Micro Exam 1 Questions
A bacterium that is extremely resistant to UV is __________.
Deinococcus
The earliest stromatolites were probably formed by oxygenic phototrophs. anoxygenic lithotrophs. anoxygenic phototrophs. oxygenic lithotrophs.
anoxygenic phototrophs.
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? Bacteria or Archaea Algae Archaea Bacteria Protozoa
archaea
Organisms in the Vibrio group and enteric bacteria differ in that Vibrio __________.
are oxidase-positive
Which of the following bacterial structures excludes small particles like those found in India ink? fimbriae flagella pili capsules
capsules
The bacterial cytoskeleton influences __________.
cell shape
You are studying 12 new isolates from the human skin. Their 16S rRNA gene sequence identity is 97%.The isolates would most likely be classified as individual strains of the same species. split into different families. classified as individual species of the same genus. classified as the same species if they can mate via conjugation.
classified as individual strains of the same species.
Which of the following habitats is home to the largest percentage of prokaryotic biomass on Earth? marine subsurface oceans surface soils freshwater terrestrial subsurface
marine subsurface
Like all forms of life on Earth, all microbial cells perform three major types of activities: __________. growth, genetic exchange, and evolution growth, differentiation, and metabolism metabolism, growth, and evolution metabolism, growth, and genetic exchange
metabolism, growth, and evolution
Which organisms are parts of domain Archaea? methanogens microsporidia cyanobacteria rickettsia
methanogens
What sole source of carbon results in the pink-pigmented biofilms found in toilets, shower curtains, and caulk?
methanol
What is the name for organisms that require oxygen for their metabolic processes but cannot tolerate it at atmospheric levels?
microaerophiles
The number of colonies obtained in a plate count does NOT depend on the inoculum volume. type of culture medium. size of the colonies. incubation time.
size of the colonies.
Louis Pasteur developed vaccines for all of the following diseases EXCEPT __________. smallpox rabies fowl cholera anthrax
smallpox
The antibiotic penicillin inhibits __________.
transpeptidation
The final step in peptidoglycan synthesis is __________.
transpeptidation
β-lactam antibiotics inhibit peptidoglycan glycan tetrapeptide precursor formation. transpeptidation. transglycosylation. transglycosylation and transpeptidation. autolysins.
transpeptidation
Which of the following is NOT a toxic form of oxygen? singlet oxygen hydroxyl radical superoxide anion triplet oxygen
triplet oxygen
Lactobacilli are important, economically valuable bacteria used in the production of __________.
yogurt
The major source of carbon was _________ for early cells and the major fuel for energy was __________ for early cells. O2 ; CO2 N2 ; H2 CO2 ; N2 CO2 ; H2
CO2 ; H2
The epsilon proteobacteria include __________.
Campylobacter and Helicobacter
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? Cell walls are made primarily of peptidoglycan. It can survive at a temperature over 100°C. The organism lacks a nucleus. The lipids in its plasma membrane consist of glycerol bonded to isoprenoid side chains.
Cell walls are made primarily of peptidoglycan.
Who was the scientist that discovered endospores?
Cohn
Which of the following statements is FALSE? Humans contain 10 times more bacterial cells than human cells. Eighty percent of life's history on Earth is exclusively microbial. Estimates of the total number of prokaryotic cells on Earth are about 2.5 x10^30. There are no known pathogenic Archaea. Microbial biomass on Earth likely exceeds that of higher organisms.
Humans contain 10 times more bacterial cells than human cells.
Which statement shows which adaptations are necessary for hyperthermophilic proteins to stay functional at temperatures above 80°C? Hyperthermophiles have decreased ionic bonds to stabilize the proteins. Hyperthermophiles have increased ionic bonds to stabilize the proteins. Hyperthermophiles have highly hydrophilic interiors to stabilize the proteins. Hyperthermophiles synthesize proteins with completely unique amino acid sequences to stabilize the proteins.
Hyperthermophiles have increased ionic bonds to stabilize the proteins.
Which of the following is NOT a limitation to performing a direct microscopic count to estimate cell numbers? Live cells and dead cells appear the same. Sample debris can be mistaken for microbial cells. It requires little time to perform. The movement of motile cells is not a limitation.
It requires little time to perform.
In energizing its flagella, how has Bacillus firmus adapted to life at high pH?
It uses a sodium motive force rather than a proton motive force.
Which of the following statements regarding LUCA is FALSE? LUCA is the ancestor of archaea and bacteria. LUCA was the first form of life. LUCA was likely a hyperthermophile living at hydrothermal vents. LUCA fixed carbon and nitrogen. None of the statements are false.
LUCA was the first form of life.
Check all the reasons why a microbial species is difficult to define. Molecular techniques don't work on microbes. Microbes don't use sexual reproduction. There is a very limited fossil record for microbes. Microbes have limited morphological features. Microbes are very difficult to sequence.
Microbes don't use sexual reproduction. There is a very limited fossil record for microbes. Microbes have limited morphological features.
The proteins __________ direct FtsZ to the midpoint of the cell.
MinC, MinD, and MinE
The major shape-determining factor in Bacteria is the protein MreB. FtsZ. MinD. crescentin.
MreB
Consider the following two statements: I) Ecosystems are influenced by microbial activities. II) Microbial ecosystems remain constant over time.
Only statement I is correct.
Which technique is frequently used in phylogenetic analysis to obtain sufficient copies of a gene for sequencing?
PCR
What is NOT a limitation of molecular phylogeny? Horizontal and vertical gene exchanges occur. Several different trees can fit the data equally well. Problems decrease in proportion to evolutionary time. Organisms can share a trait not inherited from a common ancestor.
Problems decrease in proportion to evolutionary time.
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? SPC = 12 × 10^6 cfu/ml; SPEC = 11 × 10^7 cfu/ml SPC = 100 cfu/ml; SPEC = 10 cfu/ml SPC = 12 × 10^6 cfu/ml; SPEC = 12 × 10^6 cfu/ml SPC = 12 × 10^7 cfu/ml; SPEC = 11 × 10^3 cfu/ml
SPC = 12 × 106 cfu/ml; SPEC = 11 × 107 cfu/ml
Consider solution A (pH 6) and solution B (pH 9). Which of the following statements is CORRECT? Solution B is 3,000 times more alkaline (basic) than solution A. Solution B is 1,000 times more alkaline (basic) than solution A. Solution A is 300 times more acidic than solution B. Solution A is 3 times more acidic than solution B.
