Lab Practical II, Expiraments: 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 27

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Riverside Community College, Moreno Valley Campus Microbiology Lab Manual. Stations 1-18
updated 7 years ago by Tish
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1

HYDROLYSIS OF STARCH (EX. 11)

WHAT ENZYME IS CAUSING THE HYDROLYSIS OF STARCH?

AMYLASE

2

HYDROLYSIS OF STARCH

WHAT IS THE END PRODUCT OF STARCH HYDROLYSIS?

GLUCOSE

3

HYDROLYSIS OF STARCH

WHAT REAGENT IS ADDED POST INCUBATION TO INTERPRET THIS TEST?

IODINE

4

HYDROLYSIS OF STARCH

IN A POSITIVE STARCH HYDROLYSIS TEST, THE AGAR:

A) TURNS DARK BLUE
B) REMAINS IODINE COLOR (NO COLOR CHANGE)
C) TURNS RED

REMAINS IODINE COLOR (NO COLOR CHANGE)

5

HYDROLYSIS OF STARCH

IN A NEGATIVE STARCH HYDROLYSIS TEST, THE AGAR TURNS

A DARK PURPLE COLOR AROUND THE STREAK LINE

6

HYDROLYSIS OF GELATIN (EX. 12)

WHAT ENZYME DOES BACTERIA PRODUCE TO HYDROLYZE GELATIN?

GELATINASE

7

HYDROLYSIS OF GELATIN

WHAT ARE THE END PRODUCTS OF GELATIN HYDROLYSIS?

AMINO ACID

8

HYDROLYSIS OF GELATIN

HOW CAN YOU TELL WHICH TUBE IS POSITIVE FOR GELATIN HYDROLYSIS?

THE GELATIN IS IN LIQUID FORM

9

HYDROLYSIS OF GELATIN

WHY MUST YOU READ THE RESULTS OF THIS TEST AT ROOM TEMPERATURE?

GELATIN WILL MELT AT TEMPERATURES EXCEEDING 25°C, WHICH IS ROOM TEMPERATURE, AND IT WOULD GIVE A FALSE POSITIVE.

10

HYDROLYSIS OF GELATIN

HOW CAN YOU TELL WHICH TUBE IS NEGATIVE FOR GELATIN HYDROLYSIS?

THE GELATIN REMAINS SOLID

11

FERMENTATION OF CARBOHYDRATES (EX. 13)

THESE CARBOHYDRATE BROTH TUBES CONTAIN GLUCOSE, PROTEIN AND A pH INDICATOR CALLED

PHENOL RED

12

FERMENTATION OF CARBOHYDRATES

AN INVERTED TUBE CALLED A(N)

DURHAM

13

FERMENTATION OF CARBOHYDRATES

WHAT IS THE PURPOSE OF THIS INVERTED TUBE?

COLLECT GAS

14

FERMENTATION OF CARBOHYDRATES

WHAT COLOR DOES THE pH INDICATOR TURN UNDER ACIDIC CONDITIONS?

YELLOW

15

FERMENTATION OF CARBOHYDRATES

HOW CAN YOU TELL WICH TUBE GIVES THE FOLLOWING RESULTS: A/G+ (ACID/GAS (+))

THE TUBE WILL BE YELLOW W/BUBBLES

16

FERMENTATION OF CARBOHYDRATES

CONSIDERING THE INGREDIENTS OF A CARBOHYDRATE FERMENTATION BROTH TUBE, WHY IS IT MANDATORY THAT YOU READ THE RESULTS WITHIN 24 TO 48 HOURS (BE SPECIFIC)?

YOU MIGHT GET A FALSE NEGATIVE BECAUSE THE BACTERIA CAN FERMENT ALL OF THE CARBOHYDRATES WITHIN 48 HOURS AND THEN BREAKDOWN PROTEIN WHICH WILL CHANGE THE pH BACK TO BASIC.

