Although mitochondria were discovered over 100 years ago, scientists have only recently begun to decipher the many life-giving, and life-taking, secrets of these complex bean-shaped structures.
Mitochondria are roughly the size of bacteria and float in the cytoplasm of almost every cell in the human body. They possess the unique characteristic of having a double membrane and their structure allows a number of different biochemical reactions to occur; one of the most important being cellular respiration.
Cellular respiration consists of three stages;
- The Krebs cycle
- Electron transport chain
It allows carbohydrates, fats, and proteins from the food we eat to be converted into fuel for cells. This fuel is called adenosine triphosphate or ATP.
ATP is considered by biologists to be the energy currency of life. Cells that require the most energy - such as the brain, heart, skeletal muscles, and the eye - contain the most mitochondria. Mitochondria have their own DNA and RNA so can increase their numbers in response to increased energy demands of the cell, such as after repeated muscle contraction.
Scientists now know that mitochondria are more than just the powerhouse of the cell.
They are vital for calcium regulation, cell specialization, DNA and RNA production, cell growth, and also cell death. They send messages to the nucleus and other structures in the cell which modify cellular activities. The ability of cells to correctly “hear” these messages determines how well our bodies grow, repair themselves and fight off infection.
Dysfunctional mitochondria send incorrect messages, disrupt ATP production, and produce more waste in the form of free radicals. Defective mitochondria replicate their own damaged DNA into new mitochondria, eventually displacing all well-performing mitochondria. Diseases such as Parkinson’s, Diabetes, Alzheimer’s, Multiple sclerosis, Rheumatoid arthritis and even ageing have been associated with mitochondrial dysfunction.
Scientists are only just realizing how vulnerable mitochondria are to subtle changes in their environment. Pollution, drugs, low concentrations of vitamins, minerals and coenzyme Q10 can all effect performance.
Treatments have already been developed that target mitochondria. Future research hopes to one day unlock a cure for many currently incurable illnesses. Perhaps mitochondria might hold that key.