Lab Math
Diagnostics
Lab Safety
Microscopy
Identifying Organisms
100
If I need to make 100mL of a 10% solution of NaCl in deionized water, how much of each reagent will I need?
10g of NaCl
100mL of deionized water
100
Is Macconkey agar a selective media, differential media or both?
both
100
What are first and last things you have to do in lab?
Wash your hands and wash off your bench with ethanol or bleach
100
How do you carry a microscope?
With one hand on the neck and the other at the base
100
On a wet mount, you see an organism that is bell-shaped with a stalk. What organism is this?
Vorticella
200
I need to dilute a 10X stock of TAE to 1X solution of TAE. I need a final volume of 1L of the 1X solution. How would I go about this? How much diluent (water) will I need?
Use C1V1=C2V2.
(10X)(x mL)=(1X)(1000mL)
x= 100 mL of 10X TAE
900 mL of deionized water
200
How do we quantify DNA concentration after performing PCR?
Using a spectrophotometer at 260nm (nucleic acid conc.) and 280nm (protein conc.)
200
How long should you wash your hands for?
30 seconds
200
What magnifications do you use the oil on?
ONLY 100X
200
After performing a Gram stain, I am seeing both pink and purple organisms. Why am I seeing two colors?
Either the culture is cross-contaminated OR the organism is Gram-variable
300
On a 10^-7 Petrifilm, there are 24 colony forming units. What is the original bacterial count in the sample?
*keep in mind what notation the answer should be in*
2.4e8
300
Is this alpha, beta, or gamma hemolysis? What does this result indicate about the organism?
Alpha hemolysis. the organism produces hydrogen peroxide which oxidizes the hemoglobin contained in the blood agar
300
How should you dress for microbiology lab? (3 things)
close-toed shoes, make sure long hair is always pulled back, and always wear your lab coat
300
What do you use to clean the oil off the lens?
Lens Paper
300
This organism is rod-shaped and is connected in chains. What genus does this organism likely belong to?
Streptobacillus
400
On a P200, reading from the top, the numbers are 0516. How many microliter is this?
51.6 uL
400
During PCR, what is used to release DNA from the bacterial cells? Where is the DNA after doing this? Why is this necessary?
Centrifuging with the tube containing Chemiglass/magic beads will burst the cells and release the DNA. The DNA is then contained in the supernatant. This is necessary because if you do not lyse the cells there is no way to get the DNA isolated so you can amplify the sequence, it would still be inside of the cell and unavailable for PCR.
400
What should you do when there is a spill?
Report all spills to your TA
400
Is this gram + or -
Gram Negative
400
What organism is this?
air bubble
500
I need a drug solution that is diluted 1:1000. Should I weigh out 5g of my drug into 5000 mL of diluent? If not, how should I go about this?
*there may be a series of steps to do this*
Make a 1:10 dilution of solution (5g of drug into 500mL of diluent). Dilute that further by performing another 1:10 dilution. Dilute this second solution further one more time, for a final dilution factor of 1:1000.
500
In PCR, why are primers necessary to amplify the DNA?
Primers are necessary to amplify DNA because Taq polymerase (or any polymerase) binds to the primers in order to start DNA amplification. This means that without primers the polymerase would never be able to amplify the gene because it cannot bind to the template strand without a primer to create the complementary strand.
500
Where should you dispose your gloves?
Biohazard
500
The steps to kohlering
Focus on 10x, close field diaphragm, raise the condenser and slowly lower it until you see clear defined borders. Then open the field diaphragm and enjoy!
500
There is a media that can determine whether an organism is Gram-positive or Gram-negative. What media is it and which type does it select for?
MacConkey agar
Gram-negative