Solution B is 1,000 times more alkaline (basic) than solution A.
________ are charged molecules that are partially responsible for the ________ charge of the gram-positive bacterial cell surface. Lipopolysaccharides / negative Diaminopimelic acids / positive Phospholipids / negative Peptide interbridges / neutral Teichoic acids / negative
Teichoic acids / negative
Predict the effect of greatly reduced levels of FtsZ proteins in growing E. coli cells. 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. The cells will divide uncontrollably, leading to very small, almost coccoid cells. The cells will continue to elongate but will be unable to form a septum and divide, leading to very elongated cells. The cells would stop growing and soon die.
The cells will continue to elongate but will be unable to form a septum and divide, leading to very elongated cells.
Which of the following regarding prokaryotic cell shape is FALSE? The largest known prokaryote has an elongated shape with membrane infoldings. The most common shape in many environments is a rod. Cell shape in many wall-less bacteria is determined by the cytoskeleton. Shape influences nutrient uptake, motility, attachment, and reproduction. Cell shape is determined largely by the cell wall.
The largest known prokaryote has an elongated shape with membrane infoldings.
One organism grows optimally at pH 6, whereas another grows optimally at pH 9. What is the difference in hydrogen ion concentration between these two environments?
The pH 6 environment has 1000 times higher hydrogen ion concentration.
Which of the following is the best explanation for how membranes conserve energy? They trap ATP molecules within their lipid bilayers. They prevent the passive diffusion of water across the membrane. The hydrolysis of membrane lipids is coupled to ATP synthesis. They develop proton motive force, which drives the activity of ATP synthase.
They develop proton motive force, which drives the activity of ATP synthase.
How do osmophiles obtain the water necessary for their continued growth?
They pump compatible solutes from the environment into the cell so that osmosis drives water into the cell.
Which statement illustrates the chemical basis for the predominant type of fatty acids in the plasma membrane of a psychrophile? Saturated fats have straight side chains that prevent tight packing as temperatures drop. Unsaturated fats have straight side chains that prevent tight packing as temperatures drop. Unsaturated fats have kinked side chains that prevent tight packing as temperatures drop. Saturated fats have kinked side chains that prevent tight packing as temperatures drop.
Unsaturated fats have kinked side chains that prevent tight packing as temperatures drop.
The Mollicutes are distinguished by the __________.
absence of a cell wall
Arrange the types of microorganism in the order they evolved on Earth. aerobes, oxygenic phototrophs, anoxygenic phototrophs, anaerobes, multicellular organisms anaerobes, multicellular organisms, aerobes anaerobes, anoxygenic phototrophs, oxygenic phototrophs, aerobes, multicellular organisms anaerobes, anoxygenic phototrophs, aerobes, oxygenic phototrophs, multicellular organisms
anaerobes, anoxygenic phototrophs, oxygenic phototrophs, aerobes, multicellular organisms
Sphingolipids are synthesized by __________.
bacteroides
which of the following is a problem when defining bacterial and archaeal species as having more than 70% DNA-DNA hybridization? a) the 70% cut-off needs to be lowered, as it will split microbes of the same species into different species b) the DNA sequences in bacterial species cannot be directly compared due to differences in genome sizes c) horizontal gene transfer can cause large parts of the genome to be different in microbes of the same species d) this method is only accurate for defining archaeal species e) both b and d
c) horizontal gene transfer can cause large parts of the genome to be different in microbes of the same species
The curved-rod shape typical of Caulobacter is due to MreB. crescentin and MreB. crescentin. neither crescentin nor MreB.
crescentin and MreB.
Which choice illustrates best what occurs in the stationary phase of bacterial growth? cryptic growth, where the number of new cells equals the number of dying cells unbalanced growth, where the number of dead cells increases while the number of new cells decreases cryptic growth, where the number of dead cells decreases while the number of new cells increases balanced growth, where the number of dead cells equals the number of new cells
cryptic growth, where the number of new cells equals the number of dying cells
All of the following contain chloroplasts in their cells EXCEPT __________. plants cyanobacteria red algae green algae
cyanobacteria
For binary fission to begin, the bacterial chromosome must attach to what cell structure?
cytoplasmic membrane
What molecules reduce the water content of a bacterial endospore?
dipicolinic acid and calcium
Which of the following choices is the highest level of taxonomic hierarchy? order family domain class
domain
which is true in regard to microbes? a) their size is typically measured in mm b) they exist as collections of cells c) they make up roughly 30% of the planet's biomass d) if you count each living thing, 50% of the planet is microbial e) they have a large surface to volume ratio to allow for exchange with surroundings
e) they have a large surface to volume ratio to allow for exchange with surroundings
What is the name of the hypothesis that mitochondria and chloroplasts originated from prokaryotic organisms?
endosymbiotic hypothesis
During prokaryotic cell division, segregation of the chromosome to the cell poles __________.
ensures each daughter cell gets a single copy of the genome
Control of infectious diseases currently is the result of all of the following EXCEPT __________. eradication of hundreds of pathogens improved sanitary and public health practices increased understanding of disease processes the use of antimicrobial agents
eradication of hundreds of pathogens
Biofilm formation has __________. only 1 basic stage three basic stages four basic stages six basic stages
four basic stages
Scientists have identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains? ecological characteristics such as the ability to survive in extreme environments genetic characteristics such as ribosomal RNA sequences metabolic characteristics such as chemoautotrophy and photosynthesis microscopically observed staining characteristics of the cell wall metabolic characteristics such as the production of methane gas
genetic characteristics such as ribosomal RNA sequences
Nomenclature follows the binomial system, which means that the names of organisms are composed of which of the following?
genus names and species epithets
Predict which type of organism would be more difficult to treat with antibiotics and why. gram-positive organisms -- thicker peptidoglycan layer gram-positive organisms -- no LPS layer gram-negative organisms -- thinner peptidoglycan layer gram-negative organisms -- extra layer of LPS
gram-negative organisms -- extra layer of LPS
For what type of organisms is the biological species concept NOT meaningful?
haploid organisms
Proteins MinC, MinD, and MinE interact to determine cell shape. initiate peptidoglycan synthesis. assist chromosome segregation. help guide FtsZ to the cell midpoint.
help guide FtsZ to the cell midpoint.
