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1

What three conditions can affect microbial growth?

Different temperatures
different pH levels
different osmotic pressures

2

What are the cardinal temperatures?

minimal
optimal
maximal

3

What are the classification of organisms based on their cardinal temperatures?

Hyperthermophiles
Thermophiles
Mesophiles
Psychrotrophs
psychrophiles

4

Psychrophiles can only grow at temperatures less than _______.

20 C (-5 to 20)

5

Psychrotrophs typically have a growth range of ____ to ______

0 to 30 C

6

What percentage of bacteria can grow <= 10 C

80%

7

Psychrophiles can be found in ____ ____, _______, and ________.

alpine soils, icefields, oceans

8

Psychrophiles are not human __________

pathogens

9

Psychrotrophs can be found in ___, _____ ____, and in ______

soils, surface water, foods

10

Psychrotrophs can be human ______

pathogens

11

Mesophiles have a typical range for growth of ___ to ____

15 to 40 C

12

Mesophiles have an optimal temperature that is approximately normal _____ _____ temperature.

human body

13

Mesophilic bacteria can be human _______

pathogens

14

Thermophiles have a typical range of growth of ____ to _____

40 to 75 C

15

Hyperthermophiles have a typical range for growth of ____ to _____

65 to 110 C

16

Thermophiles can be found growing in ____ ____

hot springs

17

_______ can be isolated from ocean floor thermal vents/ridges.

hyperthermophiles

18

pH is the concentration of _______ ions in a solution

hydrogen

19

pH is measured on a _______ scale from 0-14 based on the hydrogen concentration

logarithmic

20

pH =

-log[H+]

21

Pure water is considered ______ and was assigned a pH of _____. This means that water has 10^-7 moles of H+ ions per liter.

neutral; 7

22

As the concentration of H+ increases, the pH _____ and the solution becomes more _____

decreases; acidic

23

As the concentration of H+ decreases, the pH _____ and the solution becomes more ______

increases; basic

24

What are the three classifications of organisms based on the growth pH range?

Acidophile
Neutrophile
Alkaliphile

25

Acidphiles grow well in acidic environments with a pH of <=

4.5 to 5.5

26

Alkaliphiles grow well in basic enviroments at a pH of >=

8 to 8.5

27

Acidophiles can be found growing in such places as ____ ____ _____ and the _____

acid mine drainage; stomach

28

Alkaliphiles can be found in the soil of ____ ____ or in places like the shores of Mono Lake, California where the pH is 10

alkali flats

29

Neutrophiles grow well at a neutral pH between ___ and ___

5.5; 8

30

Most human ______ are neutraphiles since most bodily fluids are at neutral pH.

pathogens

31

_____ is required by all forms of life including bacteria?

Water

32

For bacteria ______ is necessary to maintian ____ pressure

water; turgor

33

______ pressure is the pressure inside a cell that is required for survival

turgor

34

If the correct turgor pressure is not maintained a bacterium could _____ (rupture) or ______ (shrink).

lysis; plasmolysis

35

To regulate turgor pressure, bacteria maintain high concentration of ____ and ______ ions in their cytoplasm

potassium; sodium

36

High concentrations of potassium and sodium ions within the cell and lower concentrations of these ions outside the cell creates a _______ ______.

concentration gradient

37

formation of a concentration gradient leads to ______

osmosis

38

what is the movement of water from an area of low solute concentration to an area of high solute concentration in order to achieve equilibrium?

Osmosis

39

What is the force with which water flows from an area of low solute concentration to an area of high solute concentration?

osmotic pressure

40

What are the three types of osmotic environments a bacteria could encounter

Hypotonic
Isotonic
Hypertonic

41

In hypotonic enviroments, there is a _____ solute concentration inside the cell than outside which creates a ____ osmotic pressure, and water moves _____ the cell which causes the cell to ____.

higher; low; into; lysis

42

In isotonic environments, there is ______ solute concentration inside and outside the cell and water moves in and out of the cell at an ______ rate.

equal; equal

43

In hypertonic environments, there is a ____ solute concentration inside the cell than outside which creates a ____ osmotic pressure, and water moves ____ of the cell which causes the cell to ______.

lower; high; out; plasmolysis

44

The concentration of _____ in a solution can affect osmotic pressure.

