Stay Woke, a documentary about the rise of the Black Lives Matter movement, will premiere Thursday on BET. Photo: David McNew/Getty Images Even the most casual social media user has almost certainly seen references to the slang term woke, as in stay woke.
The major lethal lesions are pyrimidine dimers in DNA (produced by UV-B and UV-C)--these are the result of a covalent attachment between adjacent pyrimidines in one strand. This is shown here for a thymine-thymine dimer and here for a thymine-cytosine dimer. third type of spontaneous DNA damage that occurs frequently is damage to the bases by free radicals of oxygen. These arise in cells as a result of oxidative metabolism and also are formed by physical agents such as radiation.
Attached to each sugar ring is a nucleotide base, one of the four bases Adenine (A), Guanine (G), Cytosine (C), and Thymine (T). The first two (A, G) are examples of a purine which contains a six atom ring and five atom ring sharing two atoms. The second two (C, T) are examples of a pyrimidine which is composed of a single six atom ring. A base pair is one of the pairs A-T or C-G. Notice that each base pair consists of a purine and a pyrimidine. The nucleotides in a base pair are complementary which means their shape allows them to bond together with hydrogen bonds. The A-T pair forms two hydrogen bonds. The C-G pair forms three.