Compared to Eukaryotes, Bacteria and Archaea have ________ surface-to-volume ratios, causing ________ nutrient exchange and growth rates. lower / higher lower / lower higher / lower higher / higher
higher / higher
Energy-generating metabolism in primitive cells may have relied on what substance?
pyrite
In microscopy, what is the limiting factor in our ability to see microorganisms clearly?
resolution
What is the technique called that analyzes the restriction fragments of organisms' rRNA genes?
ribotyping
Small gram-negative obligate, intracellular parasites are members of __________.
rickettsias
In Bacillus, what kind of regulatory system activates sporulation under adverse environmental conditions ?
two-component regulatory system
Microorganisms play key roles in the cycling of important nutrients in plant nutrition, particularly those of nitrogen. sulfur. carbon, nitrogen, sulfur, and phosphorus. carbon. carbon and nitrogen
carbon, nitrogen, sulfur, and phosphorus.
In Caulobacter stalked cells, which of the following definitions is true? cells that lack flagella and are involved in reproduction free-swimming cells that are involved in reproduction cells that live in nutrient-poor environments and are unable to divide cells that are attached to a surface by a stalk and are responsible for population dispersal
cells that lack flagella and are involved in reproduction
Which of the following is NOT part of phenotypic analysis? physiology of the cell cell morphology cell wall chemistry cellular genome
cellular genome
This phylum only contains two genera of bacteria that are obligate, intracellular parasites with poor metabolic capabilities.
chlamydia
Which of the following terms refers to a bacterium with a spherical shape? spirochete bacillus coccus spirillum
coccus
Relative to enzymes in mesophilic microorganisms, which of the following is NOT characteristic of enzymes in psychrophiles? decreased beta sheets less hydrogen bonds less ionic bonds decreased alpha helices
decreased alpha helices
Which of the following structures enable a Bacterial or Archaeal cell to adjust its position in a water column? polyphosphate granules gas vacuoles S-layer proteins type IV pili
gas vacuoles
Which of the following processes permits novel functions to develop through continued mutation? gene duplication gene deletion neutral mutation harmful mutation
gene duplication
An example of a differential stain is __________.
gram stain
The addition of thioglycolate into a growth medium would LEAST support the growth of a(n) microaerophilic aerobe. facultative aerobe. aerotolerant anaerobe. obligate anaerobe.
microaerophilic aerobe.
Which types of organisms are the most important for the maintenance of life on Earth? microorganisms plants animals humans
microorganisms
The largest mass of living material on Earth comes from plants and animals together. microorganisms. plants. animals
microorganisms.
Accurately counting cells in a biofilm would be challenging when using turbidity measurement. microscopic direct county, turbidity measurement, and viability counts with spread plating. viability counts with spread plating. microscopic direct counting.
microscopic direct county, turbidity measurement, and viability counts with spread plating.
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
most likely an archaeon.
The morphology of a cell influences its motility and surface-to-volume ratio. surface-to-volume ratio. metabolism. motility
motility and surface-to-volume ratio.
Gram-positive bacteria that stain positive with the acid-fast stain are __________.
mycobacteria
In phylogeny, which of the following is NOT a domain? Eukarya Archaea Bacteria Plantae
plantae
An organism of the genus Staphylococcus is ________, while an organism of the genus Spirochaeta is ________. spherical / rod shaped spiral / spherical spherical / spiral rod shaped / spiral
spherical / spiral
The aerial filaments of the Streptomyces are called __________.
sporophores
What allows for a planktonic organism to float in water?
the gas the organism is growing in
What was LUCA? the type of prokaryote that evolved into a eukaryote the last eukaryote before eukaryotes diversified the first cellular organism to evolve the last organism prior to the divergence of bacteria and archaea
the last organism prior to the divergence of bacteria and archaea
In what size range is the diameter of a typical prokaryotic cell?
0.5 to 2 μm
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? 136 bacteria/ml 1.36 × 10^5 bacteria/ml 1.36 × 10^8 bacteria/ml 1.36 × 10^6 bacteria/ml
1.36 × 10^8 bacteria/ml
A colony on a Petri plate arises from a single cell. How many cells does a typical bacterial colony contain?
10^7
What is thought to be the maximum temperature for life to exist? 150°C 125°C 250°C 500°C
150°C
The phylum Proteobacteria is currently divided into six classes based on __________.
16S rDNA sequences
What is the most recent date when all cells on Earth still lacked a membrane-enclosed nucleus?
2 BYA
What is the recommended DNA-DNA hybridization value to say that two organisms are members of the same species?
70%
The attachment stage in biofilm formation is __________. a lead-up to expression of biofilm specific genes facilitated by flagella facilitated by pili initially due to a random collision with a cell All of the listed responses are correct
All of the listed responses are correct
Alphaproteobacteria __________. fill a host of diverse ecological niches are rod shaped synthesize peptidoglycan at the poles grow via budding All of the listed responses are correct.
All of the listed responses are correct.
Fts proteins are essential for bacterial cell division because they __________. are involved in the forming of the divisome are involved in the pulling apart the two copies of the chromosome are involved in peptidoglycan synthesis All of the listed responses are correct.
All of the listed responses are correct.
Scientists believe life may have begun as an RNA world because __________. RNA is essential to processes found in all cells RNA can have catalytic activity RNA can bind small molecules All of the listed responses are correct.
All of the listed responses are correct.
Which of these statements is/are TRUE? Nonphototrophic organisms are able to grow at higher temperatures than phototrophic organisms. In general, prokaryotic organisms can grow at higher temperatures than eukaryotic organisms. The most thermophilic prokaryotes are species of Archaea. All of the statements are true.
All of the statements are true.
Under which of the following conditions is a long lag phase LEAST likely to occur? An exponentially growing culture is transferred into the same medium under the exact same conditions of growth. An inoculum is taken from a stationary-phase culture and transferred into the same medium. An inoculum of damaged cells is transferred into the same medium. A microbial population is transferred from a rich culture medium to a poor one.
An exponentially growing culture is transferred into the same medium under the exact same conditions of growth.
