Final answer:
The statement is false because purines, such as adenine and guanine found in DNA and RNA, have a double-ring structure with a total of nine atoms, not a nine-membered singular ring.
Step-by-step explanation:
The statement that purines are nine-membered nitrogen containing ring compounds found in both RNA and DNA is false. Purines, specifically adenine and guanine, are heterocyclic aromatic compounds with a double-ring structure, consisting of a six-membered ring fused to a five-membered ring, both of which contain nitrogen atoms. Purines are fundamental components of nucleic acids, and they are present in both DNA and RNA. Purines differ from pyrimidines, which include cytosine, thymine (found only in DNA), and uracil (found only in RNA), that have a single six-membered ring with two nitrogen atoms. The primary structure of a purine is not nine-membered, but rather consists of a total of nine atoms making up the two fused rings (six in the larger and three in the smaller).