The total number of cells in a culture is counted using the trypan blue exclusion assay and is found to be 6.8 x 106 cells/ml. Each well in a 6 well plate requires 2 x 105 cells. How should the solution be diluted so that 1ml can be added to each well?

The statement, “In the laboratory, a sterile inoculating loop is moved across the agar surface in a culture dish, thinning a sample and isolating individuals", describes which technique?

in most probably number (MPN) testing what media is used for confirming test and what does a positive result looks like?

A plaque assay is performed beginning with 1 mL of a solution containing bacteriophages. This solution is serially diluted 3 times by combining 0.1 mL of each sequential dilution with 9.9 mL of liquid medium. Then 0.1 mL of the final dilution is plated in the plaque assay and yields 12 plaques.What is the initial density of bacteriophages in the original 1 mL? Enter your answer to two significant figures ( for example: 1.1 * 10^2)

If there is 50 bacterial colonies on a 1:1000 dilution streak plate. How many cfu/mL are there?

You have several different media onto which you inoculated eight strains of yeast (A-H). The media include a rich medium, an unsupplemented minimal medium, and minimal media each supplemented with one vitamin. Of the yeast strains, one is a prototroph and seven are auxotrophs for a vitamin. After overnight incubation, the following results were observed (tan patches represent growth): D plate 1 (A) B DE F GH plate 5 plate 4 plate 6 Which plate contains an unsupplemented minimal medium? [Select] Which plate contains a rich medium? [Select] plate 2 Which strain is a prototroph? [Select] Strain E is an auxotroph for niacin. Which plate reveals this specific auxotrophy? [ Select] plate 3 plate 7 One strain is an auxotroph for both choline and pantothenic acid. Which one is this most likely to be? [Select]

Explain why a semi-log plot should be used for determining antigen concentration by ELISA.

"If you count 70 colonies from a urine culture obtained using 0.001ml calibrated loop, how many colony forming units (CFU) will be reported?"     70     700     7000     70000     700000

You are determining the concentration of your culture, and have counted the following on your hemocytometer as shown in Figure below: (note, blue cells have taken up Trypan blue & thus are dead. Red x's are cells that should not be counted because touching one of 2 sides of square). If your cells were diluted 1:2 before counting, what is the concentration of cells in your original culture?

Briefly explain why this is ELISA referred to as colorometric assay.