17

FERMENTATION OF CARBOHYDRATES

B/G- (BASE/GAS (-))

RED (BASIC)

18

FERMENTATION OF CARBOHYDRATES

A/G- (ACID/GAS (-))

YELLOW W/O BUBBLES

19

PRODUCTION OF DECARBOXYLASE (EX. 16)

THE ABILITY OF BACTERIA TO DECARBOXYLATE (REMOVE THE CARBOXYL GROUP FROM AN AMINO ACID) IS MOST OFTEN DEMONSTRATED WITH WHICH 3 AMINO ACIDS?

1. LYSINE

2. ARGANINE

3. ORNITHINE

20

PRODUCTION OF DECARBOXYLASE

WHICH pH INDICATOR IS IN THE MEDIA?

BROM CRESOL PURPLE

21

PRODUCTION OF DECARBOXYLASE

WHAT COLOR IS A POSITIVE APPEARANCE?

PURPLE

22

PRODUCTION OF DECARBOXYLASE

WHAT COLOR IS A NEGATIVE APPEARANCE?

YELLOW

23

PRODUCTION OF DECARBOXYLASE

THE MATERIAL ON TOP OF THE CULTURE IS?

MINERAL OIL

24

PRODUCTION OF DECARBOXYLASE

WHAT IS THE PURPOSE OF OVERLAYING THE CULTURE WITH MINERAL OIL?

TO CREATE AN ANAEROBIC ENVIRONMENT

25

PRODUCTION OF DECARBOXYLASE

THIS MEDIA IS USED TO TEST FOR THE ENZYME

DECARBOXYLASE

26

S I M REACTIONS: PRODUCTION OF HYDROGEN SULFIDE (EX. 18)

"S I M" ISAN ACRONYM FOR

SULFIDE

INDOLE

MOTILITY

27

S I M REACTIONS: PRODUCTION OF HYDROGEN SULFIDE

THE "S" TEST FOR THE PRODUCTION OF

HYDROGEN SULFIDE

28

S I M REACTIONS: PRODUCTION OF HYDROGEN SULFIDE

THE HYDROGEN SULFIDE REACTS WITH IRON SULFATE IN THE MEDIUM RESULTING IN THE FORMATION OF

BLACK PERCIPITANT (IRON SULFIDE)

29

S I M REACTIONS: PRODUCTION OF HYDROGEN SULFIDE

THE AMINO ACID WITH SULFUR IN ITS R-GROUP, WHICH IS INCLUDED IN THE S I M MEDIA IS

CYSTEINE

30

S I M REACTIONS: PRODUCTION OF HYDROGEN SULFIDE

WHAT COLOR IS A POSITIVE TEST FOR HYDROGEN SULFIDE?

BLACK PERCIPITATE

31

S I M REACTIONS: PRODUCTION OF HYDROGEN SULFIDE

WHAT COLOR IS A NEGATIVE TEST FOR HYDROGEN SULFIDE?

YELLOW (NO CHANGE)

32

S I M REACTIONS: PRODUCTION OF INDOLE

WHAT AMINO ACID IS HYDROLYZED FORMING THE PRODUCT INDOLE?

TRYPTOPHAN

33

S I M REACTIONS: PRODUCTION OF INDOLE

THE PRESENCE OF INDOLE IS INDICATED BY A SIMPLE COLORMETRIC TEST IN WHICH ONE ADDS WHAT REAGENT?

KOVAC'S

34

S I M REACTIONS: PRODUCTION OF INDOLE

WHAT COLOR IS A POSITIVE TEST FOR INDOLE?

RED LAYER

35

S I M REACTIONS: PRODUCTION OF INDOLE

WHAT COLOR IS A NEGATIVE TEST FOR INDOLE?

YELLOW (NO CHANGE)

36

S I M REACTIONS: PRODUCTION OF INDOLE

IS THIS A POSITIVE OR NEGATIVE TEST FOR MOTILITY?

