The amino acid composition of thermostable proteins is not particularly unusual, except
for a bias for increased levels of amino acids that form α-helices.
Both environmental conditions and nutrient resources strongly influence the
composition of a microbial community.
Tailed bacterial viruses can be used as genetic engineering tools.
Viral hepatitis can result in acute kidney disease, followed by chronic kidney disease.
The mycelia of mycorrhizae can form underground nutrient networks where several
trees are connected.
Diphtheria toxin inactivates elongation factor 2 by catalyzing the attachment of
adenosine diphosphate ribose from NAD+.
The largest cellular genomes belong to prokaryotes that are parasitic or pathogenic.
Cyclic AMP (cAMP) is involved in the global regulation of catabolic pathways in
Escherichia coli, including the lac operon, and a low activity of adenylate cyclase that
makes cAMP is suggestive of catabolite repression.
Many defined growth media that support microbial growth lack malonate, which is an
important precursor for biosynthesis of lipid membranes. Based on this, we can infer
cells also must have a metabolic pathway to generate malonate from other compounds.
Immunity results from the actions of cells that circulate throughout the body, primarily
through the blood and lymph.
Nucleic acid probes and immunological reagents are NOT commonly used in the
clinical laboratory for the diagnosis of viral disease, because the cultivation of the virus
is often difficult or even impossible.
The antigen-binding site of ALL antibodies form by interactions between the variable
domains of the heavy and light chains.
A toxoid is an attenuated form of a toxin that retains both its antigenicity and toxicity.
Changes in food processing and distribution can increase the incidence of new and
emerging diseases.
Nucleic acid probes are NOT suitable for the detection of viruses.
A non-aerated or shaken liquid growth medium inoculated with a bacterium is one of
the best ways to culture an obligate anaerobe.
With respect to nitrogen utilization, relatively few bacteria can use NH3 whereas many
more can make use of N2.
Each chlorophyll and bacteriochlorophyll type is distinguished by its absorption
spectrum.
Heterofermentation CANNOT be differentiated from homofermentation based on the
compound fermented.
DGGE and T-RFLP are both molecular microbial ecology methods that use the
polymerase chain reaction to amplify specific genes to assess diversity.
Ideally, microbes should be eliminated from ALL foods.
Genomic analysis led to the discovery that pathogenic organisms often lack genes for
amino acid biosynthesis.
Thermotoga are hyperthermophiles and appear relatively closely related to Archaea in
comparison to other bacteria such as Salmonella.
Methanogenesis is coupled with proton motive force formation and ATP synthesis
through the activity of ATPases.
A repressor is a molecule that represses biosynthesis of an mRNA transcript.
Literally hundreds of clinically useful EIAs have been developed.
The two main biological activities in the Ca and Si cycles are the biosynthesis of shells
and exoskeletal material as well as the mineralization of these materials in sediments.
The organisms that cause pneumococcal pneumonia are rarely found as a part of the
normal flora of healthy adults.
Lysogeny is unique to bacteriophages; similar relationships have not been found among
the animal viruses.
Local and state authorities can set standards for recreational water that are above or
below the guidelines set by the United States government.
Purple phototrophic bacteria that use bacteriochlorophyll a are oxygenic.
Many Bacteria isolated from nature are natural lysogens.
Pathogen virulence NEVER changes throughout a host’s life.
Most phosphorous, such as that found in inorganic phosphate (HPO4-), exist in the +5
oxidation state in nature.
Most of the genetic diversity on earth resides in viral genomes.
An unpressurized autoclave would not be able to sterilize a growth medium with
contaminating bacteria but could still pasteurize it.
By nature of its infectivity, M13 phage can be used in the laboratory to continually
propagate a particular DNA sequence inside of Escherichia coli by simply culturing
infected E. coli in LB.
DNA replication is bidirectional in prokaryotes with circular chromosomes.
Which of the following antibiotics inhibits RNA synthesis?
A) penicillin
B) erythromycin
C) rifampin
D) azithromycin
The enzyme transposase may be coded for by insertion sequences on a
A) chromosome.
B) phage.
C) plasmid.
D) chromosome, phage, or plasmid.
The evolutionary history of a group of organisms is called its ________ and it is
inferred from ________.
A) taxonomy / phenotype
B) phylogeny / nucleotide sequence data
C) phylogeny / phenotype
D) taxonomy / morphology
Microbial biochemistry involves the discovery of microbial ________ and the
________ they perform.
A) biomolecules / functions
B) enzymes / catalyses
C) metabolic pathways / reactions
D) biomolecules, enzymes, and metabolic pathways / functions
Construct a chart to demonstrate the molecular features of the primary domains of life.
Why are there overlapping or shared molecular features between all three domains?
Relate the shared and unique molecular features of each domain to early evolution, the
last universal common ancestor (LUCA), and the evolution of the three domains
“Special pair” is the name given to the ________ in the photochemical complex of the
purple bacteria.
