The number of Vibrio cholera cells necessary to produce cholera in an exposed
individual is drastically reduced if the individual is malnourished.
Gut symbionts are lost after each molting a termite undergoes.
In antigen binding, MHC protein binds to the T cell epitope, whereas the TCR binds the
MHC motif.
The duration of logarithmic growth would increase if bacterial cells divided into three
equal daughter cells rather than two.
Carbon dioxide is the only greenhouse gas produced by anthropogenic activities.
By using a stain targeting living cells only, microscopy would be a better approach to
enumerate the number of living cells in a soil sample compared to viability counts of
serially diluted soil.
Traditional enrichment culturing circumvents issues associated with “weed” species
from overcoming the population.
Photoreceptors are analogous to chemoreceptors in that they are both proteinaceous
sensors.
Infections by “flesh-eating bacteria” can occur when exotoxins A, B, C, and E and the
bacterial surface M protein of Streptococcus pyogenes act as superantigens.
The light-stimulated proton pump of Halobacterium salinarum indirectly functions to
pump sodium out of the cell by the activity of a Na+/H+ antiport system.
When the life cycle of a disease agent is dependent on a single host species, the
pathogen can be eradicated.
Properly canned foods are sterile.
Some immature B cells are reactive to self-antigens but do not become activated even
when exposed to high concentrations of self-antigens.
Antibiotics that disrupt or halt cell wall biosynthesis are actually ineffective at harming
growth of mycoplasmas.
An individual tree can maintain a symbiotic relationship with many different species of
mycorrhizae simultaneously.
The immune response is as important as or even more important than antibiotics in the
elimination of Bordetella pertussis from the body.
Direct microscope counting of stained cells is an accurate method for calculating the
exact number of cells in a sample.
There are many genes in archaealgenomes that have no known function.
Organisms that degrade hydrocarbons in crude oil are ubiquitous in the environment
and have evolved special strategies, such as surfactant production, that allow them to
readily use hydrocarbons as electron donors and carbon sources.
Adapter molecules associate covalently with their respective antigen receptors in the
membrane.
Penetration requires that the entire virus is inserted within the host.
Water is considered to be the third most important common source of infectious
diseases.
In specialized transduction, virtually any genetic marker can be transferred from donor
to recipient.
T cell receptors on a particular T cell can recognize more than two antigens.
More carbon is present in dead organic material on Earth than in living organisms.
Many parasites, such as those that cause malaria, use antigenic variation to decrease
virulence within a specific host.
Temperate viruses can enter into either a lytic or lysogenic cycle.
As a malarial infection (Plasmodium falciparum) progresses, gametocytes are formed.
The gametocytes unite in the bloodstream before being picked up by the insect vector.
Viruses can redirect host metabolic functions.
Due to the genetic similarities of non-pathogenic and pathogenic enterics, phenotypic
assays are often performed in favor over taxonomy-based sequencing/probing to
distinguish pathogens from non-pathogens.
Immunoglobins associate with the adapter molecules Igα and Igβ.
ATP-binding cassette transport systems have high substrate affinity and thus help
microorganisms survive in low nutrient environments.
While rhizobia usually associate with plant roots, nodules can also be formed along the
stems of leguminous plants.
The mercury in fish is normally in the form of elemental mercury (Hg0).
Transcriptional regulation is considered negative when an inducer binds to and
deactivates a repressor.
The cytoplasmic domains of immunoglobulins and TCRs have cytoplasmic tyrosines
that can be phosphorylated.
Organisms grown with CO2 as its sole carbon source must have energy in the form of
ATP as well as reducing power.
Reassortment of the genes of the influenza virus is facilitated by the fact that the
genome is segmented.
Many fungi produce ________ that can cause significant disease.
A) cellulases
B) mycotoxins
C) endotoxins
D) chitinases
________ use inorganic electron donors released from deep-sea hydrothermal vents.
A) Chemolithotrophs
B) Photoheterotrophs
C) Chemoheterotrophs
D) Photolithotrophs
Some microorganisms can undergo ________ in which various cell types can become
specialized and arise from one parent cell type.
A) differentiation
B) genetic exchange
C) maturation
D) mutagensis
A poorly immunogenic vaccine often suggests the foreign proteins were not properly
recognized by the immune system due to a lack of ________ necessary, which can also
be engineered to occur with additional molecular manipulations.
