Deck 3: Tools of the Laboratory: Methods of Studying Microorganisms

Question 1

A microbiologist must culture a patient's feces for intestinal pathogens.Which of the following would likely be present in selective media for analyzing this fecal specimen?

A)NaCl
B)sheep red blood cells
C)bile salts
D)thioglycolic acid
E)peptone

Answer 1

C

Question 2

A nutrient medium that has all of its chemical components identified and their precise concentrations known and reproducible would be termed

A)complex.
B)reducing.
C)enriched.
D)enumeration.
E)synthetic.

Answer 2

E

Question 3

Which of the following magnifies the specimen to produce the real image of the specimen?

A)condenser
B)objective lens
C)ocular lens
D)body
E)nosepiece

Answer 3

B

Question 4

A pure culture contains only

A)one species of microorganism.
B)bacteria.
C)a variety of microbes from one source.
D)All of these choices are correct.

Question 5

All of the following are examples of different types of microbiological media except

A)broth.
B)enriched.
C)agar.
D)Petri dish.
E)gelatin.

Question 6

A common medium used for growing fastidious bacteria is

A)chocolate agar.
B)trypticase soy agar.
C)mannitol salt agar.
D)MacConkey medium.
E)a reducing medium.

Question 7

A microbiologist inoculates Staphylococcus aureus into a culture medium.Following incubation, both Staphylococcus aureus and Staphylococcus epidermidis are determined to be growing in this culture.What is the most likely explanation?

A)The microbiologist used too much inoculum.
B)The culture is contaminated.
C)The incubation temperature was incorrect.
D)The culture medium must be selective.
E)The culture medium must be differential.

Question 8

Which of the following is essential for development of discrete, isolated colonies?

A)broth medium
B)differential medium
C)selective medium
D)solid medium
E)assay medium

Question 9

A reducing medium contains

A)sugars that can be fermented.
B)extra oxygen.
C)hemoglobin, vitamins, or other growth factors.
D)substances that remove oxygen.
E)inhibiting agents.

Question 10

The term that refers to the purposeful addition of microorganisms into a laboratory nutrient medium is

A)isolation.
B)inoculation.
C)immunization.
D)infection.
E)contamination.

Question 11

Which method often results in colonies developing down throughout the agar and some colonies on the surface?

A)streak plate
B)spread plate
C)pour plate
D)All of these choices are correct.

Question 12

A microbiologist inoculates Staphylococcus epidermidis and Escherichia coli into a culture medium.Following incubation, only the E.coli grows in the culture.What is the most likely explanation?

A)The microbiologist used too much inoculum.
B)The culture is contaminated.
C)The incubation temperature was incorrect.
D)The culture medium must be selective.
E)The culture medium must be differential

Question 13

The Six "I's" of studying microorganisms include all of the following except

A)inoculation.
B)incubation.
C)infection.
D)isolation.
E)identification.

Question 14

Mannitol salt agar is selective for which bacterial genus?

A)Salmonella
B)Streptococcus
C)Neisseria
D)Staphylococcus
E)Escherichia

Question 15

If a microbiologist is studying a specimen at a total magnification of 950X, what is the magnifying power of the objective lens if the ocular lens is 10X?

A)100X
B)950X
C)85X
D)850X
E)95X

Question 16

A microbiologist decides to use a nutrient medium that contains thioglycolic acid.What type of microbe is she attempting to culture?

A)fastidious
B)gram positive
C)anaerobe
D)gram negative
E)virus

Question 17

Which of the following characteristics refers to the microscope's ability to show two separate entities as separate and distinct?

A)resolving power
B)magnification
C)refraction
D)All of these choices are correct.

Question 18

Which of the following will result when 1% to 5% agar is added to nutrient broth, boiled and cooled?

A)a pure culture
B)a mixed culture
C)a solid medium
D)a liquid medium
E)a contaminated medium

Question 19

Syphilis is diagnosed either with microscopy or serology because the causative agent (Treponema pallidum) does not grow on any microbiological media.Which term best describes this aspect of the T.pallidum?

A)Fastidious
B)Nonculturable
C)Commensalistic
D)Symbiotic

Question 20

Which type of medium is able to distinguish different species or types of microorganisms based on an observable change in the colonies or in the medium?

A)differential
B)selective
C)enumeration
D)enriched
E)reducing

Question 21

The primary purpose of staining cells on a microscope slide is to

A)kill them.
B)secure them to the slide.
C)enlarge the cells.
D)add contrast in order to see them better.
E)see motility.

Question 22

A microbiologist makes a fixed smear of bacterial cells and stains them with Loeffler's methylene blue.All the cells appear blue under the oil lens.This is an example of

A)negative staining.
B)using an acidic dye.
C)simple staining.
D)using the acid-fast stain.
E)capsule staining.

Question 23

Media that contains extracts from plants, animals, or yeasts are

A)synthetic.
B)complex.
C)reducing.
D)enriched.
E)All of these choices are correct.

