Chapter 27 Mastering Biology

25 July 2022
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question
Substances required by typical nitrogen-fixing cyanobacteria.
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Carbon dioxide, water, nitrogen, light, and some minerals
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Which of the following is a disease caused by bacteria?
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Tuberculosis
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Bacteria function primarily in which ecological role?
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Commensalism, parasitism, mutualism, decomposition
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What are biofilms?
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Biofilms are cooperative colonies of bacteria.
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Which subgroup of proteobacteria contains many species that are closely associated with eukaryotic hosts in mutualistic or parasitic relationships?
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alpha
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Which of the following mechanisms is/are (a) means of genetic recombination in prokaryotes?
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Transduction, transformation, conjugation
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Why is salt a good preservative to use for foods such as pork and fish?
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Prokaryotic cells living in the food will shrink from their cell walls, impacting their ability to reproduce.
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Which of the following is not one of the most common prokaryotic cell shapes? -spherical -rod-shaped -spiral -cuboidal
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Cuboidal
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Acquiring an R plasmid would allow a bacterium to do what?
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Resist antibiotics
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Which of the following characteristics is a reason why a Gram-stain to distinguish gram-positive from gram-negative bacteria is an important tool in a medical diagnosis of a bacterial infection?
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-The outer membrane of a gram-negative bacterium helps protect it from the body's defenses -The cell walls of many gram-negative bacterium are toxic -Certain gram-positive bacteria are resistant to antibiotics
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Which of the following is not a true statement concerning bacterial flagella?
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Bacterial flagella are homologous to the flagella of eukaryotic cells
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Which of the following is a structure that bacteria, archaea, and eukaryotes have?
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plasma membrane
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What is a difference between the cell walls of prokaryotes and the cell walls of eukaryotes?
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The cell walls of prokaryotes are made of molecules different from those comprising the cell walls of eukaryotes
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Antibiotics administered in human medicine work against bacterial infections by __________
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interfering with an aspect of bacterial metabolism or structure that differs from that of eukaryotic cells
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Plasmids __________
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-often contain antibiotic resistant genes -replicate independently of the main chromosome -allow bacteria to survive adverse conditions -are transferred from one bacterium to another by conjugation
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What is the structural feature of gram-positive bacteria that results in their retaining a crystal violet dye stain and thereby being distinguished from gram-negative bacteria in a Gram-stain technique?
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Gram-positive bacteria have thicker cell walls
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The Desulfovibrio bacterium breaks down organic matter (which it must have) and uses sulfate (not oxygen) as an electron acceptor. As a result, it produces hydrogen sulfide (H2S), accounting for the "rotten egg" smell of swamp muck. Oxygen is a deadly poison to Desulfovibrio. We would call Desulfovibrio a(n) __________.
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obligately anaerobic chemoheterotroph
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Which group of bacteria is unusual in that they lack peptidoglycan in their cell walls?
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Chlamydias
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Which subgroup of proteobacteria contains many species that are predators of other bacteria?
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delta
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Which of the following does not contribute to bacteria's ability to evolve rapidly? -large populations -genetic recombination -mutation -sexual reproduction -short generation times
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Sexual reproduction
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Bacterial flagella have a very complex structure composed of 42 distinct proteins. What is the most likely explanation for the evolution of these complex structures?
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Exaptation
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Portions of the genomes of certain prokaryotic species are very similar to portions of the genomes of distantly related prokaryotes. The process that most likely accounts for this genetic similarity is __________.
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Horizontal gene transfer
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In an experiment, a microbiologist put equal numbers of each of the following organisms into a flask of sterile broth, consisting mostly of sugar and a few amino acids. She then placed the flask in the dark. Which of the following organisms would be most likely to survive? -cyanobacteria -thermoacidophilic bacteria -photoheterotrophs -chemoheterotrophic bacteria -photoautotrophs
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Chemoheterotrophic bacteria
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Some prokaryotes stick to their substrate or to one another by means of hairlike appendages, each called a __________.
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fimbria
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Bacteria that use light for their energy source and CO2 for their carbon source are called __________.
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photoautotrophs
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Bacteria that __________ tend to have abundant internal membranes.
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are photosynthetic
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Prokaryotes found inhabiting the Great Salt Lake would be __________.
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Extreme halophiles
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An F+ bacterial cell __________
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acts as a donor during conjugation
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Which of the following statements about cyanobacteria is true?
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-nitrogen-fixing cyanobacteria are the most self-sufficient of all organisms -They are the only prokaryotes that perform plantlike, oxygenic photosynthesis -some are single cells whereas others live in filamentous colonies -some species may carry on nitrogen fixation
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What is the function of a bacterial endospore?
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To facilitate persistence in temporarily harsh environments