1. You want to infect 10 plates of cells with virus "X" at an MOI of 20. You use a volume of 0.5 ml for the infections. You have 2 x 106 cells on each of the dishes you want to infect, and your virus "X" stock contains 1.25 x 109 PFU/ml. Describe a dilution scheme that will give you the appropriate amount and concentration of virus needed for your infection.

2. How much 4X sample buffer do you need to add to 10 ul of DNA in order to run it out on an agarose gel?

3. A 100 mm dish has a surface area of 57 cm2, and a 60 mm dish has a surface area of 19 cm2. How many 60 mm dishes can you make from five 100 mm dishes if you passage the cells at a 1:5 ratio?

4. You need to stain cells with neutral red prepared in Hank's buffered saline. Neutral red is prepared as a 40X stock in distilled water. How much of this stock solution do you need in order to prepare 200 ml of the stain?

5. Some solutions are prepared as percent weight/weight (% w/w). For ex, a 50% (w/w) sucrose solution is prepared by adding 50 grams of sucrose and 50 ml (50 g) of water. Can you apply the same formulas used in this class to dilute the sucrose solution? Why or why not?

6. You need 200 ml of physiological saline (0.9% NaCl). At your disposal is a 1M (58.44 g/L) stock of NaCl. What volume of the stock solution and how much water should you use to make the 0.9% solution?

What is the molarity of salt in physiological saline?