Lab quiz 2

what is the refractive index of bacteria similar to

water

what is essential for structure and morphological detail

greater magnification with better resolution

contrast between cells and the backround

definition of a dye

organic compound containing chromophore and auxochrome

what are chromophore and auxochrome

chemical grouping attachted to benzene ring

what is chromophore resbonsible for

color

examples of chromophore

NN(aso)

NO(nitrose)

NO₂(nitro)

CS(thio)

what is auxochrome resbonsible for

increasing solubility of the molecule and enhance the chromophore group

examples of auxochrome

NH₂(amino)

OH(hydroxyl)

how are dyes classified

as acidic or basic

depending on if the salt is formed with a base or an acid

how acidic dye works

the salt dissociates into negatively charged chromogenic ion (anion) and metal cations

acid dye features

their negative charge bind to positively charged microbial structures

how basic dye works

salt dissociates into positively charged chromogenic ion (cation) and an anion

features of basic dye

beind to negatively charged molecules like nucleic acid and many proteind

why is basic dye commonly used in bacteriology

bacterial cell walls are often negatively charged

what is benzene

colorless cyclic six carbon compound with no staining properties

how to form yellow colored derivative with benzene ring

replace 3 alternating hydrogens with nitro (NO₂) radicals

what is the yellow colored derivative using benzene ring called

trinitrobenzene

what is a chromogen

gives a color but not a true dye because it is insoluble in water

features of trinitrobenzene

a chromogen that contains chromophore groups not a true dye

what is made by replacing a hydrogen in trinitrobenezne with a hydroxyl group

picric acid dye

features of picric acid

soluble and dissociates slightly froming salts with bases

what type of dye is picric acid and why

acidic dye

the chromogentic potion dissociates in solution to anions able to make salts with bases

what is a simple stain

one dye that stains a component of the microbial cell

what is the most usful dye

basic dye methylene blue

acidic components of the cell that stain more deeply then less acidic components examples

metachromatic granules or voltuin

what is methylene blue useful in diagnosing and what do they stain

diphtheria-stain throat smears

also stain raw milk

how are smears of blood stained

using methylene blue in combination with eosin

what happens when methylene blue is in combination with eosin on lactose agar base

produces a medium inhibitory to gram + bacteria

what is a medium inhibitory to gram + bacteria good for differenciating

E.coli and Enterobacter aerogenes

materials for simple stain Ex 3A

Saccharomyces cerevisiae

loeffler’s methylene blue

do stained smears use a cover slip

NO

what to focus on first with microscope to examine stain specimen

a clear color pattern under low objective

what is a differential stain

uses two or more dyes and can be used to categorize cells into groups

what is the primary stain in gram staining

crystal violet

what is the mordant stain in gram staining

iodine solution

what is the decolorizer stain in gram staining

ethyl alcohol

what is a mordant

a chemical that fixes a dye in or on a substance by combing with dye to from an insoluble compound

what type of counterstain is needed in gram staining

basic dye

what is a counterstain

has color that contrasts with primary stain

what is an important factor when gram staining

the age of the culture

how does gram positive old culture act when gram staining

acts as a negative gram stain

how young are cultures recommended to be

12 to 18 hours

materials for frist gram stain Ex3B

Staphylococcus epidermidis Bacillus subtilis Escherichia coli

what do capsules look like

moist glistening appearance

what are capsules being correlated to

formation of disease producing abilities

why can u not normally see capsules when staining

gummy material is destroyed or distorted in preparation

what stain technique is best to see capsules

negative staining

what does the negative stain actually stain

background not microorganism

how organisms look with negative staining

as clear spaces in a colored background

how negativ staining works

since microorganisms carry a negative electric charge the similarly charged colloidal dyes are repelled by them

what dye can be used for negative stains

india ink and nigrosin

what bacteria was used in negative stain demo Ex3C

Klebsiella

why is it difficult to stain flagella

flagella is extremely small in diameter and easily breakable

what is the basic reagent of all flagella staining

a mordant which precipitates onto the flagella to increase diameter to a size that can be seen by microscope

