MICROBIOLOGY LAB 250 PRACTICAL EXAM QUESTIONS
WITH CORRECT ANSWERS COMPILATION
Petri Dish - ✔✔ Flat dish used for culturing microorganisms on agar, keep closed to minimize
air exposure.
Sterilization - ✔✔ Process of eliminating all microorganisms from surfaces.
Disinfecting - ✔✔ Reducing microbial load on surfaces before use.
Inoculating Loop - ✔✔ Tool used to transfer microorganisms to media.
Stir Bar - ✔✔ Magnetic device used to stir liquids in flasks.
Contamination - ✔✔ Unwanted introduction of microorganisms into cultures.
Optimal Sterilizing Temperature - ✔✔ Temperature required for effective sterilization
(1500°F/816 C).
Microbial Growth Examination - ✔✔ Analyzing colonies on agar for research purposes.
Culture Preparation - ✔✔ Process of creating media for growing microorganisms.
Aseptic - ✔✔ sterile state resulting from proper use of microbial control protocols
,Fomite - ✔✔ inanimate item that may harbor microbes and aid in disease transmission
Antiseptic - ✔✔ antimicrobial chemical that can be used safely on living tissue
Storage of plates and why - ✔✔ store upside down (agar side up) to prevent excess condensation
forming in the lid bc it could drip onto the agar causing issues with the experiment or increasing
the risk of contamination.
Does handwashing disinfect or sterilize. - ✔✔ disinfects b/c handwashing just reduces the
number of pathogens whereas sterilization removes all microorganisms
Flask cleaning - ✔✔ Immediately flush the flask with hot tap water to remove any remaining
agar
List 4 things you can do for aseptic techniques - ✔✔ 1. cleaning and disinfecting lab surfaces
prior to use
2. effectivley sterilizing equipment
TSA - ✔✔ Trypticase Soy Agar
Aseptic technique - ✔✔ Sterility technique
Degree to turn the 4 streak plate between each spread area? - ✔✔ 90
,What materials are used for a spread plate? - ✔✔ bent glass rod, petri dish, 95% ethyl alcohol
What 5 characteristics are used to described Nutrient Agar SLANTS? - ✔✔ 1) abundance of
growth
2) pigmentation
3) optical characteristics
4) forms
5) consistency
What 5 characteristics are used to described Nutrient Agar PLATES? - ✔✔ 1) size
2) pigmentation
3) form
4) margin
5) elevation
Describe form: circular - ✔✔ unbroken, peripheral edge
Describe form: irregular - ✔✔ indented, peripheral edge
Describe form: rhizoid - ✔✔ rootlike spreading growth
Describe margin: entire - ✔✔ sharply defined, even
, Describe margin: lobate - ✔✔ marked indentations
Describe margin: undulate - ✔✔ wavy idnentations
Describe margin: serrate - ✔✔ toothlike appearance
Describe margin: filamentous - ✔✔ threadlike, spreading edge
Describe elevation: flat - ✔✔ elevation not discernible
Aseptic Technique - ✔✔ Methods to prevent microbial contamination of the culture, the
environment, and the individual.
Agar - ✔✔ Polysaccharide from algae used to help solidify media, when heated it will melt & go
into solution and remain liquid until cooled to ab 45 C .
Broth - ✔✔ Liquid medium for growing microorganisms.
Hot Plate - ✔✔ Heating device used to dissolve & sterilize agar in media.
Tryptic Soy Agar (TSA) - ✔✔ Common complex culture medium for bacteria.
Microincinerator - ✔✔ Gasless, flameless sterilizer using infrared heat, creates an updraft to
prevent contamination.
WITH CORRECT ANSWERS COMPILATION
Petri Dish - ✔✔ Flat dish used for culturing microorganisms on agar, keep closed to minimize
air exposure.
Sterilization - ✔✔ Process of eliminating all microorganisms from surfaces.
Disinfecting - ✔✔ Reducing microbial load on surfaces before use.
Inoculating Loop - ✔✔ Tool used to transfer microorganisms to media.
Stir Bar - ✔✔ Magnetic device used to stir liquids in flasks.
Contamination - ✔✔ Unwanted introduction of microorganisms into cultures.
Optimal Sterilizing Temperature - ✔✔ Temperature required for effective sterilization
(1500°F/816 C).
Microbial Growth Examination - ✔✔ Analyzing colonies on agar for research purposes.
Culture Preparation - ✔✔ Process of creating media for growing microorganisms.
Aseptic - ✔✔ sterile state resulting from proper use of microbial control protocols
,Fomite - ✔✔ inanimate item that may harbor microbes and aid in disease transmission
Antiseptic - ✔✔ antimicrobial chemical that can be used safely on living tissue
Storage of plates and why - ✔✔ store upside down (agar side up) to prevent excess condensation
forming in the lid bc it could drip onto the agar causing issues with the experiment or increasing
the risk of contamination.
Does handwashing disinfect or sterilize. - ✔✔ disinfects b/c handwashing just reduces the
number of pathogens whereas sterilization removes all microorganisms
Flask cleaning - ✔✔ Immediately flush the flask with hot tap water to remove any remaining
agar
List 4 things you can do for aseptic techniques - ✔✔ 1. cleaning and disinfecting lab surfaces
prior to use
2. effectivley sterilizing equipment
TSA - ✔✔ Trypticase Soy Agar
Aseptic technique - ✔✔ Sterility technique
Degree to turn the 4 streak plate between each spread area? - ✔✔ 90
,What materials are used for a spread plate? - ✔✔ bent glass rod, petri dish, 95% ethyl alcohol
What 5 characteristics are used to described Nutrient Agar SLANTS? - ✔✔ 1) abundance of
growth
2) pigmentation
3) optical characteristics
4) forms
5) consistency
What 5 characteristics are used to described Nutrient Agar PLATES? - ✔✔ 1) size
2) pigmentation
3) form
4) margin
5) elevation
Describe form: circular - ✔✔ unbroken, peripheral edge
Describe form: irregular - ✔✔ indented, peripheral edge
Describe form: rhizoid - ✔✔ rootlike spreading growth
Describe margin: entire - ✔✔ sharply defined, even
, Describe margin: lobate - ✔✔ marked indentations
Describe margin: undulate - ✔✔ wavy idnentations
Describe margin: serrate - ✔✔ toothlike appearance
Describe margin: filamentous - ✔✔ threadlike, spreading edge
Describe elevation: flat - ✔✔ elevation not discernible
Aseptic Technique - ✔✔ Methods to prevent microbial contamination of the culture, the
environment, and the individual.
Agar - ✔✔ Polysaccharide from algae used to help solidify media, when heated it will melt & go
into solution and remain liquid until cooled to ab 45 C .
Broth - ✔✔ Liquid medium for growing microorganisms.
Hot Plate - ✔✔ Heating device used to dissolve & sterilize agar in media.
Tryptic Soy Agar (TSA) - ✔✔ Common complex culture medium for bacteria.
Microincinerator - ✔✔ Gasless, flameless sterilizer using infrared heat, creates an updraft to
prevent contamination.
