How Do Viability Stains Usually Distinguish Between Living Cells and Dead

Question

How do viability stains usually distinguish between living cells and dead cells?
A) The chemical fluoresces only when bound to ribosomes that are actively synthesizing proteins.
B) The chemical stain is taken up by living cells and once metabolized becomes fluorescent.
C) The dye specifically targets intact cytoplasmic membranes.
D) The dyeʹs fluorescence is quenched by dead cells.

Accepted Answer

Viability stains typically target the integrity of the cytoplasmic membrane. Living cells have intact membranes that exclude the dye, while dead cells have compromised membranes that allow the dye to enter and stain the cytoplasm, allowing for differentiation between the two.