OBSERVE THE STAB LINE & SURFACE OF DEEP FOR EVIDENCE OF MOTILITY:

1. POSITIVE = CLOUDY (MOTILE)

2. NEGATIVE = NOT CLOUDY (NON-MOTILE)

37

MR-VP REACTIONS (EX. 19)

MR-VP IS THE ACRONYM FOR WHICH TWO TESTS?

1. METHYL RED

2. VOGES PROSKAUER

38

MR-VP REACTIONS

WHAT REAGENT IS USED IN THE MR TEST?

METHYL RED

39

MR-VP REACTIONS

THIS IS A TEST TO DETERMINE WHETHER OR NOT A MICROBE CAN FERMENT _________ AND PRODUCE PREDOMINANTLY ACID END PRODUCTS TO THE DEGREE THAT THE pH OF THE MEDIA WILL BE LOWERED, PRODUCING AN ACID COLOR.

GLUCOSE

40

MR-VP REACTIONS

WHAT IS THE pH INDICATOR USED IN THE MR TEST?

METHYL RED

41

MR-VP REACTIONS

UNDER ACID CONDITIONS WHAT COLOR DOES METHYL RED TURN?

RED

42

MR-VP REACTIONS

UNDER BASIC CONDITIONS WHAT COLOR DOES METHYL RED TURN?

YELLOW

43

MR-VP REACTIONS

WHAT IS THE END PRODUCT OF THE VP TEST?

ACETYL METHYL CARBINAL (AMC)

44

MR-VP REACTIONS

WHAT SPECIAL PRECAUTION MUST BE PRACTICED IN THE ANALYSIS FOR THE PRODUCTS OF THE VP TEST?

A) READ BEFORE 20 MINUTES HAVE ELAPSED
B) WAIT A MINIMUM OF 10-20 MINUTES FOR THE
FINAL READING
C) ADD THE POTASSIUM HYDROXIDE FIRST
D) INCUBATE AT ROOM TEMPERATURE
E) NONE OF THE ABOVE

NONE OF THE ABOVE

***YOU MUST ALLOW THE SAMPLE TO STAND FOR A MINIMUM OF 20-30 MINUTES (PG. 99).

45

MR-VP REACTIONS

WHAT COLOR INDICATES A POSITIVE VP REACTION?

RED

46

MR-VP REACTIONS

WHAT COLOR INDICATES A NEGATIVE VP REACTION?

YELLOW

47

MANNITOL SALT AGAR (EX. 22)

THIS IS A SELECTIVE AND DIFFERENTIAL MEDIA FOR THE ISOLATION OF WHAT GENERA OF BACTERIA?

STAPHYLOCOCCUS

48

MANNITOL SALT AGAR

THE MEDIA TURNS YELLOW BECAUSE THE MICROBE FERMENTS WHAT SUGAR?

MANNITOL

49

MANNITOL SALT AGAR

WHAT INGREDIENT INCORPORATED INTO A MSA PLATE MAKES THE MEDIA SELECTIVE?

7.5% SALT

50

MANNITOL SALT AGAR

WHAT TWO INGREDIENTS INCORPORATED INTO A MSA PLATE MAKES THE MEDIA DIFFERENTIAL?

1. MANNITOL

2. PHENYL RED

51

MANNITOL SALT AGAR

WHEN STAPHYLOCOCCUS AUREUS FERMENTS MANNITOL, WHAT COLOR DOES THE pH INDICATOR (PHENOL RED) CHANGE TO?

