Microbiology With Diseases by Taxonomy 5th Edition By Bauman – Test Bank

 

 

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Sample Questions

 

 

Microbiology with Diseases by Taxonomy, 5e (Bauman)

Chapter 4   Microscopy, Staining, and Classification

 

4.1   Multiple Choice Questions

 

1) Viruses are generally measured in

1.    A) nanometers.

2.    B) millimeters.

3.    C) micrometers.

4.    D) centimeters.

5.    E) decimeters.

Answer:  A

Bloom’s Taxonomy:  Knowledge

Section:  Units of Measurement

Learning Outcome:  4.1

 

2) Which of the following is an incorrect pairing?

1.    A) magnification; refraction of radiation

2.    B) contrast; staining techniques

3.    C) numerical aperture; curved glass

4.    D) simple microscope; Leeuwenhoek

5.    E) electron beams; shorter wavelength

Answer:  C

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.4, 4.8

 

3) The ability of a lens to gather light is referred to as its

1.    A) resolution.

2.    B) numerical aperture.

3.    C) refraction.

4.    D) contrast.

5.    E) magnification.

Answer:  B

Bloom’s Taxonomy:  Knowledge

Section:  Microscopy

Learning Outcome:  4.6

 

 

4) Which of the following are magnifying lenses?

1.    A) objectives

2.    B) oculars

3.    C) condensers

4.    D) prisms

5.    E) both objectives and the oculars

Answer:  E

Bloom’s Taxonomy:  Application

Section:  Microscopy

Learning Outcome:  4.8

5) If you were trying to visualize flagella without staining, which microscope would you use?

1.    A) phase-contrast

2.    B) dark-field

3.    C) fluorescent

4.    D) confocal

5.    E) bright-field

Answer:  A

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.9

 

6) Why does immersion oil improve resolution?

1.    A) It allows light to travel at a uniform speed on its way to the lens.

2.    B) It decreases the working distance.

3.    C) It increases the numerical aperture.

4.    D) It increases numerical aperture and maintains a uniform light speed.

5.    E) It increases the angle of refraction of the light.

Answer:  D

Bloom’s Taxonomy:  Application

Section:  Microscopy

Learning Outcome:  4.6

 

7) You are shown a micrograph from a light microscope in which the specimens appear bright compared to the background. The micrograph is probably from a(n) ________ microscope.

1.    A) dark-field

2.    B) phase-contrast

3.    C) Nomarski

4.    D) bright-field

5.    E) atomic force

Answer:  A

Bloom’s Taxonomy:  Application

Section:  Microscopy

Learning Outcome:  4.9

 

 

8) The microscope preferred for viewing living specimens is the ________ microscope.

1.    A) bright-field

2.    B) phase-contrast

3.    C) scanning electron

4.    D) scanning tunneling

5.    E) transmission electron

Answer:  B

Bloom’s Taxonomy:  Knowledge

Section:  Microscopy

Learning Outcome:  4.9

9) Which of the following is NOT associated with an electron microscope?

1.    A) an electron beam

2.    B) magnetic fields

3.    C) a prism

4.    D) a fluorescent screen

5.    E) a vacuum

Answer:  C

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.11

 

10) All of the following are types of light microscopes EXCEPT

1.    A) fluorescent.

2.    B) confocal.

3.    C) phase-contrast.

4.    D) scanning tunneling.

5.    E) bright-field.

Answer:  D

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.9, 4.11

 

11) One-millionth of a meter is called a

1.    A) centimeter.

2.    B) decimeter.

3.    C) micrometer.

4.    D) millimeter.

5.    E) nanometer.

Answer:  C

Bloom’s Taxonomy:  Comprehension

Section:  Units of Measurement

Learning Outcome:  4.2

 

 

12) If a microbiology lab student left the safranin out of the Gram stain procedure, what would be the result?

1.    A) All cells would be purple.

2.    B) Gram-positive cells would be purple and Gram-negative cells would be colorless.

3.    C) All cells would be pink.

4.    D) Gram-positive cells would be pink and Gram-negative cells would be purple.

5.    E) Gram-positive cells would be colorless and Gram-negative cells would be pink.

Answer:  B

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.15

13) All of the following are common to both the Gram stain and the acid-fast stain EXCEPT

1.    A) primary stain.

2.    B) counterstain.

3.    C) a decolorizing agent.

4.    D) a chemical mordant.

5.    E) a decolorizing agent and a counterstain.

Answer:  D

Bloom’s Taxonomy:  Application

Section:  Staining

Learning Outcome:  4.15

 

14) Safranin dye is used as the counterstain in ________ stain(s).

