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MICB 3301 Lab > Quiz 2 > Flashcards

Quiz 2 Flashcards

(52 cards)

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1
Q

Dye

A

An organic compound containing chromophore and auxochrome chemical groupings attached to benzene rings

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2
Q

Chromophore

A

The structural grouping responsible for color
* -NN (azo)
* -NO (nitrose)
* -NO2 (nitro)
* -CS (thio)

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3
Q

Auxochrome

A

Groups that increase the solubility of the molecule and augment the effects of chromophore groups
* -NH2 (amino)
* -OH (hydroxyl)

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4
Q

Basic Dye

A

Salt dissociates into a positively charged chromogenic ion (cation) and an anion, often used in bacteriology due to most cells being negatively charges

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5
Q

Acidic Dye

A

Salt dissociates into a negatively charged chromogenic ion (anion) and a metal cation, also bind to positively charged microbial structures

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6
Q

Trinitrobenzene

A

Benzene with 3 NO2 groups in the meta/para/ortho orientations

Produce a yellow chromogen (not true dye as it is not soluble)

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7
Q

Picric Acid

A

Benzene with 3 NO2 groups in the meta/para/ortho orientations, and also had a hydroxyl group

Acidic dye, where the nitro radical is the chromophore group and the hydroxyl radical the auxochrome group

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8
Q

Simple Stain

A

Consists of one dye that stains a component of the microbial cell

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9
Q

Most useful simple stain, basic, used in diagnosis of diptheria

A

Methylene blue

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10
Q

3A

A

Simple staining procedure using yeast (Saccharomyces cerevisiae) sample and methylene blue

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11
Q

Saccharomyces cerevisiae

A

Yeast culture used in exercise 3A

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12
Q

Differential Stains

A

Use two or more dyes and can be used to categorize cells into groups (ex. Gram staining)

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13
Q

Gram Stain Procedure (3B)

A
  1. Prepare on a single slide smears of each species (Staphylococcus epidermidis, Bacillus subtilis, and Escherichia coli)
  2. Once coagulated using heat set, apply drops of crystal violet, let rest for 1 minute then rinse with water
  3. Cover with fresh iodine solution, let rest for 1 minute before rinsing with water
  4. Add decolorizer dropwise to smear until no more primary stain is observed (2-5 secs)
  5. Gently rinse with water 2-5 secs
  6. Counterstain for 30 secs with 2% aq. safranin and rinse the slide with water for 2-5 secs
  7. Carefully blot the slide dry
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14
Q

Negative Stain (3C)

A

Consists of staining the background rather than the microorganism, which appears as clear spaces (observed Klebsiella)

India ink is often used, which is a negatively charged dye that repels the negative bacterial components

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15
Q

Endospores

A

Dormant structures produced by the “mother cell” during the process of sporulation, which is viewed as a survival mechanism during periods of cell starvation

Created by members of the genera Bacillus and Clostridium

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16
Q

Spore Staining (3D)

A

Malachite green (basic dye) penetrates the Bacillus subtilis spore wall when heated. After that, the vegetative cell is counterstained with 0.5% aq. safranin

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17
Q

Flagella Staining (3E)

A

Utilizes the mordant to make the flagella visible under dark-field microscopy

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18
Q

Mordant

A

Precipitates onto the flagella to increase their diameter to a size within, also sets stain in other applications

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19
Q

Acid-Fast Staining (3F)

A

Acid-fast bacteria resist decolorization with acidified alcohol, a characterisitc of members of the genus Mycobacterium (causative agent of tuberculosis) which are resistant to Gram staining.

Stain Mycobacterium phlei and Staphylococcus epidermidis samples with Ziehl’s carbol fuchsin before decolorizing with acidified alcohol and counterstaining with methylene blue. Also test Gram stain to visualize resistance of M. phlei

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20
Q

Acid-Fast Staining Procedure

A
  1. Swab bacteria culture, take swab and rotate in 10-15 drops of carbol fuchsin (dark blue)
  2. Immerse tube into a boiling water bath for 10 minutes
  3. Remove the stained suspension, roll swab across a slide to make a smear, heat fix over a Bunsen burner
  4. Decolorize with acid alcohol, 2-5 secs
  5. Rinse, counterstain with methylene blue, 10-30 secs
  6. Rinse for 2-5 secs, blot to dry
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21
Q