YELLOW

52

REDUCTION OF NITRATES (EX. 14)

A TUBE OF NITRATE BROTH WAS INOCULATED WITH BACILLUS SPIZIZZENII AND INCUBATED FOR 4 DAYS AT 37°C. AFTER INOCULATION AND INCUBATION, SULFANIC ACID AND DIMETHYL-α-NAPHTHYLAMINE (DAN) WAS ADDED AND THE SOLUTION TURNED RED. THIS INDICATES WHAT TYPE OF REACTION FOR NITRATE REDUCTION:

A) POSITIVE FOR NITRATE REDUCTION
B) NEGATIVE FOR NITRATE REDUCTION
C) INDETERMINATE FOR NITRATE REDUCTION
D) POSITIVE FOR NITRITE REDUCTION

POSITIVE FOR NITRATE REDUCTION

53

REDUCTION OF NITRATES

AFTER INCUBATING AN INOCULATED TUBE OF NITRATE BROTH, SUFANILIC ACID AND DAN WERE ADDED AND THE SOLUTION DID NOT CHANGE COLOR. AT THIS POINT, THE TEST IS INTERPRETED AS:

A) POSITIVE FOR NITRATE REDUCTION
B) NEGATIVE FOR NITRATE REDUCTION
C) INDETERMINATE FOR NITRATE REDUCTION
D) POSITIVE FOR NITRITE REDUCTION

INDETERMINATE FOR NITRATE REDUCTION

54

REDUCTION OF NITRATES

WHAT DO YOU ADD TO THE NITRATE BROTH TUBE AFTER YOU HAVE ADDED THE TWO REAGENTS AND NO COLOR CHANGE OCCURRED?

ZINC

A) IF THE NITRATE BROTH TURNS RED AFTER THE ZINC
IS ADDED THEN THE RESULTS ARE NEGATIVE.

B) IF THE NITRATE BROTH STAYS THE SAME COLOR AFTER
THE ZINC IS ADDED THEN THE RESULTS ARE
POSITIVE.

55

REDUCTION OF NITRATES

MANY MICROORGANISMS CAN REDUCE NITRATE COMPOUNDS TO NITRITE COMPOUNDS UNDER ANAEROBIC CONDITIONS (ANAEROBIC RESPIRATION). IN THIS PROCESS THE NITRATE TAKES THE PLACE OF OXYGEN AS THE FINAL _________ ACCEPTOR.

ELECTRON

56

REDUCTION OF NITRATES

WAS THERE A TEST PERFORMED IN THE REDUCTION OF NITRATES?

NO

57

CATALASE TEST (EX. 15)

WHAT REAGENT IS ADDED TO BACTERIAL GROWTH TO DETECT THE PRESENCE OF CATALASE?

HYDROGEN PEROXIDE

58

CATALASE TEST

WHAT GAS IS PRODUCED IN A CATALASE REACTION?

OXYGEN

59

CATALASE TEST

DESCRIBE A NEGATIVE CATALASE REACTION

NO BUBBLES

60

CATALASE TEST

DESCRIBE A POSITIVE CATALASE REACTION

BUBBLES

61

CATALASE TEST

WHY WOULD YOU NOT WANT TO PERFORM A CATALASE TEST ON COLONIES GROWING ON A SHEEP BLOOD AGAR PLATE?

IT WILL GIVE YOU A FALSE POSITIVE BECAUSE BLOOD CONTAINS CATALASE.

62

CATALASE TEST

WHAT TWO GENERA MENTIONED IN CLASS, CAN THE CATALASE TEST BE USED TO DISTINGUISH?

1. GENERA: STAPHYLOCOCCUS
CATALASE REACTION: + (POSITIVE)

2. GENERA: STREPTOCOCCUS
CATALASE REACTION: - (NEGATIVE)

63

HYDROLYSIS OF UREA (EX. 17)

WHAT ENZYME IS RESPONSIBLE FOR THE HYROLYSIS OF UREA?

UREASE

64

HYDROLYSIS OF UREA

WHAT IS THE DETECTABLE PRODUCT OF UREA HYDROLYSIS?

AMMONIA

65

HYDROLYSIS OF UREA

THIS DETECTABLE PRODUCT CAUSES THE MEDIA TO TURN (ACID OR BASIC)?

