Microbio Exam 1 Flashcards


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1

1) Which of the following statements is INCORRECT regarding prokaryotic cells?

A) Their DNA is not enclosed within a membrane.

B) They lack membrane-enclosed organelles.

C) They typically have a circular chromosome.

D) They reproduce by binary fission.

E) They lack a plasma membrane.

E) They lack a plasma membrane.

2

2) Each of the following statements concerning the gram-positive cell wall is true EXCEPT

A) it maintains the shape of the cell.

B) it is sensitive to lysozyme.

C) it protects the cell in a hypertonic environment.

D) it contains teichoic acids.

E) it is sensitive to penicillin.

C) it protects the cell in a hypertonic environment.

3

3) Which of the following statements best describes what happens when a bacterial cell is placed in a solution containing 5% NaCl?

A) Sucrose will move into the cell from a higher to a lower concentration.

B) The cell will undergo osmotic lysis.

C) Water will move out of the cell.

D) Water will move into the cell.

E) No change will result; the solution is isotonic.

C) Water will move out of the cell.

4

4) A gram-positive bacterium suddenly acquires resistance to the antibiotic methicillin. This trait most likely occurred due to acquisition of new genetic information through

A) conjugation.

B) binary fission.

C) meisosis.

D) transformation.

E) transduction.

A) conjugation.

5

5) By which of the following mechanisms can a cell transport a substance from a lower to a higher concentration?

A) simple diffusion

B) facilitated diffusion

C) active transport

D) extracellular enzymes

E) aquaporins

C) active transport

6

6) Which of the following is NOT a typical characteristic of most bacterial plasma membranes?

A) site of energy production

B) composed of a phospholipid bilayer

C) contains proteins

D) contains cholesterol

E) is selectively permeable

D) contains cholesterol

7

7) Which one of the following organisms has a cell wall?

A) protoplasts

B) fungi

C) L forms

D) mycoplasmas

E) animal cells

B) fungi

8

8) Which of the following statements is TRUE?

A) Endospores are for reproduction.

B) Endospores allow a cell to survive environmental changes by producing a dormant period with no growth.

C) Endospores are easily stained in a Gram stain.

D) A cell produces one endospore and keeps growing.

E) A cell can produce many endospores.

B) Endospores allow a cell to survive environmental changes by producing a dormant period with no growth.

9

9) Which of the following pairs is mismatched?

A) endoplasmic reticulum — internal transport

B) Golgi complex — secretion

C) mitochondria — ATP production

D) centrosome — food storage

E) lysosome — digestive enzymes

D) centrosome — food storage

10

10) Which of the following organelles most closely resembles a prokaryotic cell?

A) nucleus

B) mitochondrion

C) Golgi complex

D) vacuole

E) cell wall

B) mitochondrion

11

11) Antibiotics that target cell wall synthesis ultimately cause bacterial cell death as a result of

A) osmotic lysis.

B) inhibition of molecular transport.

C) decreased synthesis of plasma membrane.

D) plasmolysis.

E) cell shrinkage.

A) osmotic lysis.

12

12) Bacteria are a commonly used organism for studies of genetic material in the research laboratory. The nucleic acids must first be isolated from the cells for these studies. Which of the following would most likely be used to lyse gram-positive bacterial cells for nucleic acid isolation?

A) lysozyme

B) polymixins

C) alcohol

D) water

E) mycolic acid

A) lysozyme

13

13) Which of the following statements about gram-negative cell walls is FALSE?

A) They protect the cell in a hypotonic environment.

B) They have an extra outer layer composed of lipoproteins, lipopolysaccharides, and phospholipids.

C) They are toxic to humans.

D) They are sensitive to penicillin.

E) Their Gram reaction is due to the outer membrane.

D) They are sensitive to penicillin.

14

14) Which of the following structures is NOT found in some prokaryotic cells?

A) flagellum

B) axial filament

C) cilium

D) pilus

E) peritrichous flagella

C) cilium

15

15) Functions of the glycocalyx include all of the following EXCEPT

A) biofilm formation.

B) increased virulence.

C) source of nutrition.

D) protection against dehydration.

E) binary fission.

E) binary fission.

16

16) Which structure acts like an "invisibility cloak" and protects bacteria from being phagocytized?

A) slime layer

B) fimbriae

C) capsule

D) cell membrane

E) cell wall

C) capsule

17

17) Which of the following is NOT part of the passive transport process?

