Despite being called the reverse citric acid cycle, it is currently identified as the most
ancient autotrophic pathway.
Although the sulfate-reducing bacteria are thought to be critical in the corrosion of
metal structures, the mechanism of metal corrosion is not well understood.
DNA vaccines are bacterial plasmids that contain cloned DNA with an antigen of
interest are unlike attenuated vaccines because there is no chance of causing disease.
Regeneration of oxaloacetate is essential for the citric acid cycle to be cyclical.
Proteins and nucleic acids absorb light maximally at 260 nm; hence, proteins protect
cells from UV effects.
Potable water is NOT safe for human consumption.
Hydrogen sulfide production is assayed by growth in a medium containing ferric iron
(Fe3+).
The activity of MinC and MinD direct whether a bacterial cell will be coccoid or
bacillus shaped.
Some Archaea are chemoorganotrophs and use organic compounds as electron donors
for energy metabolism.
Toxigenicity in Corynebacterium diphtheriae is due to phage conversion.
Studying the transcriptional activity of flagellar genes would not likely reveal
differential changes when the cells are actively motile compared to nonmotile activity,
because a two-component regulatory system is sufficient to control flagellar activity.
rRNA has an enzymatic role in all stages of protein synthesis.
Diazotrophs are obligately symbiotic bacteria that fix N2 into ammonia, thus providing
a critical source of nitrogen to their host.
An RNA genome itself serves as mRNA in negative-stranded RNA viruses.
Streptococcus mutans can produce dextran when sucrose is present in the absence of the
enzyme dextransucrase.
In chemolithotrophic Archaea, H2 is a common electron donor.
Some species in the genus Acidobacteria are classified in Bacteria while others are
considered Archaea.
Silica is a characteristic component of diatom and oomycete cell walls.
Gene families are composed of homologous genes that have different evolutionary
origins but the same function.
Each amino acid made during protein biosynthesis first requires a separate biosynthetic
pathway to be invoked by a cell.
A sudden onset of a headache, vomiting, and a stiff neck are all symptoms of
meningococcal meningitis.
TH2 cells interact directly with the pathogens.
Many Listeria spp. grow well at cold temperatures, so although refrigeration is
excellent at preventing growth of most other pathogens, it is not very useful at
minimizing growth of contaminated foods.
Agrobacterium tumefaciens can form root nodules in plants and can mate with bacteria,
which makes it an excellent host organism for genetic transformations among different
domains of life.
Varied coenzyme availability increases the diversity of enzymatic reactions in both
biosynthetic and catabolic pathways possible in a cell.
A polymer of N-acetyl-glucosamine, chitin, is a primary component to most fungal cell
walls.
Eukaryotes originated after the rise in atmospheric oxygen.
Invasion is the ability of a pathogen to enter into host cells or tissues, spread, and cause
disease.
The precipitation of soluble iron ions into solid iron occurs spontaneously in the
presence of organic carbon compounds.
Wild animals are a natural reservoir for Clostridium tetani.
A disease that is constantly present in low numbers is called an acute disease.
Pathogenic bacteria that contain S-layers are protected against host defense
mechanisms.
A small, heat-stable DNA-binding protein present in the cells of some Archaea, called
Sac7d, binds to the minor groove of DNA in a very specific manner and increases its
melting temperature by 40C.
Some chrysophytes (or “golden algae”) are actually chemoorganotrophs rather than
phototrophs.
Systemic fungal infections are difficult to treat because active antifungal drugs cause
significant host toxicity.
Which method would be LEAST effective at sterilizing a glass hockey stick to use in
the spread-plate method?
A) autoclaving
B) gamma radiation
C) ethanol soaking
D) ultrahigh-temperature pasteurization
You experimentally change the DNA sequence directly upstream of a start codon of an
operon in E. coli to investigate the function of this region of DNA. Analysis reveals that
after the change the same amount of mRNA is made from the operon, but there are very
few proteins made from the operon. What is the most likely function of the DNA
sequence that you changed?
A) The DNA sequence likely functions as a ribosome-binding site.
B) The DNA sequence likely functions as a promoter.
C) The DNA sequence likely functions as a termination sequence.
D) The DNA sequence likely functions as in transcriptional regulation.
Which metabolic strategy does NOT invoke the proton motive force for energy
conservation?
A) aerobic catabolism
B) anaerobic
C) chemoorganotrophy
D) photoautrophy
Most methanotrophs are obligate ________ because ________.
