1967/04/18 by F H Crick · 1 citation
Biochemistry, Genetics and Molecular Biology · #Genetics, Bioinformatics, and Biomedical Research
paper · doi:10.1098/rspb.1967.0031
openalex publication_date 1967/04/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Abstract Genes are made of nucleic acid. Enzymes are made of protein. The amino acid sequence of a particular protein is synthesized under instruction from a particular piece of nucleic acid. Each protein is made of one or more polypeptide chains, synthesized by condensing together amino acids, head to tail, with the elimination of water. A typical polypeptide chain is several hundred amino acid residues long. Nevertheless only twenty different kinds of amino acids are commonly found in proteins. This standard set of twenty is the same throughout nature. Nucleic acid is made of polynucleotide chains. The repeating unit of the chain is a sugar (ribose for RNA, deoxyribose for DNA) connected to a phosphate. A base is joined on to each sugar. There are four common bases in nucleic acid. DNA usually has adenine, guanine, cytosine and thymine. In RNA thymine is replaced by uracil.