Mitochondrial and DNA Breakdown in the Aging Process

DNA

• DNA is an acronym for deoxyribonucleic acid. This substance contains the genetic material for all organisms and is typically located in the nucleus of a cell, although some cells do not contain a nucleus. DNA is able to duplicate itself. Every time a cell creates a copy of itself, it also copies its DNA. In the human body, cells replicate themselves during growth or during repair, such as the repair of damaged skin tissue. Cells in a human body will replicate many times during a human's lifetime.

Mitochondria

• Mitochondria are one of several organelles, or tiny structures, within cells. Vital to the survival of humans, mitochondria are able to convert oxygen and sugars into ATP, an energy-rich molecule usable by a cell. Mitochondria are unusual among organelles in that they have their own DNA, separate from the DNA of the cell they inhabit, and containing the instructions for producing energy and performing other mitochondrial functions.

DNA Breakdown

• Over a person's lifetime, his or her DNA is subject to many damaging factors, such as oxidation or damage from ultraviolet rays. These can cause parts of a DNA strand to become damaged, deleted or replaced with other parts of the strand. If the cell replicates itself, these errors will be present in the new cell. In addition, the ability to repair these errors declines significantly with age. Although the evidence is inconclusive, researchers suggest that errors in cell DNA and the decreasing ability to repair them are at least partially responsible for the effects of aging.

Mitochondrial DNA Breakdown

• Mitochondrial DNA is also subject to damage and mutation. However, mitochondrial DNA accumulates errors much faster than nuclear DNA. This is because mitochondria create oxidizing molecules during the process of creating energy. These molecules are damaging to the DNA, but are also a natural part of the energy process. Over time, the mitochondria are unable to continue their function of producing energy for the cell, which kills the cell. This is thought to be a major contributing factor to aging.