perimäketjun
Perimäketjun, also known as DNA or deoxyribonucleic acid, is a molecule that carries the genetic instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses. It is a double helix structure composed of two polynucleotide chains. Each polynucleotide chain consists of a backbone of alternating sugar and phosphate groups, with nitrogenous bases attached to the sugar. The four nitrogenous bases in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T). These bases pair specifically: A always pairs with T, and G always pairs with C. This complementary base pairing is crucial for DNA replication and information transfer.
The sequence of these bases along the DNA molecule constitutes the genetic code. Genes, segments of DNA,