The incidence of HIV among hemophiliacs and transfusion recipients has remained
constant since 1994.
Some virulence genes are carried on plasmids or lysogenic bacteriophages.
Except that they are not produced in the cytoplasm, conidia produced by Streptomyces
spp. are chemically quite similar in composition to endospores produced by Bacillus
spp.
Blood serum contains cells and clotting proteins.
A microbial population can contain several microbial communities.
There is at least one known virus whose genome is actually larger than a cellular
genome.
Low return of nutrients in the pelagic zone results in relatively low primary production
in the open ocean when compared to freshwater lake systems.
Silicoflagellates use silicon compounds in substrate-level phosphorylation.
Microorganisms that grow in extreme environments typically contain larger genomes
when compared to microbes that grow in non-extreme environments.
Bacteria associated with plants fix very small amounts of nitrogen, therefore they do
NOT contribute significantly to the global N cycle.
A bacterial cell is interpreted as gram-positive when it forms purple insoluble crystal
violet-iodine complexes within the cell during the Gram stain.
Following uptake, transforming DNA becomes attached to a competence-specific
protein that prevents it from nuclease attack until it reaches the chromosome.
Some infectious agents, such as Neisseria gonorrhoeae, do NOT elicit a systemic
immune response.
Chemoorganotrophic bacteria can facilitate the formation of soil through the secretion
of organic acids.
Microbial species are difficult to define because they are often polyphyletic.
The availability of rapid antigen detection (RAD) systems for pathogenic streptococci
has eliminated the need to culture Streptococcus pyogenes.
When exposed to UV light, oxygen gas produces ozone gas.
The optimum temperature is usually closer to the minimum temperature than the
maximum temperature.
In a prokaryotic genome, either insertion elements OR transposons are present, but both
are never present at the same time.
Microbial growth is generally described as the increased number of cells rather than the
expanding size of an individual microbial cell.
One phenotypic trait used for species identification and description is the analysis of the
types and proportions of the fatty acids present in the cytoplasmic and outer
membranes. The methodology employed is often nicknamed FAME.
Akinetes and hormogonia are specialized cells, found in some cyanobacteria, that
facilitate nitrogen fixation.
Reaction centers ONLY indirectly receive photon energy via light-harvesting
molecules.
Deinococcus radiodurans is capable of withstanding especially high levels of radiation,
and the carotenoids they produce enhance this resistance.
Dendritic cells are phagocytes with antigen-presenting properties.
Not all coliforms are pathogenic.
Depending on the type of regulatory mechanism, activators and repressors can bind to
operator regions which control transcription.
The toxic lipopolysaccharides produced by MOST gram-negative bacteria are called
exotoxins.
Viruses can confer additional properties on their host cells, which can in turn be
inherited.
To detect antibodies in human serum, the direct EIA is most commonly employed.
With the exception of some gram-positive cocci, what concentration of NaCl inhibits
nearly
all bacterial growth?
A) 2.5%
B) 5%
C) 7.5%
D) 10%
Carrier-mediated transport is necessary when
A) diffusion will not allow adequate amounts of a substance to enter the cell.
B) movement into the cell is against a concentration gradient.
C) the level of nutrients in nature is very low.
D) nutrient concentration is very low in the environment, is higher inside of the cell, or
diffusion is not possible.
Homologous recombination has been observed in
A) Archaea.
B) Bacteria.
C) Eukarya.
D) Archaea, Bacteria, andEukarya.
________ ensures that each B cell produces only one immunoglobulin.
A) Self-activation
B) Allelic exclusion
C) MHC interaction
D) Clonal deletion
In most cases, the final product of sulfur oxidation is
A) hydrogen sulfide.
B) elemental sulfur.
C) sulfate.
D) thiosulfate.
Which organisms would MOST likely be isolated from aerobic growth conditions with
acetate and a soil sample heated to 80C for 10 min?
A) aerobic or facultative anaerobic acetogens
B) endospore-forming bacteria
C) hyperthermophilic heterotrophic bacteria
D) mycoplasmas
Which of these microorganisms is MOST likely to be found in the human gut?