Under which of the following conditions is a long lag phase LEAST likely to occur? An inoculum of damaged cells is transferred into the same medium. An innoculum of endospores is transferred to the medium. An exponentially growing culture is transferred into the same medium under the same growth conditions. A microbial population is transferred from a rich culture medium to a poor one. An inoculum is taken from a stationary-phase culture and transferred into the same medium.
An exponentially growing culture is transferred into the same medium under the same growth conditions.
To what domain would an organism that has ether-linked membrane lipids and no peptidoglycan belong?
Archaea
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? Archaella and type IV pili both act by rotating. Archaella are powered directly by ATP, but bacterial type IV pili are powered by a proton motive force. Archaella are important for swimming motility, while type IV pili are important in twitching motility. Archaella and type IV pili are both important in attachment to host tissues. Archaella and type IV pili have genetic similarities revealed by genomic studies.
Archaella are important for swimming motility, while type IV pili are important in twitching motility. Archaella and type IV pili have genetic similarities revealed by genomic studies.
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? Archaella are always associated with greater speeds than those allowed by bacterial flagella. Archaella propel archaeans by contracting and lengthening, but flagella propel Bacteria by rotating. Archaella are made of proteins unrelated to the flagellin in bacterial flagella. Archaella flagella have smaller diameters than bacterial flagella. Archaella are powered directly by ATP, but bacterial flagella are powered by a proton motive force.
Archaella are made of proteins unrelated to the flagellin in bacterial flagella. Archaella flagella have smaller diameters than bacterial flagella. Archaella are powered directly by ATP, but bacterial flagella are powered by a proton motive force.
Endospore-forming members of the Firmicutes are __________.
Bacillus and Clostridium
One of the hypotheses about eukaryotic cell formation proposes that a nucleus-bearing cell acquired a mitochondrial-precursor cell by endosymbiosis. Which of the following statements reflects a major problem with this hypothesis? Bacteria and Archaea do not contain a membrane-bound nucleus. Chloroplasts are found only in cells containing a membrane-bound nucleus. Mitochondria are found only in cells containing a membrane-bound nucleus. Bacteria and Eukarya have similar membrane lipids.
Bacteria and Eukarya have similar membrane lipids.
You identify a new living organism that needs to be classified into one of the three domains of life. The organism has a cell wall, a cell membrane, and a nucleoid region. Based on this information, which of the three domains could you choose?
Bacteria or Archaea
Different arrangements and structures of flagella contribute to changes in speed and direction when necessary. Which of the following correctly relates motility to flagellation? Bacteria with peritrichously arranged flagella change direction by changing the flagellar rotation and "tumbling." Peritrichously arranged flagella may only rotate counterclockwise. Certain flagellated prokaryotes exhibit gliding motility, a slower and smoother form of movement along the long axis of a cell. Bacteria with lophotrichously arranged flagella change direction only by changing the flagellar rotation.
Bacteria with peritrichously arranged flagella change direction by changing the flagellar rotation and "tumbling."
Who showed that viruses were filterable agents that were smaller than bacteria?
Beijerinck
Which of the following are true regarding both flagella and pili? Select all that apply. Both are extracellular surface appendages. Flagella and pili are made up of proteins Flagella and pili occur in both Bacteria and Archaea. Their functions include motility. Both flagella and pili are hollow inside.
Both are extracellular surface appendages. Flagella and pili are made up of proteins Their functions include motility.
Which of the following are true of capsules? Select all that apply. Capsules are considered part of the cell wall. Capsules occur in both Bacteria and Archaea. Capsules retain water and help prevent desiccation of the bacteria. Capsules help hide bacterial cells from the host immune system. Capsules are involved in the attachment of microorganisms to solid surfaces.
Capsules occur in both Bacteria and Archaea. Capsules retain water and help prevent desiccation of the bacteria. Capsules help hide bacterial cells from the host immune system. Capsules are involved in the attachment of microorganisms to solid surfaces.
In which bacteria would you find MreB proteins and why? Neisseria gonorrhea, because it is coccus-shaped E. coli, because it is rod-shaped. Staphylococcus aureus, because it is coccus-shaped Mycoplasma pneumoniae, because it is pleomorphic
E. coli, because it is rod-shaped.
All of the following regarding endospores are true EXCEPT Botulism, tetanus and several foodborne bacterial infections are caused by endospore-forming bacteria. Endospores serve as reproductive structures and enable survival in harsh environments. All endospore-forming bacteria are gram-positive Firmicutes. Endospore formation begins when growth ceases due to the lack of an essential nutrient.
Endospores serve as reproductive structures and enable survival in harsh environments.
Which statement about endotoxins is true? The source of endotoxins is endospores. Endotoxins are components of the cell wall of gram-positive bacteria. Endotoxins are proteins secreted by prokaryotes. Endotoxins are released only when Gram negative bacteria die and their cell walls break down. Endotoxins are released by lysozyme.
Endotoxins are released only when Gram negative bacteria die and their cell walls break down.
Microbes have undergone a number of adaptations to survive in the cold. Which of the following statements is FALSE? Enzyme flexibility is maintained by increasing the number of hydrogen and ionic bonds. Enzyme catalytic functionality arises through more ahelical secondary structures. Membrane fluidity is maintained by a higher percentage of unsaturated fatty acids. Membrane damage can be prevented by the production of molecules such as glycerol.
Enzyme flexibility is maintained by increasing the number of hydrogen and ionic bonds.
The lipids in the cytoplasmic membrane of Bacteria and ________ contain ester linkages, while the cytoplasmic membrane of ________ contain ether linkages. Archaea / fungi Eukarya / prokaryotes Eukarya / Archaea Archaea / Eukarya
Eukarya / Archaea
Which of the following statements best describes how fimbriae and capsules differ from each other? Fimbriae are filamentous structures, whereas capsules are not. Only capsules are involved in sticking cells to surfaces. Fimbriae are not found on pathogens, whereas capsules are found on pathogens. Only fimbriae are involved in sticking cells to surfaces.
Fimbriae are filamentous structures, whereas capsules are not.
Penicillin inhibits which of the following molecules during cell division? FtsI MinE FtsK FtsZ FtsA
FtsI
Porins are present in ______________bacteria because, in these organisms, molecules entering the cell must pass through an extra layer of ___________. Gram-negative; membrane Gram-negative; peptidoglycan Gram-positive; peptidoglycan Gram-positive; membrane both Gram-negative and Gram-positive; membrane
Gram-negative; membrane
Which statement best illustrates the importance of a high surface-to-volume ratio that is found in microorganisms? 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. 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. 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. 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.
