Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIO 286 - Microbiology > Lab Quiz 8: Water Quality Testing, Genetic Transformation, Lactose Operon Regulation, and Enterobacteriaceae Biochemistry (Bio 286 - Microbiology) > Flashcards

Lab Quiz 8: Water Quality Testing, Genetic Transformation, Lactose Operon Regulation, and Enterobacteriaceae Biochemistry (Bio 286 - Microbiology) Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

indicator organisms

A

always present when feces are present (PRESENT IN FECES); should be absent when feces are absent (ABSENT WITHOUT FECES); organism should be very EASY TO GROW; organism should be EASY TO IDENTIFY (using differential media); organism should persist in the environment slightly longer than the pathogens (there is less problem with false positives than false negatives)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

fecal coliforms

A

indicator organism used to detect fecal contamination of mammals (humans); lactose-fermenting gamma proteobacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

fecal streptococci (enterococci)

A

indicator organism used to detect fecal contamination of animals (like ducks) but not humans; glucose-fermenting bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

ratio of coliforms to streptococci

A

indicates where fecal contamination originated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

wastewater is not contaminated

A

< 400 FC/100 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

surface water is not contaminated

A

<160 FC/100 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

drinking water is not contaminated

A

< 1 FC/100 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

coliforms : enterococci ≥ 4:1

A

source of fecal contamination is human

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

2:1 ≥ coliforms : enterococci < 4:1

A

source of fecal contamination is a mix between human and animal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

0.7:1 ≥ coliforms : enterococci < 2:1

A

source of fecal contamination is unknown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

coliforms : enterococci < 0.7

A

source of fecal contamination is animal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

mFC plate

A

used to detect FECAL COLIFORMS… selective with BLUE ACIDS… differential with LACTOSE… colony color is BLUE… incubation temperature is 44.5 degrees Celsius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

mEA plate

A

used to detect FECAL STREPTOCOCCI (Enterococcus)… selective with SODIUM AZIDE… differential with GLUCOSE… colony color is RED… incubation temperature is 35 degrees Celsius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

dilution calculation (calculating number of fecal coliforms or streptococci per 100 mL)

A

[(cfu * SDF) / volume plated] x 100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

ratio of coliforms to streptococci calculation

A

Blue Colonies (fecal coliforms) / Red Colonies (enterococci)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

bacteria can horizontally transfer genes through

A

transformation, conjugation, and transduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Frederic Griffith

A

first described the process of transformation using rough and smooth strains of Streptococcus pneumoniae… mixing the dead smooth strain with the live rough strain killed injected mice, but live smooth bacteria were isolated from these dead mice… indicating that something had transformed the rough strain into a smooth strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

rough strain

A

made small compact colonies; avirulent when injected into mice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

smooth strain

A

made larger mucoid colonies; efficiently killed mice when injected into them and could be isolated from the mice postmortem (Koch’s postulates)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

heat killing the smooth strain

A

made them nontoxic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

mixing the dead smooth strain and the live rough strain

A

killed injected mice (despite non being virulent when injected individually); live smooth bacteria were isolated from the dead mice because something had transformed the rough strain into a smooths train

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Oswald Avery

A

proved that the transforming material was DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

competent

A

bacteria that are capable of transporting exogenous DNA into the cell and incorporating it into their genomes (ex: streptococcus pneumoniae)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

on the nutrient agar plate without antibiotics

A

all strains of the acinetobacter calcoaceticus grow… but quadrant 3 (with only the heat killed smooth strain) does not grow anything as only the DNA genomes are present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

on the nutrient agar plate with antibiotics (streptomycin)

A

only the smooth, resistant strain (quadrant 1) and the transformed rough -> smooth, resistant strain (quadrant 4) grows because the rough strain (quadrant 2) is susceptible and quadrant 3 only contained DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Griffith’s transformation experiment – quadrant 1

A

grow the rough, susceptible strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Griffith’s transformation experiment – quadrant 2