1.    A) the Gram

2.    B) the endospore

3.    C) the acid-fast

4.    D) the flagellar

5.    E) both the Gram and the endospore

Answer:  E

Bloom’s Taxonomy:  Application

Section:  Staining

Learning Outcome:  4.15

 

15) Heat is used to drive the stain into cells in the ________ staining procedure(s).

1.    A) endospore stain

2.    B) acid-fast stain

3.    C) capsule stain

4.    D) Gram stain

5.    E) both acid-fast and endospore stains

Answer:  E

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.13, 4.15

 

 

16) Carbolfuchsin is the ________ in the acid-fast stain.

1.    A) primary stain

2.    B) mordant

3.    C) decolorizer

4.    D) counterstain

5.    E) fixing reagent

Answer:  A

Bloom’s Taxonomy:  Knowledge

Section:  Staining

Learning Outcome:  4.15

17) Which of the following is the best definition of “empty magnification”?

1.    A) An image is magnified so much resolution and contrast are lost.

2.    B) A specimen is so lacking in color it cannot be observed on a light microscope.

3.    C) A magnified specimen is so small it cannot be resolved on a light microscope.

4.    D) The background on the field is almost totally black.

5.    E) A magnified image has lots of empty space around a small object.

Answer:  A

Bloom’s Taxonomy:  Application

Section:  Microscopy

Learning Outcome:  4.5

 

18) In a transmission electron microscope, the “lenses” are

1.    A) made of glass.

2.    B) thin films of metal.

3.    C) lasers.

4.    D) magnets.

5.    E) vacuums.

Answer:  D

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.11

 

19) You are examining a bacterial smear on a light microscope. You observe pinkish-red bacilli and blue cells of various shapes. You are probably looking at a smear prepared with the ________ stain.

1.    A) Gram

2.    B) Ziehl-Neelsen acid-fast

3.    C) Schaffer-Fulton endospore

4.    D) Gomori methenamine

5.    E) Hematoxylin and eosin

Answer:  B

Bloom’s Taxonomy:  Application

Section:  Staining

Learning Outcome:  4.15

 

 

20) The placement of an organism into a domain is made on the basis of

1.    A) G + C content.

2.    B) cell ultrastructure.

3.    C) ribosomal RNA analysis.

4.    D) serological tests.

5.    E) Gram-stain reactions.

Answer:  C

Bloom’s Taxonomy:  Comprehension

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.22

21) Which of the following is NOT a characteristic of a genus name?

1.    A) it is usually an adjective.

2.    B) it is written before the specific epithet.

3.    C) it is always capitalized.

4.    D) it is either underlined or in italics.

5.    E) it is one of two names used to identify an organism.

Answer:  A

Bloom’s Taxonomy:  Knowledge

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.20

 

22) Carl Woese proposed the concept of the domain based on differences of which of the following cellular molecules?

1.    A) transfer RNA

2.    B) membrane lipids

3.    C) ribosomal RNA

4.    D) DNA

5.    E) proteins

Answer:  C

Bloom’s Taxonomy:  Knowledge

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.22

 

23) Which of the following classification methods relies on the morphology of organisms?

1.    A) phage typing

2.    B) physical characteristics

3.    C) biochemical tests

4.    D) analysis of nucleic acids

5.    E) serological tests

Answer:  B

Bloom’s Taxonomy:  Knowledge

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.23

 

 

24) A cell’s G + C ratio is associated with which of the following classification methods?

1.    A) phage typing

2.    B) biochemical tests

3.    C) physical characteristics

4.    D) analysis of nucleic acids

5.    E) serological tests

Answer:  D

Bloom’s Taxonomy:  Analysis

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.23

25) Viruses are not included in the taxonomic scheme proposed by Carl Woese because they lack

1.    A) genetic material.

2.    B) ribosomal RNA.

3.    C) proteins.

4.    D) lipid membranes.

5.    E) cytoplasm.

Answer:  B

Bloom’s Taxonomy:  Comprehension

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.22

 

26) Why have some microbiologists proposed using ribosomal RNA as the basis for defining bacterial species?

