Brainscape's Knowledge GenomeTM

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


See full index

Micro (L) > Microbiology Lab Practical 1 > Flashcards

Microbiology Lab Practical 1 Flashcards

1
Q

What are the general nutritional requirements for growth?

A
  • water

- chemical element

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

The 4 physical factors that affect growth of an organism?

A
  • salt and sugar concentration
  • temperature
  • oxygen gas
  • pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What ingredient is used as a solidifying agent in media?

A

agar

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

What type of organism makes up agar media?

A

algae

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

what percentage of organisms can be cultured in an artificial (laboratory) setting?

A

1 percent

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

By what process do most bacteria divide?

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

The temperature (in celsius) for the the freezer is?

A

-20 degrees

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

The temperature (in celsius) for refrigerator is?

A

4-10 degrees

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

The temperature (in celsius) for room temperature is?

A

20-25 degrees

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

The temperature (in celsius) for body temperature is?

A

37 degrees

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

What percentage of organisms require oxygen for growth?

A

50%

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

Define negative control?

A
  • no growth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define positive control?

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

Why might an organism fail to grow?

A
  • none made it alive, dies before
  • culture is bad
  • physical conditions aren’t correct
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why might two different organisms show exactly the same growth features even if they aren’t supposed to?

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

what is a meniscus?

A
  • the concave appearance artifact
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What growth patterns are similar or different among the organisms tested?

A
  • bacillus only had a pellicle

- staph/e.coli were both turbid

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

Is it possible for an organism to produce more than one growth pattern in the same tube?

A

yes

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

A film growth on the surface is a what?

A

pellicle

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

Even cloudiness is called what?

A

uniform fine turbidity

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

Growth adhering to the lass at the liquid/air interface is called what?

A

a ring

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

Suspended flakes or particles are called?

A

flocculent

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

A layer of growth at the bottom of the broth is called?

A

sediment

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

How do you calculate total magnification?

A

objective x ocular = total magnification

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

If a student wants to learn morphology, arrangement and motility of an organism what type of preparations would they use?

A
  • wet mount preparation or the hanging drop procedure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Dyes that are positively charged are attracted to which components of cells?

A
  • negative components of living cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What charged dye will cause the cell to pick up the color?

A
  • positively charged dye
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Dyes that are negatively charged are attracted to what charge components?

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

What is a simple stain?

A
  • a procedure that uses one positively charged dye to give cells color
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are some examples of simple stains?

A
  • methylene blue, crystal violet, safranin, and manevals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What a negative stain?

A
  • a procedure that uses a negatively charged dye to stain the background while the cells remain virtually colorless
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are some examples of negatively charged acidic dyes?

A
  • eosin, india ink, migrosin and congo red
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is morphology?

A
  • shape
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are some advantages of making a heat fixed smear?

A
  • kills the organisms
  • organisms adhere to the slide
  • organisms take up the stain more readily
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are some disadvantages of making a heat fixed smear?

A
  • distorts the true size of the cell
  • may destroy heat- sensitive cell structures
  • may create artifacts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Why is simple staining not very useful for examining living organisms or to test an orgamism’s motility?

A
  • because many of the dyes re toxic to the cells and can paralyze flagella, cilia and so forth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Living cells have a net (negative or positive) charge and negative staining uses (negatively or positively) charged dye which is repelled by the cell’s charge.

A

Negative, Negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Why is it important NOT to heat-fix a smear that will undergo negative staining?

A

bc with negative staining you’re usually trying to identify heat-sensitive structures and heat fixation can distort the morphology and size of a cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Why do physicians rely on gram staining results for prescribing antibiotics?

A
  • some antibiotics will kill gram positive, some will kill/inhibit gram negative bacteria. Some will kill a wide array of bacteria including normal flora
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Why do older cultures stain unreliably with gram stain protocol?

A
  • waste products accumulate and break down cell walls as cultures age. Cells that usually stain gram positive will look gram negative
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What genera of bacteria may not gram stain reliably?

A
  • the mycobacterium species wont stain. They’ll look barely visible
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

How does iodine function?

