Deck 4: Microscopy, Staining, and Classification

Question 1

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

A) biochemical tests
B) analysis of nucleic acids
C) physical characteristics
D) serological tests
E) phage typing

Answer 1

B

Question 2

Bacteria and many other microbes do not _ _ and therefore do not fit Linneaus' definition species.

A) exchange genetic material
B) have nuclei
C) reproduce sexually
D) reproduce asexually
E) have cytoplasmic membranes

Answer 2

C

Question 3

Carbolfuchsin is the _ in the acid- fast stain.

A) primary stain
B) counterstain
C) fixing reagent
D) decolorizer
E) mordant

Answer 3

A

Question 4

Tannic acid is a mordant (chemical fixative) used in the _ stain.

A) flagellar
B) acid- fast
C) electron microscopy
D) negative
E) endospore

Question 5

In the Gram stain procedure, iodine serves as a

A) fixative.
B) counterstain.
C) primary stain.
D) decolorizing agent.
E) mordant.

Question 6

Which of the following phenomena produces magnification?

A) the refraction of radiation as it passes through a lens
B) the length of an objective lens
C) the numerical aperture of a lens
D) the wavelength of a radiation source
E) the thickness of a microscopic specimen

Question 7

The stain makes use of malachite green.

A) flagellar
B) acid- fast
C) electron microscopy
D) endospore
E) negative

Question 8

Which of the following statements about transmission electron microscopy is FALSE?

A) Thin segments must be used.
B) Electrons are the source of visualization.
C) Glass lenses are used.
D) Stains can be applied to improve contrast.
E) The sample is placed in a vacuum.

Question 9

Methylene blue can be used to stain DNA because it

A) changes the pH and therefore the structure of DNA.
B) is an effective fixing agent for nucleic acids.
C) covalently bonds with DNA.
D) forms ionic bonds with DNA.
E) makes DNA electron dense.

Question 10

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

A) Modern microscopes are compound instead of simple.
B) Modern lenses are made of prisms.
C) Modern microscopes have lenses with smaller numerical apertures.
D) Modern microscopes are compound and have fivefold better resolution.
E) Modern microscopes have a fivefold better resolution.

Question 11

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

A) confocal
B) phase- contrast
C) dark- field
D) bright- field
E) fluorescent

Question 12

Which of the following microscopes produces the highest resolution images?

A) scanning electron
B) dark- field
C) atomic force
D) differential interference
E) fluorescent

Question 13

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

A) counterstain.
B) primary stain.
C) a chemical mordant.
D) a decolorizing agent.
E) a decolorizing agent and a counterstain.

Question 14

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

A) Gram- positive cells would be purple and Gram- negative cells would be colorless.
B) All cells would be purple.
C) Gram- positive cells would be pink and Gram- negative cells would be purple.
D) Gram- positive cells would be colorless and Gram- negative cells would be pink.
E) All cells would be pink.

Question 15

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

A) It is written before the specific epithet.
B) It is usually an adjective.
C) It is always capitalized.
D) It is either underlined or in italics.
E) It is one of two names used to identify an organism.

Question 16

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

A) analysis of nucleic acids
B) biochemical tests
C) phage typing
D) physical (phenotypic) characteristics
E) serological tests

Question 17

Why does immersion oil improve resolution?

A) It increases numerical aperture and maintains a uniform light speed.
B) It increases the angle of refraction of the light.
C) It increases the numerical aperture.
D) It decreases the working distance.
E) It allows light to travel at a uniform speed on its way to the lens.

Question 18

The rules of naming organisms are called

A) binomials.
B) identification.
C) nomenclature.
D) classification.
E) taxonomy.

Question 19

The stain is one in which eosin is used.

A) flagellar
B) endospore
C) electron microscopy
D) negative
E) acid- fast

Question 20

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

A) Bacteria are not interbreeding populations, and ribosomal RNAs are highly conserved genes present in all prokaryotes.
B) Ribosomal RNAs are highly conserved genetic sequences present in all prokaryotes.
C) Ribosomal RNA is the basis for domain assignment.
D) Bacteria vary too little in their physical and biochemical traits.
E) The "interbreeding population" criterion does not apply to bacteria.

Question 21

All of the following are types of light microscopes EXCEPT

A) scanning tunneling.
B) bright- field.
C) phase- contrast.
D) confocal.
E) fluorescent.

Question 22

Acidic dyes

A) are used for staining negatively charged molecular structures.
B) are negatively charged and work best at low pH.
C) are lipid soluble.
D) work best in low pH environments.
E) are negatively charged.

Question 23

The kingdoms included in the Linnaeus system of classification are

A) Prokaryotae and Protista.
B) Fungi and Protista.
C) Animalia and Plantae.
D) Animalia and Prokaryotae.
E) Protista and Plantae.

Question 24

Which of the following are magnifying lenses?

A) dark- field stops
B) oculars
C) condensers
D) objectives
E) both objectives and the oculars

Question 25

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

A) a vacuum
B) magnetic fields
C) a fluorescent screen
D) a prism
E) an electron beam

Question 26

Viruses are generally measured in

A) nanometers.
B) centimeters.
C) micrometers.
D) decimeters.
E) millimeters.

Question 27

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

A) protozoal parasite
B) virus
C) fungus
D) parasitic worm larva
E) bacteria

Question 28

What role does safranin play in the Gram stain procedure?