Salt

45

Most bacteria survive and grow in salt concentrations

3%

46

Bacteria that grow optimally at salt concentrations > 3% are called what?

Halophiles

47

Extreme halophiles can ONLY survive at salt concentrations between ____ and ____.

15%; 25%

48

What type of bacteria can survive and grow over a wide range of salt concentrations?

Osmotolerant

49

Halophiles are used in the fermentation of foods products such as _____ ____.

soy sauce

50

What is the ability or inability to live in the presence of O2?

aerotolerance

51

What must have O2 to survive and grow?

obligate aerobes

52

What can grow in the presence or absence of O2?

facultative anaerobes

53

What do not need O2 but can survive in the presence of O2?

Aerotolerant anaerobes

54

what survive only when O2 levels are low?

microaerophiles

55

what can only survive when CO2 levels are high?

capnophiles

56

What can O2 kill?

obligate anaerobes

57

What removes most free O2 from media; however; as the media cools oxygen starts to diffuse back into the media?

autoclaving

58

when media is in a tube the diffusion of O2 back into the broth or agar results in a ______ ______

concentration gradient

59

the surface of the media in a tube will have a high O2 concentration while the media at the bottom with have ____ O2.

no

60

Bacteria will grow where the O2 _______ in the tube is optimal for that organism

concentration

61

____ media is used in an agar deep stab to ensure that the bottom of the tube is anaerobic.

more

62

bacteria are stabbed once all the way to the ______ of the tube with an inoculating needle

bottom

63

What are the important ingredients in fluid thioglycollate medium?

sodium thioglycollate
L-cystine
resazurin

64

What is the purpose of sodium thioglycollate?

reducing agent (reduces O2 to water)

65

What is the purpose of L-cystine?

reducing agent (reduces O2 to water

66

What is the purpose of Resazurin

oxidation-reduction indicator
turns red/pink in the presence of O2
straw color in the absence of O2

67

Tubes of aerotolerant organisms will appear what?

cloudy all over

68

facultative anaerobes will be appear how in a tube?

concentrated at top but growth throughout

69

Obligate anaerobes will grow where in a tube?

only at bottom

70

Obligate aerobes will grow where in a tube?

only at top

71

what are used to produce anaerobic conditions required for aerotolerance examination of plates?

GasPack

72

The GasPak become activated by exposure to air and ______ is produced

CO2

73

How long does it take for anaerobic conditions to be reached with a GasPack?

around 2.5 hours

74

Methylene blue strip or tablet turns what color in the presence of O2?

blue

75

Wht is the most common reason anaerobic conditions were not achieved?

not proper sealing; hole in plastic bag

76

The majority of bacteria are what in terms of oxygen tolerance?

anaerobic

77

are most anaerobic bacteria pathogens?

No

78

Anaerobic chambers are often used to study _____

anarobes.

79

Bacteria replicate by what?

Binary fission

80

What is the time taken to get from 2^x to 2^(x+1)

doubling/generation time

81

Nf =

Ni*(2^n)

82

The average doubling time is generally between what?

20 to 60 minutes

83

environmental factors like temperature, pH, and nutrient availability can have a direct impact on the _____ ____ of an organism.

doubling time

84

in a laboratory setting the effects of various environmental factors on a bacterium's growth rate can be examined using a _____ _____ ______.

Closed Growth System

85

A closed-growth system is an environment in which ____ nutrients are added and ____ waste products are removed

no;no

86

How many distinct phases of growth can be observed in a closed growth system and what are they?

4, Lag, Logarithmic, Stationary, Death

87

Which phase is the initial phase of the growth curve where the organisms are acclimating to a new environment?

Lag Phase

88

During which phase is there no cell division but is a time of high metabolic activity in preparation for growth?

Lag

89

The more drastic the change in the environment, the longer the ____ phase is.

Lag

90

After a bacterium is acclimated to a new environment, it begins to divide during which stage?

Log

91

During what phase is the maximum growth rate exponential and at regular intervals of time?

