Brainscape's Knowledge GenomeTM

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


See full index

Micro Lab Quiz 1 > Micro Lab Final > Flashcards

Micro Lab Final Flashcards

1
Q

Set up Kholer illumination

A

refer to lab manual 2-9

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

Smear prep from broth culture

A

manual 3-6

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

gram stain

A

3-7

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

streak plate from broth

A

4-3

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

cell morph (terms and table prep for g stain)

A

4-13
colony colour
g rxn (-/+)
cell shapes
cell size (um)
cell grping

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

mic clean up

A

discard slides in beaker
remove oil from 100x lens w paper
10x lens and aperature
turn off light

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

set up serial dilution

A

manual 5-5

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

spread plate

A

manual 5-6

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

why is a sample turbid

A

cloudiness bc scattered light (more cells = more scatter = greater turbitity)

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

how do we meas turbidity/scattered light

A

spectrophotometer can meas dif bw amnt of light that enters sample and amnt of unscattered light that leaves sample

unit = optical density (OD)

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

what is optical density

A

directly proportional to number of cells in sample

as turb increase, so does OD

allows us to see total number of cells

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

why are OD meas’s better than plate count method

A

same broth can be checked many times and can track rate cells numbers increase

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

what is a standard curve

A

scatter plot that relates OD (y axis) to cells per mL (x axis)

to est standard curve, need to count # of cells in sample you’re taking OD reading from

get cells #’s by plate count method

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

what are the lim’s of OD to cell #’s relationship

A
  1. direct rel bw OD and # of cells/mL breaks down at high turb (rel strongest bw 10^7-9)
  2. a/t that can affect cell size/shape/grpings will change standard curve (make new curve is change org, growth med, incub condition)
  3. some bact form clumps/long chains as rep/divide and some grow in films (vortex before sampling to avoid)
  4. dif media have dif baseline optical densities dep on colour/pigmentation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is imp to know ab standard curve

A

stand curve does not provide any info ab how quickly a pop is growing

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

what is the cell density meter set to

A

600 nm for bact and yeast (not for mammalian cells)

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

why should the red set be redone every 15 min in density meter

A

avoid drift (use NB and press R)

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

when looking at series of OD readings, how do you check if they’re valid

A

should drop by half

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

what are coliforms

A

indicator organisms

from fam enterobacteriaceae that serves as index for potential contam by entero pathogens

safer, cheaper, easier faster

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

what do bacteriological evaluations of water meas

A

specific subpops of bact rather than testing for every potential pathogens individually

quality of water det’d by kinds of bact present not how many

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

what do water quality analytical procedures and purification/treatment methods rely on

A

vol, source, initial quality of water

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

what is the total coliform (TC)

A

grp of bact includes many dif genus and species

coliforms found in many env including intestinal flora (imp habitat bc many coliforms are thermotolerant and passed through fecal wastes)

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

why are coliforms used as indicators for potential contam

A
  1. natural habitats are imp sources of water contam
  2. capacity to survive fresh and marine water is similar to that of entero-pathogens
  3. density usu correlates w degree of water contam
  4. do not reprod in water (as long as water is not nutrient laden)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how do we distinguish coliforms

A

facultative aerobic
g neg
rod
non-spore forming
non motile or motile by peritrichous flagella
ferment lactose w prod of gas w in 48h at 35C

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

what is dif ab thermotolerant coliforms

A

usu of fecal origin
prod acid (alongside gas) w in 24 h at 44C

if get thermotol fecal coliforms, indicates fecal contam

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

what is the most common fecal coliform

A

Escherichia coli

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

what is imp to remember ab testing for coliform contam

A

most coliforms are not pathogenic but presence in water indicates the likely presence of pathogens

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

two techniques to test for total coliforms and/or thermotolerant (fecal coliforms)

A

membrane filtration method

most probable number of coliforms technique

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

what is selective media

A

permit or enhance growth of desired org while suppressing/inhibiting growth of another

