Lab Exam 2 Flashcards
What is a culture?
growing bacteria in a lab setting
What is an inoculum?
placing bacteria in a growth medium
- Why do we use aseptic technique in lab?
to prevent cross contamination
the difference between a broth and an agar
broth is liquid growth media
agar is solid growth media
What are the types of agars that we use in class?
within a test tube: angled (slant)
in a petri dish: (plate)
What were the three tools that we have used to inoculate new cultures?
loop
cotton swab
What does the abbreviation TSA & TSB stand for?
Tryptic soy Agar
Tryptic soy broth
What is the difference between a complex and a defined media
Complex media = Exact contects are unknown
Defined media = Every ingredient is know in its exact amount
Give some examples of what can be used as nutrients in a complex medium
Extracts from eggs, years, soy, animals
amino acids
glucose
vitamins
nitrogen
Is our standard media for our lab complex or defined?
complex
You should know the scientific foundation of an enrichment medium even though we do not use them in our lab
what have been the 3 plating techniques introduced in lab?
Lawn, zigzag, streak
Steps for streak plating:
- spread one loopful of bacteria on 1/4 of plate
- flame loop
- start in zone 1 and spread bacteria over 1/4 of plate
- flame loop
- start in zone 2 and spread bacteria over 1/4 of plate
- flame loop
- start in zone 3 and spread bacteria over 1/4 of plate, avoiding zone 1 & 2
Steps for zigzag:
use loop to swab left and right in a few zig-zags
Steps for lawn plating:
- used a sterile cotton swab and aseptic technique to apply bacteria to the lawn plate
- Smeared the entire surface, leaving no gaps
Which of the plating techniques is used to produce pure, isolated colonies from a mixed sample?
Streak plating
Why do we flame the loop between each zone when making a streak plate?
To prevent build up because you want to reduce bacterial numbers
Bacterial Transformation Lab
what bacteria did we use for bacterial transformation?
Escherichia coli
Bacterial Transformation Lab
What genes are found on the pGLO plasmid? what do they code for?
bla gene: allows resistance to ampicillin
araC gene: blocks GFP gene from being able to express (glow) all the time
GFP gene: codes for fluorescence
Bacterial Transformation Lab
which gene, when expressed, allows the colonies to glow? what does it stand for? come from?
GFP gene
green fluorescence protein
jellyfish
Bacterial Transformation Lab
what is required in media in order for colonies to glow?
arabinose in the plate allows GFP gene to be expressed (glow) by blocking the araC gene from blocking GFP gene
Bacterial Transformation Lab
what is the purpose of LB in the plates?
to provide microbes with nutrients
Bacterial Transformation Lab
what inoculated plates or side of plates showed transformation? why?
LB/amp (+pGLO side) - because growth was present due to bla gene being present within the plasmid
LB/amp/arabinose plate - because growth was present and it fluoresced
Bacterial Transformation Lab
what plate shows GFP expression?
LB/amp/arabinose plate
Bacterial Transformation Lab
In the LB/amp plate, what side (+ or -) should show growth?
the positive side
Bacterial Transformation Lab
what is the name of the antibiotic resistance gene? what antibiotic is it resistant towards?
bla gene - resistant to ampicillin
Gram + or gram - : Bacillus subtilis?
gram +
Gram + or gram - : Escherichia coli?
gram -
Gram + or gram - : Staphylococcus aureus?
gram +
Gram + or gram - : Mycobacterium smegmatis?
acid-fast gram +
Gram + or gram - : Pseudomonas aeruginosa?
gram -