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.
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? -Certain flagellated prokaryotes exhibit gliding motility, a slower and smoother form of movement along the long axis of a cell. -Bacteria with lophotrichously arranged flagella change direction only by changing the flagellar rotation. -In general, organisms with polar flagella move more quickly than peritrichously flagellated organisms. -Bacteria with amphitrichously arranged flagella change direction by periodically stopping to reorient themselves or by changing the flagellar rotation. -Peritrichously arranged flagella may only rotate counterclockwise. -Bacteria with peritrichously arranged flagella change direction by changing the flagellar rotation and "tumbling."
In general, organisms with polar flagella move more quickly than peritrichously flagellated organisms. -Bacteria with amphitrichously arranged flagella change direction by periodically stopping to reorient themselves or by changing the flagellar rotation. -Bacteria with peritrichously arranged flagella change direction by changing the flagellar rotation and "tumbling."
What is the function of bactoprenol? It is a hydrophobic alcohol that transports peptidoglycan precursors across the cytoplasmic membrane. It triggers the recruitment of FtsZ and the initiation of the divisome. It is responsible for forming the peptide cross-links between muramic acid residues in adjacent glycan chains. It supplies the energy necessary for transpeptidation to occur.
It is a hydrophobic alcohol that transports peptidoglycan precursors across the cytoplasmic membrane.
Which is/are a function(s) of the cytoplasmic membrane in prokaryotes? It is a major site of energy conservation. It serves as a permeability barrier, a docking station for proteins involved in bioenergetics reactions and transport, and a site for energy conservation. It functions as a permeability barrier. It is an anchor for many proteins involved in bioenergetic reactions and transport.
It serves as a permeability barrier, a docking station for proteins involved in bioenergetics reactions and transport, and a site for energy conservation.
Which of the following molecules is shared by both Gram-positive and Gram-negative organisms? lipid A endotoxin lipopolysaccharide lipoteichoic acid N-acetylmuramic acid
N-acetylmuramic acid
Which of the following is found in pseudomurein but NOT peptidoglycan? l-lysine l-alanine N-acetylglucosamine N-acetyltalosaminuronic acid
N-acetyltalosaminuronic acid
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? Only the Bacteria will be lysed. None of the cells will be lysed. Only the Archaea will be lysed. All cells will be lysed.
Only the Bacteria will be lysed.
Which of the following bacterial structures serves the same function as adipose tissue in animals? PHA granules polyphosphate granules sulfur globules magnetosomes
PHA granules
What is one piece of evidence that supports the RNA world hypothesis? RNAs can have catalytic activity. RNAs can replicate themselves. There are traces of RNA that have been dated and found to be older than any traces of DNA. Early cells relied more heavily on RNA than on DNA. RNA is more stable than DNA and therefore more likely to have been able to exist in such a harsh environment.
RNAs can have catalytic activity
Which of the following is NOT a difficulty when using turbidity to track cell growth? Some bacteria have short generation times. Some bacteria form filaments of attached cells. Some cells clump together. Some cells form biofilms on the sides of culture vessels.
Some bacteria have short generation times.
Gliding motility in bacteria involves which of the following? Specialized cell-surface proteins and slimy polysaccharides Specialized cell-surface proteins, flagella, and slimy polysaccharides Specialized cell-surface proteins Flagella Slimy polysaccharides
Specialized cell-surface proteins and slimy polysaccharides
The production of the virulence factors streptolysin O and S is diagnostic for __________.
Streptococcus pyogenes
This genus of the gram-positive bacteria has a filamentous morphology and synthesizes antimicrobial secondary metabolites.
Streptomyces
Which of the following choices represents one of the most common reasons bacterial growth is limited in a batch culture? Metabolic processes decrease the temperature of the medium, and this stops growth. Space becomes limiting as the cells become too tightly packed to grow. Metabolic processes increase the temperature of the medium, and this stops growth. The accumulation of waste products is toxic to cells.
The accumulation of waste products is toxic to cells.
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? The concentration of MinCDE proteins is highest in the midpoint of the cell. MinCDE proteins are fixed at the site of septum formation. MinCDE proteins form the scaffold for septum construction. The concentration of MinCDE proteins is lowest in the midpoint of the cell.
The concentration of MinCDE proteins is lowest in the midpoint of the cell.
If photosynthetic organisms were present when the earth was primarily anoxic, why was the development of cyanobacteria critical for the oxidation of the atmosphere? The early forms of photosynthesis were carried out in the water and there was no way for the oxygen to move into the atmosphere. Cyanobacteria carry out anoxic photosynthesis. The early forms of photosynthesis did produce oxygen, but it was not enough to make a difference in the atmosphere. The early forms of photosynthesis did not produce oxygen as a waste product.
The early forms of photosynthesis did not produce oxygen as a waste product.
As a general trend, which of the following statements is most true concerning the maximal growth rate of psychrophiles? The maximum growth rates of psychrophiles are less than the maximum growth rates of mesophiles. The maximum growth rates of psychrophiles are equal to the maximum growth rates of mesophiles. The maximum growth rates of psychrophiles are observed at their maximum growth temperature. The maximum growth rates of psychrophiles are greater than the maximum growth rates of mesophiles.
The maximum growth rates of psychrophiles are less than the maximum growth rates of mesophiles.
If two microbes were going to be considered for the same species, what criteria would apply? (Check all that apply) The two microbes must be found colonizing the same environment. The two microbes must have at least 70% whole genome similarity, as determined by DNA-DNA hybridization. The two microbes must be grown in pure culture. The two microbes must have phenotypic similarity. There must be less than 3% divergence in rRNA gene sequences between the two microbes.
The two microbes must have at least 70% whole genome similarity, as determined by DNA-DNA hybridization. The two microbes must have phenotypic similarity. There must be less than 3% divergence in rRNA gene sequences between the two microbes.
Explain why the presence of a capsule or slime layer would benefit a bacterial cell. These outer layers prevent water from entering the cell, causing rapid dehydration. These outer layers can aid in attachment to solid surfaces. These outer layers can help the immune system recognize foreign organisms. These outer layers can prevent added virulence during a bacterial infection.
These outer layers can aid in attachment to solid surfaces.
