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 ...

Due to DNA’s complexity, scientists theorize that a simpler molecule preceded it billions of years ago during early life ...

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 ...