1.    A) Ribosomal RNAs are highly conserved genetic sequences present in all prokaryotes.

2.    B) the “interbreeding population” criterion does not apply to bacteria.

3.    C) ribosomal RNA is the basis for domain assignment.

4.    D) bacteria vary too little in their physical and biochemical traits.

5.    E) bacteria are not interbreeding populations, and ribosomal RNAs are highly conserved genes present in all prokaryotes.

Answer:  E

Bloom’s Taxonomy:  Application

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.18

 

27) Which of the following phenomena produces magnification?

1.    A) the wavelength of a radiation source

2.    B) the refraction of radiation as it passes through a lens

3.    C) the thickness of a microscopic specimen

4.    D) the numerical aperture of a lens

5.    E) the length of an objective lens

Answer:  B

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.6

 

28) A virologist wants to observe the surface features of virus particles she is studying. Which of the following microscopes would NOT be useful for her observations?

1.    A) differential interference contrast

2.    B) scanning tunneling

3.    C) scanning electron

4.    D) transmission electron

5.    E) atomic force

Answer:  A

Bloom’s Taxonomy:  Application

Section:  Microscopy

Learning Outcome:  4.9, 4.11

29) A structure that appears in a transmission electron micrograph but is not actually present in the specimen is known as a(n)

1.    A) antigen.

2.    B) biofilm.

3.    C) artifact.

4.    D) refraction.

5.    E) mordant.

Answer:  C

Bloom’s Taxonomy:  Knowledge

Section:  Microscopy

Learning Outcome:  4.11

 

30) Which of the following statements about transmission electron microscopy is CORRECT?

1.    A) Three-dimensional images are produced.

2.    B) Lasers are used for visualization.

3.    C) Up to 1,000,000X magnification may be achieved.

4.    D) Living specimens may be used.

5.    E) Stains can be applied to create a color image.

Answer:  C

Bloom’s Taxonomy:  Application

Section:  Microscopy

Learning Outcome:  4.11

 

31) Acidic dyes

1.    A) work best in low pH environments.

2.    B) are negatively charged.

3.    C) are used for staining negatively charged molecular structures.

4.    D) are lipid soluble.

5.    E) are negatively charged and work best at low pH.

Answer:  E

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.14

 

 

32) The kingdoms included in the Linnaeus system of classification are

1.    A) Animalia and Prokaryotae.

2.    B) Protista and Plantae.

3.    C) Fungi and Protista.

4.    D) Animalia and Plantae.

5.    E) Prokaryotae and Protista.

Answer:  D

Bloom’s Taxonomy:  Comprehension

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.21

33) The Gram stain works because of differences in the ________ of bacteria.

1.    A) genetic characteristics

2.    B) cell walls

3.    C) cell membranes

4.    D) antigens

5.    E) capsules

Answer:  B

Bloom’s Taxonomy:  Knowledge

Section:  Staining

Learning Outcome:  4.15

 

34) The rules of naming organisms are called

1.    A) taxonomy.

2.    B) nomenclature.

3.    C) classification.

4.    D) binomials.

5.    E) identification.

Answer:  B

Bloom’s Taxonomy:  Knowledge

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.20

 

35) Why are modern light microscopes better than the ones Leeuwenhoek used?

1.    A) Modern microscopes have a fivefold better resolution.

2.    B) Modern microscopes are compound instead of simple.

3.    C) Modern microscopes have lenses with smaller numerical apertures.

4.    D) Modern lenses are made of prisms.

5.    E) Modern microscopes are compound and have fivefold better resolution.

Answer:  E

Bloom’s Taxonomy:  Application

Section:  Microscopy

Learning Outcome:  4.6, 4.8

 

 

36) In the Gram stain procedure, iodine serves as a

1.    A) counterstain.

2.    B) decolorizing agent.

3.    C) mordant.

4.    D) primary stain.

5.    E) fixative.

Answer:  C

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.15

37) What role does safranin play in the Gram stain procedure?

1.    A) primary stain

2.    B) mordant

3.    C) decolorizing agent

4.    D) counterstain

5.    E) negative stain

Answer:  D

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.15

 

38) In Gram staining, ethanol-acetone is used as a

1.    A) decolorizing agent.

2.    B) counterstain.

3.    C) mordant.

4.    D) drying agent.

5.    E) primary stain.

Answer:  A

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.15

 

39) A sample from a patient is prepared using the Gomori methenamine silver stain. What type of microbe is suspected of being present?

