Microbiolody chapter 3

43. Bacterial cells that are variable in shape are called A. vibrio. B. pleomorphic. C. coccobacilli. D. hyphal.

B. pleomorphic.

47. Rigid bacteria with a helical cell shape are called A. vibrios. B. spirilla. C. spirochetes. D. coccobacilli.

B. spirilla.

52. The lipopolysaccharide (LPS) that is found in the outer membrane of gram-negative bacteria is also known as A. exotoxin. B. teichoic acid. C. murein. D. endotoxin.

D. endotoxin.

75. Copper (Cu) is considered a micronutrient.

TRUE

15. A __________ is a polysaccharide layer that lies outside the cell wall and is not easily removed.

capsule

83. Many bacteria facilitate the uptake of iron by secreting low molecular weight molecules, called ___________, to form complexes with the iron that can then be readily transported into the cell.

siderophores

14. A __________ layer consists of diffuse unorganized polysaccharide material that lies outside the cell wall and is easily removed.

slime

11. When the cell wall is removed from a Gram-negative bacterium without removing the outer membrane, the resulting form is called a(n) __________.

spheroplast

1. The genus of bacteria that undergoes cell division in random planes, forming grapelike clusters of round bacteria, are the __________.

staphylococci or staphylococcus

36. Matching: Match the definition with the word. 1) monotrichous 2) peritrichous 3) lophotrichous 4) amphitrichous a. a single flagellum b. a single flagellum at each pole of an organism c. a cluster of flagella at one or both ends of an organism d. a relatively even distribution of flagella over the entire surface of the bacterium

1-a, 2-d, 3-c, 4-b

98. Order the following structures (layers) that a small molecule must pass through as it moves from outside of an encapsulated gram negative cell to the cytoplasm. 3 Periplasm and Peptidoglycan 4 Plasma membrane 1 Capsule 2 Outer membrane

3 Periplasm and Peptidoglycan 4 Plasma membrane 1 Capsule 2 Outer membrane

105. You have been studying the effect of a concentration gradient on the rate of transport of a nutrient into a bacterial cell. If a carrier protein is involved in the transport of this nutrient, which curve would you expect to see? A. A B. B C. C

A. A

90. Which of the following processes can be used to bring nutrients into a cell against a concentration gradient? A. Active transport B. Facilitated diffusion C. Passive diffusion D. Active transport and facilitated diffusion

A. Active transport

22. Which of the following structures is NOT found in an endospore? A. Capsule B. Coat C. Core D. Exosporium

A. Capsule

59. All of the following statements about the periplasmic space are true except: A. It is found only in gram-positive bacteria. B. It is located between the plasma membrane and outer membrane of gram-negative bacteria. C. It contains hydrolytic enzymes and binding proteins involved in nutrient acquisition. D. All of the choices are true.

A. It is found only in gram-positive bacteria.

10. Predict how the plasma membrane fatty acid composition would change as the temperature of the habitat of an aquatic bacterial species warms from 2oC to 15oC during the spring and summer months. A. The percentage of saturated fatty acids would increase. B. The percentage of unsaturated fatty acids would increase. C. The percentage of saturated fatty acids would decrease. D. The percentage of saturated fatty acids would remain unchanged.

A. The percentage of saturated fatty acids would increase.

103. Predict the change in surface area and volume of a spherical cell if the diameter of the cell doubles: A. The surface area will increase by a factor of 4, while the volume will increase by a factor of 8. B. The surface area will increase by a factor of 8 while the volume will increase by a factor of 4. C. The surface area and volume will both increase by a factor of 4. D. The surface area will increase by a factor of 2 and the volume will increase by a factor of 4.

A. The surface area will increase by a factor of 4, while the volume will increase by a factor of 8.

57. Lipids with polar and nonpolar ends are said to be A. amphipathic. B. amphibolic. C. bilateral. D. None of the choices are correct.

A. amphipathic.

50. The term used to describe bacteria that have a spherical shape is A. coccus. B. bacillus. C. vibrio. D. coccobacillus.

