In natural samples it is often difficult to differentiate live cells from dead cells or cells
from nonliving matter.
Metabolism is a unifying characteristic of all cellular organisms.
The purpose of the enrichment culture technique is to enrich for organisms with specific
physiological properties from a microbial community.
The gut flora is relatively stable over long time periods in healthy adults, suggesting its
highly evolved role in the human body.
The Winogradsky column is a method for assessing the entire gene complement of a
habitat, revealing both the biodiversity and metabolic capabilities of the microbial
community at the same time.
Nitrogenase is an oxygen-sensitive enzyme even though many diazotrophs are aerobic
microorganisms.
Treatment of ALL pathogenic E. coli infections involves supportive therapy and, in
some cases, may also include antimicrobial drugs.
Localized infections by pyogenic bacteria often form boils or abscesses.
Few genes in all organisms have common evolutionary roots.
Antihistamines are used to treat some allergic symptoms because they neutralize the
histamine mediators that cause rapid dilation of blood vessels and contraction of
smooth muscles that initiate the symptoms of systemic anaphylaxis.
Codon usage and even the genetic code itself varies from one organism to the next.
While many Archaea are bacilli or cocci, unusual morphologies such as square,
flattened and irregular discs have also been identified in certain species.
Cyclic di-guanosine monophosphate is upregulated as Pseudomonas aeruginosa cells
are declining.
Some proteins that bind to DNA block transcription, whereas other proteins can activate
transcription.
A disease transferred by indirect contact with a high basic reproduction number and
mortality would be an effective biological weapon.
Once the regulatory proteins and effector molecules are made, the actual mechanisms
for regulation rarely require net energy input.
Class I MHC proteins are found ONLY on the surface of B lymphocytes, macrophages,
and dendritic cells.
The relative percentage of genes devoted to protein synthesis in small-genome
organisms is high compared with that of large-genome organisms.
In the context of nutrients, a sink is one that slowly releases a particular nutrient over
time.
Acetogens can ferment glucose into acetate, but methanogens cannot.
The DNA in chloroplasts and mitochondria of eukaryotic cells is derived from Bacteria.
Although T4 encodes over 250 proteins, it does not encode its own RNA polymerase.
CD4 and CD8 proteins are used for in vitro tests as T cell markers to differentiate TH
cells from TC cells.
Taq polymerase was isolated from a thermophile and is used in the polymerase chain
reaction (PCR) technique because it does not become inactivated at high temperatures.
MOST microbiology research laboratories maintain BSL-2 standards.
A recombinant-vector virus would still be effective if the vaccinia virus is unable to
express the cloned gene as an antigenic protein.
Endotoxins are released in large amounts only when cells lyse.
The disposal of garbage or sewage in the ocean is known to cause the sudden growth of
sulfate reducers.
Bacteria make up about one-third the weight of fecal matter.
Treponema pallidum, a bacterium associated with syphilis, is not considered a pathogen
because to date it remains unculturable in the lab, and, therefore, Koch’s postulates are
unable to be fulfilled.
Sergei Winogradsky worked with bacteria involved in cycling nitrogen and sulfur.
For water to be considered safe to drink, it MUST be treated with four distinct methods.
Sulfide oxidizers are among the most ecologically diverse trophic groups because of the
different strategies they employ to access sufficient amounts of sulfide and oxygen
simultaneously.
Malaria is
A) the most common cause of death due to infectious disease worldwide.
B) prevented or treated with chloroquine.
C) controlled by reducing the population of the mosquito vector.
D) the most common cause of death due to infectious disease worldwide, although it
can be controlled by reducing the population of the mosquito vector and prevented or
treated with chloroquine.
In addition to chromosomes, some mitochondria also contain other genetic material
known as
A) plasmids.
B) transposons.
C) proteomes.
D) lysosomes.
One important difference between the C, N, and S cycles and the P, Ca, and Si cycles is
that
A) P, Ca, and Si are NOT cycled in terrestrial environments.
B) the P, Ca, and Si cycles do NOT involve redox changes or gaseous forms that can
alter Earth’s atmospheric chemistry.
C) the P, Ca, and Si cycles do NOT involve microbial activity.
D) the P, Ca, and Si cycles are NOT affected by global warming or other human
activity.
The structure that confers structural strength on the cell is known as the
A) cytoplasmic membrane.
B) cell wall.
C) ribosome.
D) cytoplasm.
Encapsulated strains of Streptococcus pneumoniae are particularly pathogenic, because
they
A) produce exotoxin A.
B) produce exotoxin B.
C) are potentially very invasive.
D) produce M protein surface antigens.
A deleterious mutation in recA results in
A) a decrease in specific recombination.
B) a decrease in homologous recombination.
