Microbiology Exam 1
Although developed over 100 years ago, Koch's postulates continue to be used successfully in all known human infectious diseases.
False
Archaeal and bacterial pili are identical in structure and function.
False
Archaeal flagella (archaella) are superficially similar to bacterial flagella, although archaella are much thicker than bacterial flagella.
False
Archaeons power their flagella by proton motive force (PMF), whereas bacteria empower their flagella by ATP hydrolysis.
False
Bacteria growing at lower temperatures have more saturated fatty acids in their membranes.
False
Chromosomal gene exchange is not useful in classification studies because prokaryotes do not reproduce sexually.
False
Coated pits containing clathrin do not permit concentration of ingested macromolecules prior to endocytosis.
False
Conjugation is useful for determining relatedness between bacteria at the species level because it never occurs between organisms of different genera.
False
During the assembly of the flagellar filament, the flagellin protein monomers assemble from the base of the flagellum within the cell envelope.
False
Edward Jenner's work in preventing rabies led to the use of the term vaccination to describe a type of procedure used in the prevention of disease.
False
Endospores are reproductive structures.
False
Extensive horizontal gene transfer between domains greatly simplifies the construction of phylogenetic trees.
False
Gram-positive bacteria have a structurally and chemically more complex cell wall than Gram-negative bacteria.
False
Gram-positive bacteria have a thinner layer of peptidoglycan than Gram-negative bacteria.
False
If Microbe A and Microbe B have whole genome similarity of 68%, as determined by DNA-DNA hybridization, they should be considered the same species.
False
If you remove the peptidoglycan layer from a Gram-positive cell, it would still stain purple with a Gram stain.
False
In terms of membrane lipids, the plasma membranes of archaeons are more similar to those of the eukaryotes than to membranes of bacteria.
False
Koch's postulates were instrumental in establishing that the intracellular parasite Mycobacterium leprae is the causative organism of leprosy.
False
Organisms usually have only a single transport system for any nutrient.
False
Phosphorus can be obtained from organic sources only.
False
Robert Koch developed a vaccine that could be used to prevent anthrax.
False
Sedimentation coefficients are proportional to the molecular weight of a particle and are not affected by the volume and shape of the particle.
False
Sulfur can be obtained from inorganic sources only.
False
The distribution of lipids in the plasma membrane of eukaryotes is symmetrical.
False
The earliest microbial fossils that have been found are dated from approximately 4.5 million years ago.
False
The hydrocarbons found in the membranes of archaea are identical to those found in bacteria.
False
The layers of peptidoglycan of the bacterial cell wall can be cross-linked by peptide intrabridges or by direct cross-linking.
False
The original differentiation of prokaryotes and eukaryotes was based on structures found in prokaryotes that are lacking in eukaryotes.
False
The rotation of bacterial flagella is powered by ATP hydrolysis.
False
The type strain is the most representative strain of a particular species.
False
The usefulness of agar in solidifying microbiological growth media is limited because it does not remain solid at temperatures above 28oC.
False
Transformation is not useful in determining relatedness between two organisms because it frequently crosses genera.
False
Viruses and bacteria were first cultured in the laboratory at about the same time.
False
Zinc (Zn) is considered a macronutrient.
False
Peritrichous
Flagella all over
Amphitrichous
Flagella at both poles of the cell
Fatty acid methyl ester (FAME) analysis is particularly important in public health because in this application, microbiologists seek to identify specific microbial pathogens in _________.
Food and water
Who described bacterial transformation?
Fredrick Griffith
The analysis of genetic relatedness by observing the DNA fragmentation patterns resulting from restriction endonuclease cleavage is referred to as _________.
Genetic fingerprinting
There are many molecular techniques to identify taxonomy of microorganisms. Match each technique to its proper resolution.
Genomic sequencing- Family, genus, species, subspecies, and strain Mole % G+C- Genus, species, and subspecies Genomic fingerprinting- Species, subspecies, and strain 16S rDNA sequencing- Family and genus
Mole percent (G+C) of DNA is useful for determining relatedness at the ________ level.
Genus
The binomial system of nomenclature assigns each organism a scientific name consisting of _________.
Genus and species
__________ is the main part of the process through which a vegetative cell is formed from an endospore.
Germination
Which of the following is notof the process by which an endospore transforms to become a vegetative cell?
