Lab Final

Question 1

Objects appear upside down and backwards through a microscope .

Answer 1

true

Question 2

Use both hands to carry the microscope; keep the instrument upright.

Answer 2

true

Question 3

The ___________ is a device invented in the seventeenth century for magnifying objects that are too small to be seen with the naked eye.

Answer 3

microscope

Question 4

To save time, look through the microscope and rapidly bring the objective lens and the specimen together by rotating the coarse-adjustment knob.

Answer 4

false

Question 5

The microscopists measures ocular micrometer disk divisions with the stage micrometer.

Answer 5

true

Question 6

When utilizing a stage micrometer scale marked in 0.01 mm, the following formula holds true: (stage divisions/ocular divisions) x (0.01 mm/stage division) = millimeters per ocular division.

Answer 6

true

Question 7

The ______ _______ gives microscopists a mathematical way of describing the light-gathering ability of a lens system.

Answer 7

numerical apenture

Question 8

Most modem microscopes are parfocal. This means the microscopist can add infinitely more lens systems for greater magnification and resolution.

Answer 8

false

Question 9

A compound microscope contains two or more sets of lenses.

Answer 9

true

Question 10

Always be sure to oil your microscope lenses before returning the instrument to its designated space.

Answer 10

false

Question 11

The space separating a specimen and the objective lens is called ________ distance

Answer 11

working

Question 12

The stage micrometer scale is generally ruled to 0.0001 mm.

Answer 12

false

Question 13

The objective lens is the one nearest the observer’s eye.

Answer 13

false

Question 14

Immersion oil has nearly the same refractive index as glass.

Answer 14

true

Question 15

The numerical aperture of an objective lens depends on the size of the cone of light it can receive and also upon the medium in which the lens is suspended.

Answer 15

true

Question 16

A specimen is normally placed on top of the stage micrometer and measured with the tiny ruler that is etched onto the stage micrometer.

Answer 16

false

Question 17

Which microscopist showed the mathematical relationship between resolution and the ability of a lens to gather light?

Answer 17

Ernst Abbe

Question 18

Which microscopist published the first drawings of bacteria in 1676?

Answer 18

Anton van Leeuwenkoek

Question 19

Lens paper can be used to remove oil from the glass components of the microscope.

Answer 19

true

Question 20

To calculate the total magnification of your microscope, add the magnifications of the objective and ocular lenses.

Answer 20

false

Question 21

The area that you see through a lens is the microscopic ________

Answer 21

field

Question 22

Increasing the size of a blurred image generally reveals further details.

Answer 22

false

Question 23

If a lens is designed to be used with immersion oil, it is able to gather more light when the oil is utilized than when air separates the lens from the specimen.

Answer 23

true

Question 24

Resolving power is the ability to rotate a new objective Jens into the observation position and have the field remain in focus.

Answer 24

false

Question 25

When utilizing a stage micrometer scale marked in 0.01 mm, the following formula holds true: (stage divisions/ocular divisions) x (10 um/stage division) = micrometers per ocular division.

Answer 25

true

Question 26

Before vortexing bacterial cells in a broth culture, always remove the test tube closure.

Answer 26

false

Question 27

Coccobacilli are cocci; palisades are groups of four cocci.

Answer 27

false

Question 28

Smears should be air dried before they are heat fixed.

Answer 28

true

Question 29

Heat fix bacterial smears by holding the slide in the hottest part of the flame for 2 minutes.

Answer 29

false

Question 30

The decolorization in the Gram stain is Gram’s iodine.

Answer 30

false

Question 31

In the Gram stain procedure, what is the color of gram-negative bacteria after the primary stain?

Answer 31

purple

Question 32

Water rinses should not be left on the smear too long during the gram stain procedure because water slowly decolorizes stained cells.

Answer 32

true

Question 33

A cation has a positive charge; chromophores are always anions.

Answer 33

false

Question 34

An aqueous solution is made with water.

Answer 34

true

Question 35

The primary stain in the Gram stain is crystal violet.

Answer 35

true

Question 36

The cell wall of a gram-negative bacterium contains lipoprotein and lipopolysaccharide.