A. coccus.

93. The movement of molecules across a membrane from an area of higher concentration to an area of lower concentration with the use of a carrier molecule embedded in the membrane is called A. facilitated diffusion. B. osmosis. C. passive diffusion. D. active transport.

A. facilitated diffusion.

67. Chemotaxis is a process by which bacteria A. move toward an attractant or away from a repellent. B. avoid phagocytosis. C. respond metabolically to the presence of autoinducer molecules. D. move on solid surfaces by means of type IV fimbriae.

A. move toward an attractant or away from a repellent

54. Proteins that are loosely associated with the cytoplasmic membrane are called __________ proteins. A. peripheral B. integral C. external D. internal

A. peripheral

82. A wide variety of microorganisms are commercially used to manufacture _________ for human consumption. A. vitamins B. sugars C. fatty acids D. none of the choices

A. vitamins

110. Which bacterial structure may survive if temperatures applied during food preservation processes are too low? A. Flagella B. Endospores C. Plasma membranes D. Ribosomes

B. Endospores

72. Which of the following is not considered a micronutrient? A. Manganese (Mn) B. Magnesium (Mg) C. Zinc (Zn) D. Copper (Cu)

B. Magnesium (Mg)

60. Which of the following protects bacteria from lysis in dilute solutions and helps to determine their cellular morphology or shape? A. Plasma membrane B. Peptidoglycan C. Capsule D. Gas vacuoles

B. Peptidoglycan

99. How do spheroplasts and protosplasts differ? A. Spheroplasts retain the peptidoglycan but protoplasts do not. B. Spheroplasts retain their outer membrane but protoplasts do not. C. There is no difference; these terms are synonyms. D. Spheroplasts form from cocci and protoplasts form from bacilli.

B. Spheroplasts retain their outer membrane but protoplasts do not.

42. The concept of a prokaryote was first fully outlined in 1962 by A. Watson and Crick. B. Stanier and Van Niel. C. Hershey and Chase. D. Gilbert and Cech.

B. Stanier and Van Niel.

100. A pathogenic bacterial species has mutated and is no longer able to synthesize a capsule. Which outcome would you predict? A. The mutated bacteria will be more virulent. B. The mutated bacteria will not be able to cause disease as readily. C. The mutated bacteria will be protected from plasmolysis in hypertonic environments. D. The mutated bacteria will undergo osmotic lysis in hypotonic environments.

B. The mutated bacteria will not be able to cause disease as readily.

49. The term used to describe bacteria that are rod-shaped is A. coccus. B. bacillus. C. vibrio. D. coccobacillus.

B. bacillus.

61. Sortase is a protein enzyme of bacteria that A. plays a key role in directing proteins to the periplasm. B. catalyzes covalent attachment of some surface proteins to peptidoglycan. C. directs secretion of proteins across the outer membrane. D. functions by transporting flagellum proteins to their extracellular site of assembly.

B. catalyzes covalent attachment of some surface proteins to peptidoglycan.

55. Proteins that are embedded within the cytoplasmic membrane and not easily extracted are called __________ proteins. A. peripheral B. integral C. external D. internal

B. integral

58. Although penicillin inhibits peptidoglycan synthesis, bacterial cells will continue to grow normally in the presence of penicillin in a(n) __________ environment. A. hypotonic B. isotonic C. hypertonic D. nonpolar

B. isotonic

56. Shrinkage of the plasma membrane away from the cell wall when the bacterium is placed in a hypertonic environment is called A. osmolysis. B. plasmolysis. C. hydrolysis. D. hypertonolysis.

B. plasmolysis.

112. Which of the following is not part of the process by which an endospore transforms to become a vegetative cell? A. Germination B. Activation C. Induction D. Outgrowth

C. Induction

96. __________ membranes allow some molecules to pass but not others. A. Permeable B. Inverted monolayer C. Selectively permeable D. Impermeable

C. Selectively permeable

101. All of the following are reasons why some scientists believe that the term "prokaryote" is a somewhat artificial designation and should be discarded except A. Some bacteria have internal membranous structures. B. Some bacteria have their genetic material enclosed within a membrane. C. Some bacteria have 80S ribosomes. D. Many bacterial have cytoskeletal elements.

