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Flashcards in Slides for final Deck (85):
1

Extracellular enzymes (exoenzymes) Function

outside the cell

2

Extracellular enzymes (exoenzymes) Purpose:

Purpose: break down macromolecules

3

Extracellular enzymes (exoenzymes) Why is this important?

It's a tool for helping us identify unknown organisms

4

What enzyme breaks down starch?

Amylase

5

What reagent is used to detect the presence of starch?

iodine

6

If starch has been hydrolyzed, what results are observed?

it forms a dark blue-brown complex Zone of clearing where starch was digested

7

which result is consistent with the hydrolysis of starch?

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B.

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8

What enzyme breaks down urea? 

urease

9

What products are formed?

ammonia, raises pH

10

What is the pH indicator associated with this media?

Phenol Red

11

If urea has been hydrolyzed, what results are observed?

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A. Pink

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12

Urease test is used to differentiate between what families of bacteria? 

Mycobacterium

13

Define casein.

the main protein present in milk

14

What enzyme breaks down casein?

casease

15

What media is used to detect casein hydrolysis?

skim milk agar

16

If casein has been hydrolyzed, what results are observed?

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Clearing around organism

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17

Define gelatin.

Gelatin: protein derived from skin, bones,

18

What enzyme breaks down gelatin?

gelatinase

19

What media is used to detect gelatin hydrolysis?

broth: beef extract and peptone

20

If gelatin has been hydrolyzed, what results are observed? 

liquid

21

What enzyme breaks down lipids?

Lipase

22

What media is used to detect lipid hydrolysis?

tributyrin agar

23

If lipid has been hydrolyzed, what results are observed?

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B. Is positive, with zone of clearing

24

What is the main difference between selective and differential media? 

  1. Selective media allow certain types of organisms to grow, and inhibit the growth of other organisms.
  2. Differential media are used to differentiate closely related organisms or groups of organisms.

25

Is Phenylethyl Alcohol (PEA) Agar selective, differential or both?

Selective medium

26

What type of bacteria can grow on PEA?

gram-positive

27

Is Mannitol Salt Agar (MSA) selective, differential or both?

Selective and differential

28

What type of bacteria can grow on MSA?

Staphylococcus

29

Is MacConkey Agar (MAC) selective, differential or both?

Selective

30

What type of bacteria can grow on MAC?

Gram negative

31

What is the mechanism of action of inhibition

lactose fermenters/non-lactose fermenters

32

how would you interpret the observations for each section of the plate?

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A. gram-negative, ferment lactose

B. gram-positive

C. gram-negative, non-lactose fermentor

33

Is Hektoen Enteric Agar (HE) selective, differential or both?

selective and differential

34

What type of bacteria can grow on HE?

gram-negative

35

In Hectoen Eenteric what is the mechanism of action of inhibition

bile salts

36

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non-lactose fermenter, reduces sulfur to H2S

37

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Non-lactose fermenter, does not reduce sulfur

38

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Fermenter

39

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gram-positive

40

MRVP media contains peptone, glucose, and a phosphate buffer.  What is the function of each ingredient?

To check for fermentation

41

In MRVP test, what color is methyl red under acidic conditions?  

Acids produce low pH, and the color is red

42

What color is methyl red under acidic conditions?  

Yellow

43

Mixed acid fermentation causes MR to appear what color?

Yellow

44

What is the purpose of the Voges-Proskauer test?

butylene glycol fermentation 

45

What are the products of this pathway?

Pathway regenerates NAD+ for glycolysis by reducing pyruvate to acetoin and butylene glycol

Turn Red: Acetoin is present

Turns copper: Acetoin not present

46

What reagent is used in the Catalase test?

hydrogen peroxide

47

What enzyme converts H2O2 into H2O and O2?

Catalase

48

What genera of bacteria can be differentiated using this method?

 strict aerobes as well as facultative anaerobes.