Answer 36

true

Question 37

The peptidoglycan layer of a gram-negative cell wall is thicker than the corresponding layer of a gram-positive cell wall.

Answer 37

false

Question 38

In the Gram stain procedure, what is the color of gram-positive bacteria after decolorization?

Answer 38

purple

Question 39

In the neutral environment of most microbiological dyes, bacteria generally carry a net negative charge.

Answer 39

true

Question 40

Gram-positivity is a characteristic that is easily lost.

Answer 40

true

Question 41

In the Gram stain procedure, what is the color of gram-negative bacteria after the mordant (iodine)?

Answer 41

purple

Question 42

Aniline dyes are derived from benzene, a coal tar derivative.

Answer 42

true

Question 43

The chromophore of a basic dye carries a negative charge.

Answer 43

false

Question 44

In the Gram stain procedure, what is the color of gram-negative bacteria after the counterstain stain?

Answer 44

pink

Question 45

The decolorization is applied before the mordant in the Gram stain procedure.

Answer 45

false

Question 46

The cell wall of gram-positive have a thick layer of peptidoglycan associated with teichoic acids.

Answer 46

true

Question 47

In the Gram stain procedure, what is the color of gram-positive bacteria after the primary stain?

Answer 47

purple

Question 48

A slide is clean enough for bacteriological smears if water coalesces on it.

Answer 48

false

Question 49

A chemosynthetic organism is able to construct cellular molecules out of carbon dioxide and oxygen.

Answer 49

false

Question 50

Antibiotic sensitivity testing is performed with pure cultures.

Answer 50

true

Question 51

what is the term for devoid of life

Answer 51

aseptic

Question 52

what is the term for A combination of various microbial species living together

Answer 52

mixed culture

Question 53

what is the term for One kind of bacteria, ideally the descendants of one cell, living together

Answer 53

pure culture

Question 53

what is the term for the introduction of unwanted organisms

Answer 53

contamination

Question 53

what is the term for free from disease-producing microorganisms

Answer 53

sterile

Question 53

Many cyanobacteria fix gaseous nitrogen.

Answer 53

true

Question 54

Sterile techniques are generally utilized with broth cultures; aseptic techniques are reserved for solid media work.

Answer 54

false

Question 55

Flaming sterilizes by incinerating organisms.

Answer 55

true

Question 56

Rotifers are protozoa.

Answer 56

false

Question 57

Endospores are resting or survival structures.

Answer 57

true

Question 58

Heterotrophic organisms require organic molecules for a carbon source.

Answer 58

true

Question 59

Aseptic techniques are performed only for their traditional value. In a modem microbiology laboratory, microbes are electronically removed from the air, workbench, inoculation instruments, and hands.

Answer 59

false

Question 60

Microbiology laboratories often maintain stock cultures. These stocks are pure cultures.

Answer 60

true

Question 61

Unstained Treponema pallidum is too thin to be observed with a compound, light, bright-field microscope.

Answer 61

true

Question 62

In a microbiology laboratory, it is generally safe to mouth pipet since most microorganisms are not killed by exposure to exhaled air.

Answer 62

false

Question 63

A photosynthetic organism is able to make cellular energy out of light energy.

Answer 63

true

Question 64

Alcohol-flaming can be employed to sterilize the tips of forceps.

Answer 64

true

Question 65

An aerosol is a visible clump of bacteria suspended in proteinaceous matter such as sputum.

Answer 65

false

Question 66

When transferring bacteria from a solid surface, be sure to gouge the agar, digging out the entire colony where it has burrowed into the medium.

Answer 66

false

Question 67

To help identify a bacterial species, a microbiologist usually performs biochemical tests on the mixed culture.

Answer 67

false

Question 68

Factors that limit the amount of growth in a broth culture include size of inoculum, availability of nutrients, temperature and duration of incubation, presence of oxygen, concentration of toxins, and so on.

Answer 68

true

Question 69

Some rods are called diphtheroids because they resemble Corynebacterium diphtheriae.

