cell suicide, also known as apoptosis or programmed cell death.

an irreversible state of dormancy, known as senescence.

A cell that has accumulated a large amount of DNA damage, or one that no longer effectively repairs damage incurred to its DNA, can enter one of three possible states: The rate of DNA repair is dependent on many factors, including the cell type, the age of the cell, and the extracellular environment.

This can eventually lead to malignant tumors, or cancer as per the two hit hypothesis. When normal repair processes fail, and when cellular apoptosis does not occur, irreparable DNA damage may occur, including double-strand breaks and DNA crosslinkages (interstrand crosslinks or ICLs). As a consequence, the DNA repair process is constantly active as it responds to damage in the DNA structure. Other lesions induce potentially harmful mutations in the cell's genome, which affect the survival of its daughter cells after it undergoes mitosis. Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA damage, resulting in tens of thousands of individual molecular lesions per cell per day.

DNA damage resulting in multiple broken chromosomesĭNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome.

System mechanic pro 21