That's because the populations of mitochondria in cells shift over time. (sandiegouniontribune.com)
He said he would like to see what the dye measures in mitochondria in organisms that do not regulate body temperature like we do, such as yeast, fruit flies or worms. (washingtonpost.com)
For example, some disturbance in metabolism or regulation of genes could prevent mitochondria from functioning properly. (hansonlab.org)