1.    A) bacteria

2.    B) parasitic worm larva

3.    C) fungus

4.    D) protozoal parasite

5.    E) virus

Answer:  C

Bloom’s Taxonomy:  Application

Section:  Staining

Learning Outcome:  4.15

 

 

40) Tungsten is a reagent used in the

1.    A) acid-fast stain.

2.    B) electron microscopy stain.

3.    C) endospore stain.

4.    D) flagellar stain.

5.    E) negative stain.

Answer:  B

Bloom’s Taxonomy:  Knowledge

Section:  Staining

Learning Outcome:  4.16

41) Acidic dyes are commonly used for ________ stains.

1.    A) acid-fast

2.    B) negative

3.    C) flagellar

4.    D) endospore

5.    E) Gram

Answer:  B

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.14

 

42) Low contrast specimens are made easier to see by

1.    A) increasing the amount of light passing through the slide.

2.    B) using dyes that react with their structures.

3.    C) adding color filters to the microscope.

4.    D) using smaller aperture lenses.

5.    E) drying them in a vacuum.

Answer:  B

Bloom’s Taxonomy:  Application

Section:  Microscopy

Learning Outcome:  4.7

 

43) Methylene blue can be used to stain DNA because it

1.    A) forms ionic bonds with DNA.

2.    B) changes the pH and therefore the structure of DNA.

3.    C) covalently bonds with DNA.

4.    D) makes DNA electron dense.

5.    E) is an effective fixing agent for nucleic acids.

Answer:  A

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.14

 

 

44) The ________ stain makes use of malachite green.

1.    A) negative

2.    B) flagellar

3.    C) endospore

4.    D) electron microscopy

5.    E) acid-fast

Answer:  C

Bloom’s Taxonomy:  Knowledge

Section:  Staining

Learning Outcome:  4.15

45) The most appropriate unit of measurement for intact archaea is the

1.    A) meter (m).

2.    B) millimeter (mm).

3.    C) micrometer (μm).

4.    D) nanometer (nm).

5.    E) centimeter (cm).

Answer:  C

Bloom’s Taxonomy:  Knowledge

Section:  Units of Measurement

Learning Outcome:  4.1

 

46) Specimens are prepared for ________ microscopy using electron-dense stains.

1.    A) atomic probe

2.    B) bright-field

3.    C) confocal

4.    D) transmission electron

5.    E) scanning tunneling

Answer:  D

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.16

 

47) An important function of nomenclature is to

1.    A) facilitate unambiguous communication.

2.    B) clarify relationships among organisms.

3.    C) provide an understanding of evolutionary relationships.

4.    D) define the characteristics used for classification.

5.    E) provide a detailed description of an organism.

Answer:  A

Bloom’s Taxonomy:  Comprehension

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.17

 

 

48) A measurement of a microbe is reported as 1 × 10-6 m, also known as

1.    A) centimeters (cm).

2.    B) millimeters (mm).

3.    C) micrometers (μm).

4.    D) nanometers (nm).

5.    E) yards.

Answer:  C

Bloom’s Taxonomy:  Comprehension

Section:  Units of Measurement

Learning Outcome:  4.1

49) One-thousandth of a meter is a

1.    A) yard.

2.    B) millimeter (mm).

3.    C) micrometer (μm).

4.    D) nanometer (nm).

5.    E) centimeter (cm).

Answer:  B

Bloom’s Taxonomy:  Knowledge

Section:  Units of Measurement

Learning Outcome:  4.1

 

50) Bacteria and many other microbes do not ________ and therefore do not fit Linneaus’ definition species.

1.    A) reproduce sexually

2.    B) have nuclei

3.    C) exchange genetic material

4.    D) have cytoplasmic membranes

5.    E) reproduce asexually

Answer:  A

Bloom’s Taxonomy:  Comprehension

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.18

 

4.2   True/False Questions

 

1) A resolution of 1 μm would be better than a resolution of 0.5 μm.

Answer:  FALSE

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.6

 

2) All types of radiation are used for microscopy.

Answer:  FALSE

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.3

 

3) The three domains proposed by Carl Woese and George Fox are the Archaea, the Eukarya, and the Protista.