Question 24

Which is incorrect about chocolate agar?

A)It can be used to cultivate Neisseria.
B)It usually uses sheep blood that has been heated.
C)It has chocolate extract in it.
D)It is an enriched medium.
E)It is used to grow fastidious bacteria.

Question 25

Bacteria that require special growth factors and complex organic substances are called

A)fastidious.
B)pathogenic.
C)harmless.
D)anaerobic.
E)aerobic.

Question 26

Which microscope achieves the greatest resolution and highest magnification?

A)bright-field
B)dark-field
C)phase-contrast
D)fluorescence
E)electron

Question 27

Which microscope is the most widely used to show stained cells against a bright background?

A)bright-field
B)dark-field
C)phase-contrast
D)fluorescence
E)electron

Question 28

All of the following are diameters of cells that would be resolved in a microscope with a limit of resolution of 0.2 µm except

A)0.2 µm.
B)0.2 mm.
C)0.1 µm.
D)0.3 µm.
E)2.0 µm.

Question 29

Brain-heart infusion, trypticase soy agar (TSA), and nutrient agar are all examples of which type of media?

A)synthetic
B)reducing
C)enriched
D)complex
E)selective

Question 30

Basic dyes are

A)attracted to the acidic substances of bacterial cells.
B)anionic.
C)used in negative staining.
D)repelled by cells.
E)dyes such as India ink and nigrosin.

Question 31

A media is designed that allows only staphylococci to grow.In addition, S.aureus colonies have a yellow halo around them and other staphylococci appear white.This type of media is

A)selective only.
B)differential only.
C)both selective and differential.
D)a reducing media.
E)enriched.

Question 32

All of the following pertain to the fluorescence microscope except it

A)uses electrons to produce a specimen image.
B)is a type of compound microscope.
C)requires the use of dyes like acridine and fluorescein.
D)is commonly used to diagnose certain infections.
E)requires an ultraviolet radiation source.

Question 33

The wavelength of light used plus the numerical aperture governs

A)illumination.
B)resolution.
C)magnification.
D)size of the field.
E)All of these choices are correct.

Question 34

The type of microscope in which you would see brightly illuminated specimens against a black background is

A)bright-field.
B)dark-field.
C)phase-contrast.
D)fluorescence.
E)electron.

Question 35

The Gram stain, acid-fast stain, and endospore stain ____________.

A)are used on a wet mount of the specimen
B)use heat to force the dye into cell structures
C)have outcomes based on cell wall differences
D)use a negative stain technique
E)are differential stains

Question 36

Which microscope does not use light in forming the specimen image?

A)bright-field
B)dark-field
C)phase-contrast
D)fluorescence
E)electron

Question 37

All of the following are examples of basic dyes except

A)methylene blue.
B)nigrosin.
C)crystal violet.
D)safranin.
E)carbol fuchsin.

Question 38

Which microscope shows cells against a bright background and the intracellular structures of unstained cells based on their varying densities?

A)bright-field
B)dark-field
C)phase-contrast
D)fluorescence
E)electron

Question 39

Which microscope bombards a whole, metal-coated specimen with electrons moving back and forth over it?

A)fluorescence
B)differential interference contrast
C)scanning electron
D)transmission electron
E)phase-contrast

Question 40

The specimen preparation that is best for viewing cell motility is

A)hanging drop.
B)fixed-stained smear.
C)Gram stain.
D)negative stain.
E)flagellar stain.

Question 41

Which of the following places the steps for microbial culture and identification in the correct order?

A)inoculation, incubation, isolation, inspection, identification
B)isolation, inspection, inoculation, incubation, identification
C)incubation, inspection, isolation, identification, inoculation
D)inspection, identification, isolation, incubation, inoculation
E)inspection, isolation, incubation, inoculation, identification

Question 42

Scanning tunneling and atomic force microscopes are used to image the detailed structure of biological molecules.

Question 43

Which type of media can be used to determine if a bacteria is motile?

A)SIM
B)MacConkey
C)enriched media
D)Thayer-Martin media
E)chocolate agar

Question 44

A selective medium contains one or more substances that inhibit growth of certain microbes in order to facilitate the growth of other microbes.

Question 45

The procedure for culturing a microorganism requires the use of a microscope.

Question 46

A bacterial species that grows on blood agar but will not grow on trypticase soy agar is termed an anaerobe.

Question 47

One colony typically develops from the growth of several parent bacterial cells.

Question 48

Which of the following media is useful for cultivating fungi?

A)Sabouraud's agar
B)MacConkey agar
C)tomato juice agar
D)phenylethanol agar
E)Mueller tellurite

Question 49

_____ is the term for a starting a new culture from an existing one.

Question 50

The bending of light rays as they pass from one medium to another is called refraction.

Question 51

Some microbes are not capable of growing on artificial media.

Question 52

Bacteria that require special growth factors and complex nutrients are termed _____.

Question 53

Mixed cultures are also referred to as contaminated cultures.