A) plasma membrane

B) transporter proteins

C) ATP

D) concentration gradient

E) aquaporins

C) ATP

18

18) In bacteria, photosynthetic pigments are found in

A) chloroplasts.

B) cytoplasm.

C) chromatophores.

D) mesosomes.

E) ribosomes.

C) chromatophores.

19

19) The difference between simple diffusion and facilitated diffusion is that facilitated diffusion

A) moves materials from a higher to a lower concentration.

B) moves materials from a lower to a higher concentration.

C) requires ATP.

D) requires transporter proteins.

E) does not require ATP.

D) requires transporter proteins.

20

20) The terms "run" and "tumble" are generally associated with

A) cell wall fluidity.

B) taxic movements of the cell in response to attractants or repellents.

C) clustering properties of certain rod-shaped bacteria.

D) cell membrane synthesis.

B) taxic movements of the cell in response to attractants or repellents.

21

21) You have isolated a motile, gram-positive cell with no visible nucleus. You can safely assume that the cell

A) has 9 pairs + 2 flagella.

B) has a mitochondrion.

C) has a cell wall.

D) lives in an extreme environment.

E) has cilia.

C) has a cell wall.

22

22) Fimbriae and pili differ in that

A) there are only one or two pili per cell.

B) pili are used for motility.

C) pili are used to transfer DNA.

D) pili are used for transfer of DNA and motility.

E) pili are used for attachment to surfaces.

D) pili are used for transfer of DNA and motility.

23

23) Where are phospholipids most likely found in a prokaryotic cell?

A) flagella

B) around organelles

C) the plasma membrane

D) ribosomes

E) the plasma membrane and around organelles

C) the plasma membrane

24

24) Where are phospholipids most likely found in a eukaryotic cell?

A) surrounding flagella

B) around organelles

C) the plasma membrane

D) ribosomes

E) the plasma membrane, around organelles, and surrounding flagella

E) the plasma membrane, around organelles, and surrounding flagella

25

25) Which of the following is NOT found or observed to occur in both mitochondria and prokaryotes?

A) circular chromosome

B) 70S ribosomes

C) cell wall

D) binary fission

E) ATP-generating mechanism

C) cell wall

26

26) Which of the following statements is correct about passive diffusion?

A) It requires an expenditure of energy by the cell.

B) It is a process in which molecules move from a region of higher concentration to a region of lower concentration (or down a concentration gradient).

C) It is a process in which molecules move from a region of lower concentration to one of higher concentration (or up a concentration gradient).

D) It may require a transport protein.

E) It involves movement of molecules down a concentration gradient and may require a transport protein.

E) It involves movement of molecules down a concentration gradient and may require a transport protein.

27

27) Oxygen crosses a plasma membrane

A) by osmosis.

B) through simple diffusion.

C) with the help of a nonspecific transporter.

D) through facilitated diffusion.

E) through porins.

B) through simple diffusion.

28

28) In a hypertonic solution, a bacterial cell will typically

A) lyse.

B) burst.

C) stay the same.

D) plasmolyze.

E) osmolyze.

D) plasmolyze.

29

29) What will happen if a bacterial cell is pretreated with a lysozyme solution, then placed in distilled water?

A) The cell will plasmolyze.

B) The cell will undergo osmotic lysis.

C) Water will leave the cell.

D) Lysozyme will diffuse into the cell.

E) No change will result; the solution is isotonic.

B) The cell will undergo osmotic lysis.

30

30) How do spirochetes and spirilla differ?

A) Spirochetes do not have a cell wall but spirilla do.

B) Spirilla are found in chains of cells whereas spirochetes exist as individual cells.

C) Spirilla have an external flagella but spirochetes have axial filaments.

D) Spirochetes have a rigid, corkscrew shape while spirilla are helical and more flexible.

E) Spirochetes and spirilla are basically the same organisms and the terms can be used interchangeably.

C) Spirilla have an external flagella but spirochetes have axial filaments.

31

31) Which one of the following pairs is mismatched?

A) metachromatic granules - phosphate storage

B) lipid inclusions - energy reserve

C) ribosomes - carbon storage

D) sulfur granules - energy reserve

E) gas vacuoles - flotation

C) ribosomes - carbon storage

32

32) Which of the following are NOT energy reserves?

A) carboxysomes

B) polysaccharide granules

C) lipid inclusions

D) ribosomes

E) metachromatic granules

A) carboxysomes

33

33) Which of the following is NOT a functionally analogous pair?