Answer:  FALSE

Bloom’s Taxonomy:  Knowledge

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.22

 

4) Gram staining of bacteria provides all the physical characterization necessary to identify bacterial species.

Answer:  FALSE

Bloom’s Taxonomy:  Comprehension

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.15, 4.18

5) A single basic dye is used in simple stains.

Answer:  TRUE

Bloom’s Taxonomy:  Knowledge

Section:  Staining

Learning Outcome:  4.15

 

6) The endospore stain reveals internal structures within cells of the genera Bacillus and Clostridium.

Answer:  TRUE

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.15

 

7) Acid-fast cells such as Mycobacterium lose the color of the primary stain in the presence of hydrochloric acid.

Answer:  FALSE

Bloom’s Taxonomy:  Knowledge

Section:  Staining

Learning Outcome:  4.15

 

8) Three-dimensional images of specimens can be obtained using scanning electron microscopes.

Answer:  TRUE

Bloom’s Taxonomy:  Knowledge

Section:  Microscopy

Learning Outcome:  4.11

 

9) Images of living specimens can be produced using atomic force microscopes.

Answer:  TRUE

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.12

 

10) Light rays that pass through the edge of a curved lens will be refracted more than those that pass through the center.

Answer:  TRUE

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.6

4.3   Short Answer Questions

 

1)

 

The part of the microscope indicated by the arrow in Figure 4.1 is the (ocular/objective/condenser) lens.

Answer:   condenser

Bloom’s Taxonomy:  Knowledge

Section:  Microscopy

Learning Outcome:  4.8

 

2) A(n) (acidic/metallic/fluorescent) molecule is one that absorbs invisible radiation and emits visible light.

Answer:  fluorescent

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.10

 

 

3) The total magnification using a 10 ocular and a 100 objective would be (110/1000/10000)×. (Be sure your answer is a numeral.)

Answer:  1000

Bloom’s Taxonomy:  Knowledge

Section:  Microscopy

Learning Outcome:  4.8

 

4) A (decolorizer/mordant/fixer) is a substance that binds to a dye and makes it less soluble.

Answer:  mordant

Bloom’s Taxonomy:  Knowledge

Section:  Staining

Learning Outcome:  4.15

5) Coating a specimen with a heavy metal is a step in preparing it for (phase/fluorescent/electron) microscopy.

Answer:  electron

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.16

 

6) A serological test that involves the clumping of antigen and antibody is the (agglutination/antigen/ELISA) test.

Answer:  agglutination

Bloom’s Taxonomy:  Comprehension

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.23

 

7) The system of taxonomy used today was originated by (Linnaeus/Darwin/Woese). (Be sure to capitalize your answer.)

Answer:  Linnaeus

Bloom’s Taxonomy:  Knowledge

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.21

 

8) Carl Woese and George Fox proposed the (phylum/domain/family), a taxon that contains multiple kingdoms.

Answer:  domain

Bloom’s Taxonomy:  Comprehension

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.22

 

 

9)

 

Figure 4.2 represents a (dichotomous/classification/taxonomic) key of the type used to identify a microbe.

Answer:  dichotomous

Bloom’s Taxonomy:  Comprehension

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.23

10) Phage typing is useful for identifying bacteria because of the specificity of (antibodies/bacteriophages/PCR) for unique bacterial structures.

Answer:  bacteriophages

Bloom’s Taxonomy:  Knowledge

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.23

 

11) A primary purpose for the use of stains in microscopy is to increase the (magnification/brightness/contrast) of a specimen.

Answer:  contrast

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.7

 

12) PCR is a method for identifying microbes based on their (antigens/genes/morphology).

Answer:  genes

Bloom’s Taxonomy:  Comprehension

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.23

 

13) In a compound microscope, the lens that directs light into the eye is the (ocular/condenser/objective) lens.

Answer:  ocular

Bloom’s Taxonomy:  Comprehension

Section:  Microscopy

Learning Outcome:  4.8

 

14) In the Schaffer-Fulton endospore stain, heat is a (fixation/mordant/staining) step.

Answer:  staining

Bloom’s Taxonomy:  Comprehension

Section:  Staining

Learning Outcome:  4.13

 

15) The resolution of a microscope lens is a function of the lens’ (aperture/color/contrast).

Answer:  aperture

Bloom’s Taxonomy:  Knowledge

Section:  Microscopy

Learning Outcome:  4.6

4.4   Essay Questions

 

1) Discuss the ways in which light rays can be manipulated to increase resolution and/or contrast.