A

iodine acts as a mordant. It forms a molecular bond with the crystal-violet

43
Q

Gram negative cells have ________ cell walls surrounded by _________. They will _______ the crystal-violet-iodine complex during decolorization.

A

very thin, outter lipid membrane called lipopolysaccharide, not retain

44
Q

Gram positive cells have ______________ cell walls. They will _______ the crystal-violet-iodine complex during decolorization.

A

very thick, retain

45
Q

if a gram positive cell is overdecolorized, it will be the color _____.

A

red

46
Q

if a gram negative cell is underdecolorized it will be the color ______.

A

purple

47
Q

Skipping the iodine step means that gram positive cells will appear _________ at the end of the protocol.

A

red

48
Q

What cell wall structure causes the stringing in the KOH test?

A

the DNA

49
Q

Why is the gram stain result important for treating physicians?

A
  • for prescribing an appropriate antibiotic and to learn the morphology and arrangement of the organism
50
Q

Which test(s) yields the quickest result ? KOH, Vancomycin or gram stain

A 
KOH
#2 gram
#3 vancomycian
51
Q

What is the advantage of performing all 3 test (KOH Vancomycian and gram stain) on an unknown specimen?

A
  • the three tests together provide a more accurate result
52
Q

What are the two genera of endospore-forming bacteria mentioned in exercise 9?

A

bacillus spp.

clostridium spp.

53
Q

Endospores are (metabolically active or inactive) while vegetative cells are (metabolically active or inactive) ?

A

inactive, active

54
Q

What is the purpose of steaming the slide while staiing the Malachite Green?

A

it increases the porosity of spore coat so stain can penetrate

55
Q

Define sporogenesis

A

the creation of an endospore

56
Q

Define germination

A

the conversion of an endospore to a vegetative cell

57
Q

What color will endospores and free spores be following the staining protocol?

A

green

58
Q

What color will vegetative cells be following the staining protocol?

A

red

59
Q

The role of water in the endospore staining protocol is (2)..

A
  • to rinse the slide of excess stain, and to decolorize malachite green from vegetative cells
60
Q

Why might a young (18 hour) culture of endospore-forming bacteria fail to have endospores? explain

A

because to produce an endospore the cell must be in harsh conditions. A young cell is not yet nutritionally stresses.

61
Q

What are three functions that capsules serve?

A
  • protect cell from desiccation
  • protect from phagocytosis
  • allows organisms to stick to each other
62
Q

Water functions as a _____ in the capsule stain.

A

decolorizer

63
Q

Is congo red a negative or positive stain? does it stain the organism or the background?

A

negative stain, stains the background

64
Q

Is maneval’s a negative or positive stain? does it stain the background or the organism?

A
  • positive stain, stains the organism
65
Q

How does TTC function in motility media?

A
  • as a tracking dye
66
Q

What might cause false positive results in the test using motility medium?

A

you could have contaminated probe…it could have moved a bit inside the medium, gas bubbles could’ve exploded and shot organisms outward

67
Q

Why is motility medium semi-solid?

A

it ensure that the motile organism will be able to swim away from the stab line

68
Q

when performing hanging drop, how is it possible to distinguish true motility from brownian motion?

A

make sure they are moving in a purposeful direction not not just vibrating in place. make sure you’re not mistaking dehydration for movement

69
Q

Describe proteus vulgaris flagellar arrangement.

A
  • had flagella all around the edges, peritrichous
70
Q

Describe spirillum voluntans flagellar arrangement.

A
  • only had flagella on the opposite ends (amphirichous)
71
Q

What was the purpose of flame sterilizing the inoculation loop in between quadrants during the streak plate technique?

A
  • to ensure you don’t pick up too much bacteria into the next quadrant. flaming it ensures you start with a clean loop into the next quadrant.
72
Q

If you have growth in quadrant one but none in 2-4 what may have caused this? streak plate technique

A
  • not waiting for the inoculation loop to cool can kill the organisms not allowing it to grow
73
Q

What sample from your own body could you have used as a mixed culture during the streak plate technique?

A
  • nose, mouth, feces, sputum, saliva, sweat
74
Q

Why is it so important to isolate organisms from a mixed culture into a pure culture?

