Question

2. RDRPkill has a molecular weight of 400. You have a small, concentrated 500 mM stock solution. a. Express this concentration in the following units:

i. M

ii. μg/μL

iii. % (w/v)

iv. weight/dL

b. How much of this compound would you have to weigh out if you were to make up 500 µL of the solution?

c. If you added 5 μL of a 500 mM solution to a cell incubation with a total volume of 2 mL i. How many moles would the incubation contain? ii. What is the final concentration of this compound in the incubation?

3. An experiment requires an incubation to be carried out with 1 μM of RDRPkill. The incubation will be carried out in a total volume of 500 μL of culture medium. What volume of each of the stock solutions below (a – d) would you need to add to the incubation to give 1 μM of RDRPkill? a. 1 mM b. 0.5% (w/v) c. 20 μg/dL d. 10 μg/mL e. Due to the toxicity of the solvent, the volume added cannot exceed 0.1% (v/v) in the final 500 μL of culture. Which of the stock solutions above COULD actually be used for this incubation?

Answer 1