49

What is the function of cytochrome c oxidase?

transfers its electrons to oxygen

50

When the reagent of the BBL Dry Slide is reduced, what color does it appear?

colorless

51

What represents a positive oxidase reaction?  

purple/blue

52

What represents a negative oxidase reaction?  

no color change (clear)

53

Nitrate broth is used to determine the presence of the enzyme ______

nitrate reductase

54

The above process results in the production of what molecule?

dntrify nitrate into nitrite

55

What reagents are added to complete the test?

  1. sulfanilic acid
  2. α-naphthylamine
  3. zinc

56

Using the figure, how would you interpret the observations for each tube?

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  1. Negative
  2. Positive
  3. Positive
  4. Positive

 

57

What is the sole source of carbon in Simmons Citrate Agar

sodium citrate

58

In the Citrate test, what is the sole source oe of nitrogen?

ammonium dihydrogen phosphate

59

What is the pH indicator of Simmons Citrate Agar?

bromthymol blue

60

Microbes that are able to use citrate as their sole source of carbon produce acidic or basic by-products?

basic

61

Define decarboxylase.

Produces alkaline (basic) end products

62

Decarboxylases catalyze reactions that produce _______________ products.

basic end products

63

What ingredients are found in Moller’s Decarboxylase Base Medium?

  1. nutrients
  2. dextrose
  3. pyridoxal 
  4. bromcresol purple
  5. resol red.

64

In the Decarboxylation test, whatis the pH indicator?

bromcresol purple

65

Why is mineral oil added to the tube?

  1. Seals out external oxygen
  2. Promotes fermentation

66

Define deaminase.

produces acidic end products

67

What reaction does phenylalanine deaminase catalyze?

Phenylpyruvate

68

In the Phenylalanine deaminase test, what reagent is added to the media to complete the test?

FeCl(Ferric chloride)

69

In Phenylalanine Deaminase Test, what is considered a positive reaction? 

  1. Produces a dark green color immediately
  2. A NEGATIVE color will produce no color change (usually yellow)

70

What ingredient is in the motility media that allows for the detection of motility? 

  • Agar (a reduced amount)

71

In the motility test, what is the mechanism of action?

the flagella

72

What media is used to detect indole production?

Tryptone broth

73

What specific amino acid is in this media?

tryptophan

74

It is commonly used to distinguish among members of the family

Escherichia

75

What reagent is added to the media to complete the test?

Kovac's

76

Define enteric bacteria. Name

From family Enterobacteriaceae

77

Clinically important genera of Enteric bacteria

Pathogenic non-coliforms (Shigella, Salmonella, Yersinia)

  • Escherichia
  • Klebsiella
  • Citrobacter
  • Proteus
  • Serratia
  • Morganella
  • Providencia
  • Edwardsiella
  • Enterobacter

78

Fungi:  

  • non-motile
  • cell wall made of chitin
  • use absorptive means of obtaining nutrients
  • most decompose dead organic matter
  • divide into unicellular yeasts and multicellular filamentous molds with asexual and sexual forms of reproducing including reproductive spores.

79

Protozoa:  

  • unicellular
  • obtain nutrients by absorption and ingestion
  • most have a non-motile (cyst) resting stage and a motile vegetative stage
  • motile by either cilia, flagella, or pseudopods.

80

Arthropods:

  • multicellular animals
  • cause infections (examples: mites and lice)
  • acts as vectors for viral, bacterial, and protozoan disease transmission (examples; mosquitoes, fleas, ticks).

81

Helminths:  

  • multicellular animals
  • obtain food by ingestion
  • some species are parasitic
  • contain egg, larva, embryo, and cyst forms
  • possess organ systems
  • although some are adapted (reduced) for parasitic lifestyle, examples include:  flukes, tapeworms, roundworms.

82

What are the following are classied as?

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Fungi

83

What are the following are classied as?

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Protozoa

84

What are the following classified as?

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Arthropods

85

What are the following classified as?

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Helminths