C. Some bacteria have 80S ribosomes.

62. Which of the following is not true of bacterial plasmids? A. They can replicate independently of the chromosome. B. They may carry genes for drug resistance. C. They are required for host growth and/or reproduction. D. They may carry genes that enhance survival of the bacterium under certain conditions.

C. They are required for host growth and/or reproduction.

95. Nutrients can be concentrated from dilute solutions by A. pinocytosis. B. endocytosis. C. active transport and group translocation. D. electron transport.

C. active transport and group translocation.

65. Export of flagellin subunits is mediated by A. an apparatus in the basal body of the flagellum that is related to the type II secretion pathway. B. the type I secretion pathway. C. an apparatus in the basal body of the flagellum that is related to the type III secretion pathway. D. None of the choices are correct.

C. an apparatus in the basal body of the flagellum that is related to the type III secretion pathway.

104. A new protein has been described that transports a growth factor across the plasma membrane. This protein is most likely a/an: A. peripheral membrane protein, facing outward. B. peripheral membrane protein, facing the cytoplasmic side. C. integral membrane protein. D. cytoplasmic protein.

C. integral membrane protein.

70. Elements that are required in relatively large amounts by microorganisms are called A. multivitamins. B. meganutrients. C. macronutrients. D. macromolecules.

C. macronutrients.

94. The movement of molecules from an area of higher concentration to an area of lower concentration without the participation of specific carrier molecules is called A. facilitated diffusion. B. osmosis. C. passive diffusion. D. active transport.

C. passive diffusion.

66. The power used by most bacterial flagellar motors is produced by A. synthesis of glucose. B. ATP hydrolysis. C. proton motive force (PMF). D. All of the choices are correct.

C. proton motive force (PMF).

46. Flexible bacteria with a helical shape are called A. vibrios. B. spirilla. C. spirochetes. D. coccobacilli.

C. spirochetes.

45. Square planar arrangement of cells that forms when round bacteria remain attached to each other during reproduction are called A. streptococci. B. staphylococci. C. tetrads. D. sarcinae.

C. tetrads.

48. The term used to describe bacteria that are shaped like curved rods is A. coccus. B. bacillus. C. vibrio. D. coccobacillus.

C. vibrio

51. The cytoplasmic membrane of bacteria A. retains the cytoplasm and its contents. B. acts as a selectively permeable barrier, allowing some molecules to pass while preventing the movement of others. C. is the major site of ATP synthesis in aerobes. D. All of the choices are correct.

D. All of the choices are correct

53. Which of the following is/are true of capsules? A. They help bacteria escape phagocytosis by host cells. B. They retain water and help prevent desiccation of the bacteria. C. They prevent entry of many bacterial viruses. D. All of the choices are correct.

D. All of the choices are correct.

63. Bacterial and archaeal ribosomes are known as _____ ribosomes, based on their sedimentation coefficient. A. 50S B. 30S C. 80S D. 70S

D. 70S

64. The type III bacterial protein secretion machinery A. has a needlelike structure through which proteins are secreted. B. includes structural features that may be evolutionarily related to the basal bodies of bacterial flagella. C. is found in gram-negative bacteria. D. All of the choices are correct.

D. All of the choices are correct.

91. Which of the following is a characteristic of active transport? A. Saturable uptake rate B. Use of ATP or a proton gradient as a source of metabolic energy C. Can move materials against a concentration gradient D. All of the choices are correct.

D. All of the choices are correct.

71. Which of the following is not considered a macronutrient? A. Carbon (C) B. Calcium (Ca) C. Potassium (K) D. Cobalt (Co)

D. Cobalt (Co)

80. Which of the following is not a major class of growth factors? A. Amino acids B. Purines and pyrimidines C. Vitamins D. Nucleic acids

D. Nucleic acids

102. A strain of Neisseria gonorrhoeae has undergone a mutation and is no longer able to make pili. Predict the most likely outcome. A. The bacterial strain will no longer be able to transport certain sugars into the cell. B. The bacteria will become more virulent and will more readily establish infection. C. The bacteria will become more resistant to antibiotics. D. The bacteria will become less virulent and will not be able to readily establish infection.

