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

Question 1

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.

Answer 1

C

Question 2

A common medium used for growing fastidious bacteria is

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

Answer 2

A

Question 3

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.

Answer 3

D

Question 4

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

Question 5

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 the choices are correct
E)None of the choices are correct

Question 6

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 7

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 8

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 9

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 10

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.

Question 11

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 12

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

Question 13

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 14

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 15

A pure culture contains only

A)one species of microorganism.
B)bacteria.
C)a variety of microbes from one source.
D)All of the choices are correct.
E)None of the choices are correct.

Question 16

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

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

Question 17

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 18

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 19

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 the choices are correct
E)None of the choices are correct

Question 20

Mannitol salt agar is selective for which bacterial genus?

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

Question 21

All of the following pertain to the fluorescence microscope except it

A)uses electron's 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 22

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 23

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)nonsynthetic
E)selective

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 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 27

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 28

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

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

Question 29

Which microscope achieves the greatest resolution and highest magnification?

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

Question 30

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 31

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 32

The wavelength of light used plus the numerical aperture governs

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

Question 33

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 34

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 35

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 36

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 37

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 38

All of the following are examples of basic dyes except

A)Methylene Blue.
B)Nigrosin.
C)Crystal Violet.
D)Safranin.
E)Carbol Fuchsin.

Question 39

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 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 puts the Six "I"s in their 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

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

Question 43

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

Question 44

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

Question 45

Mixed cultures are also referred to as contaminated cultures.

Question 46

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

Question 47

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

Question 48

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

Question 49

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

Question 50

All of the following are correct about agar except

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

Question 51

Some microbes are not capable of growing on artificial media.

Question 52

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

Question 53

_____ is the term for a culture made from one isolated colony.

Question 54

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

Question 55

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

Question 56

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

Question 57

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 58

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

Question 59

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 60

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 61

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

Question 62

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 63

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

Question 64

How will E. coli appear if the mordant is not applied?

A) Gram-positive
B) Gram-negative
C) Gram-variable
D) Colorless
E) None of these

Question 65

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 66

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

Question 67

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 68

Identification relies entirely on biochemical test results.

Question 69

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 this specimen?

A)TSA plate
B)TSB tube
C)Transport media
D)Pour plate
E)Quadrant streak plate

Question 70

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 71

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

Question 72

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 73

_____ 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 74

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