Answer 69

true

Question 70

Select organisms with a eukaryotic cell or cells. (3)

Bacteria (including cyanobacteria)
protozoa
multicellular invertebrates
algae

Answer 70

algae
protozoa
multicellular invertebrates

Question 71

which group contains endospores

Answer 71

bacteria (including cyanobacteria)

Question 72

Bacteria moving toward oxygen are displaying negative phototaxis.

Answer 72

false

Question 73

To focus on unstained, transparent cells, reduce illumination of the field far below the levels used with stained cells.

Answer 73

true

Question 74

A saprophytic organism usually parasitizes living tissue, causing disease and death.

Answer 74

false

Question 75

what has a prokaryotic cell

Answer 75

bacteria

Question 76

Alcohol-flaming should always be performed over a stack of papers so that the dripping alcohol does not burn the workbench.

Answer 76

false

Question 77

Daphnia is an alga.

Answer 77

false

Question 78

During alcohol-flaming, the tips of the forceps are not held in the burner flame until they are red-hot.

Answer 78

true

Question 79

In nature most microorganisms are found in mixed cultures.

Answer 79

true

Question 80

Spirochetes are rigid, inflexible, spiral-shaped bacteria; spirilla are flexible, spiral-shaped bacteria.

Answer 80

false

Question 81

If an organism lacks a nuclear membrane but is green and produces oxygen, it is probably a member of which group?

Answer 81

bacteria

Question 82

To preserve purity, handle cultures as little as possible. Open them all at the beginning of the laboratory period; close them once, before leaving the area.

Answer 82

false

Question 83

Inoculating needles and loops are generally constructed of Nichrome or platinum wire.

Answer 83

true

Question 84

Worms are multicellular invertebrates.

Answer 84

true

Question 85

Pairs of cocci are called packets.

Answer 85

false

Question 86

The energy of life produces order and dispels entropy.

Answer 86

true

Question 87

In a pour plate, colonies develop throughout the medium.

Answer 87

true

Question 88

Colonies are smaller in crowded areas of a pour plate than in areas where they are well separated.

Answer 88

true

Question 89

Lenticulate colonies are usually found on the surface of a pour plate.

Answer 89

false

Question 90

In microbiology laboratories, colonies are usually counted to determine the number of bacteria per milliliter of the original sample.

Answer 90

true

Question 91

A countable plate has between 1 and 300 colonies.

Answer 91

false

Question 92

The physiological characteristics of an organism are its Gram stain reaction.

Answer 92

false

Question 93

In a serial dilution, each tube contains the same dilution as the previous one.

Answer 93

false

Question 94

To fulfill Koch’s postulates, a researcher must cultivate a mixed culture of organisms from the blood of a diseased experimental animal.

Answer 94

false

Question 95

Koch’s postulates are used to prove that a specific microorganism causes a specific disease.

Answer 95

true

Question 96

Robert Koch was a pioneer of medical microbiology.

Answer 96

true

Question 97

In a sample of human sputum or feces, you usually find a mixture of many different kinds of organisms.

Answer 97

true

Question 98

In samples from nature, bacteria are usually found in mixed culture.

Answer 98

true

Question 99

The two most common methods that separate individual bacteria from each other are the pour plates and lawns.

Answer 99

false

Question 100

Be sure to flame your swab after preparing a spread plate.

Answer 100

false

Question 101

Bacterial sensitivity to antibiotics is often tested on a spread plate.

Answer 101

true

Question 102

Bacteriophage are special bacteria that are grown in spread plates.

Answer 102

false

Question 103

All bacterial colonies look alike. Only staining reveals differences between genera.

Answer 103

false

Question 104

The area of confluent growth is where colonies overlap and grow together.

Answer 104

true

Question 105

The progeny of a single cell may form a colony, a visible clump of growth, on the surface of an agar medium.

Answer 105

true

Question 106

Streaking a plate involves drawing a loopful of organisms back and forth across a solid medium in a Petri dish until the microbes fall off the loop one at a time.

Answer 106

true

Question 107

A bacterial concentration gradient is a well-dispersed mixture of bacteria, thoroughly suspended in a broth culture.

Answer 107

false

Question 108

When preparing a bacterial spread plate, swab a pure culture of bacteria evenly over the entire surface of an agar medium in a Petri dish.