D. The bacteria will become less virulent and will not be able to readily establish infection.

92. The movement of molecules across a membrane from an area of lower concentration to an area of higher concentration with the expenditure of energy is called A. facilitated diffusion. B. osmosis. C. passive diffusion. D. active transport.

D. active transport.

68. Twitching or gliding motility involves A. type IV pili. B. axial fibrils. C. movement of slime. D. both type IV pili and movement of slime can be involved in twitching or gliding motility.

D. both type IV pili and movement of slime can be involved in twitching or gliding motility.

44. The term used to describe bacteria that are intermediate in shape between spherical and rod-shaped is A. cocci. B. bacilli. C. vibrio. D. coccobacilli.

D. coccobacilli.

69. Endospores represent a challenge to the fields of industrial and medical microbiology because A. they are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive. B. endospore-forming organisms are often dangerous pathogens. C. endospores are significantly smaller than vegetative cells. D. endospores are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive, and endospore-forming organisms are often dangerous pathogens.

D. endospores are resistant to harsh environments, thus allowing survival of endospore-forming organisms under conditions in which non-endospore-forming cells would not survive, and endospore-forming organisms are often dangerous pathogens.

19. You discover a new transport system used by a newly discovered bacterial species. The sugars that are transported using this system are phosphorylated as they enter the bacterial cell. You would describe this transport system as a(n) _____. A. facillitated diffusion B. micronutrient regulator C. passive diffusion D. group translocation

D. group translocation

21. Endospores are resistant to most environmental stressors because they have _____ complexed with calcium ions which stabilize DNA.

Dipicolinic acid

111. Which of the following contribute to the environmental resistance of bacterial endospores? A. Spore coat B. Low water content of endospore C. Presence of calcium dipicolinate D. Lower pH E. All of the choices are correct.

E. All of the choices are correct.

97. Motile bacteria have been placed in an environment with a gradient of a chemical attractant. Which of the following behaviors would you predict? A. Bacteria will randomly switch back and forth between runs and tumbles. B. The bacteria will only exhibit runs away from the chemical. C. The bacteria will reduce tumbling frequency. D. The bacteria will reduce run duration in the direction of the chemical. E. The bacteria will both reduce tumbling frequency and increase run duration in the direction of the chemical.

E. The bacteria will both reduce tumbling frequency and increase run duration in the direction of the chemical.

108. Endospores are reproductive structures.

FALSE

109. The original differentiation of prokaryotes and eukaryotes was based on structures found in prokaryotes that are lacking in eukaryotes.

FALSE

23. If you remove the peptidoglycan layer from a Gram-positive cell, it would still stain purple with a Gram stain.

FALSE

25. The layers of peptidoglycan of the bacterial cell wall can be cross-linked by peptide intrabridges or by direct cross-linking.

FALSE

32. Sedimentation coefficients are proportional to the molecular weight of a particle and are not affected by the volume and shape of the particle.

FALSE

35. During the assembly of the flagellar filament, the flagellin protein monomers assemble at the cell proximal base of the flagellum.

FALSE

37. The rotation of bacterial flagella is powered by ATP hydrolysis.

FALSE

6. The cell membrane is a rigid structure that provides bacteria with their characteristic shapes.

FALSE

7. Gram-positive bacteria have a thinner layer of peptidoglycan than gram-negative bacteria.

FALSE

74. Zinc (Zn) is considered a macronutrient.

FALSE

76. Sulfur can be obtained from inorganic sources only.

FALSE

77. Phosphorus can be obtained from organic sources only.

FALSE

8. Gram-positive bacteria have a structurally and chemically more complex cell wall than gram-negative bacteria.

FALSE

86. Organisms usually have only a single transport system for any nutrient.

FALSE

9. Bacteria growing at lower temperatures have more saturated fatty acids in their membranes.

FALSE

41. __________ is the main part of the process through which a vegetative cell is formed from an endospore.

