Phosphate group

1. Figure 3.25 Distinguishing Characteristics of DNA and RNA Phosphate group Pentose Both DNA and RNA contain a series of phosphate groups and pentoses that form the backbone of their structure.

2. Figure 3.25 Distinguishing Characteristics of DNA and RNA In RNA, the bases are attached to the ribose. The bases are adenine (A) and guanine (G), the purines, and cytosine (C) and uracil (U), the pyrimidines.

3. Figure 3.25 Distinguishing Characteristics of DNA and RNA In DNA, the bases are attached to deoxyribose. The bases are adenine (A), guanine (G), cytosine (C), and thymine (T) (thymine is found instead of uracil).

4. Figure 3.25 Distinguishing Characteristics of DNA and RNA The numbering of ribose carbons is the basis for identification of the 5¢ and 3¢ ends of DNA and RNA stands. 5¢ 4¢ 3¢ 2¢ 1¢

5. Figure 3.25 Distinguishing Characteristics of DNA and RNA 5¢ 4¢ 3¢ 2¢ 1¢ RNA is single-stranded. 5¢ end 3¢ end

6. Figure 3.25 Distinguishing Characteristics of DNA and RNA DNA is double-stranded. 5¢ end 3¢ end 5¢ end 3¢ end

7. Figure 3.25 Distinguishing Characteristics of DNA and RNA Hydrogen bonds between purines and pyrimidines hold the two strands of DNA together. 5¢ end 3¢ end 5¢ end 3¢ end