Answer:  Light rays can be manipulated to increase the resolution and contrast of a specimen in a variety of ways. In bright-field microscopes, immersion oil is used to capture light rays that would otherwise be refracted and lost; the result is an increase in the resolution of the image. Dark-field microscopes purposely scatter light rays in such a way as to improve the contrast of the specimen. Phase-contrast microscopes alter the wavelengths of light rays by splitting them into different paths then rejoining them, thereby increasing contrast. Finally, fluorescent microscopes use UV light, which produces increased resolution because of its shorter wavelength, and the fluorescent dyes that are used emit a variety of colors, increasing contrast.

Bloom’s Taxonomy:  Application

Section:  Microscopy

Learning Outcome:  4.6

 

2) Compare and contrast the light microscope with the electron microscope.

Answer:  Both the light microscope and the electron microscope depend on the wavelength of radiation to achieve the resolution necessary to see fine details of specimens. Light microscopes use light rays, which, because of their relatively long wavelengths, limit the magnification of these microscopes to 2000× or less. Electron beams, by contrast, have such a short wavelength that the resolution is greatly increased, to the point that magnification of 100,000× or more is possible. Both microscopes are capable of modulating and focusing their radiation sources in such a way as to increase the quality of the magnification; however, in a light microscope the light rays are focused using glass lenses, whereas in an electron microscope the electron beam is focused with magnetic fields. Because of their higher levels of magnification and extreme resolving power, electron microscopes are capable of revealing the finest details of the cell’s ultrastructure, even molecules and atoms; light microscopes are capable of revealing only the larger cellular structures, such as organelles.

Bloom’s Taxonomy:  Analysis

Section:  Microscopy

Learning Outcome:  4.9, 4.11

 

3) You are a scientist studying the highly specific interactions of bacteriophages with their host cells when they first encounter the cell. Discuss what microscope(s) and preparation procedures you might use for this study.

Answer:  A scanning electron microscope can produce three-dimensional images of the physical contact between bacteriophage and host, providing information on what portions of the bacteriophage are in contact with what structures of the cell. A mixture of bacterial cells and bacteriophages is dried onto the surface of the sample holder and coated with metal to prepare it for the scanning electron microscope. A transmission electron microscope may provide information about structures and interactions obscured by the intact bacteriophage. Samples are dried, embedded in plastic, sliced into thin (100 nm) sections, and stained with heavy metals (osmium, tungsten, etc.) to increase contrast.

Scanning tunneling or atomic force microscopy of separate preparations of bacteriophages and bacterial cells can provide details about the structures on each that interact when the bacteriophage is in contact with the surface of the cell. The preparation of specimens for atomic force microscopy is minimal, as the material does not need to be dried, sectioned, or stained.

Bloom’s Taxonomy:  Application

Section:  Staining

Learning Outcome:  4.11, 4.12, 4.16

 

4) Compare and contrast the three domains identified by Woese and Fox: Eukarya, Bacteria, and Archaea.

Answer:  With respect to cell type, organisms in Eukarya have eukaryotic cells and the characteristics that go with this cell type, such as a nucleus and membranous organelles. Bacteria and Archaea both have prokaryotic cells lacking nuclei and membranous organelles. All three have different ribosomal RNA sequences found in the small subunit of their ribosomes that are characteristic for the domain, which is an important tool for categorizing organisms. All three have cell membranes; however, they differ in the lipids found in the cell membrane.

Bloom’s Taxonomy:  Analysis

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.22

 

 

5) List and explain five types of techniques that can be used to identify unknown microorganisms.

Answer:  There are five major types of identification techniques used in the microbiology lab. One method is simply observation and classification of the physical characteristics of an organism, which includes both cellular morphology and colony morphology. A second method is the use of biochemical tests, such as fermentation of carbohydrates or production of metabolic by-products, to place microbes in different groups. A third type of identification technique is serological testing, in which antibodies are used to detect particular antigens on the surfaces of different microbes in an effort to distinguish closely related species or strains of microbes. Phage typing is the fourth technique, which is the use of bacteriophages to infect bacterial cells; because bacteriophages are highly specific in their infection of cells, the patterns of infected and uninfected cells can be used to differentiate bacterial strains and species. A fifth method involves analyzing the genetic material of microbes, such as the percentage of G and C bases in a cell’s DNA, to demonstrate possible relationships between species.

