2. When culturing Chlamydomonas , ampicillin (amp) is added to cultures at 50mg/

Question

2. When culturing Chlamydomonas, ampicillin (amp) is added to cultures at 50mg/ml to prevent bacterial growth. You are splitting your culture and maintaining your new culture at 50 ml. You look in the freezer and realize that there are no amp stocks available for your use but you know where the amp powder is kept, so you decide to make fresh stock.

            a. What is a logical concentration for this stock? Why?

            b. Show your calculations for your stock.

            c. How much of your stock must you use to treat your culture?

Explanation / Answer

Ampicillin is added at a concentration of 50mg/ml. You are maintaining your new culture at 50 ml so we need a 2500mg of ampicillin for 50 ml culture.

Stocks are the solutions of high concentration which can be diluC.ted to make the lower concentration of solutions. We usually make them 10 times more concentrated than the working solutions. So, in this case, you can take 500mg/ml of ampicillin stock. Let's make 25ml of this stock.

B. 500mg/ml is the stock concentration, we are making 25ml of this stock solution and for that, we need 500mg x 25 = 12.5g. So we will add 12.5g in 25ml of dH2O.

C. you can use the formula C1V1= C2V2

500 X x = 50 X 50

x= 50 X 50/ 500= 5ml

5ml of the stock is required to add to 50ml of culture.

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.