Mitochondria are vital organs that produce energy to keep cells alive, but they also have a double-edged sword: they produce free radicals that can harm cells.
Humans need constant energy to stay alive and active. The main way the body gets this energy is by breaking down the nutrients in food. Specifically, carbohydrates, fats, and proteins are broken down in the cells to produce energy. Glucose is the most important source of energy, and the energy released when it is chemically broken down in the body is used for various cellular activities. The process of converting and storing this energy into a form that the cell can work with is called cellular respiration. Cellular respiration is a fundamental energy-generating process for living organisms, and without it, life would be severely compromised. Mitochondria play a key role in cellular respiration.
Mitochondria are the main organelles that produce energy within cells, often referred to as the “power plants of the cell”. Energy from cellular respiration is stored primarily in the form of ATP (adenosine triphosphate). ATP is essential for a variety of physiological activities within the cell, such as muscle contraction, protein synthesis, and cell division. Because of this, if the mitochondria are not functioning properly, the cell runs out of energy and eventually loses function and dies. In other words, mitochondria are the life and death of the cell.
The process by which mitochondria produce energy in the body is a multi-step process. First, glucose is digested from the food we eat and absorbed into the blood, where it is transported into the cells. Once inside the cell, glucose is broken down into smaller molecules and transported to the mitochondrial inner membrane, where it releases hydrogen ions. This leads to glycolysis in the cytosol, the TCA cycle (Krebs cycle) in the mitochondria, and the electron transport system, which ultimately produces ATP.
In particular, ATP production in mitochondria is a complex chemical reaction. As hydrogen ions pass through the mitochondrial inner membrane, the coenzyme NAD transports two hydrogen ions (NADH2) out of the mitochondrial inner membrane. This creates a concentration difference, with the outer membrane having a higher concentration of hydrogen ions and the inner membrane having a lower concentration. The difference in hydrogen ion concentration creates a force for hydrogen ions to move toward the inner membrane, and this force triggers the ATP-generating motor to produce ATP. To use an analogy, the water in a waterwheel is the hydrogen ions, and the height of the water is proportional to the rotation of the waterwheel, generating energy. Mitochondria efficiently “charge” ATP with energy to meet the energy needs of the cell.
ATP leaves the mitochondria to be used as an energy source for many of the cell’s activities, and in the process, it loses a phosphorus and is converted to ADP (adenosine diphosphate). ADP then re-enters the mitochondria, where it is ‘recharged’ with ATP in the ATP-generating motor. This process is an important physiological mechanism that keeps cells energized and active. The heat produced as a byproduct of this process plays an important role in maintaining body temperature.
However, mitochondria don”t always play a beneficial role. In the process of making energy, they produce free radicals that can be deadly to cells. Free radicals are a byproduct of incomplete reduction of oxygen during cellular respiration and are highly toxic to cells. They attack cell membranes and proteins, interfering with cellular function, and can damage key organelles. In severe cases, they attack the cell’s DNA and interfere with the cell’s normal regeneration process. This makes mitochondria an important part of the cell’s life support system, but also a risk factor that can harm the cell.
Modern medicine believes that free radicals are strongly linked to aging and many diseases, especially deadly ones like cancer. Excessive production of free radicals causes cellular damage, and this damage accumulates over time and contributes to many of the problems associated with aging. Therefore, it is very important for mitochondria to produce energy well while minimizing free radicals to reduce their toxicity to cells.
If mitochondria can produce energy efficiently and minimize cellular toxicity by suppressing free radical production, humanity will be one step closer to achieving longevity. To this end, modern medicine and science are constantly researching ways to improve mitochondrial function and reduce the harmful effects of free radicals. Optimizing mitochondrial function could be the key to promoting healthy aging and protecting our bodies from many diseases.
