This allows amino acids to be grouped according to the chemical properties of their side ... such as isoleucine, phenylalanine, and valine. The amino acid cysteine has a chemically reactive ...

The mystery of why life uses molecules with specific orientations has deepened with a NASA-funded discovery that RNA — a key molecule thought to have potentially held the instructions for life before ...

The chemical structure of uracil ... Uracil is part of several codons that specify different amino acids, the building blocks of proteins. For example, the codon UUU codes for the amino acid ...