Nucleotides have a variety of important functions in all cells, including:
A.
They are the precursors of DNA and RN
B.
They are essential carriers of chemical energy—a role primarily of ATP and to some extent GTP.
C.
They are components of the cofactors NAD, FAD, Sadenosylmethionine, and coenzyme A, as well as of activated biosynthetic intermediates such as UDP-glucose and CDP-diacylglycerol.
D.
Some, such as cAMP and cGMP, are also cellular second messengers.