Questions: How does the azole drug fluconazole damage yeast? Why does this drug not target human cells? Fluconazole targets ergosterol within the fungal cell membrane, but does not target human cells because human cells do not have ergosterol.

The answer is the first one: Fluconazole targets ergosterol within the fungal cell membrane, but does not target human cells because human cells do not have ergosterol.

Explanation for each option:

1. Fluconazole targets ergosterol within the fungal cell membrane, but does not target human cells because human cells do not have ergosterol.

   • Correct: Fluconazole is an antifungal medication that works by inhibiting the synthesis of ergosterol, a crucial component of the fungal cell membrane. Human cells do not have ergosterol; instead, they have cholesterol in their cell membranes. This difference allows fluconazole to selectively target fungal cells without harming human cells.

2. Fluconazole targets 80 S ribosomes within the yeast cell, but does not target human cells because human cells contain 705 ribosomes.

   • Incorrect: This statement is factually incorrect. Both human and yeast cells have 80S ribosomes in their cytoplasm. The 70S ribosomes are found in prokaryotes and in the mitochondria of eukaryotic cells. Fluconazole does not target ribosomes.

3. Fluconazole targets chitin within the fungal cell wall, but does not target human cells because human cells do not have cell walls.

   • Incorrect: While it is true that human cells do not have cell walls and fungal cells do, fluconazole does not target chitin. Instead, it targets ergosterol in the fungal cell membrane.

4. Fluconazole targets the septa within the fungal hyphae, but does not target human cells because human cells do not contain cross-walls.

   • Incorrect: Septa are cross-walls that divide the hyphae of fungi into cells. Fluconazole does not target septa; it targets ergosterol in the fungal cell membrane.

Summary: Fluconazole damages yeast by targeting ergosterol in the fungal cell membrane. This drug does not target human cells because human cells do not contain ergosterol; they contain cholesterol instead.