Which organism is correctly matched with its classification as a yeast-like fungus?

Which organism is correctly matched with its classification as a yeast-like fungus?

• A. Pneumocystis jiroveci
• B. Toxoplasma gondii
• C. Acanthamoeba
• D. Naegleria fowleri

Answer: (A)

The idea being tested is how we classify organisms that look like yeasts versus protozoa. Pneumocystis jirovecii is considered a yeast-like fungus because genetic analyses place it in the fungal kingdom and its cellular and reproductive traits resemble yeasts. It forms trophic (yeast-like) forms and cysts, and its cell wall contains fungal components such as chitin, distinguishing it from protozoan parasites. Clinically, it is an opportunistic fungal pathogen notable for causing Pneumocystis pneumonia in immunocompromised patients. In contrast, Toxoplasma gondii is a protozoan parasite in the phylum Apicomplexa, and Acanthamoeba and Naegleria fowleri are free-living amoebae—protozoa. Their biology and life cycles are not yeast-like, which is why they would not be classified as yeast-like fungi.

The idea being tested is how we classify organisms that look like yeasts versus protozoa. Pneumocystis jirovecii is considered a yeast-like fungus because genetic analyses place it in the fungal kingdom and its cellular and reproductive traits resemble yeasts. It forms trophic (yeast-like) forms and cysts, and its cell wall contains fungal components such as chitin, distinguishing it from protozoan parasites. Clinically, it is an opportunistic fungal pathogen notable for causing Pneumocystis pneumonia in immunocompromised patients.

In contrast, Toxoplasma gondii is a protozoan parasite in the phylum Apicomplexa, and Acanthamoeba and Naegleria fowleri are free-living amoebae—protozoa. Their biology and life cycles are not yeast-like, which is why they would not be classified as yeast-like fungi.