Amicrobiologist inoculates staphylococcus epidermidis and escherichia coli into a culture medium. following incubation, only e. coli grows in the culture. what is the most likely explanation?

The culture medium must be selective

Explanation:

Selective media are the media that have those ingredients which favor the growth of a particular bacterium and inhibit the growth of unwanted bacteria. So a selective media is used to selectively grow a particular micro-organism.

For example, MacConkey agar is a selective media that is used to isolate gram-negative enteric bacteria based on lactose fermenting ability. It contains ingredients like bile salt and crystal violet which inhibits the growth of gram-positive bacteria therefore it only allows the growth of gram-negative bacteria.

Staphylococcus epidermidis is a gram-positive bacteria and E.coli is gram-negative enteric bacteria so MacConkey agar can be used to select E.coli over Staphylococcus epidermidis. So the correct answer is the culture media must be selective.

a tetrad is the foursome during meiosis made by two homologous chromosomes that have each already replicated into a pair of sister chromatids.

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