A) primary stain
B) negative stain
C) decolorizing agent
D) mordant
E) counterstain

Question 29

The microscope preferred for viewing living specimens is the microscope.

A) transmission electron
B) bright- field
C) phase- contrast
D) scanning tunneling
E) scanning electron

Question 30

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

A) proteins
B) DNA
C) transfer RNA
D) membrane lipids
E) ribosomal RNA

Question 31

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.

A) phase- contrast
B) bright- field
C) Nomarski
D) atomic force
E) dark- field

Question 32

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

A) endospore stain
B) capsule stain
C) Gram stain
D) acid- fast stain
E) both acid- fast and endospore stains

Question 33

The most appropriate unit of measurement for intact archaea is the

A) nanometer (nm).
B) millimeter (mm).
C) meter (m).
D) centimeter (cm).
E) micrometer (µm).

Question 34

Which of the following is an INCORRECT pairing?

A) simple microscope; Leeuwenhoek
B) magnification; refraction of radiation
C) electron beams; shorter wavelength
D) contrast; staining techniques
E) numerical aperture; curved glass

Question 35

The primary goal of modern taxonomists is to

A) understand the phylogenetic relationships between organisms.
B) determine what defines a species.
C) establish unique identifiers for each species.
D) have a complete inventory of all living things.
E) There is no consensus among taxonomists regarding their primary goal.

Question 36

Species and strains of microbes can be distinguished from one another phenotypically using

A) ribosomal RNA analysis
B) Gram- stain reactions.
C) G + C content.
D) electron microscopy.
E) serological tests.

Question 37

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

A) millimeters (mm).
B) nanometers (nm).
C) yards.
D) centimeters (cm).
E) micrometers (µm).

Question 38

A thin film of microbes on a slide is

A) agglutination.
B) fixation.
C) a biopsy.
D) a smear.
E) a Gram reaction.

Question 39

In Gram staining, ethanol- acetone is used as a

A) counterstain.
B) drying agent.
C) mordant.
D) decolorizing agent.
E) primary stain.

Question 40

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

A) the endospore
B) the flagellar
C) the acid- fast
D) the Gram
E) both the Gram and the endospore

Question 41

Bacterial viruses, called (bacteriophages/phages /bacteriotypes), can be used to help classify different groups of bacteria.

Question 42

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

Question 43

A sample is prepared using osmium tetroxide as a stain. This sample has been prepared for a(n) microscope.

A) atomic force
B) differential interference contrast
C) phase- contrast
D) electron
E) fluorescence

Question 44

Carl Woese and his colleagues proposed the (phylum/domain ), a taxon that contains multiple kingdoms.

Question 45

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

Question 46

Figure 4- 1 represents a (dichotomous/taxonomic) key of the type used to identify a microbe.

Question 47

The Gram stain works because of differences in the of bacteria.

A) cell membranes
B) antigens
C) cell walls
D) capsules
E) genetic characteristics

Question 48

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

A) antigen.
B) mordant.
C) artifact.
D) biofilm.
E) refraction.

Question 49

One- thousandth of a meter is a

A) nanometer (nm).
B) millimeter (mm).
C) yard.
D) centimeter (cm).
E) micrometer (µm).

Question 50

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?

A) differential interference contrast
B) atomic force
C) transmission electron
D) scanning electron
E) scanning tunneling

Question 51

In a compound microscope, the lens that directs light through the specimen is the (ocular/condenser/objective) lens.

Question 52

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

A) cytoplasm.
B) genetic material.
C) ribosomal RNA.
D) lipid membranes.
E) proteins.

Question 53

Tungsten is a reagent used in the

A) flagellar stain.
B) negative stain.
C) acid- fast stain.
D) electron microscopy stain.
E) endospore stain.

Question 54

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

Question 55

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

A) contrast.
B) refraction.
C) numerical aperture.
D) magnification.
E) resolution.

Question 56

A (monocular/binocular/compound) microscope has a single ocular lens.

Question 57

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

Question 58

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

Question 59

The size of a pork tapeworm is generally described in terms of

A) decimeters (dc).
B) meters (m).
C) micrometers (µm).
D) nanometers (nm).
E) millimeters (mm.)

Question 60

The limits of resolution of atomic force microscopes is in the range of

A) micrometers (µm).
B) millimeters (mm).
C) nanometers (nm).
D) meters (m).
E) centimeters (cm).

Question 61

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

Question 62

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

Question 63

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

Question 64

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

Question 65

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

Question 66

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

Question 67

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

Question 68

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

Question 69

The Gram stain can be used to distinguish bacteria based on the structure of their cell walls.

Question 70

The process of immobilizing organisms on a glass slide through the application of either heat or chemicals is (staining/mordant/fixation).

Question 71

The three domains proposed by Carl Woese are the Archaea, the Eukarya, and the Protista.

Question 72

Compare and contrast the light microscope with the electron microscope.

Question 73

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

Question 74

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

Question 75

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

Question 76

Light rays that are in phase reinforce each other and produce a brighter image.

Question 77

An integral part of serological testing is the use of a solution called (blood/plasma/antiserum) that contains antibodies.

Question 78

Scanning tunneling microscopes map the topography of a specimen by detecting the deflection of the probe tip.

Question 79

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.

Question 80

A staining procedure that uses a single basic dye is called a (simple/basic/cationic) stain.