A) nucleus -nucleiod region

B) mitochondria - prokaryotic plasma membrane

C) chloroplasts - thylakoids

D) cilia - pili

E) 9+2 flagella - bacterial flagella

D) cilia - pili

34

34) The DNA found in most bacterial cells

A) is surrounded by a nuclear membrane.

B) utilizes histones for chromosomal packaging.

C) is circular in structure.

D) is linear in structure.

E) is found in multiple copies.

C) is circular in structure.

35

35) Which of the following compounds is NOT an enzyme?

A) dehydrogenase

B) cellulase

C) coenzyme A

D) β-galactosidase

E) sucrase

C) coenzyme A

36

36) Which organism is NOT correctly matched to its energy source?

A) photoheterotroph - light

B) photoautotroph - CO2

C) chemoautotroph - Fe2+

D) chemoheterotroph - glucose

E) chemoautotroph-NH3

B) photoautotroph - CO2

37

37) Which of the following statements about anaerobic respiration is FALSE?

A) It yields lower amounts of ATP when compared to aerobic respiration.

B) The complete Kreb's cycle is utilized.

C) It involves the reduction of an organic final electron acceptor.

D) It generates ATP.

E) It requires cytochromes.

C) It involves the reduction of an organic final electron acceptor.

38

38) What is the fate of pyruvic acid in an organism that uses aerobic respiration?

A) It is reduced to lactic acid.

B) It reacts with oxaloacetate to form citrate.

C) It is oxidized in the electron transport chain.

D) It is catabolized in glycolysis.

E) It is converted into acetyl CoA.

E) It is converted into acetyl CoA.

39

39) Fatty acids are oxidized in

A) the Krebs cycle.

B) the electron transport chain.

C) glycolysis.

D) the pentose phosphate pathway.

E) the Entner-Doudoroff pathway.

A) the Krebs cycle

40

40) Which of the following is the best definition of oxidative phosphorylation?

A) Electrons are passed through a series of carriers to O2.

B) A proton gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels, releasing energy that is used to generate ATP.

C) ATP is directly transferred from a substrate to ADP.

D) Electrons are passed through a series of carriers to an organic compound.

B) A proton gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels, releasing energy that is used to generate ATP.

41

41) Which of the following statements about substrate-level phosphorylation is FALSE?

A) It involves the direct transfer of a high-energy phosphate group from an intermediate metabolic compound to ADP.

B) No final electron acceptor is required.

C) It occurs in glycolysis.

D) The oxidation of intermediate metabolic compounds releases energy that is used to generate ATP.

E) It occurs to a lesser degree in the Krebs cycle than in glycolysis.

D) The oxidation of intermediate metabolic compounds releases energy that is used to generate ATP.

42

42) Which of the following statements about photophosphorylation is FALSE?

A) Light liberates an electron from chlorophyll.

B) The oxidation of carrier molecules releases energy.

C) Energy from oxidation reactions is used to generate ATP from ADP.

D) It requires CO2.

E) It occurs in photosynthesizing cells.

D) It requires CO2.

43

43) A strictly fermentative bacterium produces energy

A) by glycolysis only.

B) by aerobic respiration only.

C) by fermentation or aerobic respiration.

D) only in the absence of oxygen.

E) only in the presence of oxygen.

A) by glycolysis only.

44

44) The advantage of the pentose phosphate pathway is that it produces all of the following EXCEPT

A) precursors for nucleic acids.

B) precursors for the synthesis of glucose.

C) three ATPs.

D) NADPH.

E) precursors for the synthesis of amino acids.

C) three ATPs.

45

45) Which biochemical process is NOT used during glycolysis?

A) substrate-level phosphorylation

B) oxidation-reduction

C) carbohydrate catabolism

D) beta oxidation

E) enzymatic reactions

D) beta oxidation

46

46) In noncyclic photophosphorylation, O2 is released from

A) CO2.

B) H2O

C) C6H12O6.

D) sunlight.

E) chlorophyll.

B) H20

47

47) Which of the following is the best definition of fermentation?

A) the partial reduction of glucose to pyruvic acid

B) the partial oxidation of glucose with organic molecules serving as electron acceptors

C) the complete catabolism of glucose to CO2and H2O

D) the production of energy by oxidative-level phosphorylation

E) the production of energy by both substrate and oxidative phosphorylation

B) the partial oxidation of glucose with organic molecules serving as electron acceptors

48

48) Which of the following is NOT necessary for respiration?

