Mitochondria (IMAGE) Arizona State University Caption Mitochondria are membrane-bound organelles present in eukaryotic cells. Their essential role is to supply cells with energy in the form of ATP. Mitochondrial dysfunction is implicated in a range of diseases, including Alzheimer's. Credit Courtesy: Kelvinsong Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.