[DNA repair and apoptosis]

In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...

In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...

DNA Distortion and Damage
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...

Exposure to mutagens can damage DNA and result in bulky lesions that distort the double-helix structure or impede proper transcription. Damaged DNA can be detected and repaired in a process called nucleotide excision repair (NER). NER employs a set of specialized proteins that first scan DNA to detect a damaged region. Next, NER proteins separate the strands and excise the damaged area. Finally, they coordinate the replacement with new, matching nucleotides.DNA distortion and damageCells are...

Exposure to mutagens can damage DNA and result in bulky lesions that distort the double-helix structure or impede proper transcription. Damaged DNA can be detected and repaired in a process called nucleotide excision repair (NER). NER employs a set of specialized proteins that first scan DNA to detect a damaged region. Next, NER proteins separate the strands and excise the damaged area. Finally, they coordinate the replacement with new, matching nucleotides.DNA distortion and damageCells are...

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...