Answer 108

true

Question 109

To prepare a streak plate, spread bacteria evenly over the entire surface of a plate of medium.

Answer 109

false

Question 110

Neisseria gonorrhoeae and Haemophilus influenzae are generally incubated in a candle jar.

Answer 110

true

Question 111

Host-specific phages can distinguish one strain of a single bacterial species from another strain of the same species.

Answer 111

true

Question 112

Bacteria are used to treat virus strains (with ice packs and tiny Ace bandages) in bacteriophage typing.

Answer 112

false

Question 113

Since there is oxygen in the air that surrounds earth, being an aerobe is a great advantage for microorganisms in nature.

Answer 113

false

Question 114

In a broth-clearing assay, the titer of phage in the original coliphage sample equals the end-point tube’s dilution.

Answer 114

false

Question 115

A plaque assay is designed to discover the number of bacteria in a viral solution.

Answer 115

false

Question 116

Loosen the caps of screw cap tubes before incubating oxygen-utilizing bacteria in them.

Answer 116

true

Question 117

After inoculating a tube of Fluid Thioglycollate Medium, shake the tube thoroughly to aerate and separate the bacteria.

Answer 117

false

Question 118

Fermentation does not require oxygen.

Answer 118

true

Question 119

Cultivation of viruses in tissue culture is generally as quick, inexpensive, and convenient as growing bacteria in nutrient media.

Answer 119

false

Question 120

Viruses are classified by host, nucleic acid, size, shape, and presence or absence of an envelope.

Answer 120

true

Question 121

The enzyme that catalyzes the reaction 2H2O2 -> 2H2 + O2 is superoxide dismutase.

Answer 121

false

Question 122

Fermentation releases some but not all of the energy in organic compounds.

Answer 122

true

Question 123

Coliphage are common microbiological laboratory “weeds” that infect all human pathogens.

Answer 123

false

Question 124

The titer (concentration) of virions in your original coliphage sample equals the number of plaques on a countable plate times the inverse of that plate’s dilution.

Answer 124

true

Question 125

To prepare an agar shake culture, boil the medium, solidify it, and then inoculate it with a clean stab to the bottom of the tube.

Answer 125

false

Question 126

After incubation, the sealed redox potential indicator envelope is removed from a GasPak jar and opened.

Answer 126

false

Question 127

A redox potential is the opposite of an oxidation reduction potential; when one is high the other is low.

Answer 127

false

Question 128

To prepare a coliphage plaque assay, add Escherichia coli strain B to Soft Agar overlays, add dilutions of a virulent coliphage, pour the overlays into Tryptic Soy Agar in Petri dishes, incubate appropriately, then examine for liquefaction of the Soft Agar.

Answer 128

false

Question 129

A candle jar contains the best mix of gases available for culturing anaerobes.

Answer 129

false

Question 130

Pasteur discovered anaerobes, microorganisms that are poisoned by oxygen.

Answer 130

true

Question 131

A plaque-forming unit represents one bacterial cell.

Answer 131

false

Question 132

Fluid Thioglycollate Medium is pink in the bottom of the tube where the resazurin is highly reduced.

Answer 132

false

Question 133

Viruses are defined as “cellular” because they replicate inside of living host cells.

Answer 133

false

Question 134

Bacteria that are exposed to air as they grow are generally in a highly reduced envrionment.

Answer 134

false

Question 135

Spread a thick layer of petroleum jelly around the O-ring of a GasPak jar before sealing the lid.

Answer 135

false

Question 136

A viral plaque is a hole in a confluent layer of permissive host cells.

Answer 136

true

Question 137

Anaerobes grow in reduced environments.

Answer 137

true

Question 138

If nitrite is missing from an incubated culture tube of Nitrate Broth, it may indicate that the bacteria did not produce nitrate reductase.

Answer 138

true

Question 139

Proteus is urease-positive; Salmonella and Shigella are urease-negative.

Answer 139

true

Question 140

Denitrification is the complete oxidation of NO-3 to form nitrogen gas.

Answer 140

false

Question 141

Facultatively anaerobic bacteria generally do not produce nitrate reductase.

