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