Mitochondria are sometimes known as the "Powerhouses of the Cell." It is within these organelles that Cellular Respiration takes place and cells create energy to power their actions. Depending on the type of cell, the amount of mitochondria present in the cell can vary. For example, heart cells and other muscle cells contain far more mitochondria than other kinds of cells due to the fact that they need more energy at a more constant rate than other kinds of cells do.
Inside of mitochondria, there are many folds of membrane on which the reactions for metabolism take place. These are called cristae, and they are folded throughout the whole organelle and because of their folding provide the maximum amount of surface area for the cell metabolism to take place. The spaces in the cristae, also called the Mitochondrial Matrix, are the places where ATP is synthesized during Cellular Respiration.
During metabolism, Oxygen and other chemicals necessary for the process to occur enter through the outer membrane of the mitochondria, and then the created products such as ATP move out into the cytoplasm through the membrane as well. Mitochondria are some of the most important organelles in the cell, as they allow energy to be produced and otherwise