Answer 141

false

Question 142

Endoenzumes speed reactions outside of cells.

Answer 142

false

Question 143

Urease catalyzes the reduction of NO-3; nitrate reductase catalyzes the hydrolysis of NO-2.

Answer 143

false

Question 144

Probes are pieces of nucleic acid that scientists sometimes use to identify microbes.

Answer 144

true

Question 145

Proteus is generally nonpathogenic in the human intestine, but it is a common cause of urinary tract infections.

Answer 145

true

Question 146

On Starch Agar a darkened area indicates starch hydrolysis.

Answer 146

false

Question 147

Cytochrome oxidase is produced by Pseudomonas but not by members of the Enterobacteriaceae.

Answer 147

true

Question 148

Egg yolk contains the phospholipid lecithin (choline phosphoglyceride), an emulsifying agent. About two-thirds of the dry weight of egg yolks is lipid.

Answer 148

true

Question 149

To analyze the reactions of bacteria growing on Starch Agar, flood the plate with 3% hydrogen peroxide.

Answer 149

false

Question 150

Any bacteria that grow on a plate of Starch Agar are amylase producers.

Answer 150

false

Question 151

An oxidase is an enzyme that oxidizes compounds.

Answer 151

false

Question 152

Enterococcus, Streptococcus, and Lactobacillus tolerate oxygen and produce catalase.

Answer 152

false

Question 153

Gelatin suspensions are in the gel state below 25 degrees C.

Answer 153

true

Question 154

In a Nitrate Broth culture, if zinc reduces nitrate to nitrite, then the bacteria in the tube did not.

Answer 154

true

Question 155

All bacteria that utilize desulfhydrases produce hydrogen sulfide, rotten egg gas.

Answer 155

true

Question 156

Catalase helps Staphylococcus aureus poison mayonnaise by attacking fat molecules.

Answer 156

false

Question 157

Cysteine desulfhydrase yields hydrogen sulfide, hydrochloric acid, and pyruvic acid.

Answer 157

false

Question 158

Hydrogen peroxide is toxic to cells, but it is also a common by-product of reactions that accompany aerobic respiration.

Answer 158

true

Question 159

Some exoenzymes break down molecules that are too large to cross a cell membrane.

Answer 159

true

Question 160

Urea is a protein.

Answer 160

false

Question 161

Amylases hydrolyze starch by adding the Na+ and CI- ions of H2O.

Answer 161

false

Question 162

Lipids are found in all cell membranes.

Answer 162

true

Question 163

Along with other information, DNA carries the genetic code for all the enzymes that a microorganism produces.

Answer 163

true

Question 164

Starch is a large, many-branched polymer of the monosaccharide glucose.

Answer 164

true

Question 165

Urea is toxic to most cells, but urease producers can degrade this nitrogen-containing compound.

Answer 165

true

Question 166

Microbial physiology is the study of the size, shape, arrangement, and staining reactions of bacteria.

Answer 166

false

Question 167

The black precipitate that may form in a test tube containing Triple Sugar Iron Agar consists of H2S.

Answer 167

false

Question 168

Clostridium tetani toxin kills with the rigid paralysis of tetanus.

Answer 168

true

Question 169

Since agar media are largely water, a water-soluble microbial pigment tints the agar as well as the colony.

Answer 169

true

Question 170

The most deadly biological nerve toxin known is botulism toxin.

Answer 170

true

Question 171

A colony is an individual bacterial cell.

Answer 171

false

Question 172

All endospores are terminally located in swollen sporangia.

Answer 172

false

Question 173

Endospore-forming bacteria produce the ____________________ antibiotics that inhibit cell wall synthesis.

Answer 173

bacitracin

Question 174

Conditions of incubation include temperature, pH, and salinity, but not the medium and its nutrients.

Answer 174

false

Question 175

The Schaeffer-Fulton endospore-staining procedure employs ethyl alcohol and phenol to drive malachite green into endospores.

Answer 175

false

Question 176

After staining with the Schaeffer-Fulton endospore procedure, endospores appear pickle green while vegetative cells are periwinkle blue.

