There are various permanent hair straightening systems out there, but they generally use the same chemical process to alter the hairâs structure. An alkaline chemical solution is first applied to the hair, and this breaks down the many disulfide bonds within the hair that cause it to kink and curl.ons. 1  As the name suggests, this technique relaxes hair rather then leaving it poker straight, so if you want absolute stick straight and frizz-free hair, this method may not be for you. 2  As with every chemical process, the ever present risk of damage is there.
But they all consist of 4 nucleotides 2 made of purine bases which are adenine and guanine and 2 pyrimidine bases which are thymine and cytosine. The purine based nucleotides always pair with their base pair pyrimidine based nucleotide.In DNA Adenine is paired with thymine and guanine pairs with cytosine.But if it's RNA there is a special exception which replaces thymine with Uracil pairing with adenine.he purine based nucleotides always pair with their base pair pyrimidine based nucleotide. In DNA Adenine is paired with thymine and guanine pairs with cytosine.
DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen base. The four types of nitrogen bases are adenine (A), thymine (T), guanine (G) and cytosine (C). The order of these bases is what determines DNA's instructions, or genetic code. Human DNA has around 3 billion bases, and more than 99 percent of those bases are the same in all people, according to the U.S. National Library of Medicine (NLM).