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

what is differential media

A

support growth of dif orgs but allow orgs to be distinguished phenotypically based on their biochem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

how are g neg selected for medium in lab 7

A

bile salts, detergents, amphipathic dye salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what do bile salts do and how do enteric bact resist

A

bile salts destroy lipid bilayer of cell membrane
enteric bact resistant to them bc have crosslinked matrix which acts as exclusion barrier to phobic mols and amphi mols like detergents and bile salts and neg charge mols

33
Q

what also select for g neg

A

BG, basic fuschin, rosolic acid, aniline blue which are ph indicators

cant penetrate LPS of g neg but can stop growth of g pos

34
Q

how are coliforms differentiated from other g neg orgs

A

based on ability to ferment the sugar lactose w prod of gas

35
Q

when does fermentation occur

A

when bact/yeast import and break down a carb (sugar) from surrounding medium/env to release E w production of alcohol and/or acid and CO2

ETC not involved and e A usu pyruvate

36
Q

what is resp

A

uses ETC w O or a dif mol as final e A

37
Q

how to detect non soluble gases that may be produced during fermentation

A

use broth medium w durham tube

tube collects gas prod’d by bact during incubation

38
Q

how to detect acids prod’d during fermentation

A

add ph indicator dye to growth medium in addition to specific carb

39
Q

what is M-FC agar selective for

A

thermotolerant g neg bact based on ability to grow in presence of high incubation temps, bile salts, rosolic acid and aniline blue

differential for lactose fermenting abilities on basis of ph of major end prods

40
Q

what colour do mixed acid lactose fermentors (e coli) produce

A

dark blue colonies bc drop in ph

41
Q

what colour do butadienol lactose fermentors (enterobacter) appear

A

blue to blue grey (butad raises ph)

42
Q

what colour do lact fermentors appear

A

pink-reddish blue grey

salmonella and shigella

43
Q

issues of tsa plates

A

obs of colonies are often difficult due to crowding
no info ab hazardous bact vs harmless bact
max vol plated = 100 uL

44
Q

how does the membrane filter (MF) work

A

water passes thru sterile mem filt w pore size 0.45 um and only things smaller pass

filter then placed on sel and dif med for thermotolerant fecal coliforms (44.5C)

45
Q

MF advantages

A
  1. range of vols can be processed (can be large, up to 10L)
    2.water sol impurities that might interfere w indicator org growth pass through small pores and removed from growth medium
  2. provides precise quantitative enumeration
  3. usu only need single incubation step (fast and simple)
  4. colonies are sep’d on filter, makes downstream isolation easier
46
Q

MF disadvantages

A
  1. cant be used to test waters w high turbidity w out pre filter bc filter will clog
  2. scoring of colonies (differentiation) can be difficult if sample contains large numbers of non coliform bact and excessive crowding occurs in filter
  3. solid particles and chems may absorb to filter and interfere w growth coliforms
47
Q

calc fecal coliforms/100mL

A

fecal coliform colonies x 1/dil

48
Q

rules for M-FC

A
  1. lim 20-60 fecal coliforms (blue)
  2. <200 total col

put est if more than 200 or if no col present

49
Q

what is MPN of coliforms

A

indirect quant analysis
pos test indicated by growth and gas

50
Q

advantages of MPN

A
  1. flexible vols can be processed (<10mL)
  2. all kinds of water samples can be used
  3. stressed and injured coliforms can be recovered
  4. test is easy to set up and results easy to interpret
  5. precision and sensitivity can be increased w larger vol, many diltuions or greater number of replicate tubes
  6. media is cheap
51
Q

MPN disadvantages

A
  1. only semi quantitative
  2. precision is lower and relies on number of tubes used in test
  3. presumptive phase takes 48h + 24 (fec)/48h(tot) subculture confirmation
  4. if isolation req’d, need more steps on solid media
  5. coliforms can be suppressed or overgrown
  6. water sol impurities can affect coliform growth
  7. hard to process large vol
52
Q

what is the presumptive coliform step

A

enrichment step
medium contains peptones and lactose
g pos and neg can grow but s/t get false pos (would need selective media to confirm)
must produce gas and grow

