Final answer:
Nucleic acids (option C) are not a class of neurotransmitters; they are the genetic materials of cells. Common neurotransmitter classes include ATP and other purines, amino acids, and biogenic amines, but nucleic acids are related to genetics and cell function, not neurotransmission.
Step-by-step explanation:
The chemical class of neurotransmitters that is not a neurotransmitter is nucleic acids (option C). Neurotransmitters are chemicals that transmit signals across a synapse from one neuron to another. Common classes of neurotransmitters include ATP and other purines, amino acids, and biogenic amines. Biogenic amines, for example, are derived enzymatically from amino acids and play roles in various neural systems, such as the serotonergic system where serotonin operates. Amino acids themselves, like glutamate (glutamatergic system), GABA (GABAergic system), and glycine (glycinergic system), also serve as neurotransmitters. These neurotransmitters are characterized by their amino and carboxyl groups and are cleared from the synapse by reuptake. Nucleic acids, however, make up the genetic materials of cells, such as DNA and RNA, and are not involved in neurotransmission.