Which of the following is LEAST commonly associated with endospore-forming bacteria? They can survive adverse environmental conditions. They are primarily soil dwellers. They are saprophytic. They are coccus-shaped organisms.
They are coccus-shaped organisms.
Which of the following choices is NOT a reason to utilize small subunit rRNA genes in phylogenetic analysis? They are functionally constant. They have no enzymatic function. They are large enough to provide an evolutionary history. They are universally distributed.
They have no enzymatic function.
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? This shape enables this bacteria to float on surfaces and obtain better light exposure. This shape is difficult for phagocytic cells to attach to and engulf. This shape is more conducive to the formation of biofilm communities. This shape increases the surface to volume ratio enabling more efficient nutrient uptake.
This shape increases the surface to volume ratio enabling more efficient nutrient uptake.
These two gram-positive bacteria form cytoplasmic appendages called prosthecae.
Verrucomicrobium and Planctomyces
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? on Petri plates containing a low-nutrient medium a batch culture using a low-nutrient medium This organism cannot be grown in the lab. a chemostat using a low-nutrient medium
a chemostat using a low-nutrient medium
The main functions of the bacterial cell wall include all EXCEPT the following __________. resisting cell lysis due to osmotic forces limiting cell size conferring a specific shape to the cell actively transporting solutes against the concentration gradient
actively transporting solutes against the concentration gradient
Hydrogenosomes occur in the cells of __________.
anaerobic Eukarya
Which of the following characteristics was found in the earliest cellular organisms? photosynthesis multicellularity membrane-bound nucleus anaerobic metabolism
anaerobic metabolism
Explain how organisms are placed into the three major cell lineages or domains. analysis of ribosomal RNA physical characteristics metabolic characteristics analysis of DNA
analysis of ribosomal RNA
What kinds of cells do NOT have a cell wall? bacterial cells animal cells algal cells fungal cells
animal cells
Diglycerol tetraether lipids are found in some bacteria and some Archaea. form typical bilayer membranes. tend to make the membrane less rigid. are a characteristic feature of thermophilic Archaea. All of the choices are correct.
are a characteristic feature of thermophilic Archaea.
Antibiotics __________. are antimicrobial agents naturally produced by the human immune system are effective against all bacteria and viruses are antimicrobial agents naturally produced by microorganisms only target peptidoglycan synthesis in growing bacterial cells
are antimicrobial agents naturally produced by microorganisms
What molecule cleaves the β-1,4 bond between N-acetylglucosamine and N-acetylmuramic acid?
lysozyme
Koch's postulates __________. can be used to identify pathogens that can not be grown in a laboratory are used to link cause and effect in an infectious disease can identify all cases of all infectious diseases in all organisms can be applied to mixed (not pure) cultures of microorganisms
are used to link cause and effect in an infectious disease
Archaea with a plasma membrane composed of a tetraether monolayer would most likely be found ______. at a pH of 2 at a temperature of 90oC in an anaerobic environment in the soil in the mammalian gut
at a temperature of 90oC
Prokaryotic cells often have inclusions in their cytoplasm. Inclusions are used in all of the following EXCEPT buoyancy in the water column attachment to surfaces organizing metabolic functions such as fixation of carbon dioxide orienting in the magnetic field nutrient storage
attachment to surfaces
Type IV pili are involved in attachment to surfaces, twitching motility, and pathogenesis. twitching motility and attachment of cells to surfaces. twitching motility. attachment of cells to surfaces. pathogenesis
attachment to surfaces, twitching motility, and pathogenesis.
Type IV pili are involved in twitching motility and attachment of cells to surfaces. attachment to surfaces, twitching motility, and pathogenesis. attachment of cells to surfaces. twitching motility. pathogenesis
attachment to surfaces, twitching motility, and pathogenesis.
What type of enzyme inserts small gaps into peptidoglycan so that new cell wall material can be inserted?
autolysins
Which type of metabolism would NOT have developed as a result of the oxygenation of the atmosphere from oxygenic photosynthesis? Mn4+ oxidation nitrification autotrophy Fe3+ oxidation
autotrophy
which of the following is the most unique aspect of archaeal cell envelopes? a) some archaea have a protein S-layer b) some archaea have lipid monolayers in their plasma membrane c) the plasma membrane is composed of phospholipids d) the cell walls contain a modified type of peptidoglycan e) archaeal capsules can be composed of protein or polysaccharide
b) some archaea have lipid monolayers in their plasma membrane
Optical density and viable cell concentration are LEAST proportional to each other during the death phase. stationary phase. exponential growth phase. lag phase.
death phase
Which of the following antimicrobial agents kills bacteria? bacteriolytic agent bacteriocidal agent bacteriophilic agent bacteriostatic agent
bacteriocidal agent
A closed system, used for bacterial growth, where nothing is added and nothing is removed is called __________.
batch culture
HEPA filters are used in __________.
biological safety cabinets
The enzyme lysozyme kills bacterial cells by cleaving the beta 1,4-glycosidic bonds in the peptidoglycan. This leads to which of the following? breaches of the cell wall and cell lysis due to osmotic swelling out of control cell growth the inability of the cell to grow and divide lysis of the cell due to the same mechanism used by penicillin
breaches of the cell wall and cell lysis due to osmotic swelling
If an E. coli cell has a surface area-to-volume (S/V) ratio of 4.5, and a Pelagibacter ubique has an S/V ratio of 22, which cell will be able to exchange nutrients and wastes with the environment more efficiently? a) E. coli, because its cells are larger b) E. coli, because its cells are smaller c) Pelagibacter ubique, because its cells are smaller d) Pelagibacter ubique, because its cells are larger
c) Pelagibacter ubique, because its cells are smaller
A major function of prokaryotic gas vesicles is to store oxygen for aerobic growth when oxygen becomes depleted in the environment. serve as a reservoir for oxygen and carbon dioxide. keep the cell's organelles separated during flagellar motion. confer buoyancy on cells by decreasing their density.
confer buoyancy on cells by decreasing their density.
