mRNA and a special RNA-dependent DNA polymerase to fill in the gaps and replace damaged DNA.stabilizing single-stranded DNA until the next round of normal replication.cutting DNA from other parts of the genome and pasting it into the gaps or damaged areas.using specialized DNA polymerases that will synthesize a new DNA strand even if thereis not a normal complementary DNA strand to act as a template.

using specialized DNA polymerases that will synthesize a new DNA strand even if thereis not a normal complementary DNA strand to act as a template.