Germination

79. __________ __________ are required organic compounds because they are essential cell components or precursors of such components that cannot be synthesized by the organism. (2 words)

Growth factors

85. __________ are carrier proteins embedded in the membrane that increase the rate of diffusion of specific molecules across selectively permeable membranes.

Permeases

31. _______ are the site of protein synthesis in the cell.

Ribosomes

16. _______ bind ferric iron and transport it into a bacterial cell.

Siderophores

40. __________ is the process through which endospores are formed within a vegetative cell.

Sporulation

106. Endotoxic shock, resulting from the release of endotoxin by bacteria infecting a patient, is only caused by Gram-negative bacteria.

TRUE

18. Prokaryotes were once described based on structures that were present in eukaryotes, but absent in prokaryotes.

TRUE

20. Growth factors cannot by synthesized by the bacteria that use them and include amino acids, pyrimidines, and vitamins.

TRUE

26. Some photosynthetic bacteria produce gas vacuoles that regulate their buoyancy but contain no lipid.

TRUE

5. Sterol-like molecules called hopanoids are thought to be important for the structural integrity of many bacteria because of their suspected role in membrane stabilization.

TRUE

73. The trace amounts of micronutrients needed by microorganisms are usually supplied as inadvertent contaminants in water and regular media components.

TRUE

78. Nitrogen can be obtained from either organic or inorganic sources. TRUE

TRUE

87. Different transport systems for the same nutrient that are part of the same organism are usually regulated in different ways.

TRUE

88. Permease proteins that aid in the transport of nutrients resemble enzymes in their specificity for the substance to be transported. Each carrier is selective and will transport only a closely related set of substances.

TRUE

89. The extreme insolubility of ferric iron leaves little free iron available for transport into bacterial cells.

TRUE

39. In many spirochetes, multiple flagella combine to form a bundle known as a(n) ____________ fibril, which winds around the cell and confers motility on the cell.

axial

33. Bacterial flagella are composed of three parts: the ______ body, which is embedded in the cell, the hook, and the _______, which is the longest part of the flagellum.

basal; filament

12. Enzymes that are secreted out of the cell to aid in the acquisition and digestion of environmental nutrients are called __________.

exoenzymes

24. The most widely accepted current model for membrane structures is called the __________ model.

fluid mosaic

13. Molecules or regions of molecules that readily interact with water are said to be __________, whereas molecules or regions of molecules that are insoluble in water or do not readily interact with water are said to be hydrophobic.

hydrophilic

4. Actinomycetes form long filaments called ___________.

hyphae

27. Intracellular granules of organic or inorganic material that are stockpiled by bacteria for future use are called __________.

inclusions

17. Nutrients that are used by bacteria in relatively large amounts are _______________.

macronutrients

30. Some species of aquatic bacteria use inclusion bodies known as ________ to orient themselves in Earth's magnetic field.

magnetosomes

3. A branched network of hyphae formed by the Actinomycetes is called a __________.

mycelium

28. Bacteria have a region of the cytoplasm known as the __________, which is not bounded by a membrane but contains the chromosome.

nucleoid

34. Proteinacious projections from the surface of a bacterium that are used to mediate conjugation are called sex __________, whereas projections that mediate attachment to surfaces such as host cells are called __________.

pili; fimbriae

29. Small circular DNA molecules capable of replicating and containing genes that are useful but not necessary to the bacterium are called __________.

plasmids

2. Bacteria that do not have a fixed shape are said to be __________.

pleomorphic

38. The bacterium E. coli swims in a straight line, called a __________, for a few seconds; then it stops, tumbles, then swims away in a new direction.

run

84. Transport of two different substances can be linked. If the transport is in the same direction it is called __________; if the transport is in opposite directions it is called __________.

symport, antiport

81. Small organic molecules called __________ function as enzyme cofactors.

vitamins