The nucleotide shown below is called cordycepin triphosphate. It is a natural product of a fungus that is used in traditional medicines. If cordycepin triphosphate is added to a cell-free transcription reaction, the nucleotide is added onto the growing RNA chain but no more nucleotides can then be added. The added cordycepin is always found at the 3' end of an RNA Examine the structure of cordycepin and explain why it ends transcription. a) It prevents the association of RNA polymerase and sigma. b) It cannot be recognized by RNA polymerase. c) It lacks a 3'/rm OH.