Answer Key 1. D 2. B 3. B 4. D 5. C 6. C 7. C 8. D 9. C 10. C 11. B 12. B 13. B 14. A 15. B 16. D 17. B 18. E 19. C 20. C 21. E 22. E 23. C 24. B 25. D 26. F 27. T 28. F 29. T 30. T 31. A Microbiology Fundamentals: A Clinical Approach Bacteria and Archaea 1) Which of the following is not a characteristic of bacteria? A) Its DNA is not encased in a membrane. B) It has a cell wall made of peptidoglycans or other distinct chemicals. C) It does not have membrane-bound organelles. D) Its DNA is wrapped around histones. E) All of these are characteristics of bacteria. 2) The two functions of bacterial appendages are ________. A) attachment and protection B) attachment and motility C) motility and slime production D) energy reactions and synthesis E) protection and motility 3) Chemotaxis refers to the ability to ________. A) move in response to light B) move in response to a chemical C) not move in response to a chemical D) transport desired molecules into cells E) None of the choices is correct. 4) A bacterial cell exhibiting chemotaxis probably has ________. A) fimbriae B) a capsule C) thylakoids D) flagella E) metachromatic granules 5) What three components comprise the flagellum, extending from the cytoplasm to the exterior of the cell? A) Filament, hook, basal body B) Filament, basal body, hook C) Basal body, hook, filament D) Hook, basal body, filament E) Basal body, filament, hook 6) Movement of a cell toward a chemical stimulus is termed ________. A) positive phototaxis B) negative phototaxis C) positive chemotaxis D) negative chemotaxis E) a tumble 7) The short, numerous appendages used by some bacterial cells for adhering to surfaces are called ________. A) flagella B) cilia C) fimbriae D) periplasmic flagella (axial filaments) E) sex pili 8) Which structure protects bacteria from being phagocytized by white blood cells? A) Slime layer B) Fimbriae C) Cell membrane D) Capsule E) All of the choices are correct. 9) The outcome of the Gram stain is based on differences in the cell's ________. A) ribosomes B) inclusions C) wall D) membrane E) flagella 10) Which order below reflects the correct procedure for Gram staining? A) Alcohol/acetone–crystal violet–safranin–iodine B) Crystal violet–alcohol/acetone–iodine–safranin C) Crystal violet–iodine–alcohol/acetone–safranin D) Iodine–safranin–crystal violet–alcohol/acetone E) Alcohol/acetone–safranin–crystal violet–iodine 11) The cell ________ can be composed of three layers: the cytoplasmic membrane, the cell wall, and the outer membrane. A) glycocalyx B) envelope C) pathogenic package D) slime coat E) None of the choices is correct. 12) During the Gram stain, ________ cells decolorize when the alcohol is applied. A) gram-positive B) gram-negative C) both gram-positive and -negative 13) If bacteria living in salty seawater were displaced to a freshwater environment, the cell structure that would prevent the cells from rupturing is the ________. A) endospore B) cell wall C) cell membrane D) capsule E) slime layer 14) Peptidoglycan is a unique macromolecule found in bacterial ________. A) cell walls B) cell membranes C) capsules D) slime layers E) inclusions 15) Gram-negative bacteria A) are more susceptible to antibiotics that target peptidoglycan than gram-positive organisms. B) are less susceptible to antibiotics that target peptidoglycan than gram-positive organisms. C) stain purple in the Gram stain. D) encompass all pathogens. E) None of the choices is correct. 16) Which of the following is not true of the outer membrane? A) The uppermost layer is made of lipopolysaccharides. B) The innermost layer is a phospholipid bilayer. C) The porin proteins create channels through the outer membrane. D) Gram-positive bacteria have an outer membrane. E) The lipid portion of the lipopolysaccharide layer is an endotoxin. 17) The most immediate result of destruction of a cell's ribosomes would be ________. A) material would not be able to cross the cell membrane B) protein synthesis would stop C) destruction of the cell's DNA D) formation of glycogen inclusions E) loss of the capsule 18) Plasmids ________. A) are found in all bacteria B) are essential for growth and metabolism C) cannot be passed between organisms D) cannot be passed on to progeny E) are often the site of pathogenic genes 19) The chemical components of ribosomes are proteins and ________. A) mRNA B) tRNA C) rRNA D) All of the choices are correct. E) None of the choices is correct. 20) The function of bacterial endospores is ________. A) to convert gaseous nitrogen to a usable form for plants B) reproduction and growth C) protection of genetic material during harsh conditions D) storage of excess cell materials E) to act as sites for photosynthesis 21) Chemical analysis of a bacterial cell structure detects calcium and dipicolinic acid. What is the identity of this structure? A) Cell wall B) Capsule C) Slime layer D) Nucleoid E) Endospore 22) Endospores are ________. A) metabolically inactive B) resistant to heat and chemical destruction C) resistant to destruction by radiation D) living structures E) All of the choices are correct. 23) If you looked at a ________ under the microscope, you would likely see an irregular cluster of spherical cells. A) palisade B) sarcina C) staphylococcus D) streptococcus E) diplococcus 24) Two major structures that allow bacteria to adhere to surfaces are ________ and ________. A) pili; ribosomes B) fimbrae; capsules C) lipopolysaccharides; techoic acids D) actin filaments; phospholipid membrane(s) E) actin filaments; ribosomes 25) Which of the following species of bacteria is not closely related to the others? A) Staphylococcus aureus B) Staphylococcus epidermidis C) Staphylococcus saprophyticus D) Escherichia coli E) Staphylococcus capitis True or False 26) Iodine is the decolorizer in the Gram stain. 27) The cell envelope of gram-positive bacteria has two layers: a thick cell wall and the cell membrane. 28) Gram-negative bacteria do not have peptidoglycan in their cell walls. 29) Alcohol-based compounds can weaken the outer membrane. 30) Endospores of certain bacterial species can enter tissues in the human body, germinate, and cause an infectious disease. 31) Which statement below supports the argument that gram-negative cells are structurally weaker than gram-positive cells? A) Gram-negative cells have a thinner layer of peptidoglycan in their cell wall compared to grampositive cells. B) Gram-positive cells contain teichoic acids, whereas gram-negative cells lack teichoic acids in their cell wall. C) The envelope of gram-negative cells comprises a hydrophobic outer membrane. D) Gram-negative cells contain lipopolysaccharides, the lipid component of which acts as an endotoxin.