The MRC Mitochondrial Biology Unit (formerly the MRC Dunn Human Nutrition Unit) is an institution of the Medical Research Council based at the Addenbrooke’s Hospital / Cambridge Biomedical Campus site in Cambridge, England. The unit is a University of Cambridge partner institution concerned with the study of the mitochondrion, as this organelle has a varied and critical role in many aspects of eukaryotic metabolism and is implicated in a large number of metabolic, degenerative, and age-related human diseases.