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BIO 286 - Microbiology > Lab Quiz 10: Microbial Symbioses, Exoenzymes, and Gram Negative/Positive Biochemical Tests (Bio 286 - Microbiology) > Flashcards

Lab Quiz 10: Microbial Symbioses, Exoenzymes, and Gram Negative/Positive Biochemical Tests (Bio 286 - Microbiology) Flashcards

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Biology 101 flashcards
1
Q

competition

A

a contest between organisms for territory, a niche, or resources; neither organism fully thrives as both are somewhat harmed; example: soil bacteria for carbon sources

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2
Q

cooperation

A

process of groups of microbes working or acting together for their common/mutual benefit; both organisms can benefit from this interaction; example: quorum sensing

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3
Q

predation

A

interaction where a predator (an organism that is hunting) feeds on its prey (the organism that is attacked); predator benefits but the prey does not; example: Paramecium consuming bacteria

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4
Q

mutualism

A

relationship between two organisms in which individual benefits from the activity of the other; example: lichen, ruminants, and alfalfa

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5
Q

commensalism

A

class of relationships between two organisms where one organism benefits without affecting the other; example: many members of the human microbiota that benefit from humans but the humans do not benefit

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6
Q

amensalism

A

an interaction where an organism inflicts harm to another organism without any costs or benefits received by the actor; example: antibiotic production by a fungus

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7
Q

parasitism

A

interaction where one species (the parasite) benefits at the expense of the other (the host); example: bacteriophage T4 (and all viruses in general)

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8
Q

staphylococcus aureus and clostridium sporogenes have a

A

commensalistic relationship (commensalism)

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9
Q

does staphylococcus aureus or clostridium sporogenes benefit from their commensalism?

A

clostridium sporogenes

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10
Q

MacConkey Agar

A

if the microbes ferment lactose then the acids they produce turn the indicator dyes red… a positive result is red and a negative result is no change

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11
Q

indole

A

if microbes breakdown amino acid tryptophan to indole, the indole reacts with Kovac’s reagent to turn bright red… a positive result is red and a negative result is yellow

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12
Q

Triple Sugar Iron Agar (slant)

A

if ammonia is produced then the pH of the media becomes neutral – red and if lactose/sucrose is fermented then the tube will remain yellow… a positive result is yellow (A) and a negative result is red (K)

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13
Q

triple sugar iron agar (butt)

A

the butt of the TSI is always yellow – a positive result is yellow (A)

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14
Q

triple sugar iron agar (gas)

A

gases produced during fermentation will appear as bubbles or cracks… a positive result is cracking and a negative result is no change/no cracking

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15
Q

triple sugar iron agar (H2S)

A

hydrogen sulfide produced from breakdown of amino acid cysteine reacts with the iron to form ferric sulfide which is black… a positive result is black and a negative result is no change

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16
Q

MRVP (methyl red)

A

turns red in the presence of organic acids… a positive result is red and a negative result is yellow

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17
Q

MRVP (voges proskauer)

A

detects acetoin to turn red in its presence… a positive result is red and a negative result is coppery brown/no change

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18
Q

citrate

A

at acidic pH (citrate present) the media is green and if the citrate is metabolized the pH will turn blue… a positive result is blue and a negative result is green

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19
Q

urea

A

under alkaline conditions the indicator will turn pink… a positive result is bright pink and a negative result is yellow/no change

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20
Q

indole negative result

A

yellow

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21
Q

indole positive result

A

RED

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22
Q

methyl red negative result

A

yellow

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23
Q

methyl red positive result

A

RED

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24
Q

voges proskauer negative result

A

no change (yellow brown)

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25
Q

voges proskauer positive result

A

RED

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26
Q

citrate negative result

A

green

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27
Q

citrate positive result

A

BLUE

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28
Q

MacConkey Agar (MAC) negative result

A

no change (not red– brown or tan)

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29
Q

MacConkey Agar (MAC) positive result

A

RED

30
Q

urea negative result

A

no change (yellow)

