Card Set Information
Micro Laboratory Exam
Experiment 6- 11
Antisepetics are microbe- killing chemicals applied to live tissue
Example... hydrogen peroxide, rubbing alcohol , and iodine
Antibiotics are micro-killing chemical taken internally [pill/ liquid form]
Example... Penicillin, Ampicillin, Streptomycin, and Chloramphenicol
Applied to inert surfaces
Includes Chlorine bleach and Lysol
Disk- Diffusion Test
The effectiveness of these substances in killing microbes
Zone of Inhibition
The clear zone that appear around the disk.
Large the zone of inhibition the better the chemical.
Astounding diversity and number of microbes, predominantly bacterica and fungi.
Nitrogen gas that plants can utilize.
Nitrogen gas that has been converted by soil microbes to other compounds microbiological result
Example ammonia, ammonium ion and nitrate ion
Symbiotic Nitrogen- fixing bacterica
Live inside the roots of legume plants
Legume plants... clovers, beans, peas, peanuts and soybeans.
Gram-negative bacterica bind to root hair of young legume plant and cause plant to develop root nodule
Rhizobium fixes nitrogen gas into ammonia, which plant uses for nutrition
Nutrient Agar (NA)
1ml or 0.1ml has more microbes
Allows both bacteria and fungi to grow
NA 1ml has more microbes b/c 0.1ml less dilute
Czapek- Dox Agar (CD)
Discourages bacteria but encourages fungi to grow
volume of sample / (volume of sample + volume of diluent)
Pour Plate Technique
Prepare the Nutrient Agar and Czapek-Dox Agar plates.
1ml of 10
soil dilution then melted NA / CD
0.1ml of 10
soil dilution then melted NA/ CD
number of bacteria colonies and fungi colonies (fuzzy growth)
Fungus-like filamentous soil bacterica
Brown zone around the colony in surrounding agar.
Colony- Forming Units
CFU/g soil sample = (# colonies on plate) * (1/ volume of sample) * (1/dilution)
Production of ammonia from nitrogenous compounds such as casein and peptone
No ammonia or small amount of ammonia
Moderate amount of ammonia
Large amount of ammonia
yellow to orange
Unicellular, eukaryotic microbes in the Kingdom Protista.
Cause diseases in humans
Detect coliform bacteria in a water sample
follows a positive Presumptive Test, to ensure bacterial contamination due to coliforms.
Brilliant Green Bile Broth (BGBB)
used in Confirmed Test
selective medium that must indicate Gram- negative bacteria
differential medium contain lactose
gas bubble produced when coliform are grown (positive Confirmed Test)
final analysis of water sample using EMB and MAC
Eosin Methylene Blue Agar (EMB)
MacConkey Agar (MAC)
selective media that grow Gram-negative bacteria
differential media change colors when certain types of bacteria grown on them
When coliform grown on EMB agar
colonies have dark centers and green metallic sheen
When coliform grown on MAC agar
colonies will be pink/red and pink diffusate visible around the colonies
easily passed from host to host
diseases passed from host to host
one of the worst bacterial diseases of all time cause by bacterium Yersinia Petstis