Objective: UPlanSApo 100x oil/1.40	Exposure: 500 ms
Microscope: Olympus DSU/IX81	Gain: 3
Camera: Hamamatsu ImagEM	Interval: 2 s

Depending upon the metabolic requirements of an organism, a cell can contain between one and many thousands of mitochondria. First discovered with a light microscope in the 1800s, these large organelles are found in almost all eukaryotes: plants, animals, protists, and even fungi. Because of the way they appear under the microscope, the scientists who first observed them called them mito-chondria after the Greek words for “thread” and “granules” respectively. A method of isolating the organelles without damaging them was developed around the 1950s, which lead to our current understanding of the functioning of the mitochondrion. The digital video above displays normal lung fibroblast cells (FoLu line) from the Gray fox expressing monomeric green fluorescent protein (mEGFP) that has been fused to the mitochondrial targeting signal from subunit VIII of human cytochrome C oxidase.