A) complex folding
B) methylation
C) glucosylation
D) glycosylation
For bacteriophages and animal viruses ________ is the step in the viral life cycle that
determines host cell or tissue specificity.
A) attachment
B) penetration
C) synthesis
D) assembly
The Campylobacter spp. are
A) aerobes.
B) anaerobes.
C) microaerophiles.
D) facultative anaerobes.
You and your friends are hiking the Appalachian trail in North Carolina. You run out of
water and your friends want to fill up from a beautiful clear stream in the middle of the
forest. What precautions should you take before drinking the water and why?
Consider solution A (pH 6) and solution B (pH 9). Which of the following statements is
CORRECT?
A) Solution A is 3 times more acidic than solution B.
B) Solution A is 300 times more acidic than solution B.
C) Solution B is 1,000 times more alkaline (basic) than solution A.
D) Solution B is 3,000 times more alkaline (basic) than solution A.
Lignin is a complex polymer of methoxylated ________ compounds and is present in
________.
A) silica / aquatic environments
B) mineral / rocks
C) oil / fossil fuels
D) aromatic / vascular plant material
The Spanish flu of 1918 was caused by an ________ influenza virus.
A) H2N1
B) H5N1
C) H1N1
D) H2N2
The goal of wastewater treatment is to
A) produce potable water.
B) remove pathogens from wastewater before it is released.
C) reduce organic and inorganic materials in wastewater to a level that no longer
supports microbial growth.
D) remove pathogens from wastewater to produce potable water.
Which of the following an example of a biofilm?
A) soap scum
B) dental plaque
C) marine diatom
D) planktonic microcolony
Ruminants digest bacterial cells as a primary source of
A) carbohydrates.
B) vitamins and proteins.
C) proteins.
D) vitamins.
As a consequence of the immune system in humans recognizing dsRNA as foreign,
A) dsRNA viruses rarely infect humans.
B) dsRNA viruses quickly transcribe their genes into mRNA which is insensitive to
immune responses.
C) genomes of RNA viruses are often chemically modified to avoid recognition by
human immune cells.
D) the genomes of dsRNA viruses must avoid human immune cells during infection,
including replicating their genomes within their own nucleocapsids.
The Ca cycle is tightly coupled to the
A) carbon cycle through calcium carbonate formation in ocean waters.
B) phosphorus cycle through calcium phosphate formation in sediments and rocks.
C) silica cycle through calcium silicate formation in coastal ocean sediments.
D) nitrogen cycle because nitrogenase requires calcium ions.
Sedimentation in bogs and marshes develop ________ soils.
A) inorganic
B) mineral
C) organic
D) loamy
Construct a chart to show at least five major differences between the cytoplasmic
membrane and cell wall of bacteria and archaea. What are the implications of these
differences?
Assume you are the procurement manager of the medical charity “Doctors Without
Borders” and there was an imminent infectious disease epidemic threat in a remote
village in Africa. The epidemic can be prevented by vaccinating the population of
interest. However, due to bad roads and lack of fast transportation services to reach the
site of interest, which type of vaccine would you purchase for this job considering the
length of time it would take to reach the affected site and why? A live attenuated virus
or killed virus vaccines?
Clostridium perfringens food poisoning leads to diarrhea, because the
A) toxin causes the shedding of the intestinal lining.
B) permeability of the intestinal epithelium is altered by the toxin it produces.
C) disease causes such extreme thirst that the patient drinks more water than can be
absorbed.
D) organism multiplies more rapidly than the immune system can handle.
You isolate a purify a bacteriophage that can replicate in E. coli. Through chemical
analyses you determine that the only nucleic acid present is RNA. You isolate the RNA
and put it in a test tube with all of the necessary proteins and RNAs for translation. The
RNA is translated and new infectious virions are made. What does this tell you about
the bacteriophage?
A) The RNA genome is of the plus sense.
B) The RNA genome is of the plus sense and RNA replicase is present in the viral
capsid.
C) The new bacteriophage is a retrovirus.
D) RNA replicase is present in the viral capsid.
Flour and sugar are classified as ________ foods.
A) highly perishable
B) semiperishable
C) nonperishable
D) selectively perishable
Which of the following immunogens is MOST effective as a vaccine?
A) chemically inactivated bacteria
B) dead virus
C) live virus
D) toxoid
The total genetic complement of ALL cells within a microbial community is called a(n)
A) chromosomal island.
B) interactome.
C) metagenome.
D) metabolome.
