Mitochondrial Function

The study of cell organelles and their functions covers individual responsibilities of each sub unit of a cell - each organelle is a structure within a cell that has a specific function. Among the many organelles that make up a eukaryotic cell (cells that have a nucleus), is mitochondria - the powerhouse of the cell. Cellular mitochondria is made up of a double layered membrane, the inner part of which is made up of folds called cristae. Mitochondrial functions are not limited to just the generation of Adenosine Triphosphate (ATP) though this is one of its most important responsibilities. As all the organelles of a cell work cohesively to perform bodily functions, mitochondrial function in a cell are manifold.

Mitochondrial Structure and Function

Each cell organelle is uniquely designed to support its functions, as can be seen in mitochondria structure and functions. A mitochondrion is made up of two membranes: an outer membrane and an inner membrane, both made up of proteins and other complex compounds. Since both membranes have distinct properties, a single mitochondrion is made up of the intermembrane space, the crista space and the matrix, apart from the two membranes. Each part of the organelle has an important role to play, and the structure of each mitochondrion is instrumental in the performance of these.

Production of Energy
The primary mitochondrial function in animal cells is the production of energy in the form of ATP, and the regulation of cellular metabolism. The reactions that are involved in the production of ATP are collectively known as the Citric Acid Cycle or Krebs Cycle. Once food is broken down into its component parts by the process of metabolism, the food molecules are transferred to the mitochondria where they undergo further processing through the Krebs cycle to produce energy, after a number of complex reactions, in the presence of oxygen.

Programmed Cell Death
Another important function of note is the role of mitochondria in apoptosis, or programmed cell death. This is carried out by an organism in the developmental stage when there are unwanted cells that need to be destroyed - for instance it is this apoptosis that enables the digits of the hand to separate into fingers during fetal development. It is also carried out on when the body detects infections, or as an immune system response to bacteria or an illness. Since oxygen is required for the production of ATP, in conditions where the body is combating an illness, the consumption of oxygen rises, as a result of which certain mitochondrial reactions cause the production of free radicals. Free radicals, in excess of the mitochondria's ability to detoxify the cell, cause damage to the mitochondria. Abnormal cell death due to malfunction can give rise to medical conditions or interfere with organ function.

Cell Specific Functions
Mitochondrial functions also include the following:

• Building, breakdown and recycling of products that are needed for the cell to function normally
• Formation of parts of blood and hormones such as estrogen and testosterone
• Synthesis of steroids
• Regulation of membrane potential
• Monitoring of cell differentiation, growth and development
• Cell signaling of neurons

Understanding the role of mitochondria, is not purely academic - a mitochondrial function test, called an ATP Profile Test can be used to diagnose Chronic Fatigue Syndrome, or CFS, which has been linked to mitochondrial failure or inefficiency.