Log

92

When the number of bacteria versus time is plotted on a ___ ____ the ascending straight line on the curve represents the exponential growth phase.

log scale

93

You can determine the generation time using which phase?

Log

94

Which stage do nutrients become limited and the waste products begin to accumulate leading to an unfavorable environment?

Stationary

95

Which phase does the growth rate equal the death rate?

Stationary

96

The length of the stationary phase can vary among _____ bacterial species

different

97

During which phase are all the nutrients depleted and the levels of waste products toxic?

Death

98

During which phase do bacteria begin to die faster than they grow?

Death

99

Depending on what will the death occur at rapid rate or be gradual?

the bacterial species

100

If bacteria die but do not _____ there may not be a loss of turbidity and a obvious death phase will not be observed unless viable plate counts are done

Lysis

101

A bacterial growth curve can provide the length of time the bacterium is in each ____ ____.

growth phase

102

A bacterial growth curve can provide the ______ growth conditions of a bacterium

optimal

103

A bacterial growth curve can provide the mean _____ ____ of the organism

generation time

104

Bacteria replicate using what?

Binary fission

105

Nf equals what?

Ni2^n

106

Environmental factors like what have a direct impact on the doubling time of an organism?

Temperature, pH, and nutrient availability

107

The average doubling time for bacteria is what?

20 to 60 min

108

What is used to observe the effects of various environmental factors on a bacterium’s growth rate?

Closed growth system

109

In a closed growth system, ______ nutrients are added and ______ waste products are removed.

No; no

110

What are the direct methods to measure the growth of bacteria

Plate counts
Filtration and plate counts
Most probably number (MPN)
Direct counting

111

What are the pros and cons of plate counts?

Pros - measures # of viable cells

Cons- time consuming and assumes that each bacterium grows and divides to produce a single colony

112

What are the pros and cons of filtration and plate counts?

Pros - measures # of viable cells in a small quantity

Cons - time consuming and assumes that each bacterium grows and divides to produce a single colony

113

What are the pros and cons of most probable numbers?

Pros - can be used for bacteria that cannot grow on solid media

Cons - only a statement that there is a 95% statistical chance that a bacterial population falls within a certain range

114

What are the pros and cons of direct counting using manual counting?

Pros - very accurate and relatively inexpensive
Cons - very tedious and time consuming

115

What are the pros and cons of direct counting using electronic cell counters?

Pros - very accurate and results obtained relatively quickly

Cons-expensive equipment that requires significant training in order to operate

116

What are some indirect ways to measure the growth of bacteria?

Metabolic activity
Dry weight
Turbidity

117

What indirect method assumes that the amount of the metabolic product is directly proportional to the # of bacteria present?

Metabolic activity

118

What is one of the quickest, easiest, and most common method for assessing bacterial growth?

Turbidity

119

What device is used to measure turbidity?

Spectrophotometer

120

What kind of beam of light is used to measure the percent transmittance or absorbance

Monochromatic

121

What is transmittance?

The fraction of incident light that passes through a sample
T= intensity of light out/intensity of light in

Produces an exponential curve

122

What is absorbance and what is it equal to?

The quantity of light that a sample neither transmits nor reflects; Optical density

123

What kind of relationship exists between absorbance and concentration?

Linear

124

Absorbance ranges from what to what?

0 to 1.99 A

125

If a sample is 1.99 A or above what should you do to it?

Dilute it

126

If a sample is diluted 1:5 and the absorbance of this diluted samples is 0.8 A. What was the absorbance of the original sample?

0.8 * 5 = 4

127

Each McFarland standard represents a specific what?

Bacterial cell concentration

128

How do you plot a standard curve using McFarland Standards?

Plot Absorbance vs Concentration

129

The Oxidation-Fermentation Test determines what?

What catabolic pathway a bacterium can use to break down a carbohydrate

130

What are examples of catabolic pathways?

Aerobic respiration
Fermentation

131

In Aerobic respiration what is the final electron acceptor and what is required in the environment.

O2; oxygen

132

In fermentation what is the final electron acceptor and what can it occur in the presence or absence of?

Organic molecule; O2

133

Aerobic respiration occurs only in the presence of what?

