Micro 22 Lab Quiz 2 Culturing, Media, Aseptic
Technique and PG 1
1. Culture medium/media: The nutrient material prepared for growth of
microorganisms in a laboratory.
2. Inoculum: Microbes introduced into a culture medium to initiate growth
3. Microbrial culture: Microorganisms that grow and multiply in a container
4. Sterile medium: The medium initially contains no microorganisms
5. Agar: A complex polysaccharide derived from a marine alga and used as a
solidifying agent
6. Agar liquifies at: 100C
7. Agar solidifies at: 40C
8. Agar slant: A test tube of agar allowed to solidify with the test tube held at an
angle enabling a large surface area for growth
9. Agar deep: Agar solidifies in a vertical tube
10. Petri dish/petri plate: Shallow dishes with a lid that nests over the bottom to
prevent contamination. When filled, it is called a petri plate.
11. Chemically-defined media: media whose exact chemical composition is known
12. Complex media: A culture medium in which the exact composition is not known.
Made up of nutrients including extracts from yeast, meat, plants, or digests of
proteins.
13. Nutrient broth: A complex medium in liquid form
14. Nutrient agar: Nutrient broth containing agar
15. Fastidious organism: organisms that require many growth factors
16. Selective media: suppress growth of unwanted bacteria and encourage growth
of desired microbes
17. differential media: a solid culture medium that makes it easier to distinguish
colonies of the desired organism
18. enrichment media: a culture medium used from preliminary isolation that favors
the growth of a particular organism
, 19. Which environmental sample has the largest number of colonies? Why?-
: Belly button. Because the belly button is a slightly moist area, and I think I made
good contact with to get a good sample.
20. Which environmental sample had the least growth? Why?: The bottom of
my bag and the rim of the trashcan. These are dry areas and I don't think I made
adequate contact with the samples, so I do not think the swab picked up enough
samples.
21. What is the benefit of washing hands?: Potentially harmful microbes will be
removed from your hands through handwashing.
22. What is a bacterial colony?: A visible mass of microbial cells arising from one
cell or from a group of the same microbes.
23. Which T-soy ingredients are the bacteria using for nutrients?: tryptone,
soytone, and sodium chloride
24. Which T-soy ingredient is probably not being used by bacteria?: Agar
25. What is the purpose of agar?: Provide a surface for the microbes to grow on.
26. Why is agar used instead of gelatin or starch?: Bacteria have been found not
to be able to agar. However, some bacteria can digest gelatin or starch.
27. Why do incubators in clinical labs usually operate at 35-37 C?: This is
average temperature of the human body and the optimal functioning temperature
for a lot of bacteria
28. If one of your experimental sources provided no growth, does this mean
that the area you swabbed was sterile?: No. The nutrients in this medium may
not have been adequate for the microbes, or I might not have made enough contact
with the source with the swab.
29. Why are petri plates incubated upside down?: Microbes in the petri plate get
all they nutrients they want from the medium. In consuming these nutrients, they
give off heat. This heat collects on top the of the lid in the form of condensation.
They are plated upside down so the heat goes back into the agar the colonies aren't
smeared.
30. Why are aseptic techniques used?: To prevent contamination
Technique and PG 1
1. Culture medium/media: The nutrient material prepared for growth of
microorganisms in a laboratory.
2. Inoculum: Microbes introduced into a culture medium to initiate growth
3. Microbrial culture: Microorganisms that grow and multiply in a container
4. Sterile medium: The medium initially contains no microorganisms
5. Agar: A complex polysaccharide derived from a marine alga and used as a
solidifying agent
6. Agar liquifies at: 100C
7. Agar solidifies at: 40C
8. Agar slant: A test tube of agar allowed to solidify with the test tube held at an
angle enabling a large surface area for growth
9. Agar deep: Agar solidifies in a vertical tube
10. Petri dish/petri plate: Shallow dishes with a lid that nests over the bottom to
prevent contamination. When filled, it is called a petri plate.
11. Chemically-defined media: media whose exact chemical composition is known
12. Complex media: A culture medium in which the exact composition is not known.
Made up of nutrients including extracts from yeast, meat, plants, or digests of
proteins.
13. Nutrient broth: A complex medium in liquid form
14. Nutrient agar: Nutrient broth containing agar
15. Fastidious organism: organisms that require many growth factors
16. Selective media: suppress growth of unwanted bacteria and encourage growth
of desired microbes
17. differential media: a solid culture medium that makes it easier to distinguish
colonies of the desired organism
18. enrichment media: a culture medium used from preliminary isolation that favors
the growth of a particular organism
, 19. Which environmental sample has the largest number of colonies? Why?-
: Belly button. Because the belly button is a slightly moist area, and I think I made
good contact with to get a good sample.
20. Which environmental sample had the least growth? Why?: The bottom of
my bag and the rim of the trashcan. These are dry areas and I don't think I made
adequate contact with the samples, so I do not think the swab picked up enough
samples.
21. What is the benefit of washing hands?: Potentially harmful microbes will be
removed from your hands through handwashing.
22. What is a bacterial colony?: A visible mass of microbial cells arising from one
cell or from a group of the same microbes.
23. Which T-soy ingredients are the bacteria using for nutrients?: tryptone,
soytone, and sodium chloride
24. Which T-soy ingredient is probably not being used by bacteria?: Agar
25. What is the purpose of agar?: Provide a surface for the microbes to grow on.
26. Why is agar used instead of gelatin or starch?: Bacteria have been found not
to be able to agar. However, some bacteria can digest gelatin or starch.
27. Why do incubators in clinical labs usually operate at 35-37 C?: This is
average temperature of the human body and the optimal functioning temperature
for a lot of bacteria
28. If one of your experimental sources provided no growth, does this mean
that the area you swabbed was sterile?: No. The nutrients in this medium may
not have been adequate for the microbes, or I might not have made enough contact
with the source with the swab.
29. Why are petri plates incubated upside down?: Microbes in the petri plate get
all they nutrients they want from the medium. In consuming these nutrients, they
give off heat. This heat collects on top the of the lid in the form of condensation.
They are plated upside down so the heat goes back into the agar the colonies aren't
smeared.
30. Why are aseptic techniques used?: To prevent contamination