Germination, activation, outgrowth
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(n) ___________.
Group translocation
__________ __________ are required organic compounds because they are essential cell components or precursors of such components that cannot be synthesized by the organism.
Growth factors
External structures that are found in archaea but not bacteria are _________.
Hami
Studies by Emil von Behring and Shibasaburo Kitasato demonstrated that inactivated toxins can induce the synthesis of antitoxins in the blood of rabbits. These antitoxins (antibodies) are the basis of ________.
Humoral immunity
Actinomycetes form long filaments called ___________.
Hyphae
Some species of aquatic bacteria use inclusion bodies known as __________ to orient themselves in Earth's magnetic field.
Magnetosomes
The branch of microbiology that deals with diseases of humans and animals is called __________ microbiology.
Medical
The temperature at which one DNA molecule separates from the other DNA molecule in a double strand is called the __________ temperature.
Melting
Who of the following first discovered that some blood leukocytes could engulf disease-causing bacteria?
Metchnikoff
The branch of microbiology that studies the relationship between microorganisms and their habitats is called __________ ______________.
Microbial ecology
Which term is most inclusive? In other words, which term includes all the others?
Microbial species
Protein filaments with a diameter of 4-7 nm that play a role in cell movement and shape change are called _________.
Microfiaments
Which of the following has not been considered as a "gold standard" taxonomic method applied to species designation.
Microscopic cell phenotype
A filamentous organelle comprised of tubulins with a diameter of 25 nm is called _________.
Microtubule
Which of the following is not true about archaeal ribosomes?
They have similar antibiotic sensitivities to those of bacteria.
__________ are carrier proteins embedded in the membrane that increase the rate of diffusion of specific molecules across selectively permeable membranes.
Permeases
Flimmer filaments _________.
Permit flagella to pull rather than push the cell.
What was the first antiseptic?
Phenol
The general order of classification below the domain or kingdom level is _________.
Phyla, class, order, family, genus, species
Microbial __________ are scientists who investigate the synthesis of antibiotics and toxins, the production of energy with microorganisms, and the ways in which microorganisms survive harsh environmental conditions.
Physiologists
Which of the following is useful in biological systematics?
Physiology, epidemiology, ecology
Which of the following structures are external to both bacterial and archaeal cells?
Pili
Proteinaceous projections from the surface of a bacterium that are used to mediate conjugation are called sex __________, whereas projections that mediate attachment to surfaces such as host cells are called __________.
Pili; fimbriae
The light reactions of photosynthesis, which form ATP and NADPH, take place in the _________.
Thylakoid membrane
A eukaryotic flagellum can either push a cell through a liquid environment or pull it through depending on the undulating pattern of movement.
True
A theory of eukaryotic cells and nuclear origin is based on endosymbioses, where an archaeal cell is thought to have engulfed a bacterium, which then donated genes that would eventually become the nuclear genome of an ancestral eukaryote.
True
Agostino Bassi demonstrated that a type of silkworm disease was caused by a fungus and proposed that many diseases are caused by microorganisms.
True
Although there are other classification schemes for prokaryotes, the one used in Bergey's Manual is currently considered by most microbiologists to be the most accurate.
True
Charles Chamberland developed porcelain filters that allowed other scientists to demonstrate that viruses are smaller than bacteria.
True
Copper (Cu) is considered a micronutrient.
True
Different transport systems for the same nutrient that are part of the same organism are usually regulated in different ways.
True
Electron transport reactions that occur in the mitochondria of eukaryotes take place on the inner membrane of that structure.
True
Endotoxic shock, resulting from the release of endotoxin by bacteria infecting a patient, is only caused by Gram-negative bacteria.
True
Fanny Hesse first suggested that agar be used to solidify microbiological media.
True
Growth factors are molecules that cannot be synthesized by the bacteria that use them and include amino acids, pyrimidines, and vitamins.
True
John Tyndall demonstrated that microorganisms present in the air are carried on dust particles.
True
M. J. Berkeley demonstrated that the great potato blight of Ireland was caused by a water mold (then thought to be a fungus).
True
Many archaeal genomes include chromosomes and plasmids.
True
Methanogens may contribute to the greenhouse effect and global warming due to methane production.
True
Nitrogen can be obtained from either organic or inorganic sources.
True
On a phylogenetic tree, each node (branchpoint) represents a divergence event, and the length of the branches represents the number of molecular changes that have taken place between the nodes.