C) an increase in homologous recombination.
D) no change in either general or specific recombination.
An organism grown in a high nutrient liquid broth to high turbidity always appears to
produce a blue pigment and even when a large inoculum is transferred to a nutrient rich
agar plate it appears blue. When the researcher noticed it never appears blue when very
small colonies were grown in low nutrient agar plates. What is the most plausible
conclusion?
A) Large populations enabled the differentiation of a subpopulation of cells that created
the blue pigment.
B) Only high nutrient conditions provide enough energy for cells to produce this
secondary metabolite that appears blue.
C) The blue pigment production is linked to quorum sensing.
D) The strong gradient from very high to low nutrient bioavailability induces
production of the blue metabolite.
A monophyletic group is a group that
A) descended from one ancestor.
B) has the same fitness level.
C) possesses one taxonomic trait that is the same.
D) shares one phylogenetic marker.
Which of those below is NOT an important consideration when designing a fusion
protein construct?
A) Avoid hybridization of the fusion gene in the artificial construct.
B) Reading frame is the same for both the fusion gene and reporter gene.
C) Transcriptional start and stop signals are shared.
D) Translational start and stop signals are shared.
Natural killer cells like Tc cells use ________ and granzymes to kill their targets
without prior exposure or contact with the foreign cells.
A) coagulants
B) M protein
C) perforin
D) interferon gamma
The SOS regulatory system is activated by
A) the activity of DNA polymerase IV.
B) DNA damage.
C) transcription of LexA.
D) repression of RecA.
Nutrient transport requires energy because the nutrients must be transported into the cell
against a concentration gradient. The energy required for nutrient transport is supplied
by
A) ATP.
B) the proton motive force.
C) phosphoenol pyruvate.
D) ATP, the proton motive force, or phosphoenol pyruvate.
The structural and trophic foundation of coral reefs is a mutualistic relationship
between
A) cyanobacteria and sponges (Porifera).
B) chemolithotrophic bacteria and stony corals (Cnidaria).
C) dinoflagellates and stony corals (Cnidaria).
D) cyanobacteria and stony corals (Cnidaria).
Crown corrosion of concrete wastewater distribution systems is the result of
A) acidic fermentation products reacting with the gypsum in the concrete.
B) sulfate reduction in the sewage and sulfide oxidation in the oxic headspace above.
C) fungal growth in the concrete.
D) rapid iron reduction coupled to pyrite dissolution.
Which compound in fertilizer do farmers use to inhibit the production of easily leached
nitrogen compounds?
A) anhydrous ammonia
B) carbonate
C) nitrapyrin
D) nitrate
In DNA replication there are leading and lagging strands, because
A) DNA replication is conservative and a completely new DNA molecule must be
made.
B) DNA replication is semiconservative and each strand is copied simultaneously in
opposite directions.
C) the strands of DNA are parallel and are copied in the same direction simultaneously.
D) one strand of DNA is copied faster than the other.
To ensure growth of a newly discovered bacterium with unknown nutritional
requirements, it would be best to begin with a ________ medium rather than a
________ medium.
A) complex / minimal
B) minimal / complex
C) selective / complex
D) selective / differential
All proinflammatory cytokines EXCEPT ________ induce fever at the systemic level.
A) IL-4
B) IL-12
C) IL-6
D) IL-17
The structure and function of a protein are determined by its ________ sequence.
A) nucleotide
B) amino acid
C) ribonucleotide
D) translocation
The flow of biological information begins with
A) DNA replication.
B) RNA transcription.
C) mRNA translation.
D) transcriptional regulation.
The most abundant genes in prokaryotic genomes are
A) those involved in metabolism.
B) those involved in translation.
C) those involved in transport.
D) those involved in DNA replication.
An agar plate for counting colonies and maximizing statistical validity should ideally
contain
A) 1 to 100 colonies.
B) 50 to 100 colonies.
C) 30 to 300 colonies.
D) 100 to 1000 colonies.
T cells recognize antigens with their
A) antibodies.
B) leukocidins.
C) M proteins.
D) T cell receptors.
The oxic atmosphere created conditions that led to the evolution of various new
metabolic pathways, such as
A) sulfide oxidation.
B) nitrification.
C) iron oxidation.
D) sulfide oxidation, nitrification, and iron oxidation.
A serum containing antigen-specific antibodies is called an
A) antiserum.
B) antitoxin.
C) antiantigen.
D) anticoagulase.
Biosynthesis of vitamin K (menaquinone) by ________ spp. inhabiting the ________ of
humans is a potentially important mutualistic relationship for human health.
