How do codons correspond to specific amino acids?

Codons correspond to specific amino acids through the genetic code, which is essentially a set of rules for translation.

In the realm of molecular biology, the genetic code is a set of rules used by living cells to translate information encoded within genetic material into proteins. This translation process is a critical aspect of gene expression. The code defines how sequences of nucleotide triplets, known as codons, specify which amino acid will be added next during protein synthesis.

Each codon corresponds to a specific amino acid. For instance, the codon AUG codes for the amino acid methionine, and the codon UUU codes for the amino acid phenylalanine. There are 64 possible codons (4 bases taken 3 at a time), and these codons correspond to the 20 standard amino acids used by cells to build proteins. Some amino acids are specified by more than one codon, which is why the genetic code is said to be 'degenerate'.

The process of translation, where the codons are read and the corresponding amino acids are linked together to form a protein, takes place in the ribosome. The messenger RNA (mRNA) carries the genetic information from the DNA in the form of codons. Each codon on the mRNA attracts a specific transfer RNA (tRNA) molecule carrying the corresponding amino acid. The tRNA recognises the codon on the mRNA through its anticodon, a set of three nucleotides that are complementary to the codon.

The ribosome facilitates the matching of the tRNA anticodon to the mRNA codon. Once the match is made, the amino acid is added to the growing protein chain and the tRNA is released. This process continues until a stop codon (UAA, UAG, or UGA) is reached, signalling the end of protein synthesis.

In summary, the correspondence of codons to specific amino acids is a fundamental aspect of the genetic code and protein synthesis. It is through this intricate process that the information in our genes is expressed as the proteins that carry out the functions of life.