True
A lysosome containing undigested material is called _________.
A residual body
Conserved indels are _________.
A type of signature sequence particularly useful for phylogenetic analysis
Diglycerol tetraether lipids _________.
Are a characteristic feature of thermophilic Archaea.
Old cultures of bacteria that have lost their ability to cause disease are said to be ________.
Attenuated
A(n) _________ is a special type of lysosome used by a cell to selectively digest and recycle cytoplasmic contents, such as mitochondria.
Autophagosome
In many spirochetes, multiple flagella combine to form a bundle known as a(n) ____________ fibril, which winds around the cell and confers motility on the cell.
Axial
An arrangement of microtubules located in the matrix of cilia and flagella is called the __________.
Axoneme
Shrinkage of the plasma membrane away from the cell wall when the bacterium is placed in a hypertonic environment is called _________.
Plasmolysis
Bacteria that do not have a fixed shape are said to be __________.
Pleomorphic
Which of the following is most likely synthesized on free ribosomes?
Polypeptide chains that form enzymes that function in glycolysis
In an approach called ________ taxonomy, relatedness is determined by a wide range of phenotypic and genotypic information.
Polyphasic
You are studying a newly discovered prokaryotic microorganism and are attempting to determine whether it will be classified in the domain Bacteria or in the domain Archaea. All of the following would be helpful in making that distinction except _________.
Presence or absence of double-stranded circular DNA genome
Members of this group have caused "mad cow disease" and Creutzfeld-Jacob disease.
Prions
A __________ layer consists of diffuse unorganized polysaccharide material that lies outside the cell wall and is easily removed.
Slime layer
Protists are made up of which of the following?
Slime molds, algae, protozoa
Which statement correctly explains the Gram-stain reaction of archaeal cells?
Some are Gram-positive and some are Gram-negative due to the diverse chemical structure.
Which statement correctly describes archaeal cell walls?
Some have an outer layer of complex polysaccharide and some have an outer layer of protein.
Are protozoa photosynthetic?
Some of them are
Microbiology is being revolutionized by explorations in microbial genomics in all of the following ways except __________.
The complex metabolic pathways of serovars are being compared
Which of the following is not considered a micronutrient?
Magnesium (Mg)
Which of the following contribute(s) to the differences between the members of the Domain Archaea and the Domain Bacteria?
1. Archaea lack muramic acid. 2. Archaea have isopranyl glycerol ethers rather than fatty acid esters in their membrane lipids. 3. Archaea differ from bacteria in their tRNA composition, ribosome structure, and antibiotic sensitivity.
In order to distinguish them from bacterial flagella, archaeal flagella have been renamed as archaella because _________.
1. Archaean flagella are composed of more than one type of flagellin subunit 2. Some archaeon flagella don't have hooks 3. They are more slender than bacterial flagella 4. Archaean flagella are solid and not hollow
Microdomains in eukaryotic plasma membranes can participate in _________.
1. Cell movement 2. Cell division 3. Signal transduction
The Archaea generally lack which of the following that are normally found in Gram-negative bacteria?
1. Outer membrane 2. A complex peptidoglycan network 3. Lipopolysaccharide
Archaeal membranes contain which of the following lipids?
1. Phospholipids 2. Sulfolipids 3. Glycolipids
You are a medical microbiologist in Dallas, TX. A small population of individuals spread throughout the city have been experiencing alarming yet similar symptoms affecting the liver that have physicians puzzled as to the etiology, although they all suspect it is microbial in nature. What steps would you take to elucidate the organism?
1. Sample the livers from affected patients to culture and compare organisms 2. Grow the suspected organisms in culture 3. Inoculate the cultured organisms into a laboratory animal and monitor for similar symptoms 4. Culture and analyze the organism from the lab animal and determine relatedness.
Characteristics of active transport?
1. Saturable uptake rate 2. Use of ATP or a proton gradient as a source of metabolic energy 3. Can move materials against a concentration gradient
Which of the following contribute to the environmental resistance of bacterial endospores?
1. Spore coat 2. Low water content of endospore 3. Presence of calcium dipicolinate 4. Lower pH
What are Koch's postulates?
1. The same pathogen must be present in every case of the disease. 2. The pathogen must be isolated from the diseased host and grown in pure culture. 3. The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible laboratory animal. 4. The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.
