Every organism is made of cells, and every cell contains organelles. These are the “little organs” that control the life functions of that cell. Mitochondria are organelles that are vitally important to the functioning of a cell, and therefore to life itself.
If the nucleus is a cell’s central command post, the mitochondrion is its power plant. Nothing can happen in the cell without the energy provided by the mitochondria. The cell cannot use the nutrients from food molecules until the enzymes in the mitochondria combine those nutrients with oxygen and break them down to create ATP, or adenosine triphosphate, which is the chemical energy the cell needs. This process is called cellular respiration, and it is the main function of the mitochondria.
The mitochondria are the organelles that manage the basic functioning of the cell and its entire cycle of life. In addition to cellular respiration, they decompose the proteins and fats that are byproducts. Even the death of the cell involves mitochondria.
As part of the normal growth and development of an organism, old cells must die. This is called apoptosis, and it occurs as a result of a series of biochemical processes. The procedure begins when a chemical called AIF (apoptosis inducing factor) is released by the mitochondria.
Mitochondria actually monitor the cell’s growth and development. They differ from other organelles in that they have their own nucleus and DNA. They can reproduce independently of the cell that contains them. If a cell needs more energy than its mitochondria can supply, more of them can form.
The genetic material contained in mitochondria is passed on through the maternal side in species where regeneration results from sexual reproduction. A sperm cell carries mitochondria on its tail to provide it with energy to swim to the egg. Once the sperm attaches to the egg in the fertilization process, the tail falls off, leaving the new organism with only the mitochondria provided by the female’s egg.
Mitochondrial DNA has been used to study human evolution because, being passed only through the mother, it is easier to trace, and it changes at a slower rate than the genetic material in the nuclei of cells.
A mitochondrion has an outer membrane that keeps the organelle separate from the rest of the cell. It also has an inner membrane. This inner membrane is full of folds called cristae. These cristae increase the surface area, giving the organelle more room to do its work. The fluid in the cristae, which consists of water and enzymes, is called the matrix.
Since the work of the mitochondria is vital to the functioning of a cell, any mitochondrial malfunction can cause serious problems for an organism. Many disorders and diseases have been linked to problems with mitochondria.