A

for species identification, antibiotic susceptibility testing and other necessary tests
- can’t carry out copulates with a mixed culture

75
Q

Define viable

A

only counts the LIVING cells

76
Q

what is dilution?

A
  • dilution is reducting the concentration of a substance.

- it’s a fraction and in scientific notation is a negative number

77
Q

what is dilution factor?

A
  • the FACTOR by which the substance has been diluted.

- the reciprocal of the dilution

78
Q

How is MacConkey Agar both selective and differential?

A
  • it is used in selective for detecting enteric bacteria (gram negative). It is used as a differential media when differentiating between lactose fermenters (pinkish colonies)and non-lactose fermenters (beige color)
79
Q

How would you characterize a dilution series plate containing 419 CFUs?

A

too numerous to count (TNTC)

80
Q

How would you characterize a dilution series plate containing 28 CFUs?

A

too few to count (TFTC)

81
Q

How many CFUs/ml are generally present in the urine of young women?

A

10^2 - 10^3 mixed bacterial colonies

82
Q

For the urine test, why might an uncircumcised male yield higher colony counts than an circumcised male?

A

the difference in anatomy

- mucous membranes cover urethra and bacteria is in this

83
Q

How are quantitative and semi-quantitative counts different?

A

quantitative count are used to count the NUMBER of living bacteria in a unit volume
- semi-quantitative is a rough estimate in an unknown volume

84
Q

What color are the colonies produced by E.coli on BBL chrome agar orientation medium

A

dark rose-pink

85
Q

What color are the colonies produced by KES on BBL chrome agar orientation medium

A

medium blue to dark blue

86
Q

What color are the colonies produced by PMP on BBL chrome agar orientation medium

A

pale-beige colonies surrounded by dark halos

87
Q

Steps of gram stain

A
  • Crystal violet
  • Rinse with water
  • Iodine (mordant)
  • Rinse with water
  • Decolorize with ethanol/acetone
  • Rinse with water
  • Counterstain with safranin
88
Q

Steps of capsule stain

A
  • Congo red to emulsify cells (negative stain that gives background color
  • Maneval’s stain (positive stain to give cells color)
  • Decolorize with water (to decolorize the capsule)

*smears are not heat-fixed

89
Q

Steps of endospore staining?

A
  • Steam smear and stain with Malachite Green (steam drives MG into spore coat)
  • Decolorize vegetative cells with water
  • Counterstain vegetative cells with Safranin
90
Q

Antibiotics are ___ that word to inhibit or ____ microorganisms.

A

chemicals, kill

91
Q

Antimicrobials that target bacteria are usually called _____

A
  • antibiotics
92
Q

An antimicrobial that kills bacteria

A

bactericidial

93
Q

an antibiotic that inhibits bacteria

A

bacteriostatic

94
Q

The antibiotic targets in bacterial cells

A

peptidoglycan, 70’s ribosome, bacterial nucleic acid synthesis enzymes, antimetabolites, cell membrane

95
Q

Penicillin is ___ and inhibits ________

A

bactericidal, peptidoglycan synthsis

96
Q

Synthetic sulfonamides are ___ and are considered antimetabolites

A

bacteriostatic

97
Q

Quinolones interfere with _____replication

A

DNA

98
Q

Tetracycline interferes with bacterial ______ by inhibiting the _______________ ribosome.

A

protein synthesis, 70s

99
Q

Define broad spectrum

A

antibiotics that are effective against a wide array of bactria

100
Q

Define narrow spectrum

A

antibiotics that are effective aainst a narrow array of bacteria

101
Q

Define antibiotic

A

substance produced by one microorganism (typically a fungal or bacterial organism) that inhibits or kills another microorganism.

102
Q

Define semisynthetic antibiotic

A

chemically altered version of a naturally-produced antibiotic.

103
Q

Define zone of inhibition

A

the clear ring around an antimicrobial disk. It represents an area of growth inhibition.

104
Q

Define Mueller-Hinton agar

A

Medium used; contains added buffers to prevent wide fluctuations in pH, that might otherwise alter the effectiveness of the antimicrobials being tested.

Micro (L) (14 decks)

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