A) cytochromes

B) flavoproteins

C) a source of electrons

D) oxygen

E) quinones

D) oxygen

49

49) Which one of the following would you predict is an allosteric inhibitor of the Krebs cycle enzyme, α-ketoglutarate dehydrogenase?

A) citric acid

B) α-ketoglutaric acid

C) NAD+

D) NADH

E) ADP

D) NADH

50

50) In green and purple bacteria, electrons to reduce CO2 can come from

A) CO2.

B) H2

C) C6H12O6.

D) H2S

E) chlorophyll.

D) H2S.

51

51) Assume you are growing bacteria on a lipid medium that started at pH 7. The action of bacterial lipases should cause the pH of the medium to

A) increase.

B) decrease.

C) stay the same.

B) decrease

52

52) Which of the following uses CO2 for carbon and H2 for energy?

A) chemoautotroph

B) chemoheterotroph

C) photoautotroph

D) photoheterotroph

A) chemoautotroph

53

53) Which of the following uses glucose for carbon and energy?

A) chemoautotroph

B) chemoheterotroph

C) photoautotroph

D) photoheterotroph

B) chemoheterotroph

54

54) Which of the following has bacteriochlorophylls and uses alcohols for carbon?

A) chemoautotroph

B) chemoheterotroph

C) photoautotroph

D) photoheterotroph

D) photoheterotroph

55

55) Cyanobacteria are a type of

A) chemoautotroph.

B) chemoheterotroph.

C) photoautotroph.

D) photoheterotroph.

C) photoautotroph.

56

56) Which of the following statements are TRUE?

1-Electron carriers are located at ribosomes.

2-ATP is a common intermediate between catabolic and anabolic pathways.

3-ATP is used for the long-term storage of energy and so is often found in storage granules.

4-Anaerobic organisms are capable of generating ATP via respiration.

5-ATP can be generated by the flow of protons across protein channels.

A) 2, 4, 5

B) 1, 3, 4

C) 2, 3, 5

D) 1, 2, 3

E) All of the statements are true.

A) 2, 4, 5

57

57) Microorganisms that catabolize sugars into ethanol and hydrogen gas would most likely be categorized as

A) aerobic respirers.

B) anaerobic respirers.

C) heterolactic fermenters.

D) homolactic fermenters.

E) alcohol fermenters.

C) heterolactic fermenters.

58

58) Which of the following statements regarding metabolism is FALSE?

A) Heat may be released in both anabolic and catabolic reactions.

B) ATP is formed in catabolic reactions.

C) ADP is formed in anabolic reactions.

D) Anabolic reactions are degradative.

D) Anabolic reactions are degradative.

59

59) Which of the following is TRUE about this reaction?

NO3-+ 2H+ -Psudomonas-> NO2- + H2O

Nitrate ion Nitrite ion

A) This process requires O2.

B) This process occurs anaerobically.

C) This process requires the entire electron transport system.

D) This process requires light.

E) This process requires O2and the electron transport system.

B) This process occurs anaerobically.

60

60) Which of the following statements regarding the Entner-Doudoroff pathway is TRUE?

A) It involves glycolysis.

B) It involves the pentose phosphate pathway.

C) NADH is generated.

D) ATP is generated.

E) NADH and ATP are generated.

D) ATP is generated

61

61) Assume you are working for a chemical company and are responsible for growing a yeast culture that produces ethanol. The yeasts are growing well on the maltose medium but are not producing alcohol. What is the most likely explanation?

A) The maltose is toxic.

B) O2is in the medium.

C) Not enough protein is provided.

D) The temperature is too low.

E) The temperature is too high.

B) O2 is in the medium

62

62) An enzyme, citrate synthase, in the Krebs cycle is inhibited by ATP. This is an example of all of the following EXCEPT

A) allosteric inhibition.

B) competitive inhibition.

C) feedback inhibition.

D) noncompetitive inhibition.

B) competitive inhibition

63

63) If a cell is starved for ATP, which of the following pathways would most likely be shut down?

A) Kreb's cycle

B) glycolysis

C) pentose phosphate pathway

D) Krebs cycle and glycolysis

C) pentose phosphate pathway

64

64) Which of the following statements regarding the glycolysis pathway is FALSE?

A) Two pyruvate molecules are generated.

B) Four ATP molecules are generated via substrate-level phosphorylation.