The vibrio shape of Caulobacter is due to which protein?
crescentin
Which of the following pairs is mismatched? crescentin - tubulin MreB - actin FtsA - actin FtsZ - tubulin
crescentin - tubulin
Which of the following proteins is mismatched with its eukaryotic homologue? MreB - actin FtsZ - tubulin crescentin - tubulin FtsA - actin
crescentin - tubulin
which of the following is false? a) endoflagella are responsible for both motility and shape in spirochaetes b) cell envelopes of most Firmicutes lack porins c) crystalline surface layers are the most common cell wall type among Archaea d) endotoxins are usually secreted by living bacteria during exponential growth e) both pili and flagella are composed of helically arranged globular protein subunits
d) endotoxins are usually secreted by living bacteria during exponential growth
which of the following is NOT a characteristic of the last universal common ancestor (LUCA)? a) its proteins were synthesized on ribosomes b) its cells were bound by a lipid membrane c) it was autotrophic d) its genes were composed of RNA e) it used ATP as a common energy currency
d) its genes were composed of RNA
All of the following are TRUE statements concerning binary fission of microbial cells EXCEPT elongation of the cell occurs and the chromosomes are pushed apart. daughter cells produced can be of different sizes. the chromosome of the cell is replicated. a septum is formed across the midline of the cell.
daughter cells produced can be of different sizes.
Heterocysts are __________. structures that produce toxic oxygen radicals dedicated structures where nitrogen fixation occurs structures involved in septum formation structures produced to withstand desiccation
dedicated structures where nitrogen fixation occurs
Which of the following cellular properties is NOT found in all cells? growth differentiation evolution metabolism
differentiation
To speed up the growth rate in a chemostat, the ___ should be increased. To increase the cell yield as well, _____ should be increased. dilution rate / dilution rate dilution rate / limiting nutrient limiting nutrient / limiting nutrient limiting nutrient / dilution rate
dilution rate / limiting nutrient
What molecules reduce the water content of a bacterial endospore? diaminopimelic acid and calcium small acid-soluble and core proteins peptidoglycan and calcium small acid-soluble proteins and dipicolinic acid dipicolinic acid and calcium
dipicolinic acid and calcium
The Par system is necessary for septum formation. formation of a replication fork in Escherichia coli. distribution of genetic material in replicating Caulobacter. elongation of bacillus prior to cell division.
distribution of genetic material in replicating Caulobacter.
The early energy reactions used hydrogen, which is a powerful ________ and could have been used to form ________. oxidant / the proton motive force oxidant / oxygen electron acceptor / oxygen electron donor / the proton motive force
electron donor / the proton motive force
What was produced by photosynthesis before the cyanobacterial lineage developed on Earth?
elemental sulfur
Endospores represent a challenge to the fields of industrial and medical microbiology because -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. -endospores are significantly smaller than vegetative cells. they are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive. -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. -endospore-forming organisms are often dangerous pathogens.
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.
What is the method that uses selective culture media and incubation conditions to isolate specific microorganisms from natural samples?
enrichment culture
Based on recent research, eukaryotic cells are believed to have arisen independently from prokaryotic cells. by mutations that led to changes in plasma membranes, leading to internal membrane-bound organelles. independently from prokaryotic cells by mutations that led to changes in plasma membranes, leading to internal membrane-bound organelles. from the fusion of multiple archaeal cells into a larger, more complex cell. from a fusion of archaeal cells and bacterial cells.
from a fusion of archaeal cells and bacterial cells.
When you see a publication describing an enzyme from Candidatus Pseudomonas utahensis you can infer that this organism (select all that apply) is described in Bergey's Manual of Systematic Bacteriology. has been deposited in a culture collection. has not been formally recognized as a species. has not been grown in pure culture. has been grown in pure culture.
has not been formally recognized as a species. has not been grown in pure culture.
Fluorescent in situ hybridization (FISH) can be used to determine __________. Select all that apply. how many Salmonella typhimurium cells are present in a sample of unpasteurized apple juice genes of interest in the genomes of individual microbial cells the phylogenetic diversity of an environmental sample
how many Salmonella typhimurium cells are present in a sample of unpasteurized apple juice genes of interest in the genomes of individual microbial cells the phylogenetic diversity of an environmental sample
Most prokaryotic cells reside in and on nonprokaryotic organisms (including humans and other animals). in the oceanic and terrestrial subsurfaces. on Earth's surface. in lakes, rivers, and oceans.
in the oceanic and terrestrial subsurfaces.
Which of the following regarding microcompartments is false? Microcompartments are to bacteria what membrane-bound organelles are to eukaryotic cells. include carboxysomes consist of a virion-like protein shell encapsulating enzymes. include gas vesicles
include gas vesicles
All of the following structures contribute to the ability of pathogenic bacteria to cause disease EXCEPT inclusions. exotoxins fimbriae. lipopolysaccharide. capsules.
inclusions.
Which of the following best characterizes the concept of bacterial growth? increase in cell complexity transition to multicellularity cell differentiation increase in cell number
increase in cell number
When water activity is low, an organism must decrease its external solute concentration. increase its external solute concentration. decrease its internal solute concentration. increase its internal solute concentration.
increase its internal solute concentration.
Staining of microbial samples before microscopy is used to __________.
increase sample contrast for better visibility
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 __________. increase the concentration of nutrients in the medium increase the growth rate increase the dilution rate (rate of addition of medium) increase the temperature
increase the concentration of nutrients in the medium
What is the benefit of bidirectional replication in a circular genome?
increased DNA replication speed
A new protein has been described that transports a growth factor across the plasma membrane. This protein is most likely a/an: peripheral membrane protein, facing the cytoplasmic side. cytoplasmic protein. peripheral membrane protein, facing outward. integral membrane protein.
integral membrane protein.