Bloom’s Taxonomy:  Application

Section:  Classification and Identification of Microorganisms

Learning Outcome:  4.23

Microbiology with Diseases by Taxonomy, 5e (Bauman)

Chapter 7   Microbial Genetics

 

7.1   Multiple Choice Questions

 

1) All of the following are associated with nucleic acid structure EXCEPT

1.    A) ribose.

2.    B) hydrogen bonds.

3.    C) uracil.

4.    D) ionic bonds.

5.    E) phosphate.

Answer:  D

Bloom’s Taxonomy:  Comprehension

Section:  The Structure and Replication of Genomes

Learning Outcome:  7.2

 

2) Which of the following is found at the 5′ end of a DNA strand?

1.    A) a phosphate group

2.    B) a hydrogen bond

3.    C) a hydroxyl group

4.    D) histones

5.    E) a methyl group

Answer:  A

Bloom’s Taxonomy:  Comprehension

Section:  The Structure and Replication of Genomes

Learning Outcome:  7.2

 

3) The bacterial chromosome is

1.    A) usually circular.

2.    B) found in a nucleoid.

3.    C) found in a nucleus.

4.    D) both circular and found in a nucleoid.

5.    E) both circular and found in a nucleus.

Answer:  D

Bloom’s Taxonomy:  Comprehension

Section:  The Structure and Replication of Genomes

Learning Outcome:  7.1

 

 

4) Which of the following types of plasmids allows a bacterial cell to kill its competitors?

1.    A) virulence plasmids

2.    B) fertility plasmids

3.    C) bacteriocin plasmids

4.    D) resistance plasmids

5.    E) cryptic plasmids

Answer:  C

Bloom’s Taxonomy:  Knowledge

Section:  The Structure and Replication of Genomes

Learning Outcome:  7.4

5) Which of the following is found in both archaeal and eukaryotic genomes?

1.    A) chromatin fibers

2.    B) histones

3.    C) heterochromatin

4.    D) euchromatin

5.    E) nuclear envelope

Answer:  B

Bloom’s Taxonomy:  Comprehension

Section:  The Structure and Replication of Genomes

Learning Outcome:  7.5

 

6) Which of the following statements is true of bacterial plasmids?

1.    A) They are always found in the nucleoid.

2.    B) They can replicate autonomously.

3.    C) They carry genes for essential metabolic functions.

4.    D) They are small circular DNA molecules.

5.    E) They are small circular DNA molecules that can replicate autonomously.

Answer:  E

Bloom’s Taxonomy:  Comprehension

Section:  The Structure and Replication of Genomes

Learning Outcome:  7.4

 

 

7)

 

The process indicated by the arrow in Figure 7.1 represents

1.    A) lagging strand synthesis.

2.    B) leading strand synthesis.

3.    C) transcription.

4.    D) translation.

5.    E) recombination.

Answer:  A

Bloom’s Taxonomy:  Comprehension

Section:  The Structure and Replication of Genomes

Learning Outcome:  7.7

 

8) Which of the following statements concerning transcription in bacteria is FALSE?

1.    A) It occurs in the nucleoid region.

2.    B) Sigma factors are parts of RNA polymerase that recognize promoter regions.

3.    C) Different RNA polymerases are required for synthesis of mRNA, rRNA, and tRNA.

4.    D) Termination is either self-induced or due to the presence of Rho protein.

5.    E) There are a variety of sigma factors that affect transcription.

Answer:  C

Bloom’s Taxonomy:  Application

Section:  Gene Function

Learning Outcome:  7.12

9) Which of the following is involved in translation?

1.    A) rRNA only

2.    B) tRNA only

3.    C) mRNA only

4.    D) both mRNA and tRNA

5.    E) mRNA, rRNA, and tRNA are all involved.

Answer:  E

Bloom’s Taxonomy:  Comprehension

Section:  Gene Function

Learning Outcome:  7.14

 

 

10) Which of the following is a characteristic shared by DNA and RNA polymerases?

1.    A) efficiency of proofreading

2.    B) type of nucleotides used

3.    C) direction of polymerization

4.    D) speed

5.    E) dependence on helicase

Answer:  C

Bloom’s Taxonomy:  Analysis

Section:  Gene Function

Learning Outcome:  7.6, 7.9, 7.11