Chapter 27 Questions-1

Chapter 27 Questions-1 - Ch 27 Multiple Choice Identify the...

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Ch 27 Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. ____ 1. Mycoplasmas are bacteria that lack cell walls. On the basis of this structural feature, which of the statements below is true about mycoplasmas? a. They are gram-negative. b. They are subject to lysis in hypotonic conditions. c. They lack a cell membrane as well. d. They undergo ready fossilization in sedimentary rock. e. They possess typical prokaryotic flagella. ____ 2. Though plants, fungi, and prokaryotes all have cell walls, we classify them under different taxonomic units. Which of the observations below comes closest to explaining the basis for placing these organisms in different taxa? a. Some closely resemble animals, which lack cell walls. b. Their cell walls are constructed from very different biochemicals. c. Some have cell walls only for support. d. Some have cell walls only for protection from herbivores. e. Some have cell walls only to control osmotic balance. ____ 3. Which of the following have been present in Earth's living organisms for the least amount of evolutionary time? a. enzymes that catalyze glycolysis b. photosystems I and II c. cell walls d. nuclei e. genes composed of DNA ____ 4. Which of the following statements about bacterial cell walls is false? a. Bacterial cell walls differ in molecular composition from plant cell walls. b. Cell walls prevent cells from bursting in hypotonic environments. c. Cell walls prevent cells from dying in hypertonic conditions. d. Bacterial cell walls are similar in function to the cell walls of many protists, fungi, and plants. e. Cell walls provide the cell with a degree of physical protection from the environment. ____ 5. Which of the following statements is correct about gram-negative bacteria? a. Penicillins are the best antibiotics to use against them. b. They often possess an outer membrane containing toxic lipopolysaccharides. c. On a cell-to-cell basis, they possess more DNA than do the cells of any taxonomically higher organism. d. Their chromosomes are composed of DNA tightly wrapped around large amounts of histone proteins. e. Their cell walls are primarily composed of peptidoglycan. ____ 6. Which of the following is the most common compound in the cell walls of gram-positive bacteria? a. cellulose b. lipopolysaccharide c. lignin d. peptidoglycan e. protein
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____ 7. If penicillin is an antibiotic that inhibits enzymes from catalyzing the synthesis of peptidoglycan, then which prokaryotes should be most vulnerable to inhibition by penicillin? a. mycoplasmas b. gram-positive bacteria c. archaea d. gram-negative bacteria e. spore-bearing bacteria ____ 8. Which of the following is the correct order, from most external to most internal? 1.
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This note was uploaded on 12/13/2010 for the course ACT 101 taught by Professor Jenkins during the Spring '10 term at Alabama State University.

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Chapter 27 Questions-1 - Ch 27 Multiple Choice Identify the...

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