C) Two NADH molecules are generated.

D) One molecule of ATP is expended.

E) Two molecules of water are generated.

D) One molecule of ATP is expended

65

65) A bacterial culture grown in a glucose-peptide medium causes the pH to increase. The bacteria are most likely

A) fermenting the glucose.

B) oxidizing the glucose.

C) using the peptides.

D) not growing.

C) using the peptides

66

66) Gallionella bacteria can get energy from the reaction Fe2+ → Fe3+. This reaction is an example of

A) oxidation.

B) reduction.

C) fermentation.

D) photophosphorylation.

E) the Calvin-Benson cycle.

A) oxidation

67

67) A urease test is used to identify Mycobacterium tuberculosis because

A) urease is a sign of tuberculosis.

B) tuberculosis produces urease.

C) urea accumulates during tuberculosis.

D) some bacteria reduce nitrate ion.

E) bovis can cause tuberculosis.

B) M. tuberculosis produces urease

68

68) Researchers are developing a ribozyme that cleaves the HIV genome. This pharmaceutical agent could be described as

A) an RNA molecule capable of catalysis.

B) a hydrolase.

C) a genetic transposable element.

D) a protease inhibitor.

E) a competitive inhibitor for reverse transcriptase.

A) an RNA molecule capable of catalysis

69

69) Which statements correspond to amphibolic pathways?

  1. anabolic and catabolic reactions are joined through common intermediate
  2. shared metabolic pathways
  3. Feedback inhibition can help regulate rates of reactions
  4. both types of reactions are necessary but do not occur simultaneously

A) 1 only

B) 1, 2, 3

C) 1, 2, 3, 4

D) 2, 4

E) 2, 3, 4

B) 1, 2, 3

70

70) If cells are grown in media containing amino acids labeled with radioactive nitrogen (15N), most of the radioactivity will be found in the cells'

A) DNA.

B) proteins.

C) phospholipids.

D) DNA and proteins.

E) DNA and phospholipids.

D) DNA and proteins

71

71) Which of the following elements is NOT correctly matched with its cellular function?

A) nitrogen — needed for amino acid synthesis

B) phosphorus — incorporated into nucleic acids

C) sulfur — used for synthesis of thiamin and biotin

D) magnesium and potassium — required as cofactors for enzymes

E) phosphorus — used for production of carbohydrates.

E) phosphorus — used for production of carbohydrates

72

72) Pathogenic bacteria isolated from the respiratory or intestinal tracts of humans are

A) strict aerobes that grow best in candle jars.

B) capnophiles that grow best in carbon dioxide incubators.

C) facultative anaerobes that require reducing media for growth.

D) strict aerobes that grow best in reducing media.

E) capnophiles that prefer highly oxygenated growth conditions.

B) capnophiles that grow best in carbon dioxide incubators

73

73) The biosafety level (BSL) for most introductory microbiology laboratories is

A) BSL-1.

B) BSL-2.

C) BSL-3.

D) BSL-4.

A) BSL-1

74

74) The biosafety level (BSL) for a clinical microbiology laboratory working with potentially airborne pathogens, such as tuberculosis bacteria, is

A) BSL-1.

B) BSL-2.

C) BSL-3.

D) BSL-4.

C) BSL-3

75

75) A sample of milk is tested for its bacterial content in a plate count assay. A one-milliliter sample of the milk is diluted in a 1:10 dilution series. One milliliter of the third dilution tube is plated in a pour plate. After incubation, the plate has 54 colonies, indicating that the original milk sample contained

A) 54 cells per milliliter.

B) 540 cells per milliliter.

C) 5,400 cells per milliliter.

D) 54,000 cells per milliliter.

E) 540,000 cells per milliliter.

D) 54,000 cells per milliliter

76

76) The addition of which of the following to a culture medium will neutralize acids?

A) buffers

B) sugars

C) pH

D) heat

E) carbon

A) buffers

77

77) Salts and sugars work to preserve foods by creating a

A) depletion of nutrients.

B) hypotonic environment.

C) lower osmotic pressure.

D) hypertonic environment.

E) lower pH.

D) hypertonic environment

78

78) The term aerotolerant anaerobe refers to an organism that

A) does not use oxygen but tolerates it.

B) is killed by oxygen.

C) tolerates normal atmospheric nitrogen gas levels.

D) requires less oxygen than is present in air.

E) requires more oxygen than is present in air.