Which of the following are true of capsules?
1. They help bacteria escape phagocytosis by host cells. 2. They retain water and help prevent desiccation of the bacteria. 3. They prevent entry of many bacterial viruses.
Which of the following is a function of the mitochondrion?
1. Tricarboxylic acid cycle enzyme reactions 2. Electron transport 3. ATP synthesis
The cytoplasmic membrane of bacteria _________.
1. retains the cytoplasm and its contents 2. Acts as a selectively permeable barrier, allowing some molecules to pass while preventing the movement of others 3. Is the major site of ATP synthesis in aerobes
According to the endosymbiosis hypothesis _________.
1. the first endosymbiotic event involved an anaerobic bacterium 2. the first endosymbiont was a fermentative organism 3. the mitochondrion evolved from the same endosymbiont as the hydrogenosome
The comparison of microbial G+C content is a simple technique used to determine DNA base composition. If two organisms differ in their G+C content in more than ________, their genomes are considered to have markedly different base sequences.
10%
The primary lipid components of the membranes of extreme thermophiles are _________.
40 carbon diglycerol tetraethers
Lophotrichous
A cluster of flagella at one or both ends of an organism
An unrooted tree containing four unrelated species can become rooted by adding _________.
A distantly related outgroup
Which type of membrane transport is most important for nutrient acquisition in nutrient poor environments?
Active transport
Nutrients can be concentrated from dilute solutions by _________.
Active transport and group translocation
Which of the following eukaryotes typically have cell walls? (Check all that apply.)
Algae, fungi, plants
Export of flagellin subunits is mediated by _________
An apparatus in the basal body of the flagellum that is related to the type III secretion pathway
What is a viroid?
An infectious agent consisting of only RNA
Small, random genetic changes that occur over generations is known as _________.
Anagenesis
Genomic DNA sequences seem to support the idea that the first eukaryotic cell arose from within the ________ lineage.
Archael
A fundamental difference between bacterial and archaeal membranes is that __________.
Bacterial membranes are always comprised of phospholipid bilayers, whereas archaeal membranes can be bilayers or monolayers
Construction of flagella and/or cilia is directed by the _________.
Basal body
Bacterial flagella are composed of three parts: the __________ body, which is embedded in the cell, the hook, and the ________, which is the longest part of the flagellum.
Basal; filament
The most important aspect of agar that makes it a useful ingredient for solidifying media for bacterial culture is ________.
Because bacteria are unable to break it down so it remains solid
The use of enrichment cultures and selective media was pioneered by ________.
Beijerinck
__________ was the first to isolate a root nodule bacterium capable of nitrogen fixation.
Beijnerik
Proteins function in modern cells as ________.
Both catalysts and structural elements
Which of the following distinguish the field of microbiology from other fields of biology?
Both the size of the organism studied and the techniques employed in the study of organisms.
__________ are hollow tube-like structures that hold some archaeal daughter cells together after cell division while___________ are grappling hook-like structures that appear to attach archaeal cells to surfaces.
Cannulae; hami
A __________ is a polysaccharide layer that lies outside the cell wall and is not easily removed.
Capsule
Which of the following structures is NOT found in an endospore?
Capsule
Sortase is a protein enzyme of bacteria that _________.
Catalyzes covalent attachment of some surface proteins to peptidoglycan
Select the characteristics that are used in the morphological identification of microorganisms.
Cell shape, staining behavior, presence of cilia and flagella
Which of the following parts of the Golgi complex receives materials from the ER?
Cis face
The Golgi apparatus is comprised of flattened, saclike structures called __________, which may be clustered in one region or scattered throughout the cell.
Cisternae
The endoplasmic reticulum is composed of flattened sacs called _________.
Cisternae
The two major approaches used in taxonomic classification of microorganisms that have been isolated and grown in pure culture are termed __________ and ________________
Classical and molecular
The arrangement of organisms into groups is best described as _________.
Classifcation
Each of the following plays a role in the recycling of proteins in a cell except _________.
Clathrin
Which of the following is not considered a macronutrient?
Cobalt (Co)
A feature unique to some archaeal plasma membranes is that they may __________.
Consist of a lipid monolayer
The ancestors of modern _________ performed the oxygenic photosynthesis responsible for converting our anoxic planet to an oxygenated one.
Cyanobacteria
Where is the glycolysis pathway located in a cell?
