Which of the following best describes the preparation of a pure culture?

Question

Which of the following best describes the preparation of a pure culture?

Option a - Taking a swab from the mouth, streaking that onto a solid nutrient agar plate, picking multiple colonies and inoculating sterile broth media with them.

Option b - Taking a swab from the mouth and inoculating sterile broth media with it.

Option c - Taking a swab from the mouth, streaking that onto a solid nutrient agar plate, picking an isolated colony and inoculating unsterilized broth media with it.

Option d - Taking a swab from the mouth, streaking that onto a solid nutrient agar plate, picking an isolated colony and inoculating sterile broth media with it.

Would option d) be the best reparation of a pure culture?

Answer 1

The first thing we would do is define pure culture. In microbiological studies, microorganisms tend to grow in very mixed, diverse, and complex populations. These include many species. For microbiologists this can reasonably create problems when studying, because one specific and single microorganism cannot be studied effectively.

There the pure culture technique is used in order to take a population of cells to characterize and study an individual cell species through the isolation of a colony.

How are these pure cultures cultivated? We take a mixed culture (which in this case would be from the swab from the mouth). Next, move a smaller sample to the solid nutrient Algar plate for studies. In this case, we would take the isolated colony and shield this colony in sterile broth media.

Therefore, Option D is correct.

We could rule out Option A because the picking of multiple colonies would disrupt the process of creating a pure culture.

We could rule out Option B because there is no streaking and taking a smaller colony.

We could rule out Option C because the usage of unsterilized broth media.

Answer 2

Option d) "Taking a swab from the mouth, streaking that onto a solid nutrient agar plate, picking an isolated colony, and inoculating sterile broth media with it" is the best description of the preparation of a pure culture.

The process of streaking the swab onto a solid nutrient agar plate allows for the isolation of individual bacterial colonies. By picking an isolated colony from the agar plate and inoculating sterile broth media with it, you are transferring only one type of microorganism into the broth. This ensures that the culture in the broth remains pure, containing a single species or strain of microorganism. This is a standard technique used in microbiology to obtain pure cultures for further study and analysis.