Oxygen

134

During aerobic respiration a small amount of what are produced?

Acidic intermediate compounds

135

In fermentation large amounts of what are produced?

Acidic compounds

136

What are the two important media components of oxidation fermentation medium?

A carbohydrate

PH indicator like Bromthymol blue

137

The initial pH of the OF medium is ______ and the color of the medium is _______.

7.1; green

138

If the pH drops to _______ the media turns what color?

6; yellow

139

In order to produce an anaerobic environment to promote fermentation, the top of the OF medium can be overlayed with what?

Sterile mineral oil

140

If an organism can only use the oxidation pathway then the color of the OF tube overlayed with sterile mineral oil will be what?

Green

141

If an organism can only use the oxidation pathway, then in the presence of oxygen the OF tube will show that a moderate amount of acidic compounds were produced so the media will be what color only at the top?

Yellow

142

If an organism is capable of fermentation or fermentation and oxidation then the OF tube either overlayed with mineral oil or exposed to oxygen will be what color?

Yellow

143

If an organism is a weak fermenter then the OF tube that is both covered with mineral oil or exposed to oxygen will be what color?

Yellow at the top of both

144

If the organism cannot metabolize the carbohydrate in the OF tube then both the mineral oil covered tube and the tube exposed to oxygen will be what color?

Green

145

What test is used to determine what carbohydrate a bacterium can ferment?

Phenol Red broth test

146

The end products generated by fermentation are what?

Alcohols, acids, and gas

147

What are the three important points to remember about the fermentation pathway?

1. Glucose is not the only carbohydrate that can be used in glycolysis

2. The end products of fermentation include acidic compounds

3. Gas can also be an end product of fermentation

148

Is phenol red broth considered a differential media?

Yes

149

What are the important media components of phenol red broth?

1. It is purchased as a base broth that allows one to add any single carbohydrate for testing

2. Peptone which serves as a source of amino acids

3. Durham tube which is placed upside down in the broth to determine if a gas is produced.

150

The pH of the phenol red broth starts out as what which means the color of the media is what?

7.3; red

151

If the pH of phenol red broth drops to what the media turns what color?

6.8; yellow

152

If the pH of phenol red broth raises above what the media turns what color?

7.3 reddish-pink

153

If the bacterium can ferment the carbohydrate in the phenol red broth then the media will be what color?

Yellow

154

If the bacterium cannot ferment the carbohydrate in the phenol red broth then the media remains what color?

Red

155

If the bacterium cannot ferment the carbohydrate but breaks down peptone in the media then the media will turn what color?

Reddish pink

156

Both aerobic and anaerobic respiration consist of what 3 steps?

Glycolysis, the Kreb’s cycle, and the electron transport chain (ETC)

157

In what two steps are aerobic and anaerobic respiration identical?

Glycolysis and Krebs cycle

158

The difference in aerobic and anaerobic respiration during the ETC is what?

The final electron carrier

159

In Aerobic respiration what is the final electron acceptor?

O2

160

In anaerobic respiration what is the final electron acceptor?

Non oxygen final electron acceptor (SO4^2-)(NO3-)(CO3^2-)

161

The electron transport chain passes electrons down a chain of molecules that alternate between becoming what?

Oxidized and reduced

162

For aerobes and facultative anaerobes the final electron acceptor is or can be what?

Oxygen

163

Premature electron leakage can occur in the ETC which produces what?

Superoxide

164

A bacterium must be able to break down superoxide due to its to toxicity. What enzyme breaks down superoxide?

Superoxide dismutase

165

When superoxide dismutase breaker down superoxide, it produces what toxic compound?

Hydrogen peroxide

166

In order to survive when H2O2 is produced, organisms must be able to break down H2O2. What enzyme breaks down H2O2?

Catalase

167

The presence of catalase is determined by the production of what?

O2 gas

168

In protein catabolism proteolytic enzymes (proteases) are used to break down proteins into peptides and peptides down to their basic what?

Amino acid components

169

Specific what break down amino acids?

Enzymes

170

What is decarboxylation?

The removal of the carbonyl group of an amino acid

171

What is decarboxylase?