Cytoplasm
Archaeal cell walls _________.
Lack murein and D-amino acids
What is the most compelling reason why DNA, rather than RNA, evolved to be the storage repository for genetic information in cellular life forms?
DNA molecules are more chemically stable than RNA molecules.
Antiseptic surgery was pioneered by _______.
Lister
Receptor mediated endocytosis _________.
Depends on formation of clathrin coated pits that pinch off and is used to internalize molecules such as hormones, growth factors, iron, and cholesterol
Stacks of cisternae in the Golgi apparatus are referred to as _________.
Dictyosomes
The cell membranes of archaeons that lack a cell wall are strengthened by _________.
Diglycerol tetraethers
Endospores are resistant to most environmental stressors because they have ______ ______ complexed with calcium ions which stabilize DNA.
Dipicolinic acid
Food vacuoles and phagocytic vacuoles are most similar to _________.
Lysosomes
Enzymes that are secreted out of the cell to aid in the acquisition and digestion of environmental nutrients are called __________.
Exoenzymes
Which mechanism of nutrient acquisition is not seen in bacteria?
Endocytosis
The major site of cell membrane synthesis is the _________.
Endoplasmic reticulum
Which bacterial structure may survive if temperatures applied during food preservation processes are too low?
Endospores
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
The lipopolysaccharide (LPS) that is found in the outer membrane of Gram-negative bacteria is also known as _________.
Endotoxin
Which of the following has flagella that wave back and forth?
Eukarya
Theories that address the origin of the eukaryote nucleus must take into account the fact that _________.
Eukaryotes possess both archaeal and bacterial traits
Which of the following statements is false regarding the differences between bacterial and eukaryotic cytoskeletal proteins?
Eukaryotic cells have cytoskeletal fibers comprised of tubulin and actin proteins, whereas bacterial cells lack cytoskeletal proteins.
The determination of the taxon to which an organism belongs is called _________.
Identification
Which of the following must leave the nucleus via the nuclear pore complexes?
Immature ribosomal subunits, tRNA, and mRNA
In eukaryotic cells, the enzymes involved in the tricarboxylic acid cycle (Kreb's cycle) are located _________.
In the matrix of the mitochondria
Intracellular granules of organic or inorganic material that are stockpiled by bacteria for future use are called __________.
Inclusions
Choose the incorrect statement about Koch's postulates.
Infecting an animal model without causing symptoms of the same disease
The enzymes and electron carriers involved in electron transport and oxidative phosphorylation are located in the __________ membrane of the mitochondrion.
Inner
Protein filaments with a diameter of about 10 nm that are major components of the cytoskeleton are called _________.
Intermediate filaments
Although penicillin inhibits peptidoglycan synthesis, bacterial cells will continue to grow normally in the presence of penicillin in a(n) __________ environment.
Isotonic
All of the following statements about the periplasmic space are true except __________.
It is only found in Gram-positive bacteria
Who is credited with developing and documenting the first vaccination procedure against smallpox?
Jenner
Who determined the source of a cholera outbreak?
John snow
Who of the following developed a set of criteria that could be used to establish a causative link between a particular microorganism and a particular disease?
Koch
Many clinical microbiology laboratories and public health laboratories use techniques such as microbial staining, microbial growth, enzymatic testing, fermentation testing, and microscopic analysis to identify pathogens in samples. Which categories of classical characteristics for taxonomy are represented here? (Check all that apply.)
Morphological, metabolic and physiological, and biochemical characteristics
Penicillin inhibits bacterial growth by preventing the cross-linking during peptidoglycan synthesis. Why does penicillin not inhibit growth of archaeal cells?
Most archaeal cells have a cell wall, but it is not composed of peptidoglycan
Chemotaxis is a process by which bacteria _________.
Move toward an attractant or away from a repellant
A branched network of hyphae formed by the Actinomycetes is called a __________.
Mycelium
Bacteria have a region of the cytoplasm known as the __________, which is not bounded by a membrane but contains the chromosome.
Nucleoid
Monotricious?
One flagellum
Which of the following is not true about the G + C content percentages in DNA of organisms?
Organisms with similar G + C percentages have similar base sequences.
While each of these processes are believed to have evolved prior to aerobic respiration, which one is the most critical process, without which aerobic respiration could never have developed?