Answer 176

false

Question 177

Endospores preserve life in a/an __________
state with no measurable metabolic activity.

Answer 177

cryptobiotic

Question 178

Bacillus anthracis is the etiologic agent of anthrax.

Answer 178

true

Question 179

When the scientific method of investigation is employed, only experiments that prove the accuracy of the original hypothesis are useful.

Answer 179

false

Question 180

Opaque means translucent.

Answer 180

false

Question 181

A control is a test in which only one factor is different than in the experiment.

Answer 181

true

Question 182

Endospores in cooked food may germinate at room temperatures and lead to food poisoning.

Answer 182

true

Question 183

Bacterial endospores are hard, dry structures that burst forth as external buds on certain genera of flowering rods.

Answer 183

false

Question 184

The appearance of a colony reflects the biochemistry of the species that formed it, so all bacterial colonies look alike.

Answer 184

false

Question 185

Which is the decolorizer in the Schaeffer-Fulton endospore-staining procedure?

Answer 185

water

Question 186

Which is the primary dye used in the Schaeffer-Fulton endospore-staining procedure?

Answer 186

malachite green

Question 187

In the Schaeffer-Fulton endospore stain, which of these is the counterstain?

Answer 187

safranin

Question 188

Which of these is a common aniline dye used by microbiologists but not employed in the Schaeffer-Fulton endospore-staining procedure?

Answer 188

methylene blue

Question 189

When utilizing the scientific method of investigation, you must first recognize a problem or situation and then gather information concerning it.

Answer 189

true

Question 190

Scrubbing the hands with antiseptic solution and a brush for 40 seconds always kills all bacteria on the cleansed area.

Answer 190

false

Question 191

Soap cleans by chemically linking oil to grease.

Answer 191

false

Question 192

Soaps are formed when fats are heated in the presence of an acid such as hydrochloric acid.

Answer 192

false

Question 193

The carboxylate end of a soap molecule is soluble in the hydrocarbons, the oily end in water.

Answer 193

false

Question 194

Washing hands usually reduces their microbial load of transient flora.

Answer 194

true

Question 195

Any cleansing solution, including soap, is a detergent.

Answer 195

true

Question 196

If 38 colonies develop on a 10-6 dilution plate, it seems likely that between 0 and 5 colonies might grow on a 10-5 plate prepared from the same original suspension of bacteria.

Answer 196

false

Question 197

Thoroughly scrubbing the hands and fingernails with hot soapy water for 1 minute removes all bacteria from the area cleansed.

Answer 197

false

Question 198

Filtration and cultivation of colonies on a filter will determine __________________________The measurement of optical density will measure ___________________ Spread plate colony count is used for ____________________
Fit 1 from either: quantification of viable microorganisms only. Quantification of both viable and nonliving microorganisms.

Answer 198

Filtration and cultivation of colonies on a filter will determine quantification of viable microorganisms only.
. The measurement of optical density will measure
quantification of both viable and nonliving microorganisms.
. Spread plate colony count is used for
quantification of viable microorganisms only.

Question 199

Soap forms a chemical link between oil and water.

Answer 199

true

Question 200

Only a living colony-forming unit forms a colony.

Answer 200

true

Question 201

Hand washing by medical personnel helps reduce the patient’s risk of nosocomial (hospital-acquired) infections.

Answer 201

true

Question 202

A colony-forming unit may be a single cell or a clumps of bacteria.

Answer 202

true

Question 203

During saponification a sodium salt of an acid is produced

Answer 203

true

Question 204

The soapy scum that forms in oily, hard water removes bacteria when it sinks to the bottom of the liquid, weighted down by its load of heavy mineral salts.

Answer 204

false

Question 205

If you pour 15 ml of agar medium into a Petri dish that contains 1 ml of a 10-6 bacterial dilution, the dilution of the plate is still recorded as 10-6.

Answer 205

true

Question 206

Saponification is a highly complex chemical process, but soap making is fairly straightforward.

Answer 206

false

Question 207

Estimation of microbial population size are useful for industrial microbiologist but are of little value to the medical or public health microbiologist.

Answer 207

false