Akardoust

Cells are usually prototrophic but some can be auxotrophic, meaning they would need that certain metabolite to grow. The "wild type" cell is prototrophic and noted as "+" or "WT" in relation to the metabolite while the auxotrophic version is noted with a "-" in relation to the metabolite. For example, a cell can be noted as "his-" if it needs histidine or "his+" if it does not.

DIAGRAM

Consider this diagram of two colonies of bacteria place on different media. If it is assumed that colony A is prototrophic and colony B is auxotrophic to metabolite "1", then A can grown on any minimal media. Colony B, however, can only grow if there is at least minimal media and metabolite "1".

Peer Review (Kristen)

I thought your article was really good and was simplified enough to understand. Also, it was well organized and expanded well on the topic. Some suggestions:

Since the article is on autotrophy, not prototrophy maybe have a separate section where you talk about prototrophy rather than having it in the lead
Expand more on each paragraph in the auxotrophic genetics section.
Maybe add some images that exhibit auxotrophy. For example, having two different plates with different growth requirements, one in which colonies/auxotrophs grew.
Adding a subsection on replica plating under applications and how this plating tests for auxotrophy might be helpful for people who don’t know what replica plating is
Add more citations to validate statements, especially auxotrophy in genetics section
You could add a section that talks about different types of auxotrophs you can have or experiments that have been done to find them (temperature dependent, amino acid requirements, vitamin requirements, etc)