What is the genetic code, and how is it read to synthesize proteins?

The genetic code is the sequence of nucleotides in DNA that determines the sequence of amino acids in proteins.

The genetic code is read in a process called protein synthesis, which occurs in two main stages: transcription and translation. During transcription, the DNA sequence is copied into a complementary RNA sequence by RNA polymerase. This RNA molecule, called messenger RNA (mRNA), carries the genetic information from the DNA to the ribosome, where it will be translated into a protein.

During translation, the mRNA sequence is read by the ribosome, which uses transfer RNA (tRNA) molecules to bring the correct amino acids to the growing protein chain. Each tRNA molecule has an anticodon that matches a specific codon on the mRNA, ensuring that the correct amino acid is added to the protein. The ribosome moves along the mRNA, reading each codon and adding the corresponding amino acid until a stop codon is reached, signalling the end of the protein.

The genetic code is degenerate, meaning that multiple codons can code for the same amino acid. For example, both the codons UUU and UUC code for the amino acid phenylalanine. However, each codon codes for only one amino acid, and the order of codons determines the sequence of amino acids in the protein. Mutations in the DNA sequence can alter the genetic code, potentially changing the amino acid sequence and function of the resulting protein.