A

grow the smooth, resistant strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Griffith’s transformation experiment – quadrant 3

A

heat kill the smooth, resistant strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Griffith’s transformation experiment – quadrant 4

A

mix the dead smooth strain with the rough, susceptible strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

proteins encoded by the lac operon

A

β-galactosidase (product of lacZ gene), lactose permease (product of lacY gene), and lactose transacetylase (product of lacA gene)

31
Q

lac transcript is polycistronic

A

it contains more than one coding sequence

32
Q

lacI

A

lac repressor; tetramer of four identical subunits… it binds to DNA near lac promoter and prevents transcription of the structural genes and it binds to the INDUCER (allolactose)– this is cooperative [binding of one molecule of inducer makes binding of the next one more favorable… repressor binds inducer in all or none fashion]… or it binds to the OPERATOR (lacO) which partially overlaps promoter [allows RNA polymerase to bind to promoter and form an open complex but not to elongate transcription]

33
Q

lacI^s

A

REPRESSED EXPRESSION; proteins never leave operator

34
Q

lacO^c

A

loss of repressor binding; CONSTITUTIVE EXPRESSION

35
Q

merozygote

A

two copies of the relevant control genes exist

36
Q

Jacob and Monod

A

used fertility plasmid (F) from E.coli to study regulation of lactose operon; used a variant (F’) that contained a normal functional copy of the lactose operon genes (normal LacI and LacZ proteins)

37
Q

ONPG

A

a colorless chemical analog of lactose used to measure enzyme activity of LacZ… when cleaved by LacZ it become yellow ortho-nitrophenol

38
Q

two grey tubes -> one grey and one pale yellow

A

lacZ

39
Q

one grey and one pale yellow -> one grey and one bright yellow

A

WT (wild type)

40
Q

two pale yellow tubes -> one grey and one pale yellow

A

lacI-

41
Q

two pale yellow tubes -> one pale yellow and one bright yellow

A

lacO^c

42
Q

two grey tubes -> two grey tubes

A

lacI^s

43
Q

enterobacteriaceae

A

family of gamma proteobacteria that includes Escherichia, Salmonella, Yersinia… BACILLI that are typically 1-5 micrometers in length… stain GRAM NEGATIVE and are FACULTATIVE ANAEROBES… can ferment sugars (all can ferment glucose and some can ferment lactose) and reduce nitrate to nitrite via ANAEROBIC RESPIRATION… generally LACK CYTOCHROME C OXIDASE… most have FLAGELLA… NON-SPORE FORMING… PRODUCE CATALASE

44
Q

coliforms

A

Members of the family enterobacteriaceae that ferment lactose

45
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

46
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

47
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)

48
Q

triple sugar iron agar (butt)

A

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

49
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

50
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

51
Q

MRVP (methyl red)

A

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

52
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

53
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

54
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

55
Q

indole negative result

A

yellow

56
Q

indole positive result

A

RED

57
Q

methyl red negative result

A

yellow

58
Q

methyl red positive result

A

RED

59
Q

voges proskauer negative result

A

no change (yellow brown)

60
Q

voges proskauer positive result

A

RED

61
Q

citrate negative result

A

green

62
Q

citrate positive result

A

BLUE

63
Q

MacConkey Agar (MAC) negative result

A

no change (not red– brown or tan)

64
Q

MacConkey Agar (MAC) positive result

A

RED

65
Q

urea negative result

A

no change (yellow)

66
Q

urea positive result

A

PINK

67
Q

TSI (slant) negative result

A

K - red

68
Q

TSI (slant) positive result

A

A - YELLOW

69
Q

TSI (Butt) negative result

A

K - red

70
Q

TSI (Butt) positive result

A

A - YELLOW

71
Q

TSI (gas) negative result

A

no change/no cracks

72
Q

TSI (gas) positive result

A

CRACKS

73
Q

TSI (H2S) negative result

A

no change/yellow

74
Q

TSI (H2S) positive result

A

BLACK

BIO 286 - Microbiology (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions