They play important roles in generating energy for cells, transporting signals to and from the brain, muscle contractions, and more. (onnit.com)
The technique, called mitochondrial replacement, is intended to avoid harmful mutations in a mother's mitochondria — the compartments that generate energy in a cell — passing to her children. (newscientist.com)
Because the sun is low in the horizon for most of the year, it is difficult for plants to generate energy from photosynthesis. (en.wikipedia.org)