A) does not use oxygen but tolerates it

79

79) Which of the following is an advantage of the standard plate count?

A) can readily count cells that form aggregates

B) determines the number of viable cells

C) can be performed on very dilute samples, such as lake water

D) provides immediate results

E) can be used to count heat-sensitive bacteria

B) determines the number of viable cells

80

80) Which of the following is an advantage of the direct microscopic count?

A) can readily count organisms that are motile

B) can easily distinguish live from dead cells

C) requires no incubation time

D) sample volume is unknown

E) requires a large number of cells

C) requires no incubation time

81

81) Most bacteria reproduce by

A) aerial hyphae.

B) fragmentation.

C) mitosis.

D) binary fission.

E) budding.

D) binary fission

82

82) Thirty-six colonies grew in nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample?

A) 4 per milliliter

B) 9 per milliliter

C) 18 per milliliter

D) 36 per milliliter

E) 72 per milliliter

D) 36 per milliliter

83

83) Most bacteria grow best at pH

A) 1.

B) 5.

C) 7.

D) 9.

E) 14.

C) 7

84

84) Most fungi grow best at pH

A) 1.

B) 5.

C) 7.

D) 9.

E) 14.

B) 5

85

85) Consider a culture medium on which only gram-positive organisms such as Staphylococcus aureus colonies can grow due to an elevated NaCl level. A yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the pH as a result and changing the color of a pH indicator chemical. This type of medium would be referred to as a(n)

A) selective medium.

B) differential medium.

C) enrichment culture.

D) selective and differential medium.

E) differential and enrichment culture.

D) selective and differential medium

86

86) A culture medium consisting of agar, peptone, and beef heart is a

A) chemically defined medium.

B) complex medium.

C) selective medium.

D) differential medium.

E) reducing medium.

B) complex medium

87

87) Which of the following pairs of microbe classification terms and optimal growth temperatures is mismatched?

A) psychrotroph — growth at 0°C

B) thermophile — growth at 37°C

C) mesophile — growth at 25°C

D) psychrophile — growth at 15°C

E) hyperthermophiles — growth at 85°C

B) thermophile — growth at 37°C

88

88) During which growth phase will gram-positive bacteria be most susceptible to penicillin?

A) lag phase

B) log phase

C) death phase

D) stationary phase

E) The culture is equally susceptible during all phases.

B) log phase

89

89) Which of the following is the best definition of generation time?

A) the length of time needed for lag phase

B) the length of time needed for a cell to divide

C) the minimum rate of doubling

D) the duration of log phase

E) the time needed for nuclear division

B) the length of time needed for a cell to divide

90

90) Which of the following is NOT a direct method to measure microbial growth?

A) direct microscopic count

B) standard plate count

C) filtration on a support membrane followed by incubation on medium

D) metabolic activity

E) most probable number (MPN)

D) metabolic activity

91

91) Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt?

A) psychrophiles

B) facultative halophiles

C) anaerobes

D) thermophiles

E) hyperthermophiles

B) facultative halophiles

92

92) Which of the following is an organic growth factor?

A) glucose

B) vitamin B1

C) peptone

D) Mg+2

E) H2O

B) vitamin B1

93

93) Which of the following is an example of a metabolic activity that could be used to measure microbial growth?

A) standard plate count

B) glucose consumption

C) direct microscopic count

D) turbidity

E) most probable number (MPN)

B) glucose consumption

94

94) An experiment began with 4 cells and ended with 128 cells. How many generations did the

cells go through?

A) 64

B) 32

C) 6

D) 5

E) 4

D) 5

95

95) Three cells with generation times of 60 minutes are inoculated into a culture medium. How many cells are there after 5 hours?

A) 900

B) 180

C) 96

D) 32

E) 15

C) 96

96

96) In one hospital, Pseudomonas aeruginosa serotype 10 infected the biliary tract of 10 percent of 1300 patients who underwent gastrointestinal endoscopic procedures. After each use, endoscopes were washed with an automatic reprocessor that flushed detergent and glutaraldehyde through the endoscopes, followed by a tap water rinse. P. aeruginosa serotype 10 was not isolated from the detergent, glutaraldehyde, or tap water. What was the source of the infections?

A) bacterial cell walls in the water

B) a biofilm in the reprocessor

C) contaminated disinfectant

D) fecal contamination of the bile ducts

E) None of the answers is correct.

