8.3 A focus on diluting solutions

In molecular cloning, bacteria are often transformed (genetically modified) to be resistant to certain antibiotics. This allows you to grow the transformed bacteria in selective media (which contains the antibiotic) and prevent the growth of untransformed bacteria and any other microorganisms.

If you need to prepare 150 ml of Luria-Bertani (LB) agar medium containing 25 µg ml1 ampicillin, how much 50 mg ml1 ampicillin stock solution would you need to add?

 

Diluting Solutions

Khizar Iftikar is a graduating student studying biomedicine. He faced the problem above in his final year practical subject. Watch an interview with Khizar to find out how he solved it and how confidence in being able to do these kinds of calculations can help you in your later studies – and beyond!

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