What is DNA?
DNA can be thought of as a long term storage material for code in each of your cells which which describes how to make you.
What is it made of?
DNA is made of the elements Carbon, Hydrogen, Oxygen, Nitrogen and Phosphorus, joined in different ways.
What makes these atoms join to form DNA?
Atoms are attracted to each other
The DNA segments that carry this genetic information are called genes ..."
How does DNA get damaged?
"DNA can be damaged by many different sorts of mutagens, which change the DNA sequence."
What is a mutagen?
A mutagen is a "physical or chemical agent that changes the genetic information (usually DNA)". Said another way, a mutation is a change to the nucleotide sequence of the genetic material of an organism.
DNA is certainly one of the key targets for UV-induced damage in a variety of organisms ranging from bacteria to humans. UV radiation induces two of the most abundant mutagenic and cytotoxic DNA lesions such as cyclobutane-pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4PPs) and their Dewar valence Isomers. However, cells have developed a number of repair or tolerance mechanism to counteract the DNA damage caused by UV or any other stressors. Photoreactivation with the help of the enzyme photolyase is one of the most important and frequently occurring repair mechanisms in a variety of organisms. Excision repair, which can be distinguished into base excision repair (BER) and nucleotide excision repair (NER), also plays an important role in DNA repair in several organisms with the help of a number of glycosylases and polymerases, respectively. In addition, mechanisms such as mutagenic repair or dimer bypass, recombinational repair, cell-cycle checkpoints, apoptosis and certain alternative repair pathways are also operative in various organisms. - nih
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