B) a biofilm in the reprocessor

97

97) Assume you inoculated 100 cells, with a generation time of 20 minutes, into 100 ml of nutrient broth. You then inoculated 100 cells of the same species into 200 ml of nutrient broth. After incubation for 4 hours, you can reasonably expect to have

A) more cells in the 100 ml.

B) more cells in the 200 ml.

C) the same number of cells in both.

D) The answer cannot be determined based on the information provided.

C) the same number of cells in both

98

98) The source of nutrients in nutrient agar is

A) agar.

B) gelatin.

C) peptone and beef extract.

D) peptone and NaCl.

E) agar and NaCl.

C) peptone and beef extract

99

99) Which enzyme catalyzes the reaction: O2- + O2- + 2H+ → H2O2 + O2?

A) catalase

B) oxidase

C) peroxidase

D) superoxide dismutase

D) superoxide dismutase

100

100) Which enzyme catalyzes the reaction: 2H2O2 → 2H2O + O2?

A) catalase

B) oxidase

C) peroxidase

D) superoxide dismutase

A) catalase

101

101) Which enzyme catalyzes the reaction: H2O2 + 2H+ → 2H2O?

A) catalase

B) oxidase

C) peroxidase

D) superoxide dismutase

C) peroxidase

102

102) Patients with indwelling catheters (long-term tubes inserted into body orifices for drainage, such as through the urethra and into the urinary bladder) are susceptible to infections because

A) injected solutions are contaminated.

B) their immune systems are weakened.

C) infections can be transmitted from other people.

D) biofilms develop on catheters.

E) bacteria cause infections.

D) biofilms develop on catheters

103

103) Which of the following is the best method to sterilize heat-labile solutions?

A) dry heat

B) autoclave

C) membrane filtration

D) pasteurization

E) freezing

C) membrane filtration

104

104) Which of the following best describes the pattern of microbial death?

A) The cells in a population die at a constant rate.

B) All the cells in a culture die at once.

C) Not all of the cells in a culture are killed.

D) The pattern varies depending on the antimicrobial agent.

E) The pattern varies depending on the species.

A) The cells in a population die at a constant rate.

105

105) Which of the following chemical agents is used for sterilization?

A) alcohol

B) phenolics

C) ethylene oxide

D) chlorine

E) soap

C) ethylene oxide

106

106) Which of the following substances is used for surgical hand scrubs?

A) phenol

B) chlorine bleach

C) chlorhexidine

D) soap

E) glutaraldehyde

C) chlorhexidine

107

107) Which of the following pairs of terms is mismatched?

A) bacteriostatic — kills vegetative bacterial cells

B) germicide — kills microbes

C) virucide — inactivates viruses

D) sterilant — destroys all living microorganisms

E) fungicide — kills yeasts and molds

A) bacteriostatic — kills vegetative bacterial cells

108

108) The antimicrobial activity of chlorine is due to which of the following?

A) the formation of hypochlorous acid

B) the formation of hydrochloric acid

C) the formation of ozone

D) the formation of a hypochlorite ion

E) disruption of the plasma membrane

A) the formation of hypochlorous acid

109

109) Which of the following regarding antimicrobial control agents is FALSE?

A) Contaminating organic debris such as blood or sputum decrease effectiveness.

B) Some agents kill by denaturing microbial cell proteins.

C) Some agents affect microbial cell membranes by dissolving lipids.

D) Silver is used for treating antibiotic-resistant bacteria.

E) Alcohols effectively inactivate nonenveloped viruses by attacking lipids.

E) Alcohols effectively inactivate nonenveloped viruses by attacking lipids.

110

110) Which of the following does NOT achieve sterilization?

A) dry heat

B) pasteurization

C) autoclave

D) supercritical fluids

E) ethylene oxide

B) pasteurization

111

111) Which of the following is a limitation of the autoclave?

A) It requires an excessively long time to achieve sterilization.

B) It cannot inactivate viruses.

C) It cannot kill endospores.

D) It cannot be used with heat-labile materials.

E) It cannot be used with glassware.

D) It cannot be used with heat-labile materials

112

112) An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n)

A) disinfectant.

B) antiseptic.

C) aseptic.

D) fungicide.

E) virucide.

A) disinfectant

113

113) Application of heat to living cells can result in all of the following EXCEPT

A) breaking of hydrogen bonds.

B) alteration of membrane permeability.

C) denaturation of enzymes.

D) decreased thermal death time.

E) damage to nucleic acids.

