Question

You have a 100X stock of cytochalasin (a drug that depolymerizes actin). You want to treat some cells with cytochalasin and caffeine to see what happens. The cells are already in 200μl of a solution of caffeine at approximately the right concentration. How much cytochalasin would you add to the cells in caffeine?

Answer 1

You have a 100X stock of cytochalasin (a drug that depolymerizes actin). You want to treat some cells with cytochalasin. So, you have to make this reagent into 1X. The cells are already in 200 μl of a solution of caffeine. You have to mix this reagent to this solution and the final concentration of the cytochalasin would be 1X. Therefore, if you mix 2 μl of cytochalasin in 200 μl of cell solution the final concentration of cytochalasin will be 1X. So, 2 μl of cytochalasin you have to add to the cells in caffeine.