A) two bacteriochlorophyll a molecules
B) two bacteriochlorophyll b molecules
C) two quinones
D) two reaction centers
For a carbon source, chemoorganotrophs generally use compounds such as
A) acetate, succinate, and glucose.
B) bicarbonate and carbon dioxide.
C) nitrate and nitrite.
D) acetate, bicarbonate, and nitrate.
During the Jurassic Period, several different mammalian lineages independently
evolved an herbivorous lifestyle for obtaining energy. This has resulted in
A) different digestive patterns in herbivorous animals, some that depend on gut
microbiota to digest plant material and some that do not.
B) different digestive patterns in herbivorous animals that all depend on gut microbiota
to digest plant material.
C) the evolution of foregut fermentation, as seen in ruminants, as the only digestive
pattern that depends on fermentative gut microbiota.
D) horizontal gene transfer of genes for glycoside hydrolases and polysaccharide lyases
from bacteria to mammals.
Genomes of species in both Bacteria and Archaea show a strong correlation between
genome size and
A) noncoding RNA.
B) codon bias.
C) number of ORFs.
D) number of introns.
An example of a cyclical disease is
A) diphtheria.
B) smallpox.
C) influenza.
D) anthrax.
Animal-transmitted diseases are generally spread to accidental hosts by
A) direct contact.
B) aerosols.
C) bites.
D) direct contact, aerosols, and bites.
Which of the following forms of oxygen is/are generally toxic to living organisms?
A) superoxide anion
B) hydrogen peroxide
C) hydroxyl radical
D) superoxide, hydrogen peroxide, and hydroxyl radicals are all toxic
The first documented description of a microorganism was of a ________ by ________.
A) bacterium / Ferdinand Cohn
B) fungus / Robert Koch
C) mold / Robert Hooke
D) yeast / Martinus Beijerinck
Two common or important bacterial pathogens found in the blood are
A) Pseudomonas aeruginosa and Escherichia coli.
B) Enterobacter andProteus.
C) Shigella and Salmonella.
D) HIV and Escherichia coli.
More than ________ % of all T cell precursors that enter the thymus do NOT survive
the selection process.
A) 15
B) 25
C) 45
D) 95
Which type of regulator(s) specifically bind to operator regions of DNA?
A) activators
B) activators and inducers
C) repressors
D) repressors and corepressors
Which organism would likely harbor the MOST two-component regulatory systems?
A) an archaeon living in an extreme environment
B) a bacterium occupying a heterogeneous niche will high nutrient mixing
C) an organism capable of quorum sensing
D) a parasitic bacterium living inside another organism
Which spores are NOT involved in sexual reproduction of fungi?
A) ascospores
B) basidiospores
C) conidia spores
D) zygospores
T4 genes are transcribed by host RNA polymerase, yet the transcription of T4 genes is
carefully controlled so that groups of T4 genes are transcribed at specific times after
infection. How is this accomplished?
A) Early T4 genes encode for proteolytic enzymes that destroy the host RNA
polymerase. Subsequently a viral polymerase is created that transcribes the middle and
late genes in the correct order.
B) Early and middle T4 genes encode for proteins that modify the activity of sigma
factors and host RNA polymerase to regulate the expression of T4 genes.
C) Each group of T4 genes has a different promoter that indicates that order in which
they should be transcribed in based on the affinity of the promoter for the host RNA
polymerase.
D) Rolling circle replication of the viral genome ensures that the genes are available for
transcription in the correct order.
The incidence of HIV/AIDS among transfusion recipients has
A) increased since the discovery of HIV.
B) decreased since the discovery of HIV.
C) remained the same since the discovery of HIV.
D) never been more than a few individuals per year.
Supercoiling is important for DNA structure, because
A) it holds together the antiparallel strands of DNA in the double helix.
B) it provides energy for transcription.
C) it condenses the DNA so that it can fit inside the cell.
D) it prevents RNA from pairing with DNA in the double helix.
Archaea is divided into three phyla.
Blocking polyomavirus SV40’s ability to integrate its genome into host cells would
A) avoid cancer development from the virus.
B) increase the rate of transformation.
C) increase the latent period of SV40.
D) switch SV40 into a lytic lifecycle which would be especially harmful to the host
cells.
Ecological theory states that for every organism there is at LEAST one ________, and
the microenvironment where the organism is MOST successful is called the ________.
A) population / community
B) niche / prime niche
C) prime niche / niche
D) community / population
________ was the first to identify a new form of autotrophy in which energy is obtained
from oxidizing inorganic compounds called ________.
A) Martinus Beijerinck / heteroautotrophy
B) Martinus Beijerinck / chemolithotrophy
C) Sergei Winogradsky / heteroautotrophy
D) Sergei Winogradsky / chemolithotrophy
Epsilonproteobacteria are most dominant in hydrothermal vents because they
A) reduce nitrogen.