Oxygenic photosynthesis
Who is credited with developing a vaccine against chicken cholera?
Pasteur
Who of the following provided the evidence needed to discredit the concept of spontaneous generation?
Pasteur
What is one thing bacteria have that archaea don't
Peptidoglycan
Which of the following protects bacteria from lysis in dilute solutions and helps to determine their cellular morphology or shape?
Peptidoglycan
What are prions composed of?
Protein
What are viruses composed of?
Protein and nucleic acid
RNA is a key intermediate molecule involved in the process that uses the information stored in DNA to ultimately produce __________.
Proteins
The power used by most bacterial flagellar motors is produced by __________.
Proton motive force
_______ is a peptidoglycan-like molecule found in the cell walls of some archaea.
Pseudomurein
The pace of evolution does not always occur at a constant rate but is periodically interrupted by rapid bursts of speciation; this is known as _________ ________.
Punctuated equilibrium
Mitochondria differ from hydrogenosomes in that __________.
Pyruvate is catabolized as a continuation of the respiratory pathway in mitochondria, whereas in hydrogenosomes, fermentation takes place
Each of the following provides evidence in support of the primary role of RNA in the evolution of life EXCEPT _______.
RNA is less chemically stable than DNA
New ecotypes arise largely as a result of ________.
Random mutations that confer a growth advantage and are passed to subsequent generations
An Italian physician, __________, challenged the concept of spontaneous generation by demonstrating that maggots do not arise from decaying meat but rather from developing fly eggs.
Redi
Endocytic events _________.
Remove membrane from the cell surface
According to genome analysis, a member of the genus _________ is most closely related to the mitochondrion.
Rickettsia
The bacterium E. coli swims in a straight line, called a __________, for a few seconds; then it stops, tumbles, then swims away in a new direction.
Run
A(n) __________ is a layer of protein or glycoprotein that exhibits a pattern resembling floor tiles.
S layer
You discover a new microbe while working on a citizen scientist project. The microbe is taken to a lab that specializes in placing organisms in their correct phylogenic niche. In order to determine its evolutionary relatedness to other microbes, the lab carries out __________.
SSU rRNA analysis
Which of the processes named here is the least likely to contribute to the evolution of genetic diversity of bacteria and archaea?
Sexual reproduction
_______ bind ferric iron and transport it into a bacterial cell.
Siderophores
A microbial __________ is a collection of strains that share many stable properties and differ significantly from other groups of strains.
Species
A theoretical concept that is used to understand how and why certain organisms can be sorted into discrete taxonomic groups is known as the _________.
Species concept
When the cell wall is removed from a Gram-negative bacterium without removing the outer membrane, the resulting form is called a(n) __________.
Spheroplast
How do spheroplasts and protosplasts differ?
Spheroplasts retain their outer membrane but protoplasts do not.
Which cellular shape is seen among members of domain Bacteria that is not found among the domain Archaea?
Spiral or corkscrew shapes
Rigid bacteria with a helical cell shape are called _________.
Spirilla
Flexible bacteria with a helical shape are called _________.
Spirochetes
The concept that living organisms arise from nonliving material is called ________.
Spontaneous generation
__________ is the process through which endospores are formed within a vegetative cell.
Sporulation
The concept of a prokaryote was first fully outlined in 1962 by _________.
Stanier and van Niel
A population descending from a single organism or pure culture isolate is called a _________.
Strain
Morphovars, serovars, biovars, and pathovars are examples of terms that refer to microbial ___________.
Strains
The formation of carbohydrate (CO2 fixation) in the dark reaction of photosynthesis, takes place in the _________.
Stroma
The scientific study of organisms with the ultimate goal of characterizing and arranging them in an orderly manner is _________.
Systematics
A general term used to describe groups based on mutual similarity or evolutionary relatedness is _________.
Taxa
The science dealing with classification is called _________.
Taxonomy
Square planar arrangement of cells that forms when round bacteria remain attached to each other during reproduction are called _________.
Tetrads
While inspecting the genome sequence of your newly discovered organism, you note that while the genome overall is 50% G + C, there is a cluster of genes comprising about 20,000 bp that is 64% G + C. The best explanation for this is _______.
The 20,000 bp segment is a recent acquisition via horizontal gene transfer
A strain of Neisseria gonorrhoeae has undergone a mutation and is no longer able to make pili. Predict the most likely outcome.