A) Helicobacter pylori
B) Streptococcus sobrinus
C) Streptococcus mutans
D) Roseobacter denitrificans
The microorganism Cryptosporidium parvum is a
A) fungus.
B) bacterium.
C) protozoan.
D) virus.
What would MOST likely result if an exponentially growing culture of Lactobacillus
sp. fermenting glucose was accidentally transferred into a highly aerated environment?
A) Aerobic catabolism of glucose would begin rather than aerobic degradation, due to
the presence of O2.
B) Fermentation of glucose would continue, because the cells are insensitive to O2
despite lacking aerobic metabolism capabilities.
C) The cells would halt their metabolism due to the presence of N2, which acts as a
global repressor of fermentation in this group.
D) The population would die due to the presence of O2, because it is a strict anaerobe.
Many parabasalids lack ________, which makes them different than most other
eukaryotes.
A) endoplasmic reticula
B) introns in their genomes
C) mitochondria and hydrogenosomes
D) Golgi complexes
Filoviruses (such as Ebola virus) that cause severe hemorrhagic fevers generally have
high ________ but low ________.
A) incidence / prevalence
B) prevalence / mortality
C) mortality / morbidity
D) morbidity / mortality
Disease ________ is measured by the total number of new reported disease cases within
a population over a period of time.
A) incidence
B) frequency
C) morbidity
D) prevalence
A bacterium that either partially or fully catabolizes an acyl-homoserine lactone will
likely disrupt
A) attenuation.
B) chemotaxis.
C) endospore formation.
D) quorum sensing.
Dissimilatory sulfide-oxidizers use a variety of unique ecological strategies in order to
A) avoid the toxicity of hydrogen sulfide.
B) position themselves at interfaces where sulfide and oxygen meet.
C) position themselves where there is sufficient light for sulfide oxidation.
D) find organic carbon substrates.
The pan genome of a microbial species is constantly changing because of
A) bottleneck events.
B) horizontal gene transfer.
C) substitutions.
D) substitution and bottleneck events.
In the United States, every clinical and research institution requires that workers be
protected from ________ that is contracted almost exclusively from handling patient
specimens (rather than from known exposure or accidents).
A) anthrax
B) hepatitis B
C) drug-resistant mycobacteria
D) influenza
Adaptive immune responses are directed at pathogen molecules called
A) antigens.
B) antibodies.
C) T-cell receptors.
D) PAMP.
Chemokines produced by activated macrophages include
A) CXL8.
B) CCL2.
C) MCP-1.
D) CXL8, CCL2, and MCP-1.
Which rickettsial disease can lead to endocarditis?
A) Q fever
B) typhus
C) Rocky Mountain spotted fever
D) scrub typhus
Many hyperthermophiles of Archaea are ________; however, Staphylothermus is a
chemoorganotroph.
A) chemolithotrophs
B) mixotrophs
C) parasites
D) photoheterotrophs
Bacterial symbionts of termite hindguts play a critical role in the termite’s
A) reproduction.
B) nitrogen metabolism.
C) resistance to fungal infection.
D) reproduction and nitrogen metabolism.
Systemic lupus erythematosus (SLE) is an example of a disease caused by type
________ hypersensitivity.
A) I
B) II
C) III
D) IV
One factor that seems to aid in maintaining lipid stability in hyperthermophilic Archaea
is that dibiphytanyl tetraether lipids form a(n)
A) covalently bonded monolayer cytoplasmic membrane.
B) interlocking bilayer cytoplasmic membrane.
C) interlocking lattice with the cell wall.
D) pseudomembrane immediately inside the cytoplasmic membrane.
The pH of MOST foods is
A) basic.
B) neutral or basic.
C) acidic.
D) neutral or acidic.
One laboratory group repeated the same experiment described by others with the
identical bacterial isolate and the same growth medium and conditions used but were
unable to achieve the same O.D. at 600 nm. What is the LEAST likely cause for this
discrepancy of turbidity measured?
A) One lab used 16 mm wide test tubes and the other used 18 mm wide test tubes.
B) One lab subtracted the yellow color of the growth medium away from the final
turbidity reported whereas the other lab used colorless water.