All phototrophic bacteria use a monophyletic photosystem in photosynthesis, thus there
is intense competition for light between different phototrophic bacteria.
Nitrogen fixation is
A) rare among microorganisms.
B) widespread among microorganisms.
C) limited to Proteobacteria.
D) common in Bacteria, but absent in Archaea.
Most of the carbon in amino acid biosynthesis comes from
A) citric acid cycle intermediates.
B) citric acid cycle intermediates and glycolysis products.
C) glycolysis products.
D) glycolysis intermediates and products.
Which of these is often used as a prophylactic measure to protect a person against
future attack by a pathogen?
A) antiserum injection
B) artificial passive immunity
C) vaccination
D) None of these are correct.
You have discovered a new coccoid-shaped microorganism with no nucleus, a rigid cell
wall, and a diameter of 2 m. Chemical tests reveal that its cell wall does NOT contain
peptidoglycan. The new microorganism is
A) most likely a bacterium.
B) most likely a eukaryote.
C) most likely an archaeon.
D) either a bacterium or an archaeon.
Which of the following are molecular mediators of inflammation?
A) chemokines
B) cytokines
C) erythrocytes
D) both chemokines and cytokines
A(n) ________ gene is a gene that encodes a protein that is easy to detect and assay.
A) encoder
B) translational
C) reporter
D) recorder
Which technique would be used to estimate the concentration of naturally occurring
Escherichia coli in a wastewater sample?
A) agar dilution tube method
B) laser tweezers method
C) most probable number (MPN) method
D) cell tagging using GFP method
Discuss how recent advances in the molecular biology of nucleic acids have
revolutionized methods used for the identification of infectious disease agents and how
they are favored over traditional biochemical tests.
Distinguish an ecotype from a species, and provide an example of an ecotype.
Describe which diseases human papillomavirus (HPV) can cause in males and females.
What is the most common symptom of HPV infection, and why is this of concern?
A mutant you made in the laboratory with 5-bromouracil suddenly regains the wild-type
phenotype. You discuss this phenomenon with your advisor and colleagues, and they
suggest you try transposon mutagenesis to avoid this problem and create stable mutants.
Why would mutants created with 5-bromouracil be more likely to regain the wild-type
phenotype than mutants created via transposon mutagenesis?
Illustrate the reaction center of a purple bacterium with the following features
highlighted: antenna pigments, the special pair, protein H, protein L, protein M, quinone
pool, and ATPase. Also explain the importance of proximity for these components
within a reaction center.
What key features of Bacillus anthracis makes the anthrax disease impossible to
eradicate?
What functional group (or groups) of microbes would be most useful in a microbial fuel
cell in which electrons are transferred to and from solid metal electrodes? Why?
Why are public health officials concerned about smallpox being used as a biological
weapon? Give several reasons in your answer.
Illustrate and explain an operon that is subject to both positive and negative control
containing the operator region, the operon, the promoter, the activator binding site, and
the functional genes in a DNA sequence. Also compare and contrast the roles activators
and repressors have in regulating the illustrated operon.
Why is fever the universal result of endotoxin exposure?
Explain how diet plays a role in host susceptibility to infection.
Why does Neisseria gonorrhea adhere only to mucosal epithelial cells in the
genitourinary tract, eye, rectum, and throat?
Chytridiomycosis is thought to be associated with increases in environmental
temperature associated with global warming. Design a series of experiments that would
help to prove or disprove this hypothesis.
Explain the phenomenon known as diauxic growth. Hypothesize why this type of
regulation might be important for survival of a microbe in a community as well as a
situation where lacking it might be advantageous.
You are studying swimming motility in a pathogenic bacillus. You create mutations in
random genes and then test which mutations effect swimming motility by looking at the
mutant cells under the microscope. One of the mutant bacteria can not swim anymore,
but still rotates around in a one spot when you watch them. Using electron microscopy
you discover that some parts of the flagella are still present in the cell wall, but no long
flagella are visible. Which gene do you think is mutated (i.e., missing) and which
motility-related parts are still present in this mutant?
Differentiate between exergonic and endergonic in terms of free-energy calculations.
The text states that antibiotics are derived from microorganisms. What is the benefit to
an antibiotic-producing microorganism of producing an antibiotic in its natural habitat?
Describe how orally taken antibiotics can result in the harmful alteration in digestive
functions and disease.
Explain why the amount of energy released in a redox reaction depends on the nature of
both the electron donor and the electron acceptor.