is a true picture of flagella staining ever achieved

no

what has been using for observation of the flagella

dark field illumination

how is flagella stained(name of procedure)

leifson’s technique

how leifson staining procedure works

mordant and dye are mixed and ADDED AT THE SAME TIME they form a precipitate that when absorbed by the flagella increases the diameter and becomes colorized

spore staining compared to gram staining

spore staining is more rigorous

how Ziehl Neelsen stain works(acid fast staining)

bacteria is stained with carbol fuchsin and washed then decolorized using acidified alcohol then counter stained with methylene blue

what is an acid fast bacteria

it resists the decolorization of acidified alcohol

example of acid fast bacteria

mycobacterium

features of mycobacterium cell wall

gram + but has a very high lipid concentration and contains waxes called mycolic acid

what are mycolic acid

wax in G+ cell wall of mycobactrium that IS IMPERVIOUS TO GRAM STAINING

acid fast staining applied to clinical material

stain sputum which is useful in diagnoses of tuberculosis

what causes turberculosis

Mycobacterium tuberculosis

materials in acid fast stain Ex3F

Mycobacterium phlei and Staphylococcus epidermidis

ziehls carbol fuchin and loeffer’s methylene blue

acidified alc (3% HCl in 95% ethyl alcohol)

what was the heated plate set to

80C

what are insoluble granules

materials that accumulate in bacterial cell

what are metachromatic granules

reserves of polymerized meta phosphates and sometime called volutin

what bacteria contain metachromatic granules

Corynebacterium diphtheriae it causes diphtheria

where does the name metachromatic come from

granules property of changing colors

what deeply stain metachromatic granules how does it apear

methylene blue

granules are dark blue on light blue cell

what happens when you use loeffers methylene blue for granule staining

polychrom effect — slight alkalinity of the staining solution brings purple and violet red shades from the methylene blue

what differential stain is used for metachromatic granules

albert stain-used for diphtheria

how albert stain works

two basic dyes toluidine blue and malachite green when stained cytoplasm of bacillus shaped C.diphtheria stains green while granules are blueish black

bacteria used for granule stain demo Ex3G

Corynebacterium xerosis

what are protoplasts

cells with no cell walls

what can remove cell walls

lysozyme it attacks peptidoglycan

how does lysozyme break peptidoglycan

hydrolyzes the glycosidic bond connect NAM to NAG

bacteria use in protoplast demo Ex3H

Bacillus subtilis

fungi habitats

usally terrestrial some are aquatic

what are fungi nutritionaly

chemoorganohetrotrophs

how do fungi feed

by secreting exoenzymes into the environment and then absorbing digested nutrients

what are molds

multicellular filamentous fungi that form branching network of cells

examples of molds

Penicillium

bread mold Rhizopus

what are yeast

unicellular fungi that can reproduce sexually through the formation of spores or asexualy known as budding

examples of yeast

Candida albicans

Saccharomyces cerevisia

what are mushrooms

macroscopic fruiting bodies of certin fungi

what does mushrooms grow under ground

network of hyphae called mycelium

mycelium primary role

produce and release spores

what are you looking at when looking at a mushroom

reproductive structure of a fungus

how does growth begin for mushrooms

formation of a small filament as a fungal spore germenates or grows out

what typicaly forms mycelium

mold

what is the hyphae cell walls made of

polysaccharide chitin

what is a septate

individual hyphae with regular cross walls

what is aseptate or nonseptate

hyphae not inturrupted by cross walls and usally have multiple nuclei dispearsed throughout hyphae structure

sporangiospores

develope in saclike structures located at the tips of hyphae

Conidiospores

not enclosed in a sac usally located at either tips or sides of hyphae important in spore dispersal

4 major subdivisions of fungi

Chytridiomycota

Zygomycota

Ascomycota

Basidiomycota