Plants & Animals | Bacteria | Fungi

Define oxidization and reduction.
Janus Green is colorless when it is reduced.

Mitochondria may be observed in living cells with the aid of a vital stain called Janus Green B. This stain is colored when it is an oxidizing agent. When the mitochondria are actively engaged in cellular respiration, the stain acts as a hydrogen acceptor and becomes reduced and colorless. The Janus Green B will stain the mitochondria right away, but as you watch over a few minutes, the stain will fade.

Chinese hamster ovary cell. The nuclear DNA is blue, the mitochondria are green, and the lysosomes are red. Photo by Douglas Kline.