Quizzes – Flashcard
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In what/which domain(s) of life is/are microorganisms represented?
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Archaea, Bacteria, and Eukarya
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The theory of spontaneous generation was refuted by the work of
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Louis Pasteur.
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Robert Koch received the 1905 Nobel Prize in Physiology or Medicine for
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identifying Mycobacterium tuberculosis as the causative agent of tuberculosis.
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Which structure is responsible for swimming motility in bacteria?
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Flagellum
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Which type of microscopy requires that samples be sliced into thin sections?
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Transmission electron
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Compared to large cells, small cells have ________ surface-to-volume ratios, causing ________ nutrient exchange and growth rates.
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higher / higher
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The use of the Gram stain in microbiology is important because it differentiates
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bacterial cells with different types of cell walls
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You have discovered a new coccoid-shaped microorganism with no nucleus, a rigid cell wall, and a diameter of 2 µm. Chemical tests reveal that its cell wall does NOT contain peptidoglycan. The new microorganism is
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most likely an archaeon.
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The prokaryotic transport system that involves a substrate-binding protein, a membrane-integrated transporter, and an ATP-hydrolyzing protein is
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the ABC transport system.
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What is the biological function of endospores?
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They enable organisms to endure extremes of temperature, drying, and nutrient depletion.
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Microorganism X is Gram-negative rod, can live either aerobically or anaerobically, and reduces NO3- to NO2- during anaerobic respiration. Microorganism X is most likely:
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Escherichia coli
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Which of the following would be used by a chemoorganotroph for energy?
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C2H3O2-
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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
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complex / minimal
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If ΔG0' is negative, the reaction is
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exergonic and energy will be released
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From the standpoint of the microorganism, in glycolysis the crucial product is
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ATP; the fermentation products are waste products.
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In aerobic respiration, the final electron acceptor is
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oxygen.
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Supercoiling is important for DNA structure, because
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it condenses the DNA so that it can fit inside the cell
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Which of the following is formed on the lagging strand during DNA synthesis?
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Okazaki fragments
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In the process of transcription, promoters are specific sequences of ________ that are recognized by ________.
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DNA / sigma factors
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Transfer RNA molecules
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function to transfer the correct amino acids to the ribosome during translation.
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A monophyletic group is a group that
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descended from one ancestor.
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Which feature of the 16S rDNA gene allows relationships between close relatives to be inferred?
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Variable regions
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The uptake of DNA released from a cell is ________, while transfer of DNA with cell-to-cell contact would most likely result in ________.
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transformation / conjugation
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Hfr strains of Escherichia coli
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have an integrated F factor.
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The designations Phe-, Leu-, and Ser+ refer to an organism's
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phenotype
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Which of the following methods could be used to measure the genomic mutation rate?
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Mutation accumulation
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What kind of mutation is a single base-pair insertion in a coding region?
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Frameshift
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Under genetic drift, drastic changes in allele frequency are more likely in
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Small populations
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Purifying selection is
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inefficient in small populations.
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Myxococcus xanthus lives
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in motile social groups
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Suppose that Bacillus subtilis carries two paralogous genes, "A1" and "A2". "A1" encodes leucine synthase, while "A2" encodes isoleucine synthase. A close relative, Bacillus cereus, has only similar gene, whose protein product is both a leucine synthase and an isoleucine synthase. "A1" and "A2" were probably maintained by
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subfunctionalization
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The pan genome of a species is the genomic content that is
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present in one or more strains of the same species
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The earliest stromatolites were probably formed by
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anoxygenic phototrophs.
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Oxygen did not accumulate in the early atmosphere until it reacted with reduced materials, especially ________, in the oceans
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ferrous iron
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Comparisons between different species of green algae can help us to understand which major evolutionary transition?
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Multicellularity
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Whether an organism is classified as a photoheterotroph or a photoautotroph depends on its
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carbon source
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The path of electron flow in oxygenic phototrophs is referred to as the ________ scheme
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Z
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In green sulfur bacteria, carbon fixation occurs via the
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Reverse citric acid cycle
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Frozen methane molecules are called
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methane hydrates
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Photosynthetic _____ account for 80% of productivity in the oceans
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Cyanobacteria
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Following antibiotic therapy, patients are often administered ________ to facilitate recolonizaton of normal flora
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probiotics
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Which of these microorganisms is MOST likely to be found in the human gut?
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Helicobacter pylori
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The total genetic complement of ALL cells within a microbial community is called a(n)
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metagenome
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A polymerase chain reaction (PCR) copies an individual gene segment in vitro with a(n) ________ primer(s)
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pair of DNA
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What technique(s) can be used to characterize the phylogenetic composition of a microbial community without culturing any of the members?
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fluorescent in situ hybridization
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The 13C/12C isotopic ratio of geological rocks of different ages has been used as evidence for or against past biological activity, because compounds of biological origin
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have a lower proportion of 13C that compounds of geological origin
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Microbes are sometimes used in secondary treatment of wastewater to
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remove organic matter
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Microbial immobilization is the best strategy for uranium bioremediation, because
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uranium contamination is widespread and thus difficult to physically remove
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Capsules are particularly important for
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protecting bacteria from host defense mechanisms.
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Cytolytic toxins
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are extracellular proteins that cause cell lysis and death by damaging the host cytoplasmic membrane