Final answer:
Ergosterol is found in fungal cell membranes and targeted by antifungal drugs such as azoles, allylamines, and polyenes that impair cell membrane integrity or ergosterol biosynthesis, providing a selective mechanism to treat fungal infections.
Step-by-step explanation:
Ergosterol is the predominant sterol found in fungal cell membranes, which is distinct from human cells that contain cholesterol. Membranes containing ergosterol are therefore unique to fungi, making it an attractive target for antifungal drugs.
These drugs, such as azole and allylamine families, function by disrupting the biosynthesis of ergosterol, impairing the fungal cell membrane's integrity and leading to the destruction of the fungal cell. Moreover, a class of antifungal drugs known as polyenes binds directly to ergosterol to create membrane pores, further compromising fungal cell membranes. These classes of drugs, including triazoles, are used to treat various systemic yeast infections due to their selective toxicity and fewer side effects compared to other antifungal agents.