AMP. Computer graphic representation of a molecule of adenosine monophosphate (AMP). Atoms are depicted as spheres, joined by atomic bonds. Atoms are colour-coded: carbon (green), nitrogen (blue), oxygen (orange), phosphorus (yellow), hydrogen (white). The AMP molecule is a carrier of cell metabolic energy, and levels in the cell dictate rates of many biochemical pathways. This structure contains only one phosphate group (top right). When AMP gains two more phosphate groups it becomes ATP, the energy rich adenosine triphos- phate form. It now appears that many hormones exert their effect by first altering levels of AMP in the cell.