Emäparisidokset

Emäparisidokset, often translated as base pairing, are fundamental to molecular biology, describing the specific hydrogen-bonded interactions between nucleotide bases. In DNA and RNA, these pairings are highly selective. Adenine (A) always pairs with thymine (T) in DNA, and adenine (A) pairs with uracil (U) in RNA. Guanine (G) always pairs with cytosine (C) in both DNA and RNA. This complementarity is crucial for the structure and function of nucleic acids.

The A-T (and A-U) pairing involves two hydrogen bonds, while the G-C pairing involves three hydrogen bonds. The stronger G-C bond contributes to the thermal stability of DNA molecules. This specific binding mechanism is the basis for DNA replication, where each strand serves as a template for synthesizing a new complementary strand. It is also the principle behind transcription, the process of creating an RNA molecule from a DNA template, and translation, where the sequence of mRNA codons dictates the order of amino acids in a protein, with tRNA anticodons pairing to mRNA codons. The fidelity of these base pairings ensures the accurate transmission and expression of genetic information.