MasteringBiology #1 – Flashcards
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Which group was not described in Woese's tree of life analysis?
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Prokarya
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What characteristics were used to classify organisms before Woese's tree of life analysis?
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Presence of a membrane-bound nucleus
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True or false? Data showing that the Bacteria were the first lineage to diverge from the common ancestor of all living organisms suggest that the Archaea and Eukarya are more closely related to each other than they are to the Bacteria.
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True
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Which of the following statements about phylogenetic trees is true?
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A paraphyletic group consists of a common ancestor and some of its descendants.
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Which molecule did Carl Woese study to produce his tree of life?
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Ribosomal RNA
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What is lateral gene transfer?
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Physical transfer of a gene from a species in one lineage to a species in another lineage.
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Classify each statement or picture as applying to gram-positive bacteria, gram-negative bacteria, or both.
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Gram-positive bacteria: -appear purple after Gram staining -have a thick peptidoglycan layer -alcohol rinse does not remove crystal violet
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Classify each statement or picture as applying to gram-positive bacteria, gram-negative bacteria, or both.
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Gram-negative bacteria: -appear pink after Gram staining -have thin peptidoglycan layer -alcohol rinse easily removes crystal violet -have an outer membrane as part of their cell wall structure
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Label the diagram below to show the relationship between nutritional modes of bacteria.
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a) autotrophs b) heterotrophs c) chemoautotrophs d) photoautotrophs e) photoheterotrophs f) chemoheterotrophs g) phototrophs h) chemotrophs
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Azotobacter is a genus of bacteria that live in soil and have the following characteristics: They are bacilli. They are gram-negative. They are obligate aerobes. They can fix nitrogen. (Unlike some other nitrogen-fixing bacteria, which associate with the roots of plants, Azotobacter species are free-living.) Select the four statements that are true for bacteria in the genus Azotobacter.
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They can convert atmospheric nitrogen to ammonia. They have a relatively thin layer of peptidoglycan in their cell wall. They use O2 for cellular respiration. They are shaped like rods.