An enzyme that catalyzes the removal of an amino acid’s carbonyl group

172

What coenzyme is required for decarboxylase activity?

Pyridoxyl phosphate

173

What is a polyamine?

An organic compound with 2 or more primary amino (NH2) groups

174

Why are polyamines important?

-have role in the regulation of gene transcription and translation
-have role in biofilm formation
-associated with bacterial iron scavenging molecules
-involved in the bacterial response to low pH

175

The presence of what can help raise the intracellular pH?

Decarboxylases

176

Ornithine, lysine, and arginine decarboxylases are all regulated in a bacterium and are produced specifically under what conditions?

Acidic

177

The by-products of decarboxylase reactions are alkaline compounds that can be used to what?

Neutralize and raise the low intercellular pH

178

What medium is used for a decarboxylation text?

Moller’s decarboxylase base medium

179

What are the important components of Mollers decarboxylase base medium?

-beef extract and peptone
-pyridoxal phosphate (coenzyme required for decarboxylase activity)
-Bromcresol purple pH indicator
- media is initially between pH 5.2 -6.2 so it appears copper in color

180

What can be added to Mollers decarboxylase broth to test for a specific decarboxylase?

A large amount of a specific amino acid

181

If the decarboxylase media starts out at a neutral pH something must be done to create what?

An acidic environment

182

What pathway produces a large amount of acidic products that can lower the pH of media?

Fermentation

183

The decarboxylase media contains what, which many bacteria can use for fermentation?

Glucose

184

What conditions are the most favorable to promote fermentation of glucose?

Anaerobic conditions

185

If an organism cannot ferment glucose the color of the decarboxylation media will be what?

Copper

186

If an organism cannot ferment glucose under anaerobic conditions in the media the organism is considered what?

Decarboxylase indeterminant

187

If an organism can ferment glucose but the decarboxylase is not present then the decarboxylation media will turn what color?

Yellow

188

If then decarboxylation media turns yellow the organism is considered what?

Decarboxylase negative

189

If the organism can ferment glucose under anaerobic conditions and can decarboxylase the specific amino acid then the media turns what color?

Purple

190

If the decarboxylation media turns purple than the organism is considered what?

Decarboxylase positive

191

The last complex of the ETC is called what?

Cytochrome C oxidase (complex IV)

192

In a bacterium, cytochrome oxidase specifically transfers electrons from cyctochrome c to what?

O2

193

Cytochrome oxidase does what to cytochrome c and oxygen?

Oxides cytochrome c and reduces O2

194

What is a chromogenic reducing agent?

A chemical that can donate an electron to another molecule and in so doing undergoes a color change

195

What chromogenic reducing agent is used in an oxidase test?

Tetramethyl - p - phenylenediamine (TMPD)

196

What color does TMPD turn when it becomes oxidized?

Dark blue

197

If there is no color change during an oxidase test then the TMPD remains in a reduced form and the organism is considered what?

Oxidase negative

198

If the paper turns dark blue during an oxidase test then the cytochrome c oxidase was present and the organism is considered what?

Oxidase positive

199

TMPD is unstable so the test must be read within what?

20 to 30 seconds

200

If nitrate (NO3-) is used as the final electron acceptor then the bacteria can perform either what or what?

Nitrate Respiration (Denitrification) or Ammonification

201

What is denitrification?

A multi step process performed by a group of enzymes that leads to the production of nitrogen gas from NO3

202

What is ammonification?

A multi step process performed by a group of enzymes that leads to the production of ammonia from NO3

203

The first step of either denitrification or ammonification is what?

The reduction of nitrate (NO3) to nitrite (NO2)`

204

What enzyme reduces nitrate?

Nitrate reductase

205

What is the purpose of the nitrate reduction test?

To determine if an organism can use nitrate for either denitrification of ammonification

206

What are the key components of a nitrate broth?

Potassium nitrate (KNO3)

A Durham tube

The broth is clear prior to inoculation

207

If the organism used in a nitrate test is a non fermentor as determined by a fermentation test (OF or phenol red broth) then the gas must be produced through what?

Denitrification

208

If there is gas in the nitrate reduction test then the organism is what? What is the source of gas? What is the gas?