Question 54

A medium that is gel-like has less agar in it compared to a solid medium.

Question 55

Fixed smears of specimens are required in order to perform the Gram stain and endospore stain on the specimens.

Question 56

Why is immersion oil often used when viewing specimens under the microscope?

A)to stain the cells blue
B)to prevent the smear from drying out
C)to slow bacterial movement so you can see cells better
D)to increase the resolution
E)to reduce the amount of heat reaching the slide from the light source

Question 57

The three physical forms of laboratory media are: solid, semisolid, and _____.

Question 58

The correct microbiological term for the tiny sample of specimen that is put into a nutrient medium in order to produce a culture is the _____.

Question 59

At the end of the Gram stain, gram-positive bacteria will be seen as purple cells.

Question 60

All of the following are correct about agar except

A)it is flexible.
B)it melts at the boiling point of water (100^°C).
C)it is a source of nutrition for bacteria.
D)it solidifies below 42^°C.
E)it is solid at room temperature.

Question 61

Microbes can be challenging to study because they often grow in complex communities and it may be difficult to separate the various species from one another to study individually.Which of the following laboratory "tools" or techniques may be of the the most help with separating out different species from complex mixtures?

A)use of transmission electron microscopy
B)use of enriched agar for culture
C)use of selective agars for culture
D)use of light microscopy

Question 62

The _____ of the microscope holds and allows selection of the objective lenses.

Question 63

How will

A)gram-positive
B)gram-negative
C)gram-variable
D)colorless
E)coli appear if the mordant is not applied?

Question 64

Each of the following are characteristics of microorganisms that pose unique challenges to their study EXCEPT

A)the fact that they must be viewed through a microscope rather than the unaided eye.
B)the fact that many do not have membrane-enclosed nucleus or other organelles.
C)the fact that they often exist in complex communities and individual species may be difficult to isolate from others.
D)the fact that they usually must be grown and studied under somewhat artificial conditions in vitro rather than in their natural habit.

Question 65

_____ has the same optical qualities as glass and thus prevents refractive loss of light as it passes from the slide to the objective lens.

Question 66

You are doing research on a bacterial species, trying to determine the shape, distribution, and arrangement of a number of filamentous structures that protrude from the cell surface.Which type of microscopy would best enable you to do this?

A)scanning electron microscopy
B)transmission electron microscopy
C)bright-field microscopy
D)dark-field microscopy

Question 67

Explain how and why immersion oil increases resolution but not magnification when using the 100X objective.

Question 68

A contaminated food sample contains several different species of bacteria.A food microbiologist is interested in studying just one of these species.Describe the sequence of procedures that the microbiologist must perform in order to obtain a pure culture of the bacterial species of interest from this food sample.Detail all the necessary media and equipment.

Question 69

_____ dyes have a negative charge on the chromophore and are repelled by bacterial cells.

Question 70

A student was given a stained smear to observe.Upon observation, the student noted rod-shaped bacteria that were clear and unstained against a darker background.What sort of stain was performed on this slide?

A)Gram stain
B)acid-fast stain
C)simple stain
D)negative stain

Question 71

You are doing research on a bacterial species, trying to determine the nature and structure of a number of intracellular inclusions.Which type of microscopy would provide the best view of these intracellular structures?

A)scanning electron microscopy
B)transmission electron microscopy
C)bright-field microscopy
D)dark-Field microscopy

Question 72

Compare and contrast the reagents and functions of negative staining versus positive staining.

Question 73

Sally had a throat sample taken at a satellite lab within her health care provider's office.What kind of media would be best suited for maintaining the quality of this specimen prior to its arrival in the clinical laboratory?

A)TSA plate
B)TSB tube
C)transport media
D)selective agar
E)differential agar

Question 74

Explain the difference and significance between a contaminated culture and a mixed culture.

Question 75

Identification relies entirely on biochemical test results.

Question 76

Which of the following reagents reacts with crystal violet as the mordant?

A)crystal violet
B)Gram's iodine
C)95% ethyl alcohol
D)safranin

Question 77

Magnification is achieved in a compound microscope through the initial magnification of the specimen by the
_____ lens.This image is then projected to the _____ lens that will further magnify the specimen to form a virtual image received by the eye.

Question 78

In lab, Tom was given a mixed culture.His objective is to isolate single colonies.What should be used to accomplish this goal?

A)sterile swab, loop dilution, TSB
B)hockey stick, spread plate technique, and 4 degree Celsius incubation temperature
C)loop dilution, TSA, hockey stick, 37 degree Celsius incubator
D)inoculating loop, incinerator, streak plate method, 37 degree Celsius incubator
E)sterile swab, streak plate method, 37 degree Celsius incubator

Question 79

Observing and characterizing colonial growth for size, shape, edge, elevation, color, odor, and texture is part of ___.

A)specimen collection
B)inoculation
C)incubation
D)isolation
E)inspection

Question 80

Newly inoculated cultures must be _____ at a specific temperature and time to encourage growth.