Salmonella, Shigella, and Escherichia coli have pathogenic strains that inhabit the human __________.
intestine
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? performing time-lapse fluorescent photomicroscopy of labeled cells during cell replication introducing a reporter gene into the chromosome next to the ori introducing a reporter gene into the chromosome that codes for a fluorescent protein that will bind to a specific DNA sequence near the ori introducing a sequence of DNA near the ori that will bind a fluorescent protein
introducing a reporter gene into the chromosome next to the ori
FtsI __________.
is a penicillin-binding protein
Endospore formation __________. is a survival mechanism present during favorable conditions only occurs when the bacterial cell has plenty of available nutrients is observed in all species of Bacteria and Archaea is a survival mechanism triggered by unfavorable conditions
is a survival mechanism triggered by unfavorable conditions
In archaeal membranes, what serves the same function as the fatty acids of bacterial membranes?
isoprene derivatives
Mathematically, how is the specific growth rate constant, k, related to g, the generation time?
k = 0.301/g
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?
lag phase
Gram-negative bacteria have __________ peptidoglycan than gram-positive cells, and their cell walls are __________ complex structurally. more ... less less ... less None of the listed responses is correct. more ... more less ... more
less ... more
Going from the inside of the outer membrane to the outside, what is the composition of lipopolysaccharide?
lipid A, core polysaccharide, O-specific polysaccharide
Starting from the inside of the outer membrane to the outside, what is the composition of lipopolysaccharide?
lipid A, core polysaccharide, O-specific polysaccharide
Which of the following attaches the outer membrane to peptidoglycan? lipoprotein Sec translocase porins fimbriae
lipoprotein
Microcompartments (Select all that apply) position cells in the appropriate environment for survival. are reservoirs of energy-rich compounds or building blocks. localize enzymes to enhance reaction rates and sequester toxic intermediates. are surrounded by a lipid membrane.
localize enzymes to enhance reaction rates and sequester toxic intermediates.
The ability to form endospores in bacteria within Bacillales and Clostridiales suggests the genotype/phenotype evolved -at least two separate times in these divergent orders. -at least once, and horizontal gene transfer among relatives explains its presence in other orders. -either at least once and horizontal gene transfer among relatives occurred or once in a common ancestor. -only once in an ancestor to these two orders, due to the high number of genes required.
only once in an ancestor to these two orders, due to the high number of genes required.
When performing a viable plate count, what is the range of colony numbers/plate that gives the most statistically valid answers?
only plate counts between 30 and 300 colonies
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?
only the Bacteria will be lysed
Homologous sequences descended from the same ancestral sequence found in different species are known as __________.
orthologs
A halotolerant facultative aerobic bacterium would grow BEST in a ________ environment. oxygen depleted saline oxygen depleted non-saline oxygenated saline oxygenated non-saline
oxygenated non-saline
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 __________. penicillin kills only growing cells lysozyme cleaves the peptide cross-links in peptidoglycan. penicillin kills both bacterial and eukaryotic cells penicillin cleaves the peptide cross-links in peptidoglycan. penicillin cleaves the glycosidic bonds in the peptidoglycan
penicillin kills only growing cells
Two types of light microscopy that do not use stains but are able to increase the contrast of samples being viewed are __________.
phase contrast and dark-field microscopy
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? Any of these methods would work equally well in this case, assuming that standard curves are produced. plate counts microscopic counts turbidity measurements
plate counts
Which of the following bacterial structures serves the same function as adipose tissue (fat) in animals? polyhydroxyalkanoate granules polyphosphate granules sulfur globules magnetosomes
polyhydroxyalkanoate granules
Biofilm formation in Pseudomonas aeruginosa __________. prevents the penetration of antibiotics prevents intracellular communication between members of the species decreases its pathogenicity prevents quorum sensing in the pathogen
prevents the penetration of antibiotics
Swiss cheese is made using __________.
propionic acid-fermenting bacteria
A group of gram-positive bacteria found in Swiss cheese is __________.
propionic bacteria
For unicellular organisms within certain limits, what is the relationship between optical density and cell numbers?
proportional
Which of the following is NOT a function of the cytoplasmic membrane? barrier to hydrophilic molecules protection from hypotonic stress transport of nutrients generation of proton motive force
protection from hypotonic stress
What is the energy source of bacterial flagellar motility?
proton motive force
A microbe growing in a refrigerator is likely psychrotolerant or psychrophilic. hyperthermophilic. psychrophilic. mesophilic
psychrotolerant or psychrophilic.
Metagenomics involves the analysis of a microbial community by __________. generating a phylogenetic tree based on all of the versions of a gene in an environment generating a complete sequence of the genomes of all of the organisms in an environment sequencing all of the community RNA in an environment sampling and sequencing all of the genes in an environment
sampling and sequencing all of the genes in an environment
Two systems that respond to unfavorable environmental conditions are __________. quorum sensing and Caulobacter differentiation E. coli lac operon and Bacillus sporulation sporulation in Bacillus, and Caulobacter differentiation E. coli maltose operon and Bacillus sporulation right answer feedback:
sporulation in Bacillus, and Caulobacter differentiation
The cytoplasmic membranes of mycoplasmas are unusual in that they contain __________.
sterols
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. phospholipids / lipopolysaccharides sterols / hopanoids lipids / phospholipids ether bonds / ester bonds
sterols / hopanoids
Which of the following is NOT one of the cardinal temperatures of microbial growth? optimum maximum suboptimum minimum
suboptimum
Which of the following cell inclusions resides in the periplasm of gram-negative bacteria? PHA inclusions glycogen inclusions sulfur globules polyphosphate granules
sulfur globules
What type of glassware was used to settle the controversy surrounding spontaneous generation?
swan-necked flask
Which of the following events took place after the endosymbiotic events leading to the formation of mitochondria? a rise in atmospheric oxygen the development of enzymes such as superoxide dismutase the evolution of respiratory metabolism the development of multicellular eukaryotes
the development of multicellular eukaryotes
What is chemolithotrophy?
the oxidation of inorganic compounds linked to energy conservation within a cell
Mycoplasma species are bacteria that do not possess a cell wall. What accounts for the extra strength and rigidity of a mycoplasmal cell membrane? the presence of hopanoids in their membranes the presence of LPS in their membranes the near absence of proteins in their membranes the presence of ether-linked lipids in their membranes. the presence of sterols in their membranes
the presence of sterols in their membranes
An endotoxin is a toxin known for its primary attack on the epidermis of mammals. a toxin produced within archaeal cells. the toxic portion of the LPS. a toxin produced in the periplasm of most bacteria.
the toxic portion of the LPS.
Bioremediation is _____. the use of biological processes to remedy diseases the modification of prokaryotes for industrial purposes the use of prokaryotes in producing pharmaceutical products the use of organisms to remove pollutants from the environment the use of prokaryotes in producing transgenic organisms
the use of organisms to remove pollutants from the environment
For identification purposes, to which of the following types of organisms is FAME limited? those that can be grown under specified conditions those containing 18S rRNA those that have developed ester bonds those that have undergone ribotyping
those that can be grown under specified conditions