Non-fermentor; denitrification; nitrogen gas

209

If an organism produces gas in the nitrate reduction test the organism is determined to be what?

Nitrate reductase positive

210

If the organism was determined to be a fermentor from an OF test then the type of gas produces is what?

Unknown

211

If there is growth overnight but no gas produced or gas production occurred and organism is a fermentor, what must be added to the culture?

Sulfanilic acid and naphthylamine

212

After addition of sulfanilic acid and naphthuylamine the broth will turn red in color and the organism will be considered what?

Nitrate reductase positive

213

If the addition of the reagents to the nitrate reduction test produce no change in color what must happen?

Further testing

214

If after reagents are added to a nitrate reduction test and there was no change in color, what can be added to catalyze the reduction of any nitrate source in the broth to nitrite?

Zinc

215

If the broth turns red after zinc is added the organism is considered what?

Nitrate reductase negative

216

If after zinc is added to the nitrate reduction test there is no change in color, then the organism is considered what?

Nitrate reductase positive

217

What test determines whether a bacterium can perform mixed acid fermentation?

Methyl Red Test (MR)

218

What test determines whether a bacterium can perform 2,3-butanediol fermentation?

Votes Proskaur Test (VP)

219

Mixed acid fermentation produces what acids?

Lactic acid
Acetic acid
Formic acid
Succinct acid

220

MR and VP broths are the same and consist of what components?

Peptone, acts as a source of proteins

Glucose

Phosphate buffer which maintains the media at a neutral pH at low amounts of acid.

221

If after several drops of MR are added, at a pH of 4.4, the color will be what?

Red

222

If after several drops of MR are added at a pH of 6.2 the color will be what?

Yellow

223

If a bacterium can not perform mixed acid fermentation only a small amount of acid is produced so the color will be what?

Yellow

224

If bacterium can perform mixed acid fermentation, large amounts of acids are produced and the methyl red indicator will be what color.

Red

225

In 2,3-butanediol fermentation pyruvate is converted to what first and what second?

First acetoin and then 2,3-butanediol

226

Why cant a pH indicator be used to detect 2,3 - butanediol fermentation?

The acidic compounds quickly convert to neutral alcohols

227

The VP test detects what?

Acetoin

228

What two reagents are added to detect acetoin?

Alpha-naphthol and potassium hydroxide

229

When the reagents are added in the presence of acetoin what is produced?

Diacetyl

230

What color does the media turn if diacetyl reacts with guanidine form the peptone in the media?

Red

231

If no acetoin is present the color produced at the surface of the culture will be what color?

Copper

232

What are used to determine if a bacterium can survive and grow in the presence of a single carbon source or nitrogen source?

Nutrient utilization test

233

In a citrate utilization test what is used as the only carbon source and what is used as the only nitrogen source?

Citrate; ammonium phosphate

234

Citrate can enter the bacterium through the action of what enzyme?

Citrate permease

235

Once inside the cell citrate is broken down into what by what enzyme?

Oxaloacetate and acetate; citrase

236

Oxaloacetate is then converted to what which can be further broken own to produce energy?

Pyruvate

237

Ammonium phosphate is converted to ammonia and ammonia by-products which are all what?

Alkaline

238

What are the components of Simmons Citrate Agar

1. Defined media
2. Only carbon source is citrate
3. Only nitrogen source is ammonium phosphate
4. Contains pH indicator (bromothymol blue)

239

The initial color of a neutral citrate agar is what?

Green

240

If the citrate agar increases to a pH of 7.6 what color does it change to?

Blue

241

In a citrate utilization test, if there is no growth, no pH change the media will be what color and what does that mean the organism is defined as?

Green; citrate negative

242

If the organism grows but the media remains green during a citrate utilization test, then the organism is considered what?

Citrate positive

243

If the organism can utilize the nitrogen source then it will grow on the on the slant and the media turns what color? What is the organism defined as?

Blue; citrate positive

244

What is deamination?

The removal of the amine group from an amino acid

245

What is deaminase?

An enzyme that catalyzes the removal of an amino acid’s amine group

246

Specific deaminases act on specific what?

