Micro lab exam 3

Which one of the following would be identified using MSA (mannitol salt agar)

Staphylococcus sp.

Coagulase enzyme causes:

plasma to clot

If gram stained, proteus and enterobacter appear as:

gram - rods

using the IMViC reaction, which genus tests positive for indole and methyl red and negative for VP (acetyl methyl carbonyl) and citrate: (common in polluted water)

escherichia

If enterobacter is present and gives a negative H2S reaction on TSI agar slants what color is the medium

amber

enteric coliform are characterized by all of these except:

gram +

which of these is not a physical means of controlling microbial growth

antibiotics

If a bacterial colony with new characteristics appeared on a plate exposed to ionizing radiation it may be:

mutated

Heavy metal ions interfere with the growth of microbes due to:

oligodynamic activity

Beta hemolysis of blood and positive bacitracin test

s. Pyogenes

which of these is NOT a chemical means of controlling microbes

autoclave

a 'no growth' area around a chemical containing sensi-disc (Kirby-Bauer) is called

zone of inhibition

why can some foods be preserved by salting

dehydrate microbes

which technique is routinely used to determine the degree of contamination of foods and milk

standard plate count

when citrate agar tubes are inoculated with a bacterium that can metabolize this substrate, the medium turns what color after incubation

blue

water may carry all of the following except

lyme disease

which of the is not part of water purity testing

cell wall staining

presumptive, confirmed and completed phases are part of

MPN test

Trichomonas vaginalis is the causative agent of

vaginitis

the mordant for the gram reaction is

iodine

when transferring microbes from tube to tub or tube to plate, the means if sterilizing the loop is

flaming

which of these has the same index of refraction as glass

immersion oil

total magnification working under low power is

100x

which one permits bacterial motility

flagellum

which of these can produce spores (2 answers)

b. cereus and c. tetani

which of these would produce spores for reproduction

aspergillum
penicillin
Rhizopus
all of these

which one grows red pigmented colonies at 25c

s. marcescens

which of these grows metallic green colonies on EMB

e.coli

which of these would not grow preferentially at the top of a broth culture tube

strict anaerobes

which stain technique is used to identify e.coli 0157

gram

all of the following are basic stains except

congo red

serial dilutions were used in making

pour plates

staphylococcus aureus is not characterized by

MSA negative

which broth culture characteristic appears as uniform cloudiness

turbid

the plant body of a mold is called a cyst stage

false

Rhizomes and Aspergillus are examples of Protista

false

Candida albicans may cause lung and vaginal problems

true

when the diameter of the zone of inhibition is largest, the seeded bacterium is probably susceptible to the tested antibiotic

true

plasmodium falciparum is transmitted by a mosquito vector

true

giardiasis lamblia may cause sleeping sickness

false

Yeasts are usually unicellular and often pigmented

true

fungi such as candida and trichophyton may be parasitic

true

protozoan parasites are multicellular

false

Yeasts such as torula may be a food contaminant

true

Cephalosporium mold is a source of antibiotics

true

the red indole ring is extracted by kovac's test

true

starch with clear zones after the use of iodine indicates that amylase is active

true

enterotube tests distinguish among a family of gram positive coliforms

false

e.coli produces spores after 24 hours of growth

false

plasmodium vivid may cause and STD

false

streptococcus lactic shows a gammahemolysis and is found in yogurt

true

EMB plates are both elective and differential

true

cheese products never contain live cultures

false

methyl red is red when acid is present

true

gram negative bacteria appear purple

false

name one food which uses drying technique for prevention

fish

list one heavy mental and one chemical disinfectant that may inhibit bacterial growth

cadmium alcohol

how would you distinguish between an antiseptic and a disinfectant

an antiseptic is applied to the body and a disinfectant is applied to a non-living surface

why is the ELISA test so important in helping us to identify diseases

the acronym ensures that you Assess and Identify for the disease correctly for the proper antibiotic

why are biofilms important? explain and give specific examples of good and bad biofilms

biofilms are important to see how bacteria grows
good: pond water
bad: one on teeth

why are winogradsky columns so useful in studying a variety of aquatic and soil environments

help obtain cultures of a large variety of microbes and help display the growth of new organisms

why is electrophoresis such a helpful tool in identifying various ideas agents

it helps identify and compare different diseases for example DNA strands in gel electrophoresis move to the same location when the DNA is the same

what is the difference between a broad spectrum and a narrow spectrum antibiotic based on observations

broad is more generalized and narrow is considered more specific

what happens if 80 c nutrient agar is poured over plate count culture

it is too hot and will kill the organism needs to be cooled first

why is blood agar such a useful culture medium (give 2 reasons)

see how bacteria affects and grows in blood and more nutrients for growth

an enzyme in staphylococcus that clots plasma

coagulase

in the IMViC reactions e.coli and e.aerogenes show (choose from: same, similar or opposite) reactions

different

list a helpful role of slime molds

help consumption of dead organic materials

give a helpful role for saccharomyces

treating and preventing diarrhea

name a harmful fungus

candidiasis

list 2 positive signs that a sugar has been fermented

growth of yeast and ethanol

why is McConkey's agar considered a selective medium

it helps grow gram negative bacteria

name two helpful protists

Trichonumpha and euglena

what effects does streptococcus progenies have on blood agar

produces a clear hemolysis

name 2 harmful protists

giardia lamblia and plasmodium