Chapter_27 - Chapter 27: Prokaryotes 1) Mycoplasmas are...

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Chapter 27: Prokaryotes 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 such as peptidoglycans. 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 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. 4) Which of the following is the most common compound in the cell walls of gram-positive bacteria? A) cellulose B) lipopolysaccharides C) lignin D) peptidoglycan E) protein 5) 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 6) Which of the following is the correct order, from most external to most internal? 1. cell wall 2. plasma membrane 3. capsule A) 1, 2, 3 B) 1, 3, 2 C) 2, 1, 3 D) 3, 2, 1 E) 3, 1, 2 7) In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located together on the same plasmid within a particular bacterium. If this bacterium performs conjugation involving a copy of this plasmid, then the result should be A) a transformed bacterium. B) the rapid spread of tetracycline resistance to other bacteria in that habitat.
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This note was uploaded on 11/11/2009 for the course BIO 1500 taught by Professor Shroeder during the Summer '07 term at Kasetsart University.

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Chapter_27 - Chapter 27: Prokaryotes 1) Mycoplasmas are...

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