A) Bifidobacterium / intestinal tract
B) Bifidobacterium / stomach
C) Escherichia / intestinal tract
D) Escherichia / stomach
The peptide interbridge crosslinking between peptidoglycan layers is found ONLY in
the cell walls of
A) Archaea.
B) Eukarya.
C) gram-positive Bacteria.
D) gram-negative Bacteria.
Which of the following is NOT a subunit of lipopolysaccharide (LPS)?
A) O-specific polysaccharide
B) lipid A
C) core polysaccharide
D) M protein
Which group of organisms is thought to be responsible for the corrosion of submerged
metal structures and oil pipelines?
A) fermentative microorganisms
B) acidophilic iron-oxidizers
C) sulfate reducers
D) hydrocarbon-degrading anaerobes
Which of the following is formed on the lagging strand during DNA synthesis?
A) DNA secondary structures
B) Okazaki fragments
C) RNA polymerase
D) replisomes
Phosphonate comprises 25% of the ________ phosphorous pool in marine
environments.
A) inorganic
B) organic
C) insoluble
D) biologically unavailable
You have discovered a new microorganism, but you want to know if it is a eukaryote or
a prokaryote. To investigate this question you prepare a slide with a simple stain and
view it with a light microscope with a 40X objective lens and 10X ocular lens. You also
prepare a control slide using Saccharomyces cerevisiae (a unicellular eukaryote). You
can see the cells on your control slide, but you don’t see cells when you look at your
unknown microorganism. What can you conclude from this experiment?
A) The experiment failed to visualize the organism because the stain killed it.
B) Your new unknown microorganism is probably a virus.
C) The cells of the new unknown microorganism may be too small to see with the
objective and ocular lenses you used.
D) The new unknown microorganism is probably an archaeon.
What is unusual about phage MS2 infection of Escherichia coli?
A) All proteins are synthesized simultaneously during infection so there are no early
and late proteins.
B) It attaches to the host’s pilus rather than the cell’s surface.
C) It enters through a host cell porin.
D) More than one MS2 phage can be present in an individual E. coli cell.
In all cells a gene encodes for
A) a protein (via mRNA).
B) a tRNA.
C) an rRNA.
D) a protein, tRNA, or rRNA depending on the specific gene.
An organism living in the bottommost region of a body of water is described as being
A) benthic.
B) litoral.
C) neritic.
D) pelagic.
What process allows evolution to “experiment” with genes to create novel functions?
How is this manifested in extant genes (presently existing) and their relationships to
each other?
Propose a unique target for a drug that would inhibit replication of retroviruses in
humans.
Why are some microorganisms specialized to only certain parts of the body? Describe
an example that supports your answer.
Recommend what type of data should be collected and analyzed in a systems biology
approach to investigate how a non-pathogenic bacterial strain becomes pathogenic.
Describe what scientific fields and methods would be involved in your
recommendation.
Explain why DNA fragments migrate toward the positive electrode and why some
fragments migrate more rapidly than others during gel electrophoresis. How does this
electronegativity influence observations and conclusions drawn from DNA migrated
through an agarose gel?
Explain why infectious diseases are much less lethal in developed countries than in
underdeveloped countries.
What are the major antigenic barriers for tissue transplantation from one individual to
another?
During outdoor activities, it is not uncommon to be bitten by mosquitoes several times,
so how does an individual know he/she has been infected with the West Nile virus?
How would an infected individual be treated for the disease?
Rodents have been associated with numerous severe epidemics in the past, prompting
microbiologist Hans Zinsser in the 1930s to write a book, Rats, Lice, and History, in
which he documented the important role of rodents in epidemics. Discuss why rodent
control is still desirable, even in an age when it is perceived that the “magic bullets” of
chemotherapy and immunization to control infectious disease are readily available.
Discuss the theory of secondary endosymbiosis and defend the theory by providing
evidence that supports it.
Explain the process of site-directed mutagenesis, and discuss some applications of this
technique.
If you were in charge of preserving ancient stone ruins and sculptures in an outdoor
environment, what strategies would you use to prevent deterioration of the stone?
How can NanoSIMS be used to determine which Roseobacters most strongly use
DMSP as a sulfur source within a coastal marine environment? Explain the NanoSIMS
methodology in your answer.
Design an experiment using omic methods to test how Escherichia coli adapts to
different growth temperatures.
Describe three molecular effects high pressure has on the physiology of organisms.
Explain how leeches are used today in medical replants and transplants.
Categorize the circumstances under which the same substance (molecule) can be either
an electron donor or an electron acceptor.
Explain why the discovery of iron-oxidizing phototrophs has important implications for
both understanding the evolution of photosynthesis and explaining the large deposits of
ferric iron (Fe3+) found in ancient sediments on Earth.
Describe two capabilities of microbes that exemplify their dynamic nature.