Aminohappokoodit

Aminohappokoodit, also known as codons, are sequences of three nucleotides within a messenger RNA (mRNA) molecule that specify a particular amino acid or a stop signal during protein synthesis. The genetic code, which is universal for almost all living organisms, consists of 64 possible codons. Out of these, 61 codons code for the 20 standard amino acids, while the remaining three are stop codons that signal the termination of translation.

The sequence of codons in an mRNA molecule dictates the sequence of amino acids in a protein. This process, called translation, occurs in ribosomes. Transfer RNA (tRNA) molecules, each carrying a specific amino acid and possessing an anticodon complementary to a particular mRNA codon, bind to the mRNA. This pairing ensures that the correct amino acid is added to the growing polypeptide chain.

The genetic code is degenerate, meaning that more than one codon can specify the same amino acid. This degeneracy can provide some protection against mutations, as a change in a single nucleotide may not alter the resulting amino acid. The start codon, typically AUG, not only codes for the amino acid methionine but also initiates the translation process, setting the reading frame for the subsequent codons. Understanding aminohappokoodit is fundamental to comprehending gene expression and protein synthesis.