C) One lab vigorously dispersed the biofilm-forming bacteria with vortexing and the
other did not.
D) The two labs varied with 1000 m elevation and did not consider the influence of
pressure.
Using bright-field microscopy to look at a slide prepared with a basic dye you observe
cells under 400X magnification with a clear inner compartment within the cell. The cell
is most likely a(n)
A) prokaryote.
B) bacterium.
C) archaeon.
D) eukaryote.
Which of the following is a cure for mumps?
A) a vaccine
B) an antibiotic
C) host antibodies
D) an antiviral
The presence of genes encoding RubisCO enzymes in Methanocaldococcus jannaschii
and a species of Pyrococcus indicates that the organisms
A) incorporate carbon dioxide via the acetyl-CoA pathway.
B) incorporate carbon dioxide via the Calvin cycle.
C) incorporate carbon dioxide via the reverse citric acid cycle.
D) utilize molecular hydrogen as an electron donor in chemolithotrophic metabolism.
Vibrio cholerae primarily infects the
A) stomach.
B) small intestine.
C) large intestine.
D) rectum.
A student travels to Brazil by boat on the Amazon River, without visiting the doctor
prior to traveling for recommended vaccinations for travel to South America. The
student becomes ill during the trip and is quarantined. Which of the diseases listed
below does the student most likely have?
A) hantavirus
B) yellow fever
C) Ebola
D) Q fever
Whether an organism is classified as a photoheterotroph or a photoautotroph depends
on its
A) energy source.
B) carbon source.
C) oxygen requirements.
D) carbon and energy sources.
What is the advantage of enhanced biological phosphorus removal (EBPR) over
chemical precipitation?
A) Chemical precipitation produces sludge containing arsenic.
B) EBPR removes significantly more phosphorus than chemical precipitation.
C) Significantly less sludge is produced by EBPR compared to chemical precipitation.
D) EBPR is a more stable process.
Clostridium botulinum is a gram- ________ rod that produces an ________.
A) negative / endotoxin
B) negative / exotoxin
C) positive endospore-forming / exotoxin
D) positive endospore-forming / endotoxin
The mutagens 2-aminopurine and 5-bromouracil are examples of
A) alkylating agents.
B) nucleotide base analogs.
C) chemicals reacting with DNA.
D) None of the answers are correct.
Why is it incorrect to say that an object is partially sterile?
Explain why the presence of many Archaea has been confirmed only by community
sampling of rRNA genes and not by culture in the laboratory. How has metagenomics
helped to solve this problem?
Use specific examples to describe the difference between a differential and a selective
medium.
How does insect ecology and the life cycle of Plasmodium impact the epidemiology
and pathogenesis of classic malaria?
Explain how Clostridium tetani cells that rarely leave their initial site of infection can
cause death in their hosts.
Explain the strengths and limitations of using 16S rRNA for phylogenetic analyses.
Enumerating the viable and total cell concentration of a population of a microbial
isolate can be a really laborious task for a microbiologist. Especially when a
microbiologist studies the same isolate for several years, it often becomes practical to
determine the relationship between optical density (OD) and cell concentration. Once
this relationship (determined by a standard curve) is determined, the OD of an isolate in
a broth can be routinely used to determine the population’s concentration. Why must a
standard curve be prepared for each isolate when using OD measurements to determine
cell concentration? Also describe an experiment that would generate this type of
standard curve.
How do Cyanobacteria impact the ecology of both aquatic and terrestrial environments
on Earth?
Propose a set of procedures or steps to sequence an individual cell’s genome present in
lake water.
What is the similarity between the flora found in a female at the menopause stage and a
female at the pre-puberty stage? How different is it from a female between the stages of
puberty and menopause?
How do dental lactic acid bacteria cause dental caries?
Briefly describe how B cells are activated.
Describe the stages chlamydia cells go through during infection of human cells and the
significance for the key steps in the cycle.
Explain the endosymbiotic theory. What is the evolutionary value of endosymbiosis?
What is the difference between chlorophyll and bacteriochlorophyll, and which
organisms contain each?