Fig. 4 |. Terminology for mitochondrial science organized as a hierarchy of mitochondrial needs.

a, inspired by Maslow’s pyramid of human needs²¹⁷, depicted is a hierarchy of biological organization from molecules to complex organellar behaviours. Lower levels combine to enable higher levels of organization. Each level can be studied using specific types of laboratory methods and analytical approaches. Thus, different approaches provide different types of information about the molecular features, activities, functions and behaviours that define specific mitochondrial phenotypes. b, Operationalization and examples for different levels of organization available to examine and perturb mitochondrial biology. Biomedical terminology related to organismal characteristics (left), and terminology related to cell biology (middle) are provided as parallel illustrative examples at each level of description for mitochondrial biology.