Brainscape's Knowledge GenomeTM

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


See full index

Micro > Lab Quiz 2 > Flashcards

Lab Quiz 2 Flashcards

1
Q

What two things are accomplished by staining cells?

A

greater magnification with better resolution

contrast between cells and background

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

Define a dye

A

an organic compound containing chromophore and auxochrome chemical groups attached to a benzene ring

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

What part of a dye is responsible for the color

A

chromophore

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

What part of a dye increases the solubility

A

auxochrome

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

Basic dyes bind to ____ charged molecules and acidic dyes bind to ____ charged molecules

A

basic, negatively

acidic, positively

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

Why are basic dyes commonly used in bacteriology?

A

Because surfaces of bacterial cells and basic dyes bind to negative molecules

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

What’s the difference between trinitrobenzene and picric acid?

A

tribitrlobenzene has three nitro groups, which are common chromophore groups, but is not considered a dye because it is insoluble in water
picric acid is a trinitrobenzene with an hydroxyl group, an auxochrome group, which makes it soluble, and is considered a dye

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

What is an organic molecule that has a chromophore group but not an auxochrome group called?

A

chromogen

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

What is a simple stain?

A

a stain that consists of one dye that stains a component of a microbial cell

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

What does methylene blue bind to?

A

since it is basic, it binds to acidic constituents

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

What’s the basic procedure for simple staining?

A

Use a sterile loop to place a small drop of water on a slide
Add a small amount of culture to the water
Let air dry
Heat fix the sample
Apply several drops of the dye (methylene blue)
Let slide dry
Examine under microscope with immersion oil

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

What’s the purpose of heat fixing?

A

it coagulates the protein causing the organism to where to the slide

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

Approximately how big is a yeast cell?

A

7 x 15 µm

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

What is differential staining?

A

the use of two or more dyes that are used to categorize cells into groups

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

What dye did we use as a simple stain?

A

methylene blue

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

What species did we observe with simple staining?

A

Saccharomyces cerevisiae

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

What dye did we use for differential staining?

A

Gram’s staining solutions

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

What’s the basic procedure for Gram’s technique?

A 
Use a sterile loop to place a small drop of water on a slide
Add a small amount of culture to the water
Let air dry
Heat fix the sample
Apply crystal violet dye solution
Let sit for a minute
Rinse with water
Apply iodine solution
Let sit for a minute
Rinse with water
Apply decolorized drop by drop until runoff is clear
Rinse with water
Apply safranin counterstain
Let sit for 30 seconds
Rinse with water
Let dry
Examine under oil immersion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

In Gram staining, what solution is the mordant?

A

iodine

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

In Gram staining, what solution is the mordant?

A

iodine

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

What is a counterstain?

A

dye that has a color that contrasts the primary stain

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

In Gram staining, what solution is the counterstain?

A

safranin

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

What color are Gram-positive cells after staining?

A

purple

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

What color are Gram-negative cells after staining?

A

pink/red

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

What causes the differences in the gram stain reaction?

A

the structural differences between the cell walls of Gram-positive and Gram-negative cells
crystal violet-iodine complex is more readily removed from Gram-negative because Gram-positive cells have thick layers of peptidoglycan

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

What is the approximate size of a rod shaped bacterium?

A

1 x 3 microns

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

What is the approximate size of a coccus shaped bacterium?

A

1 micron in diameter

28
Q

What is the approximate size of a spiral shaped bacterium?

A

0.5 x 15 microns

29
Q

What species did we find to be Gram-negative?

A

Escherichia coli

30
Q

What species did we find to be Gram-positive?

A

Staphylococcus epidermidis

Bacillus subtilis

31
Q

Moist, glistening appearance of a colony is often due to what?

A

capsule

32
Q

What are capsules composed of?

A

polysacchraides

33
Q

What type of staining is used to visualize capsules?

A

negative stains

34
Q

What is a negative stain?

A

stains the background, rather than the organism

35
Q

What’s the dye used for negative staining?

A

India ink

36
Q

What species was observed for capsules?

A

Klebsiella

37
Q

What’s the process called that produces endospores?

A

sporulation

38
Q

What are two genera that form endospores?

A

Bacillus

Clostrridium

39
Q

When does endospore formation typically begin?

A

when cell growth ceases due to lack of nutrients

40
Q

Why can’t capsules typically be seen with normal staining?

A

they get destroyed in the process

41
Q

Why can’t spores typically be seen with normal staining?

A

resist penetration of most dyes

42
Q

What species was used to observe spores?

A

Bacillus subtilis

43
Q

What’s the basic procedure for Spore staining?

A 
Place a swab in a tube of malachite green stain
Let sit in a boiling bath for 10 minutes
Rub swab onto slide
Heat fix
Decolorize with water
Counterstain with safranin
Let sit for 30 seconds
Rinse with water
Let dry
View under oil immersion
44
Q

What is it called when a spore is still inside the vegetative cell?

A

sporangium

45
Q

Why can’t flagella typically be seen with normal staining?

A

they are way too small and can be broken easily

46
Q

What’s the name of the technique used to visualize flagella?

A

Leifson’s Technique

47
Q

What two things are used during Leifson’s Technique? What do they do when added together?

A

dye and mordant; they form a complex that causes the flagellum to increase in diameter and become colorized

48
Q

What’s the name of the technique used to determine if it’s acid-fast?

A

Ziehl-Neelsen

49
Q

What dye is used in Ziehl-Neelsen stain?

A

carbol fuchsin

50
Q

What counterstain is used in Ziehl-Neelsen stain?

A

methylene blue

51
Q

How do acid-fast organisms react to staining?

A

resist decolorization

52
Q

Acid-fastness is characteristic of what genus?

A

Mycobacterium

53
Q

What species did we find to be acid-fast?

A

Mycobacterium phlei

54
Q

What species did we find to not be acid-fast?

A

Staphylococcus epidermidis

55
Q

Describe the basic technique for Acid-fast staining

A 
Swab the first species and mix into carbon fuchsin stain
Swab the second species and place swab in the tube of carbon fuchsin stain
Let sit in a boiling bath for 10 minutes
Rub swab onto slide
Heat fix
Decolorize with acid alcohol
Rinse with water
Counterstain with methylene blue
Let sit for 30 seconds
Rinse with water
Let dry
View under oil immersion
56
Q

What are granules?

A

reserves of materials that sometimes accumulate in bacterial cells

57
Q

What are metachromatic granules?

A

reserves of polymerized meta phosphates that appear dark blue when stained with methylene blue

58
Q

What species was used to observe granules?

A

Corynebacterium xerosis

59
Q

What stains were used for granule staining?

A

methylene blue and neutral red as counterstain

60
Q

What happens if the cell wall is removed in a hypotonic solution?

A

water will flow in and it will lyse

61
Q

What happens if the cell wall is removed in a hypertonic solution?

A

water will flow out and the cytoplasm will shrivel

62
Q

What happens if the cell wall is removed in an isotonic solution?

A

cell contents will become spherical and continue metabolic functions - become protoplasts

63
Q

What enzyme is used to remove cell walls?

A

lysozyme

64
Q

How does lysozyme work?

A

attacks peptidoglycan by hydrolyzing the glycosidic bond

65
Q

What species was used to observe protoplasts?

A

Bacillus subtilis

Micro (15 decks)

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