The bacteria will become less virulent and will not be able to readily establish infection.
Motile bacteria have been placed in an environment with a gradient of a chemical attractant. Which of the following behaviors would you predict?
The bacteria will both reduce tumbling frequency and increase run duration in the direction of the chemical.
Select the correct statement about archaeal ribosomes.
The chemical components of archaean ribosomes are more similar to those of eukaryotic ribosomes than to those of bacterial ribosomes.
A pathogenic bacterial species has mutated and is no longer able to synthesize a capsule. Which outcome would you predict?
The mutated bacteria will not be able to cause disease as readily.
The evolution of membrane-bound organelles and thus compartmentalization within eukaryotic cells likely arose due to all of the following except __________.
The need to prevent mixing of cellular macromolecules such as proteins and polysaccharides
Predict how the plasma membrane fatty acid composition would change as the temperature of the habitat of an aquatic bacterial species warms from 2oC to 15oC during the spring and summer months.
The percentage of saturated fatty acids would increase.
Structural differences between Gram-positive and Gram-negative bacteria are observed following the Gram-staining procedure since __________.
The thick layer of peptidoglycan in Gram-positive bacteria is dehydrated during the alcohol step, thus acting as an impermeability barrier retaining the crystal violet/iodine complex
Which of the following is not true of bacterial plasmids?
They are required for host growth and/or reproduction
One hypothesis explaining the first nucleated eukaryotic cell is based upon the fusion of an archaeon and a bacterium that, over time, saw archaeal genes involved in metabolism being lost while bacterial genes involved in information processing were also degraded.
True
Permease proteins that aid in the transport of nutrients resemble enzymes in their specificity for the substance to be transported. Each carrier is selective and will transport only a closely related set of substances.
True
Phylogenetic trees show inferred evolutionary relationships in the form of multiple branching lineages connected by nodes.
True
Ribosomes are not considered to be organelles because they are not membrane—bound.
True
Serovars are strains of a species that have distinctive antigenic properties.
True
Some archaeal cells lack a cell wall.
True
Some archaeons are symbionts in animal digestive tracts.
True
Some microorganisms are useful in bioremediation processes that reduce the effects of pollution.
True
Sterol-like molecules called hopanoids are thought to be important for the structural integrity of many bacteria because of their suspected role in membrane stabilization.
True
The G + C content of a DNA sample can be estimated from its melting temperature.
True
The extreme insolubility of ferric iron leaves little free iron available for transport into bacterial cells.
True
The first disease to be identified as being caused by a virus was tobacco mosaic disease.
True
The major difference between the vacuoles of eukaryotes and the inclusion bodies of bacteria and archaea is that the former are membrane-bound, whereas the latter are not.
True
The relationship between specific bacteria and specific diseases was first demonstrated by Koch.
True
The trace amounts of micronutrients needed by microorganisms are usually supplied as inadvertent contaminants in water and regular media components.
True
The type strain is a well-characterized strain to which other strains are compared for inclusion in or exclusion from a particular species.
True
rRNA signature sequences can be used to place microorganisms in the correct domain.
True
Whose work on spontaneous generation first demonstrated the existence of a very heat-resistant form of bacteria that are called endospores?
Tyndall
Twitching motility involves _________.
Type IV pili
A(n) ____________ tree simply represents phylogenetic relationships but does not indicate which organisms are more primitive relative to others. In contrast, a(n) __________ tree gives a node that serves as the common ancestor and shows the development of the species from this origin.
Unrooted; rooted
Who of the following was the first to observe and accurately describe microorganisms?
Van Leeuwenhoek
The term used to describe bacteria that are shaped like curved rods is _________.
Vibrio
Which of the following provides the best explanation for why viruses are not included in the three domain system?
Viruses are not a cellular lifeform
Small organic molecules called __________ function as enzyme cofactors.
Vitamins
__________ discovered that soil bacteria could oxidize iron, sulfur, and ammonia to obtain energy.
Windogradsky
The ribosomal RNA studies that led to the division of prokaryotic organisms into the Bacteria and the Archaea were begun by ________.
Woese
Do fungi have cell walls?
Yes
The DNA of some archaeons is stabilized by association with archaeal histone proteins forming particles resembling eukaryotic nucleosomes.
Yes
The nucleolar organizer is a part of a specific chromosome that directs the synthesis of _________.
rRNA