A) aerobes / the initial step of methane oxidation requires O2
B) anaerobes / methane is produced in anaerobic environments
C) fermenters / methane only provides enough energy for fermentation
D) heterotrophs / methane does not provide enough carbon for growth
The earliest diverging lineage of fungi are the
A) chytridiomycetes.
B) zygomycetes.
C) glomeromycetes.
D) ascomycetes.
You are looking at a sample from the top green layer of a colorful bacterial mat. Using
phase contrast and fluorescence microscopy, you see evenly spaced cells in the middle
of a filament that are slightly smaller than the others. The smaller cells are not
fluorescent, indicating they lack photosystem II, but the rest of the filament is
fluorescent. What is the most likely function of the smaller cells in the filament?
A) survival in the dark
B) nitrogen fixation
C) sulfur storage
D) nitrate storage
The Fe and Mn cycles include
A) reduced and oxidized forms that are very chemically reactive.
B) large reservoirs of solid mineral forms that are chemically inert.
C) incorporation of Fe and Mn into the exoskeletons of diatoms and other alga.
D) toxic forms that can poison aquatic ecosystems if the cycles are imbalanced.
One microenvironment of the skin is an area where glands produce an oily substance
called
A) mucus.
B) sebum.
C) fimbrae.
D) lipid A.
Impetigo is due to an infection caused by
A) Staphylococcus aureus but not Streptococcus pyogenes.
B) Streptococcus pyogenes but not Staphylococcus aureus.
C) either Staphylococcus aureus or Streptococcus pyogenes.
D) neither Staphylococcus aureus nor Streptococcus pyogenes.
How do viability stains usually distinguish between living cells and dead cells?
A) The chemical fluoresces only when bound to ribosomes that are actively
synthesizing proteins.
B) The chemical stain is taken up by living cells and once metabolized becomes
fluorescent.
C) The dye specifically targets intact cytoplasmic membranes.
D) The dye’s fluorescence is quenched by dead cells.
Bioluminescence develops when
A) population density is high.
B) oxygen is depleted.
C) ambient light is low.
D) the host induces the bioluminescence genes.
All of the following are non-protein electron carriers EXCEPT
A) FADH2.
B) FMNH2.
C) cytochromes.
D) quinones.
The earliest stromatolites were probably formed by
A) anoxygenic phototrophs.
B) anoxygenic lithotrophs.
C) oxygenic phototrophs.
D) oxygenic lithotrophs.
The presence of specific ________ signals that a given water source might be
contaminated with pathogens.
A) exotoxins
B) chemical compounds
C) endotoxins
D) indicator microorganisms
Transcription of various genes under particular environmental conditions can be studied
by
A) CARD-FISH.
B) using a reporter gene that encodes for green fluorescent protein (GFP).
C) T-RFLP.
D) using a reporter gene that encodes for green fluorescent protein (GFP) or
CARD-FISH.
Consider a mutation in which the change is from UAC to UAU. Both codons specify
the amino acid tyrosine. Which type of point mutation is this?
A) silent mutation
B) nonsense mutation
C) missense mutation
D) frameshift mutation
The function of leghemoglobin in root nodules is to
A) bind oxygen.
B) chelate iron.
C) produce iron.
D) produce nitrogen.
The Archaea are
A) primarily ancient organisms that have not evolved very much in the last billion
years.
B) phylogenetically diverse, but functionally restricted to extremophiles and
chemolithotrophs.
C) diverse microorganisms that inhabit almost every environment on Earth, including
the colon of humans and other mammals.
D) functionally diverse, but restricted to thermophilic or hyperthermophilic
environments.
Lymphogranuloma venereum is a sexually transmitted disease caused by distinct strains
of ________.
A) Chlamydia trachomatis
B) herpes simplex 2 virus (HSV-2)
C) Neisseria gonorrhoeae
D) Haemophilus ducreyi
Coliforms can be present in 5% of drinking water samples tested within a month and
still be considered safe according to the U.S. Environmental Protection Agency (EPA).
The ________ and ________ domains of the class II MHC protein interact to form a
peptide-binding site.
A) B / T
B) light / heavy
C) C / V
D) α1 / β1
Most halobacteria are motile by means of lophotrichous flagella.
Regarding the viral membrane of an enveloped virus, the lipids are derived from the
________, and the proteins are encoded by ________.
A) host’s cell membrane / viral genes
B) virion / viral genes
C) host’s cell membrane / host’s genes
D) virion / host’s genes
The most prevalent human infectious diseases are caused by
A) bacteria.
