Mitochondria help take energy from sugar or glucose and convert it into a simpler form, called ATP, that the cell can more easily use. This process is called cellular respiration, and the mitochondria plays a central role in it.Mitochondria are composed of two membranes.An outer membrane covers the organelle like a skin, protecting it.An inner membrane, that is folded over again and again to create a layered structure called crista, which is studded with proteins. The fluid inside these folds is called the matrix.Chloroplasts are very similar to mitochondria, but are found only in the cells of plants and some algae. Like mitochondria, chloroplasts produce food for their cells. Chloroplasts help turn sunlight into food that can be used by the cell, a process known as photosynthesis.