31
Q

urea positive result

A

PINK

32
Q

TSI (slant) negative result

A

K - red

33
Q

TSI (slant) positive result

A

A- YELLOW

34
Q

TSI (Butt) negative result

A

K - red

35
Q

TSI (Butt) positive result

A

A - YELLOW

36
Q

TSI (gas) negative result

A

no change/no cracks

37
Q

TSI (gas) positive result

A

CRACKS

38
Q

TSI (H2S) negative result

A

no change/yellow

39
Q

TSI (H2S) positive result

A

BLACK

40
Q

mannitol salt agar

A

selective and differential media; contains 6.5% NaCl, phenol red dye, and mannitol…. microbes that are able to grow may ferment mannitol or not (if they do, the acids they produce turn the indicator dyes in the media yellow)

41
Q

mannitol salt agar (MSA) growth positive result

A

GROWTH

42
Q

mannitol salt agar (MSA) growth negative result

A

no growth

43
Q

mannitol salt agar (MSA) fermentation negative result

A

red

44
Q

mannitol salt agar (MSA) fermentation positive result

A

YELLOW

45
Q

catalase

A

enzyme that decomposes hydrogen peroxide to water and oxygen gas– when H2O2 is placed on the microbes, the production of bubbles indicates a positive reaction

46
Q

catalase (H2O2) negative result

A

no bubbles

47
Q

catalase (H2O2) positive result

A

BUBBLES

48
Q

EF broth

A

media containing a fermentable sugar (glucose) and an acid indicator (bromcresol purple)– glucose fermentation results in acid end products, which cause the media to turn yellow… the media also contains a metabolic poison sodium azide, allowing only azide-resistant microbes to grow

49
Q

EF broth negative result

A

purple

50
Q

EF broth positive result

A

YELLOW

51
Q

NaCl broth

A

contains 6.5% NaCl, allowing only halotolerant microbes to grow and turn the media cloudy

52
Q

NaCl broth negative result

A

clear

53
Q

NaCl broth positive result

A

CLOUDY

54
Q

bile esculin slant

A

media used to detect the metabolism of a compound called esculin– if it is converted to esculetin, it will react with iron in the media and turn completely black… bile acids in this media inhibit the growth of most gram positive organisms

55
Q

bile esculin (BE) slant negative result

A

tan

56
Q

bile esculin (BE) slant positive result

A

BLACK

57
Q

DNase

A

breaks down DNA to nucleotides by adding HCl to the DNA plate after microbes have been cultured– the low pH causes DNA to precipitate within the media, turning the late cloudy. any areas where DNA has hydrolyzed will not precipitate, leaving clear areas around growth of positive cultures

58
Q

DNase (HCl) negative result

A

no clearing

59
Q

DNase (HCl) positive result

A

CLEARING

60
Q

sheep blood agar

A

some bacteria break down blood cells using toxins called hemolysins… resulting in three patterns of hemolysis clearings- alpha, beta, and gamma… additionally, bacitracin and optochin are antibiotics used to determine susceptibility

61
Q

alpha hemolysis

A

partial breakdown of red blood cells– resulting in smoky green color (no longer red but no clearing)

62
Q

beta hemolysis

A

complete breakdown of red blood cells, resulting in complete clearing– can read text through the plates

63
Q

gamma hemolysis

A

no clearing, the plates have growth on them but are just as red

64
Q

hemolysis results

A

alpha (A), beta (B), or gamma (G)

65
Q

bacitracin

A

an inhibitor of peptidoglycan biosynthesis that group A streptococci are particularly susceptible to

66
Q

bacitracin negative result

A

no zone (R)

67
Q

bacitracin positive result

A

ZONE (S)

68
Q

optochin

A

a copper containing compound that pneumococci are particularly susceptible to

69
Q

optochin negative result

A

no zone (R)

70
Q

optochin positive result

A

ZONE (S)

71
Q

lysozyme

A

protein found in tears/saliva/other secretions and egg whites… a peptidoglycan hydrolase and is an important component of our innate immune defenses

72
Q

Alexander Fleming

A

described lysozymes

BIO 286 - Microbiology (21 decks)

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