B) viruses.
C) fungi.
D) protozoans.
The term “phage” is generally reserved for the viruses that infect
A) animals.
B) plants.
C) bacteria.
D) multiple species.
How do arbuscular mycorrhizae (AM) help plants obtain more nutrients from the soil?
A) Byproducts of AM metabolism serve as primary nutrient sources for the plants.
B) The AM increase the total surface area to absorb more nutrients.
C) The hyphae develop as specialized nodules that directly produce nutrients for the
plant.
D) Signaling molecules in the plant are passed to the AM to initiate electron flow,
which is in turn used to create ATP.
Which of the following is the first, or initiator, reaction in acid mine drainage and
leaching?
A) oxidation of reduced sulfides to sulfate and the release of reduced iron (Fe2+)
B) rapid spontaneous reduction of oxidized iron (Fe3+)
C) rapid oxidation of sulfides to sulfate by oxidized iron (Fe3+)
D) microbial sulfate reduction
Why is so much emphasis placed on the genomic composition (e.g., ssRNA, dsDNA) of
individual viruses. Provide examples to support your explanation.
Which of the following are NOT phagocytes?
A) dendritic cells
B) monocytes
C) neutrophils
D) erythrocytes
Both deletions and insertions occur during the evolution of microbial genomes.
Insertions bring in new genes that may be useful for the cell, but deletions
A) may increase fitness of a microorganism by eliminating unneeded genes.
B) always result in a severe loss of fitness for the microorganism.
C) are uncommon because they are usually lethal.
D) always result in a severe loss of fitness but keep microbial genomes compact.
In Hashimotos’s disease, autoantibodies are made against ________, a product of the
thyroid gland.
A) bacteria
B) hemoglobin
C) thyroglobulin
D) viruses
The most common circulating antibody, comprising about 80% of the serum
immunoglobin, is
A) IgA.
B) IgC.
C) IgD.
D) IgG.
The MOST serious types of fungal infections are
A) subcutaneous infections.
B) mycotoxic infections.
C) systemic mycoses.
D) superficial mycoses.
Ignicoccus has several unique structural features that have lead scientists to propose
that it may be the modern descendent of the ancestral cell type that gave rise to the
origin of eukaryotic cells. What are the unique features of Ignicoccus and why do they
support this hypothesis?
Hyperthermophilic Archaea have been found to contain dibiphytanyl tetraether lipids.
Why are these lipids different from lipids present in non-hyperthermophiles? What
special properties and structures do they confer?
How do phagocytes interact speedily and effectively with pathogens?
Compare and contrast the life cycles of the cellular and the acellular slime molds.
Describe the pathogenesis of HIV to explain how the number of CD4 lymphocytes
decline in an ongoing HIV infection.
How does the body respond when it first encounters a foreign particle or bacterial
pathogen?
Explain the differences between uniporters, symporters, and antiporters.
When analyzing the sequence of genes similar to ones already known, why is the amino
acid sequence of the protein more important than the DNA sequence?
Explain the sequence of events that would follow the transfer of an organism from a
complex medium to a minimal medium.
Use the events in the life cycle of Schistoma mansoni to propose two different strategies
to reduce the incidence of snail fever.
Knowing the concentration of microorganisms in a sample is often an important
consideration for environmental, industrial, and medical microbiologists, yet a
microscope is sometimes not used to accomplish this task. Explain five major
limitations to using a light microscope to directly count microorganisms.
Create an experiment where you would use both a Southern blot and a Northern blot to
determine if a newly isolated bacterium contains and actively uses the same catabolic
pathway as previously demonstrated. What is the value in doing the Southern blot first?
With results from these experiments, how would you conclude if the same pathway is
active or not?
Defend and explain how FtsZ-type proteins being found in mitochondria and
chloroplasts strengthens or weakens the endosymbiosis theory.
Explain the function of the helicases and why they are necessary.
Natural underground pyritic deposits that are not disturbed by mining activities do not
form acidic drainage waters. Why not? Explain the critical steps in the formation of
acid mine drainage in your answer.
Compare and contrast chemical, spatial, and temporal gradients as found in bacterial
regulatory systems.
Explain our present understanding of molecular adaptations to the cytoplasmic
membrane that are present in psychrophiles.
Defend how type II restriction endonucleases, which do not cleave random sites, can be
a part of an approach to random cloning library.