B) oxidize reduced sulfur compounds.
C) use oxygen as electron acceptors.
D) bind divalent cations.
According to bacterial abundance studies done so far on soils, the ________ represent
the most abundant phylum.
A) Proteobacteria
B) Acidobacteria
C) Actinobacteria
D) Firmicutes
Which regulatory mechanism does NOT depend on a conformational change in
protein/enzyme structure to change activity?
A) attenuation
B) catabolite repression
C) feedback inhibition
D) negative control
Based on its function, which type(s) of viruses likely contain(s) a gene encoding for
RNA replicase?
A) dsDNA and ssDNA viruses
B) positive ssRNA viruses
C) positive and negative ssRNA viruses
D) ssRNA and ssDNA viruses
Glucose fermentation by Clostridium spp. produce ATP only when acetate and butyrate
are produced. Why do these organisms produce acetone and butanol after strong initial
activity of generating ATP with acetate and butyrate byproducts?
A) Acetate and butyrate accumulation creates a deadly acidic environment, which
acetone and butanol do not.
B) Acetate and butyrate are no longer needed for biosynthetic pathways.
C) Acetone and butanol serve as better sources for NAD(P)+ reduction.
D) Acetone and butanol production is favored for stability to store intracellular carbon
sources for potential nutrient poor conditions.
Escherichia coli is a chemoorganotrophic, facultative aerobe and belongs to the
Proteobacteria phylum. Based on this information, which of the following functional
groups does E. coli most likely belong to?
A) green sulfur bacteria
B) ammonia-oxidizing bacteria
C) denitrifying bacteria
D) nitrite-oxidizing bacteria
The human oral flora consists of
A) a small group of phylogenetically related aerobic microorganisms.
B) diverse aerobic and anaerobic microorganisms.
C) monoculture biofilms on tooth surfaces.
D) the same phyla that are found in the human gut.
Bacteriochlorophyll and chlorophyll contain ________ as a cofactor.
A) iron (II)
B) iron (III)
C) magnesium
D) manganese
Discuss the ecological importance of the enzyme nitrogenase, the diversity and
physiology of the various groups of organisms that contain it, and the strategies these
organisms use to optimize conditions for the enzyme.
Describe the hypothesis of viruses occurring before living cells and how DNA might
have evolved. What is the current hypothesis about the evolutionary relationships
between RNA, DNA, viruses, and cellular life?
Why do so many eukaryotic pathogens cause highly refractory and long-term chronic
infections that are difficult to treat in contrast with prokaryotic pathogens?
What type of methods are used in microbial systematics? Why are multiple methods
used to characterize and classify microbial species? Be sure to define the methods and
describe the general strengths and weaknesses of each type.
What measures would be taken if a case of smallpox were recognized in a world
traveler after the individual had debarked from Heathrow airport in England following
several days of sightseeing in London?
A study of the human gut performed in 1982 used various types of plates under
different growth conditions to describe and enumerate the microbes in the human gut.
They concluded that the majority of the microbes in the human gut are
Gammaproteobacteria. A study conducted in 2010 using next-generation sequencing to
characterize 16S rRNA sequences concluded that the majority of the microbes in the
human gut are Firmicutes and Bacteriodetes. Why did these studies have different
conclusions? Which study do you think is most accurate?
A cocktail of 30 compounds was identified to harbor a corepressor, and subsequent
separation and purification was performed to test individual compounds. Describe an
experiment that would enable you to identify the specific compound that acts as a
corepressor for a catabolic pathway. Be certain to explain what will be measured and
how you could conclude which compound is a corepressor.
Explain why GC-rich DNA requires a higher temperature to denture or melt than
AT-rich DNA and hypothesize as to why the GC content of chromosomes in
microorganisms from different environments varies widely.
Contrast prokaryotic and eukaryotic regulation of gene expression.
Why are microbial doubling times in nature typically longer than those obtained in the
laboratory?
Consider a pizza dough made by vigorously mixing to form gluten and evenly disperse
the ingredients such as baker’s yeast (Saccharomyces cerevisiae). Predict the metabolic
differences yeast would have in a thinly flattened dough and in a spherical dough ball.
A beer-making microbiologist noticed that no matter how long the brewing process
went, 3% alcohol was the maximum produced. Hypothesize what is causing this low
level of alcohol in reference to the brewer’s recipe and recommend how a higher
alcohol yield could be achieved. Ethanol is toxic at high concentrations, but ignore this
factor to focus on microbial metabolism.
Both lichens and corals are symbioses involving phototrophic microorganisms.
Compare and contrast lichens and corals, including the types of organisms involved, the
role of each partner, the specificity of the interaction, and the method of transmission
for each symbiosis.
Compare and contrast generalized transduction with specialized transduction.
Compare and contrast the prokaryotic and eukaryotic light-gathering machinery
function and spatial organization. Why do various chlorophylls show different
absorption spectra?