Mitochondria

The primary function of mitochondria in eukaryotic cells is to convert energy from oxygen and nutrients via oxidative phosphorylation into ATP, a usable form of cellular energy.

A mitochondrion can occur as a single organelle or may be fused to one another, forming a complex mitochondrial network. The complexity of these networks increases with an increase in the cell's ATP demand.

Moreover, the mitochondria per cell vary widely depending on the energy demand of different kinds of cells. For example, neutrophils contain very few mitochondria, whereas cardiac muscle cells have about five thousand mitochondria per cell.

In addition to the production of energy molecules, mitochondria are also involved in the biosynthesis of macromolecules such as nucleic acids, proteins, and lipids.

For example, the mitochondrial ribosome generates polypeptide chains that can fold and become functional protein centers of the electron chain complexes.

Additionally, mitochondria produce reactive oxygen species or ROS that can trigger cell damage and death.

To prevent this ROS-induced damage to the healthy cells, the enzymatic antioxidant systems of mitochondria neutralize excessive ROS, thus, protecting the normal cells from any damage.