D) decreased thermal death time

114

114) Which of the following disinfectants acts by disrupting the plasma membrane?

A) soaps

B) aldehydes

C) bisphenols

D) halogens

E) heavy metals

C) bisphenols

115

115) Oxidizing agents include all of the following EXCEPT

A) chlorine.

B) glutaraldehyde.

C) hydrogen peroxide.

D) iodine.

E) ozone.

B) glutaraldehyde

116

116) Disinfection of water is achieved by all of the following EXCEPT

A) ozone.

B) UV radiation.

C) chlorine.

D) copper sulfate.

E) peracetic acid.

E) peracetic acid

117

117) All of the following substances are effective against nonenveloped viruses EXCEPT

A) alcohol.

B) chlorine.

C) ethylene oxide.

D) ozone.

E) None of the answers is correct; all of these are equally effective against nonenveloped viruses.

A) alcohol.

118

118) Which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes?

A) lyophilization

B) nonionizing radiation

C) freezing

D) ionizing radiation

E) pasteurization

C) freezing

119

119) Which concentration of ethanol is the most effective bactericide?

A) 100 percent

B) 70 percent

C) 50 percent

D) 40 percent

E) 30 percent

B) 70 percent

120

120) All of the following factors contribute to hospital-acquired infections EXCEPT

A) some bacteria metabolize disinfectants.

B) gram-negative bacteria are often resistant to disinfectants.

C) invasive procedures can provide a portal of entry for bacteria.

D) bacteria may be present in commercial products such as mouthwash.

E) None of the answers is correct; all of these factors may contribute to hospital-acquired infection.

E) None of the answers is correct; all of these factors may contribute to hospital-acquired infection

121

121) Which of the following treatments is the most effective for controlling microbial growth?

A) 63°C for 30 minutes

B) 72°C for 15 seconds

C) 140°C for 4 seconds

D) They are equivalent treatments.

E) None of the answers is correct.

D) They are equivalent treatments

122

122) Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper?

A) autoclave

B) gamma radiation

C) microwaves

D) sunlight

E) ultraviolet radiation

B) gamma radiation

123

123) Which of the following regarding antimicrobial control agents is FALSE?

A) Contaminating organic debris such as blood or sputum will decrease effectiveness.

B) Some agents kill by denaturing microbial cell proteins.

C) Some agents affect microbial cell membranes by dissolving lipids.

D) Some agents are utilized as both an antiseptic and a disinfectant.

E) A true antimicrobial control agent is equally effective against both bacteria and viruses.

E) A true antimicrobial control agent is equally effective against both bacteria and viruses.

124

124) Which of the following results in lethal damage to nucleic acids?

A) heat

B) radiation

C) certain chemicals

D) heat and radiation

E) heat, radiation, and some chemicals

E) heat, radiation, and some chemicals

125

125) Which of the following pairs is mismatched?

A) Ag — wound dressings

B) alcohols — open wounds

C) CuSO4— algicide

D) H2O2— open wounds

E) organic acids — food preservation

B) alcohols — open wounds

126

126) An iodophor is a(n)

A) phenol.

B) agent that reduces oxygen.

C) quaternary ammonium compound.

D) form of formaldehyde.

E) iodine mixed with a surfactant.

E) iodine mixed with a surfactant

127

127) Ethylene oxide

A) is a good antiseptic.

B) is not sporicidal.

C) requires high heat to be effective.

D) is a sterilizing agent.

E) is the active chemical in household bleach.

D) is a sterilizing agent

128

128) All of the following substances are used to preserve foods EXCEPT

A) biguanides.

B) nisin.

C) potassium sorbate.

D) sodium nitrite.

E) calcium propionate.

A) biguanides

129

129) All of the following are effective for destroying prions EXCEPT

A) boiling.

B) incineration.

C) NaOH + autoclaving at 134°C.

D) proteases.

E) None of the answers are correct; each of these will destroy prions.

A) boiling

130

130) Which of the following pairs is mismatched?

A) ionizing radiation — hydroxyl radicals

B) ozone — takes electrons from substances

C) plasma sterilization — free radicals

D) supercritical fluids — CO2

E) ultraviolet radiation — desiccation

E) ultraviolet radiation — desiccation

131

131) All of the following are methods of food preservation EXCEPT

A) desiccation.

B) high pressure.

C) ionizing radiation.

D) microwaves.

E) osmotic pressure.

D) microwaves.