Which of the Following Properties Describe Both Purines and Pyrimidines

Question

Which of the following properties describe both purines and pyrimidines?
A) they are aromatic
B) they are composed of 6-membered rings
C) they exhibit strong absorption of UV light
D) they always contain a carbonyl group
E) both A and C are correct

Accepted Answer

Purines (adenine and guanine) and pyrimidines (cytosine, thymine and uracil) are both aromatic, and they both exhibit strong absorption of UV light. Therefore, choices A and C are correct. However, only pyrimidines are composed of a single 6-membered ring, while purines have a fused double-ring structure. Therefore, choice B is incorrect, and choices D and E are incorrect based on this reasoning.