BASIC

66

HYDROLYSIS OF UREA

WHAT IS THE pH INDICATORIN UREA BROTH?

PHENYL RED

67

HYDROLYSIS OF UREA

WHAT IS THE COLOR INDICATOR WITH AN ACIDIC SUBSTANCE?

ORANGE/PEACH

68

HYDROLYSIS OF UREA

WHAT IS THE COLOR INDICATOR WITH A VERY BASIC SUBSTANCE?

HOT PINK

69

HYDROLYSIS OF UREA

WHICH OF THE FOLLOWING REAGENTS IS ADDED AFTER INCUBATION TO PERFORM A UREA HYDROLYSIS TEST?

A) SULFANILIC ACID
B) METHYL RED
C) DAN
D) UREASE
E) NO REAGENT IS REQUIRED

NO REAGENT IS REQUIRED

70

HYDROLYSIS OF UREA

WHAT COLOR IS A POSITIVE TEST?

HOT PINK

71

HYDROLYSIS OF UREA

WHAT COLOR IS A NEGATIVE TEST?

ORANGE/PEACH

72

COAGULASE PRODUCTION (EX. 23)

WHAT IS THE NAME OF THE VIRULENCE FACTOR THAT ALL STAPHYLOCOCCUS AUREUS PRODUCE?

COAGULASE

73

COAGULASE PRODUCTION

HOW DOES COAGULASE AID IN THE VIRULENCY OF S. AUREUS?

THE COAGULASE PROTECTS S. AUREUS FROM PHAGOCYTOSIS BY INACTIVATING THE SODIUM CITRATE WHICH CONTAINS CLOTTING FACTORS, THEREBY CAUSING THE PLASMA TO CLOT.

74

COAGULASE PRODUCTION

WHAT IS THE CHARACTERISTIC OF A POSITIVE TEST FOR COAGULASE?

SOLID (CLOT)

75

COAGULASE PRODUCTION

WHAT IS THE CHARACTERISTIC OF A NEGATIVE TEST FOR COAGULASE?

LIQUID (NO CLOT)

76

COAGULASE PRODUCTION

WHAT IS THE MEDIA USED IN THE COAGULASE TEST?

RABBIT PLASMA

77

COAGULASE PRODUCTION

WHAT IS THE POSSIBLE IDENTITY (GENUS & SPECIES) OF THE ORGANISM IN A POSITIVE COAGULASE TEST?

S. AUREUS

78

COAGULASE PRODUCTION

WHAT IS THE POSSIBILE IDENTITY (GENUS & SPECIES) OF THE BACTERIA IN A NEGATIVE COAGULASE TEST?

S. EPIDERMIDIS

79

SIMMONS CITRATE (EX. 20)

THE MEDIUM USED IN THIS TEST DETERMINES WHETHER OR NOT A BACTERIUM CAN UTILIZE ________ AS ITS SOLE SOURCE OF ______.

CITRATE, CARBON

80

SIMMONS CITRATE

THE pH INDICATOR IN THIS MEDIA IS ________ AND WILL TURN A ________ COLOR IF THE TEST IS POSITIVE

BROMTHYMOL BLUE, DEEP PRUSSIAN BLUE

81

SIMMONS CITRATE

IF THE TEST IS NEGATIVE, THE pH IN BROMTHYMOL BLUE WILL ___________.

REMAIN UNCHANGED (GREEN)

**EVEN THOUGH THE NAME IS BROMTHYMOL BLUE, IT IS THE COLOR GREEN AT NEUTRAL pH BUT TURNS BLUE ONLY ABOVE pH 7.6

82

WATER ANALYSIS (EX. 27)

IF 3 DIFFERENT COLIFORM TEST WERE PERFORMED ON 3 DIFFERENT TUBES, HOW CAN YOU TELL WHICH TUBE CONTAINS POSSIBLE COLIFORMS?