53
Q

what is the confirmed (total) coliform test

A

only use pos from presump test
use brilliant green lactose broth (has peptones, sel dyes, lactose, bile salts)
need growth and gas

54
Q

what is the fecal (thermotolerant) coliform test

A

from presump tests that were pos
medium selects for thermotol coliforms w 44.5C inc temp
growth and gas

aka EC broth tubes

55
Q

what are the recreational water quality standards

A

health can - <500 TC/100mL
<200 fecal coliforms/100mL
<35 enterococci/100mL

US env protection agency <200 fecal coliforms/100ml

WHO <100 e coli/100 ml

56
Q

what are drinking water quality standards

A

no coliform pres/detectable

57
Q

what are enteric bact

A

oxidase-neg, catalase pos, prod acid from glucose, reduce nitrate to nitrite

many = chemoorganotrophs

hard to ID bc all g neg rods that are beige cols, round smooth

58
Q

how do enterobact break down sugars

A

embden meyerhoff pathway/glycolysis

happens during:
aerobic resp (e A = O; etc), anaer resp (NO3, CO2 etc; etc), ferm (pyruvate, not etc)

59
Q

what are the dif categories of ferm and prods generated useful for

A

ID process of orgs in ent fam

60
Q

key pts when looking at microbial fermentations

A

NADH ox’d to nad+
O2 not req’d
term e A usu pyruvate and no etc

61
Q

what are mixed acid fermentors

A

prod ethanol and stable acids

62
Q

what are butanediol fermentors

A

prod butanediol, ethanol, co2, some lactic acid and formic acid

63
Q

what is the phenol red broth test

A

general medium, not sel
have durham tube
dye = yellow at low ph; bright pink at high ph

if bact can ferment test carb, acidic end prods lower ph (yellow) and get growth

if no ferm, no acids, still get growth but neg, high ph (orange/red)

64
Q

what is MRVP broth test

A

to dif enterobact based on major ferm end prods when supplied w glucose

MR - red at low ph, yellow at high
mixed acid ferm’s prod stable acid end prods and lower ph

VP - detects for presence of acetoin (precur of but)
brown-red = pos
brown green-yellow if neg

65
Q

citrate slant

A

sel for bact that can use citrate as sole c source

bromothymol blue dye = green at low ph/blue at high ph (blue if pos)

66
Q

urea broth

A

differential for bact that are rapid urease pos (hydrolyze urea fast)

pos = high ph = neon pink
neg = pale orange/pink

67
Q

TTC motility

A

use triphenyl tetrazolium chloride semi solid agar medium

red colour where cells have grown (all enterobact can grow) but will see red beyond stab line if mobile

68
Q

SIM

A
  1. tests for sulfur reduction (get black precipitate)
  2. tests for tryptophan deamination (bact that prod tryptophanase can deaminate aa tryptophan and get indole); use kovac’s reagent
  3. motility (look for cream colour growth beyond stab line)
69
Q

which media are dif and sel

A

an blue, bril gr, carmen red, bas fusch

70
Q

which media is sel

A

bile salts

71
Q

which media is dif

A

phenol red

72
Q

Ingredient that allows the media to be differential for lactose fermentation

A

rosilci acid

73
Q

Ingredients that inhibit gram positive bacteria:

A

aniline blue, bile salts

74
Q

pos/neg phen red

A

yellow/red

75
Q

pos/neg mr

A

red/yellow-orange

76
Q

pos/neg vp

A

brown red/brown green

77
Q

pos/neg citrate

A

blue/green

78
Q

pos/neg urea

A

bright pink/pale orange

79
Q

tryptophan deamination pos/neg

A

reagent layer bright pink/yellow-orange

Micro Lab Quiz 1 (4 decks)

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