DNA repair
process of restoring DNA after damage / From Wikipedia, the free encyclopedia
DNA repair means the processes by which a cell identifies and corrects damage to its DNA molecules.
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In cells, normal metabolic activities and environmental factors such as UV light and radiation damage DNA. There are as many as a million molecular lesions per cell per day.[1] Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the affected gene. Other lesions induce potentially harmful mutations in the cell's genome, which affect the survival of its daughter cells after it divides. The DNA repair process must be constantly active so it can respond rapidly to any damage in the DNA structure.
The rate of DNA repair depends on many factors, including the cell type, the age of the cell, and the extracellular environment. A cell that has accumulated a lot of DNA damage, or one that no longer effectively repairs damage, can enter one of three states:
- an irreversible state of dormancy, known as senescence
- cell suicide, also known as apoptosis (programmed cell death)
- unregulated cell division, which can lead to the formation of a tumor that is cancerous