Three letter segments of mRNA code for specific
Three-letter segments of mRNA code for specific amino acids. These segments are called codons. Messenger RNA (mRNA) is a type of RNA that carries genetic information from DNA to the ribosome, where protein synthesis occurs. Each codon is a sequence of three nucleotides, and each codon corresponds to one of the 20 different amino acids used to build proteins or serves as a start or stop signal during protein synthesis.
For example:
- The codon AUG codes for the amino acid methionine and also serves as the start codon, signaling the beginning of translation.
- The codons UAA, UAG, and UGA are stop codons, signaling the end of the protein-coding sequence.
The sequence of codons in an mRNA molecule determines the sequence of amino acids in the protein product, with the help of transfer RNA (tRNA) molecules that bring the appropriate amino acids to the ribosome during translation. This process of translating mRNA codons into an amino acid sequence is known as translation, one of the key stages of gene expression.