selective and differential media
In you next practical you are going to be plating out bacteria onto agar plates, and there are a couple of terms you are going to come across, selective media and differential media ...so, what are these? Selective media is exactly what it sounds like - 'media' that 'selects'! (When someone says 'media' in the context of growing bacteria, they really mean food.) So, selective media is basically food that you can give to a mixture of bacteria on which only some of the types of bacteria in that mixture will be able to grow. For example, you might have an antibiotic in the media. In this case, only bacteria that are resistant to that antibiotic will be able to grow on that media - any other bacteria won't survive. Differential media is more fancy. It is selective as it will only allow certain bacteria to grow, but it also makes the colonies of the strains that it does allow to grow have different morphologies so...