Aseptic Technique and Culturing Microbes

Question 1

True/False: Aseptic techniques are designed to prevent the spread of microorganism beyond the intended working environment.

Answer 1

True

Question 2

True/False: Plates should be incubated agar side down.

Answer 2

False

Question 3

True/False: Media containers should be stored away from children and pets.

Answer 3

True

Question 4

True/False: The caps and lids of media containers should be placed on countertops when working with cultures.

Answer 4

False

Question 5

True/False: Open tubes and vials should be tilted away from the mouth and nose.

Answer 5

True

Question 6

True/False: Working surfaces should be sterilized with soap and water.

Answer 6

False

Question 7

Liquid media used to increase the number of microorganisms.

Answer 7

Broth

Question 8

Solid media used to isolate microbes.

Answer 8

Agar plate

Question 9

Normal flora bacteria used for studies involving osmotic pressure, antibiotic resistance, and biofilms.

Answer 9

Staphylococcus epidermidis

Question 10

Clump of genetically identical microorganisms.

Answer 10

Colony forming unit

Question 11

Single-celled fungi used for studies involving fermentation, genetics, and aging

Answer 11

S. cerevisiae

Question 12

Instrument used for spreading microorganisms across a streak plate.

Answer 12

Inoculation loop

Question 13

True/False: When opening cultures or sterile media:
Work quickly and efficiently.

Answer 13

True

Question 14

Agar plates should be labeled on the _____.

Answer 14

bottom

Question 15

Aseptic techniques are necessary to _____.
Responses

maintain safety

isolate pure cultures

prevent the spread of unwanted microbes

All of the above

Answer 15

all of the above

Question 16

What temperature does agar melt at?

Answer 16

80°C (176°F).

Question 17

At what temperature does agar solidify after it is melted.

Answer 17

45°C (113°F)

Question 18

What is another name for slant?

Answer 18

A type of solid media

Question 19

Define mixed culture, pure culture, and contaminated culture.

Answer 19

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.

Question 20

False/True: Agar is a solid media used in both slants and plates.

Answer 20

True

Question 21

Describe the streak plate technqiue.

Answer 21

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

Question 22

What is the name of the instrument used to streak the agar plate.

Answer 22

inoculation loop

Question 23

What is the name of the instrument used to streak the agar plate.

Answer 23

inoculation loop

Question 24

True/False; If the loop accidentally comes in contact with the first and second quadrants, the dilution is lost.

Answer 24

True

Question 25

Individual colonies that develop on a plate are called

Answer 25

colony forming units (CFUs) because each colony develops from an isolated or genetically identical clump of microorganisms.

Question 26

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

Answer 26

D

Question 27

BLANK is the size, shape, and other physical characteristics that can be used to identify microorganisms.

Answer 27

Morphology

Question 28

True/False: Morphology can be used to identify microorganisms with or without the use of a microscope.
Responses

Answer 28

True

Question 29

Blank is a rod-shaped bacteria commonly found in the lower intestine of warm-blooded organisms.

Answer 29

E. Coli

Question 30

Blank is known as baker’s yeast, is an ovoid single-celled fungi found on ripe fruits in nature.

Answer 30

saccharomyces cerevisiae

Question 31

Which microorganism irritates the digestive system of individuals suffering from Crohn’s disease and ulcerative colitis.

Answer 31

Saccharomyces cerevisiae

Question 32

Blank is a coccus-shaped bacteria commonly found on the skin of humans.

Answer 32

Staphylococcus epidermidis

Question 33

Which microbe has been linked to infections in individuals with catheters or other surgical implants?

Answer 33

Staphylococcus epidermidis

Question 34

Blank is a model organism for study of osmotic pressure regulation, antibiotic resistance, and biofilms.

Answer 34

Staphylococcus epidermidis

Question 35

____ is a rod-shaped bacteria important to the study of genetics and evolution.

Answer 35

Escherichia coli

Question 36

What temperature is ideal for incubation?

Answer 36

21 -25 C

Question 37

What is a colony and how does a colony relate to a bacterial cell? Why are colonies important in the study of microbiology?

Answer 37

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.

Question 38

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?

Answer 38

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.

Question 39

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?

Answer 39

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.

Question 40

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?

Answer 40

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

Question 41

Tryptic Soy Agar (TSA) is a _____ media.

Answer 41

General purpose solid

Question 42

Turbidity and flocculence are indicators of microbial growth in liquid media.

Answer 42

True

Question 43

A pure plated culture should exhibit colony forming units with two or more morphologies.

Answer 43

False