A neuropeptide is any one of a group of organic compounds that function as neurotransmitters. These are linear organic polymers that are formed by a large number of amino-acid residues that are bonded together in chains and a form a partial or whole protein molecule. These are also structurally referred to as short-chain polypeptides. As protein is an essential compound for the survival of all animal life forms polypeptides, the building blocks of protein, are essential for survival.