THE TUBE THAT IS A/G+ (YELLOW W/BUBBLES)

83

WATER ANALYSIS

WHAT IS THE SPECIFIC SUGAR INCORPRATED INTO THESE CARBOHYDRATE BROTH TUBES?

LACTOSE BROTH

84

WATER ANALYSIS

WHAT IS THE pH INDICATOR USED?

PHENOL RED

85

WATER ANALYSIS

ACCORING TO THE DEFINITION OF A COLIFORM AS DISCUSSED IN CLASS , NAME 4 CHARACTERITICS OF A COLIFORM:

1. GRAM (-)

2. NONENDOSPORE FORMING (ROD)

3. FERMENTS LACTOSE WITH ACID AND GAS

4. FACULTATIVE ANAEROBES OR AEROBES

86

WATER ANALYSIS

WHAT IS THE NAME OF THE TUBE INVERTED INSIDE THE CARBOHYDRATE BROTH?

DURHAM

87

WATER ANALYSIS

WHAT IS THE FUNCTION OF THIS INVERTED TUBE?

COLLECT GAS

88

WATER ANALYSIS

WHAT IS THE GENUS AND SPECIES OF THE INDICATOR ORGANISM WE ARE LOOKING FOR IN THESE TESTS?

E.COLI

89

WATER ANALYSIS

WHAT COLOR IS A POSITIVE TEST FOR THE COLIFORM, E.COLI, ON AN EMB PLATE?

GREEN METALLIC SHEEN

90

WATER ANALYSIS

WHAT DOES IT INDICATE?

FECAL CONTAMINATION

91

WATER ANALYSIS

AFTER A POSITIVE PRESUMPTIVE TEST, A CONFIRMED TEST IS DONE ON WHAT TYPE OF MEDIA?

(EMB) EOSIN METHYLENE BLUE PLATE

92

WATER ANALYSIS

THE BACTERIA THAT GROWS DURING THIS TEST IS PROBABLY

E. COLI

93

WATER ANALYSIS

WHAT TWO INGREDIENTS (DYES) MAKE THIS MEDIA SELECTIVE?

1. EOSIN

2. METHYLENE BLUE

94

WATER ANALYSIS

WHAT SUGAR IS USED IN THIS MEDIA TO MAKE IT DIFFERENTIAL?

LACTOSE

95

WATER ANALYSIS

THIS MEDIA IS SELECTIVE FOR __________ AND INHIBITORY TO ___________.

GRAM (-), GRAM (+)

96

HEMOLYSIS PRODUCTION (EX. 24)

WHICH SHEEP BLOOD AGAR PLATE DEMONSTRATES:

BETA HEMOLYSIS?

CLEAR ZONE (NO BLOOD IN THE AGAR)

97

HEMOLYSIS PRODUCTION

WHICH SHEEP BLOOD AGAR PLATE DEMONSTRATES:

ALPHA HEMOLYSIS?

GREENISH TINGE (W/SURFACE COLONIES)

98

HEMOLYSIS PRODUCTION

WHICH SHEEP BLOOD AGAR PLATE DEMONSTRATES:

GAMMA HEMOLYSIS?

THE AGAR REMAINS RED (NO CHANGE)

99

HEMOLYSIS PRODUCTION

WHAT IS AN EXAMPLE OF AN ORGANISM (GENUS AND SPECIES) CAPABLE OF CAUSING BETA HEMOLYSIS?

S. PYOGENES

100

HEMOLYSIS PRODUCTION

WHAT IS AN EXAMPLE OF AN ORGANISM (GENUS AND SPECIES) CAPABLE OF CAUSING ALPHA HEMOLYSIS?

S. PNEUMONIAE

101

HEMOLYSIS PRODUCTION

WHAT IS AN EXAMPLE OF AN ORGANISM (GENUS AND SPECIES) CAPABLE OF CAUSING GAMMA HEMOLYSIS?

E. FAECALIS