Acid-Fast Staining Procedure

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A
  1. Swab bacteria culture, take swab and rotate in 10-15 drops of carbol fuchsin (dark blue)
  2. Immerse tube into a boiling water bath for 10 minutes
  3. Remove the stained suspension, roll swab across a slide to make a smear, heat fix over a Bunsen burner
  4. Decolorize with acid alcohol, 2-5 secs
  5. Rinse, counterstain with methylene blue, 10-30 secs
  6. Rinse for 2-5 secs, blot to dry
22
Q

Metachromatic Granules

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A

Considered to be reserves of polymerized meta phosphates and sometimes called volutin

Found in several bacteria, including Corynebacterium diphtheriae (causative agent of diphtheria)

23
Q

Granule Staining (3G)

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A

Using Albert stain, cytoplasm stains green while granules stain dark blue

24
Q

Lysozyme

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A

Used in tandem with sucrose and water, can degrade the bacterial cell wall

25
Variable Staining
Occurs when older cultures are Gram stained, does not provide definitive +/- staining
26
3 Diseases Caused by Spore-Forming Bacteria
1. Anthrax 2. Tetanus 3. Botulism
27
What is the purpose of heating a stain?
To set the stain quickly
28
Why do members of the genus *Mycobacterium* resist Gram staining?
Due to high lipid content of the cell wall, stain cannot attach. Using carbol fuschsin and steam from heating causes the stain to set
29
Fungi are divided into
Yeasts and molds
30
Hyphae
A branching filament that extends with fungal cell growth
31
Mycelium
The closely interwoven network of hyphae, formed by **molds**
32
Hyphal Cell Walls
* Comprised of chitin * Can have regular cross-walls in structure (septate) or not (aseptate)
33
Sporangiospores
Develop in saclike structures located at the tips of hyphae
34
Conidiospores
Not enclosed within a sac, often located at the tips or sides of hyphae where they play an important role in dispersal
35
*Chytridiomycota*
Simplest of fungi, unique in formation of motile zoospores with flagella, sexual and asexual reproduction
36
*Zygomycota*
Common in soil and decaying plant material, hyphae lack cross-walls (aseptate), sexual and asexual reproduction (ex. bread mold *Rhizopus*)
37
Ascomycota
Named for sac-like reproductive structure called the ascus, major decomposers in a variety of terrestrial environments, sexual and asexual reproduction (ex. *Aspergillus* and *Saccharomyces cerevisiae*)
38
*Basidiomycota*
Club fungi, named for their characteristic spore-producing structure called the basidium, sexual and asexual reproduction (ex. *Cryptococcus neoformans* and many mushrooms)
39
Growth Features of Fungi Procedure (4)
1. Gather tape mounts of *Rhizopus nigricans* and *Aspergillus* that have had their spores killed 2. Place 1-2 drops of Lactophenol Blue stain on glass before placing the tape over top
40
Vegetative Hyphae
A portion of the mycelium adhered to the agar substrate, used by the mold to obtain nutrients and anchor it to the medium
41
Aerial Hyphae
Conspicuous strands that project upward and frequently produce spores
42
Rhizoids
Attaching vegetative hyphae of the *Rhizopus* genus
43
Stolon
Aerial hyphae that connect adjacent rhizoids
44
Sporangiophore
The fertile hyphal stalk bearing enlarged, black, spore-containing sporangium at its tip
45
Conidiophore
The upright, spore-bearing stalk
46
Conidiospores
The spores that are borne externally in short chains over the whole surface
47
Molds and Yeasts
* Both fungi * Both have hyphae * Both produce spores, can reproduce sexually or asexually
48
Bacteria and Fungi
* Both can produce asexually * Both can be stained
49
Batch Culture
A closed culture vessel with a single batch of medium. Isolation allows for **growth curve** analysis
50
Petroff-Hausser Counting Chamber
Specifically ruled for the counting of bacteria, a drawback is that it can be difficult to determine if cells are alive or dead (countered with the use of live/dead cell staining) Allows us to determine the # of cells per mL
51
Spectrophotometer
Comprised of a light source, a sample through which the light passes, and a photocell to measure optical density (OD) An increase in population of bacteria in a batch culture = a decrease in light reflected (increase in OD reading), proportional to biomass
52
Cell Enumeration Techniques
1. Total microscopic count using the Petroff-Hausser counter 2. Spectrophotometric determination of the optical density of a cell suspension 3. Viable count 4. Dry weight determination

MICB 3301 Lab (5 decks)

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