Amino acids

247

The removal of the amine group can produce what?

Pyruvate; acetyl-CoA; Krebs cycle intermediate compounds

Each of these products can be used to generate energy

248

Deamination reaction requires what?

The co-enzyme pyridoxal phosphate

249

Products of tryptophan deamination are what?

Pyruvate, ammonia and indole

250

what does an indole test use to determine whether a specific product has been made

Chemical reaction

251

What reagent is added to determine the presence of indole?

Kovac’s reagent

252

If indole is present, the color will change to what?

Red and will be along the surface

253

What components are used for the indole test broth?

Tryptone broth, consisting of amino acid produced front he break down of proteins by the enzyme trypsin

High concentration of tryptophan

Does not contain pH indicators

254

If an organism does not possess tryptophanase, then what is missing?

Red rosindole dye

255

IMViC tests are typically used to differentiate between what?

Indole
Methyl Red
Voges-Proskaur
Citrate

Enteric bacteria and/or coil forms

256

If indole and MR are negative, VP is either negative or positive, and citrate is either negative or positive what kind of bacteria is present?

Enterobacter

257

If Indole and VP are negative but MR is positive and Citrate is either positive or negative what type of bacteria might you have?

Salmonella

258

If indole is negative, MR and VP are positive, and Citrate is either negative or positive then the type of bacteria might be what?

Proteus

259

If the indole and MR tests are positive, the VP negative, and the citrate either positive or negative the bacteria may be what?

Echecheria

260

What is starch?

An extremely large polysaccharide made up of glucose molecules linked by glycosidic bonds to form very long chains

261

What are the two types of molecules that make up the structure of starch?

Amylose and amylopectin

262

Amylose is what?

A long chain of glucose molecules

263

What is amylopectin?

Branded chains of glucose molecules

264

What enzyme breaks down glycosidic bonds?

Alpha-amylase

265

What is the content of starch agar?

Starch

266

If bacteria have alpha-amlyase it will do what on the starch agar?

Secret it and diffuse into the agar

267

Iodine reacts with starch to produce what color?

Dark brown/black

268

Iodine does not react with what?

Glucose

269

If the agar around the bacteria still contains starch and is what color, the organism is determined to be what?

Dark brown/black; alpha-amylase negative

270

If the agar around the bacteria does not turn dark brown/black the the organism is considered what?

Alpha-amylase positive

271

What contains between 200 and 220 amino acids?

Casein

272

Casein is what type of protein?

Phosphoprotein

273

There are 4 different types of casein which account for what percentage of the proteins found in cow’s milk?

Casein

274

What enzyme breaks down casein?

Casease

275

When secreted, casease can break the peptide bonds between what?

Adjacent amino acids

276

What is the component for milk agar?

Powdered nonfat milk

277

If there is not a color change on the milk agar the bacteria is determined to be what?

Casease negative

278

If there is a zone of clearing around the bacteria on a milk agar then the bacteria is determined to be what?

Casease positive

279

What is collagen?

A protein found mostly in fibrous tissues

280

What is gelatin?

Product from the hydrolysis of collagen

281

Gelatin is an abundant source of what?

Amino acids

282

What enzyme breaks down gelatin?

Gelantinase (a proteolytic enzyme)

283

What is the media used in the gelatinase test?

Nutrient gelatin

284

If the media remains solid after inoculation during a gelatinase test, the organism is determined to be what?

Gelatinase negative

285

If the growth media becomes liquified during a gelatinase test the organism is determined to be what?

Gelatinase positive

286

What is urea?

The product of the decarboxylation of certain amino acids

287

What is urease?

An enzyme present in certain bacteria that can hydrolyze urea into ammonia and CO2.

288

Because it is a basic compound, ammonia can do what within the bacterium?

Neutralize the acidic conditions

289

What are the important components of a urea broth?

A trace amount of yeast extract

Urea

Potassium phosphate (buffer)

Phenol red pH indicator

290

If the broth remains peach or slightly yellow during a urease test, the organism is determined to be what?

Urease negative.

291

If the urea in the broth is broken down then large amounts of ammonia will raise the pH and the phenol red indicator will turn what color?

Pink