This document discusses the process of protein synthesis, which involves transcription of DNA into mRNA, amino acid activation through attachment to tRNA, and translation of mRNA codons into polypeptide chains. It describes the four main stages: amino acid synthesis, transcription, amino acid activation, and translation. Transcription involves unwinding of DNA and synthesis of complementary mRNA. Translation involves ribosomes reading mRNA codons and linking corresponding amino acids through attachment to tRNA until a polypeptide is formed. The genetic code uses triplets of nucleotides to specify each amino acid in the protein chain.