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Unformatted text preview: 9-25-09 Quiz 4
True (mark “a”) or False (mark “b”) 1. Scientists have estimated the Earth’s age to be about 4.5-4.6 billion years old. 2. The Miller-Urey experiment demonstrated that small organic molecules polymerize when they are concentrated on hot sand, clay, or rock. 3. Evidence indicates that organisms similar to prokaryotes may have existed as early as 3.5 billion years ago. 4. Radiometric measurements of isotopic half-life are used to determine the relative ages of fossils. 5. If 11% of a radioactive isotope remains in a fossil, its age could be slightly more than the sum of three half-lives of the isotope. 6. A bacterial cell that stains pink/red by Gram staining is considered Gram negative. 7. If the bacteria in question 6 stained Gram positive, you would know its cell wall also has an outer membrane. 8. A chemoautotroph gets its carbon from CO2 and its energy source from organic compounds. 9. Gram staining is used to determine if a bacterial species has cocci- or bacillishaped cells. 10. Capsules only form within a bacterial cell during unfavorable conditions. Key: 1a, 2b, 3a, 4b, 5a, 6a, 7b, 8a, 9b, 10b ...
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- Fall '09