Chapter 4

Question 4

The bases of nucleic acids are purines or pyrimidines. Purines and pyrimidines are distinguished by the fact that

A. purines include the bases of cytosine and thymine; pyrimidines include the bases of adenine and guanin.
B. pyrimidines are found in RNA; purines are found in DNA.
C. purines consist of hydrogen, carbon, oxygen, and nitrogen, wereas pyrimidines have phosphorus, hydrogen, carbon, oxygen, and nitrogen.
D. purines have only single bonds in their structure, whereas pyrimidines have both single and double bonds in their structure.
E. purines are double-ring structures, wereas pyrimidines are single-ring structures.

Answer 4

E