Üksiknukleotiid

Üksiknukleotiid refers to a single nucleotide, which is the basic building block of nucleic acids such as DNA and RNA. Each nucleotide consists of three components: a phosphate group, a five-carbon sugar (deoxyribose in DNA, ribose in RNA), and a nitrogenous base. There are four types of nitrogenous bases in DNA: adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) replaces thymine.

These individual nucleotides are linked together in a specific sequence to form a polynucleotide chain. The sequence of these bases carries the genetic information. During DNA replication and RNA transcription, nucleotides are added one by one to a growing chain, dictated by the template strand. The phosphodiester bonds between the sugar of one nucleotide and the phosphate group of the next form the sugar-phosphate backbone of the nucleic acid.

Understanding individual nucleotides is fundamental to molecular biology. Variations in nucleotide sequences can lead to different genes and traits. The study of nucleotide sequences, known as genomics, has revolutionized our understanding of biology and medicine, enabling advancements in areas like genetic testing, gene therapy, and the development of targeted drugs. Single nucleotide polymorphisms (SNPs) are common variations in the DNA sequence that occur when a single nucleotide differs between individuals. These SNPs can influence an individual's susceptibility to diseases or their response to certain medications.