Aseptic Technique and Culturing Microbes Flashcards
True/False: Aseptic techniques are designed to prevent the spread of microorganism beyond the intended working environment.
True
True/False: Plates should be incubated agar side down.
False
True/False: Media containers should be stored away from children and pets.
True
True/False: The caps and lids of media containers should be placed on countertops when working with cultures.
False
True/False: Open tubes and vials should be tilted away from the mouth and nose.
True
True/False: Working surfaces should be sterilized with soap and water.
False
Liquid media used to increase the number of microorganisms.
Broth
Solid media used to isolate microbes.
Agar plate
Normal flora bacteria used for studies involving osmotic pressure, antibiotic resistance, and biofilms.
Staphylococcus epidermidis
Clump of genetically identical microorganisms.
Colony forming unit
Single-celled fungi used for studies involving fermentation, genetics, and aging
S. cerevisiae
Instrument used for spreading microorganisms across a streak plate.
Inoculation loop
True/False: When opening cultures or sterile media:
Work quickly and efficiently.
True
Agar plates should be labeled on the _____.
bottom
Aseptic techniques are necessary to _____.
Responses
maintain safety
isolate pure cultures
prevent the spread of unwanted microbes
All of the above
all of the above
What temperature does agar melt at?
80°C (176°F).
At what temperature does agar solidify after it is melted.
45°C (113°F)
What is another name for slant?
A type of solid media
Define mixed culture, pure culture, and contaminated culture.
Mixed culture: Multiple culture separated into individual colonies of only one type of microbe on a plate
Pure Culture: Contains only one species of microorganism
Contaminated culture: unknown microorganisms are inadvertently introduced often via poor technique.
False/True: Agar is a solid media used in both slants and plates.
True
Describe the streak plate technqiue.
Uses four quadrant dilution that systematically reduces bacterial numbers until they are diluted enough to form isolated colonies.
1.) Streak across top of plate (horizontally)
2.) Streak down the side of plate vertically
3.) Streak horizontally opposite side of the plate.
4.) Streak vertically the other side of the plate
What is the name of the instrument used to streak the agar plate.
inoculation loop
What is the name of the instrument used to streak the agar plate.
inoculation loop
True/False; If the loop accidentally comes in contact with the first and second quadrants, the dilution is lost.
True
Individual colonies that develop on a plate are called
colony forming units (CFUs) because each colony develops from an isolated or genetically identical clump of microorganisms.
The inoculation loop must be sterilized _____ when creating a streak plate.
a.) before use
b.) between use in each quadrant
c.) after completing all quadrants
d.) all the above
D
BLANK is the size, shape, and other physical characteristics that can be used to identify microorganisms.
Morphology
True/False: Morphology can be used to identify microorganisms with or without the use of a microscope.
Responses
True
Blank is a rod-shaped bacteria commonly found in the lower intestine of warm-blooded organisms.
E. Coli
Blank is known as baker’s yeast, is an ovoid single-celled fungi found on ripe fruits in nature.
saccharomyces cerevisiae
Which microorganism irritates the digestive system of individuals suffering from Crohn’s disease and ulcerative colitis.
Saccharomyces cerevisiae
Blank is a coccus-shaped bacteria commonly found on the skin of humans.
Staphylococcus epidermidis
Which microbe has been linked to infections in individuals with catheters or other surgical implants?
Staphylococcus epidermidis
Blank is a model organism for study of osmotic pressure regulation, antibiotic resistance, and biofilms.
Staphylococcus epidermidis
____ is a rod-shaped bacteria important to the study of genetics and evolution.
Escherichia coli
What temperature is ideal for incubation?
21 -25 C
What is a colony and how does a colony relate to a bacterial cell? Why are colonies important in the study of microbiology?
A colony is a group of microorganism grown together which all originate from the same mother cell. Colonies are important because scientists can identify characteristics about microorganisms and study their ideal growth conditions.
Are bacteria easier to observe on a plate or in a broth? How do the bacteria look on the plate as compared to the broth?
The bacteria is significantly easier to examine in an agar plate as opposed to the broth. The physical characteristics such as the circular shape, margin, elevation, and size of the bacteria was visible on the agar plate and not in the broth. The broth only displayed an abundance of bacteria, consistency, and color.
How could you tell if one of the colonies on your pure plate was a contaminant from the environment and did not come from your original culture?
Each microorganism has its unique physical characteristics. If a colony was a contaminant it might not resemble what the majority of the petri dish looks like. Additionally, if there is a colony growing in an area on the petri dish that was not streaked, then it would be a contaminant from the environment.
Was the streak plate method effective at diluting the population size in each of the plates? How could your methods be improved in the future?
The streak plate method does appear to be effective in diluting the population size. The population size of the colony was spread out fairly evenly across the plates. I do believe that I could have used a pattern streak such as using a quadrant streak rather than a continuous streak
Tryptic Soy Agar (TSA) is a _____ media.
General purpose solid
Turbidity and flocculence are indicators of microbial growth in liquid media.
True
A pure plated culture should exhibit colony forming units with two or more morphologies.
False
