Kvælstofbaserne
Kvælstofbaserne, also known as nitrogenous bases, are organic molecules containing nitrogen atoms and having basic properties. They are fundamental components of nucleic acids, DNA and RNA, which carry genetic information in all living organisms. In DNA, the four nitrogenous bases are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) replaces thymine. These bases pair up specifically: adenine always pairs with thymine (or uracil in RNA), and guanine always pairs with cytosine. This complementary base pairing is crucial for DNA replication and transcription.
There are two main types of nitrogenous bases: purines and pyrimidines. Purines have a double-ring structure