Reverse transcriptase is a(n)
A) RNA-dependent DNA polymerase.
B) DNA-dependent DNA polymerase.
C) RNA-dependent RNA polymerase.
D) DNA-dependent RNA polymerase.
The primer for retrovirus reverse transcription is a specific
A) tRNA encoded by the cell.
B) tRNA encoded by the virus.
C) nuclear tRNA.
D) nuclear tDNA.
Which of the following can function as intracellular signaling molecules?
A) acylated homoserine lactones
B) hydrophilic lipids
C) quinones
D) proteorhodopsins
Which of the following are the hosts for most enveloped viruses?
A) Bacteria
B) animals
C) Archaea
D) fungi
The membrane-enclosed compartments that contain digestive enzymes in eukaryotic
cells are called
A) cristae.
B) mitosomes.
C) lysosomes.
D) stromas.
High-efficiency natural transformation
A) is common in Bacteria and Archaea.
B) requires specialized DNA uptake, DNA binding, and integration proteins.
C) is only common in Archaea.
D) usually involves plasmids.
Which intermediate compound(s) in the citric acid cycle is/are often used for
biosynthetic pathways as well as carbon catabolism?
A) α-ketoglutarate
B) oxaloacetate
C) succinyl-CoA
D) α-ketoglutarate, oxaloacetate, and succinyl-CoA
The PAMP recognized by mannose-binding lectin (MBL) is the sugar mannose, found
as a repeating subunit in
A) human mucus.
B) lymphocyte receptors.
C) bacterial and fungal polysaccharides.
D) bacterial peptidoglycan.
Which of the following types of microscopy can be used with live cells?
A) phase-contrast microscopy
B) transmission electron microscopy
C) bright-field microscopy
D) scanning electron microscopy
What form of photosynthesis evolved first on Earth?
A) oxygenic
B) anoxygenic
C) autotrophic
D) heterotrophic
A cell that lacks sulfite oxidase but can still oxidize sulfur for energy could be identified
by
A) adenosine phosphosulfate reductase coupled with substrate-level phosphorylation.
B) electrons being transferred to cytochrome c prior to shuttling them into the electron
transport chain.
C) identifying an alternative quinone, flavoprotein, or cytochrome.
D) quantifying the release of sulfate byproduct.
The SOS system repairs DNA that has gaps, breaks, and other lesions by
A) cutting DNA from other parts of the genome and pasting it into the gaps or damaged
areas.
B) stabilizing single-stranded DNA until the next round of normal replication.
C) using specialized DNA polymerases that will synthesize a new DNA strand even if
there is not a normal complementary DNA strand to act as a template.
D) using available mRNA and a special RNA-dependent DNA polymerase to fill in the
gaps and replace damaged DNA.
Which of the following diseases is NOT normally spread by a common source?
A) measles
B) foodborne diseases
C) waterborne diseases
D) cholera
Two tubes are inoculated from one test tube of a bacterial culture. The cultures are then
transferred every day for 2 months. All of the media and growth conditions are the same
in every tube. After 2 months of cultivation, the fitness and genotype frequencies of the
populations in the two tubes are compared. The fitness of the two cultures is the same,
but the genotype frequencies are very different in the two cultures. How is this
possible?
A) Two months is not long enough for different fitness levels to evolve even if the
genotype frequencies change.
B) This result is not possible because different genotype frequencies would result in
different fitness levels under the same growth conditions.
C) Natural selection caused the evolution of different genotype frequencies within the
separate test tubes.
D) Genetic drift within the small populations in the test tubes resulted in different
genotype frequencies.
The following bacterial species are all implicated in dental caries EXCEPT
A) Fusobacterium.
B) Borrelia.
C) Streptococcus.
D) Lactobacillus.
Roughly half of all adults in the United States are infected with ________ but are
asymptomatic.
A) Toxoplasma gondii
B) Trichomoniasis vaginalis
C) Cryptosporidium parvum
D) Cyclospora cayetanensis
Which of the following statements is FALSE?
A) Most bacteria are capable of using ammonia as their sole nitrogen source.
B) Some bacteria are able to use nitrates or nitrogen gas as their nitrogen source.
C) Most available nitrogen is in organic forms.
D) Nitrogen is a major component of proteins and nucleic acids.
Which of the following enzymes would you expect to find in the virion of a retrovirus,
but NOT in a bacteriophage?
A) lysozyme
B) methylase
C) restriction enzymes
D) reverse transcriptase
Sulfide is toxic to respiring organisms, because it can combine with metals present in
________ that serve a critical function in respiration.
A) glycolysis enzymes
B) oxidases
C) NADH
D) cytochromes
In Bacteria, a chromosome can be distinguished from a plasmid, because a
chromosome is a genetic element that
A) is circular.
B) is linear.
C) encodes for essential functional genes.
D) replicates via a bidirectional fork.
Laser tweezers are used for
A) testing the purity of a culture.
B) isolating individual cells.
C) separating aerobes from anaerobes.
D) enhancing the growth of fastidious organisms.
The rRNA gene sequences of hyperthermophilic Archaea and Bacteria have diverged
________ over time, likely due to ________.
A) relatively little / strong constraints on sequence changes at higher temperatures
B) substantially / higher mutation rates at higher temperatures
C) relatively little / low mutation rates in these ancient organisms
D) substantially / DNA damage at higher temperatures
Which genus within Archaea is capable of growth at the hottest temperature recorded of
122C?
A) Methanopyrus
B) Thermoproteus
C) Thermosphaera
D) Pyrococcus
Which is the MOST toxic form of mercury?
A) CH3Hg+
B) Hg0
C) Hg2+
D) Hg4+
Meningitis can be caused by
A) viral infections.
B) bacterial infection.
C) fungal infections.
D) viral, bacterial, or fungal infections.
Common contaminants in blood drawn from a vein include all EXCEPT which of the
following?
A) Staphylococcus epidermidis
B) Coryneform bacteria
C) Propionibacteria
D) Escherichia coli
In contrast to positive ssRNA viruses such as coronaviruses and polioviruses, the
genome of retroviruses
A) lacks genes encoding for tRNA primers.
B) must first integrate into the host’s genome before transcription.
C) is negative ssRNA.
D) lacks ribonuclease activity.
The factor that MOST affects the thermostability of a protein is its
A) highly hydrophobic core regions.
B) folding pattern.
C) ionic surface interactions.
D) number of hydrogen bonds.
The decrease or loss of virulence of a pathogen is referred to as
A) aging.
B) attenuation.
C) disinfectivity.
D) lethal dose.
Why are secondary or “booster” reimmunizations given?
A) Secondary immunizations are necessary for an innate immune response.
B) Secondary reimmunizations produce a secondary immune response and boost
antibody titers.
C) Secondary reimmunizations produce a phagocytic immune response that is longer
lasting than the primary immune response.
D) Frequent secondary reimmunizations are needed because the immune system doesn’t
remember antigens for more than a few years.
Transcription of chaperonins is greatly accelerated when a cell is stressed by
A) excessive osmotic pressure.
B) extremes in pH value.
C) lack of oxygen.
D) excessive heat.
Which of the following statements is FALSE?
A) A flagellar protein subunit is flagellin.
B) In flagellar motion, the basal body acts as a motor.
C) Flagellar rotation generates ATP.
D) The hook is the wider region at the base of the flagellum.