Mitochondria are organelles found in most eukaryotic cells that are known as the "powerhouses" of the cell. They have an outer and inner membrane and are the site of aerobic respiration where glucose and oxygen are used to generate ATP through cellular respiration. Mitochondria contain their own DNA and ribosomes and have a folded inner membrane with cristae that increases surface area for enzymes involved in ATP synthesis. They transform energy from food sources into ATP that cells can use for work.